BritishV8 Forum

Hi folks,  

I have a 4.6L Rover THOR-intake V8 pulled from a 2004 Discovery sitting on an engine stand in my garage, and a burning desire to drop it into an MGB.  It's a sick patient though, and I could really use some guidance and suggestions as to how to proceed.

I'm new to engine teardowns and rebuilds, but I've read Roger Williams' How to give your MGB V8 Power, I just started reading  Tom Monroe's Engine Builder's Handbook, and I have a pdf of the Rover factory rebuild manual for the 4.0/4.6.  

I bought the engine for a song (caveat emptor and all that), and I'm happy if this engine turns out to be a boat anchor.  I needed something to get my hands on, and the $250 price tag was right.  I can always sell the useful parts to recover my expenses if I have to.  

I'd like to make a rational assessment of whether this engine is worth rebuilding to a mildly tuned state, or whether I should move on to another block.  My preference is to keep costs low, to get my V8 MGB built, and to return to the engine for a major rebuild and upgrades down the road.  

Here's what I know:

The engine has approx. 125,000 miles on it.  

I bought it from a mechanic who parts out cars on the side.  This particular Discovery came into his shop, and the owner didn't want to make further attempts to repair the engine after one failed attempt, and abandoned the entire truck.  The water pump, alternator, AC compressor, crankshaft pulley/harmonic balancer, coil packs, and starter were removed and sold to other buyers before I showed up.  I never saw the engine in the truck, and I never heard it run.  

I was told the shop tried to repair a "blown head gasket," but the repair failed after about 100 miles.  The seller/mechanic suspects the problem is a stripped head bolt thread on one of the forward cylinders, and he recommended I install an ARP stud bolt kit.  Maybe it could be a slipped liner, but I think those rarely slip on the most forward cylinders?  The copper-colored gasket partially covers the engine serial-number plate, making me wonder if the gasket was installed upside-down or backward?

The seller also told me the heads had been skimmed while they were off.  

The spark plugs in all eight cylinders are pretty black, but are evenly blackened.  Mostly carbon, I think.

The entire engine is about as grease-covered as it can possibly be.  Presumably that's normal?

When I drained the oil, the first stuff to come out of the drain hole looked like liquid aluminum.  I'm guessing it's suspended water, or microscopic aluminum particles that had settled to the bottom of the oil sump, or some sort of BS engine "stop leak" additive.  In all, I drained 7 quarts of oil from the block.  The oil was very dark, and stunk with gasoline fumes.    

With a known "gasket" issue, and with no water pump attached, what diagnostics are worth doing, and in what order?  Leakdown tests would hopefully establish decent compression for 7 of eight cylinders.  

Given the mileage and the indicators I have above, what to do first?  

Any advice, observations, ideas, would be welcome.  

Many thanks!

Dave

It's quite possible that what's happening is that one of the cylinder liners has slipped. I've heard, and seen pictures, of a repair for this problem - drilling a hole in the block and inserting a bolt to pin the liner to prevent it from slipping.

Dave,

With aluminum particles in the oil, it most likely has a bad main, rod or cam bearings. If there was quite a bit then there is a very good chance that it has a spun rod bearing.
The wise thing to do would be to tear it down for a full inspection, as opposed to trying to get it running as is and risking further damage.

Bill

Hey Dave,

Bail!
Al that nice aluminiumie.. stuff in the oil was likely emulsified oil.
You are most likely looking at a cracked block. And the expense to get a machine shop to confirm that is more than the block is worth.
As well, having coolant in the oil on more than one occasion , has probably trashed the bearings and possibly the cam and lifters.
So I would pull it apart, examine it carefully, and learn from the experience.
Then go out and find a new block to put your 4.6 parts into. There are tons of 4.0 engines out there looking for your 4.6 innards.

Cheers
Fred

Many thanks Bill, Paul, and Fred,

All signs point to this engine being primarily a teaching tool and some questionable spare parts!  I do have a glimmer of hope though.

I'll explore the stuff in the oil a bit further this eve.  If it's metallic, from a spun bearing, it should be magnetic, yes?

If it's not metallic, and if I heat it up, the emulsified water should boil off, yes?

If it turns out to be an emulsion, and if there's no metallic particles or other signs of spun bearings, is it worth investigating the last head gasket job?

I attached an interesting (to me anyway) photo of what I've got now.  Is it odd to have an asymmetric bit of gasket protruding from the union between block and head, between the middle cylinders on both sides?  Maybe the last guy put the gasket on backward, or upside down, or on wrong cylinder bank?  It seems pretty thin.  Is it even the right kind of gasket for a late 4.6?  Is it reasonable to think the last gasket "repair" was too sloppy to be effective?

If I have a coolant emulsion only, I 'm thinking I'll take heads off, look for signs of coolant/corrosion in bolt holes, look for signs of slipped liner, and if I don't see either, I could try a set of ARP studs, new head gaskets, and a new leak down test.  Would that leak down test mean anything if I don't start it up and run it for a while first?  

Any diagnostics I should do before I start the tear down?

Thanks again for all your help.

Dave
image.jpeg

I would pull the oil pan, spark plugs and valve train off.
Build an adapter to let you pressurize the cylinders with air through the plug holes. Often your compression gauge has the correct fitting for this.
Pressurize each individual cylinder. But be careful as the engine will do a partial revolution each time you change cylinders.
You should be able to find the leaking cylinder easily enough this way.
I'l bet that you will find air bubbling out between one of the cylinder liners and the block.

Dave,

If it does have a spun bearing, most of the particles will usually be babbit bearing material and may not be magnetic. (Although a small amount could be if it was from the rod itself)
As Fred mentioned, I would pull the pan and plugs to do a leak down test. Then after your leak down test is completed, pull the main and rod bearing caps for inspection. This should tell you what you have to work with and whether or not if it's worth saving.
When pulling the caps be sure to mark their location!

Bill

I have read that sometimes the slipped liner issue does not show itself until the engine is a operating temperature. The cracked liner can be found without heat.

http://robisonservice.blogspot.com/2010/04/last-word-on-land-rover-liner-failures.html

An iron block solves the problem.

Jim

Hmm, a destroked Buick 300?

Hi Jim,

I'm not ready to drink the Buick 300 Kool-aid (yet!).

The diagnostic process here is something worth walking through.  The local pick-a-part yard here in VA has a half-dozen Rover v8s, all for less than $200 if you can remove it yourself, $350 if you need help.  There's real savings to be had, even if it takes three or four engines to get one that's still sound.  Sale of T he parts off the dead ones can fund further efforts.

I'll post results of Bill's air pressure pressure tests soon, hopefully after the weekend.

I also saw this comment on the Pirate4x4 website:

"TBH the liner actually slipping in the block is quite rare. Also, some if the blocks are machined with a slight ridge at the bottom of the bore that the liner almost sits on. The much more common failure is a crack behind the top area of the liner into the coolant jacket which then leaves it open to pressurisation from gases that are forced between the liner and block casting due to the complete liner being within the fire ring. During the non compression / firing stoke the pressure is released back into the cylinder as coolant & steam. This generally gives all the symptoms of head gasket failure apart from one detail ............. a compression test will show up as OK, whilst a compression test on a faulty head gasket will show poor compression on one or more cylinders."

The mechanic I bought this engine from said he saw a compression leak in one of the most forward cylinders, before and after the gasket repair.

If the above quote is accurate and valid, and if my mechanic was lucid and competent when analyzing my engine, I'm guessing I either have a garden-variety stripped head bolt causing head gasket failure, or a relatively rare type of cylinder liner or block defect.

I'm curious what y'all think, am I on the right path?

Dave

I thought everyone might like to see what came out of the oil sump.  It looks like Baileys Irish Cream.  
image.jpeg

For even more work, you can block off the coolant passages in the block, liquid soap the suspected areas and apply air pressure.  Sounds bubbly.  Good Luck, art.

I wasn't ready to "drink the Buick 300 Kool Aid" either when I did my first conversion Dave, "Too heavy" I said. "nobody's doing it" I said. "Don't need that big an engine." I said. I also said, "I can drag 215's down off Jack Sanders' hill all week long for $40 a pop."

Well, 30 years of messing with 215's have taught me a few things. (And yes, a 215 is not technically a Rover but it all still applies.)

Just trying to save you a little time and money. Ask Chris Gill what he thinks. Bear in mind he did go overboard, building a stroker motor 350 but I think he's OK with the outcome.

Jim

>Hmm, a destroked Buick 300?

Actually, I wouldn't. Stock bore +.030" and stock stroke would be the most economical and reliable build, gives great power, and is going to be docile to drive. maybe a warmer cam later on if desired. It wouldn't be your build Carl, but I know you've driven Mikey's car quite a bit. I'd be sorta surprised if you didn't like it.

The iron block would give better reliability with a high revving destroked motor. It is more rigid, has better threads, and no liner issues. But you would have to run very long rods, stock 300 rods are 5.96", already a fairly long rod, and you have around 1" to 1-3/16" that you can move the pin up in the piston, plus say if you used the 2.8" crank instead of the stock 3.4" one, that's another .300", meaning your maximum rod length could he as much as maybe 7.450". That's a lot. In a 2.8" stroke motor it gives a rod ratio of 2.66, extremely high. Acceleration forces on your pistons would be higher than with a shorter rod but side thrust would be minimal. Forged pistons would almost be mandatory. But that is at the extreme.

http://users.erols.com/srweiss/tablersn.htm#Buick

If you used your 4.2L Rover crank with the 3" stroke, (Which I know you are in love with because of the Chevy 3" stroke engines) that means your maximum rod is 7.350 so you could use the 7" Scat rods for the FHF which use the SBB bearing shells (BOPR). The weight of that rod is 564.5 grams so it's very light. A matching forged piston would be about 450 grams. The piston pin would need to be moved up about 3/4" from stock so you would have to find a piston, one with a 3/4" wrist pin, or you could probably bush the piston bores. That would give a rod ratio of 2.33, still pretty high but maybe something to consider. The SBC 302 had a 1.9 rod ratio. It would suit your preference for mid to high rpm torque. F1 and motorcycle engines go over 2:1, how far over I couldn't say. 1.75:1 is generally considered ideal, as is a 1.250" piston pin height. (leaves room for the rings, helps minimize rocking, reduces piston weight) You aren't going to get both in a destroked 300 without a very long rod.

Using the 1.75 rod ratio and working backwards gives a 5.25" rod with the 3" crank and a pretty tall piston. The Buick 215 used a 5.66" rod and that is about as close as you are going to get, giving a 1.89 rod ratio which is really quite good. But that means the wrist pin of the piston has to be moved down half an inch. The piston/rod assembly will be heavier as a result, and again a forged piston will be needed.

If you ran the 300 rods at 5.960" you would have a 1.99 rod ratio. With that you would only have to increase the piston's compression height .200" from stock 300. This then, represents the most practical destroker build, using your crank and everything from the 300 except the pistons. Your piston acceleration would be high and the piston would be rather heavy for a high winding motor as are the rods, but for a Buick based build it has potential. Add a set of TA heads and you might have a pretty good engine.

With the 340 rods: 6.387", 2.13 rod ratio. (350 rods: 6.358", 2.12 rod ratio) You might have better luck finding a piston for one of these combinations.

So a destroked engine would be feasible if you are willing to go over 2:1 on the rod ratio but below that I don't really see the point.

 Jim

[quote="Jim B.]It wouldn't be your build Carl, but I know you've driven Mikey's car quite a bit. I'd be sorta surprised if you didn't like it. [/quote]

I do like, very much. What's not to like? I have driven Mikey most excellent ride many times over the years. It is well built, well sorted, nice & tight, more than enough torque, no surprises. Even a grandma could take it to the grocery store, if her right foot behaved.

Quote from: DaveIf the above quote is accurate and valid, and if my mechanic was lucid and competent when analyzing my engine, I'm guessing I either have a garden-variety stripped head bolt causing head gasket failure, or a relatively rare type of cylinder liner or block defect.

I'm curious what y'all think, am I on the right path?

IMO the problem two separate problems. Slipped liners & small cracks in the block behind the liners.  I don't believe either are rare.

Slipped liners were a problem with earlier block. Lots of pictures out there.

The cracks behind the liner are a problem with later blocks. There are various theories about this being caused by the head bolt hole threading during manufacture or the wrong torque of the head bolt.

The knocking of the later blocks while blamed on slipped liners appears to be piston slap.

Did you read my link?

http://robisonservice.blogspot.com/2010/04/last-word-on-land-rover-liner-failures.html

http://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/28019-liner-failures-land-rover-v8-engines-whats-happening.html

"The Yamaha YZF R1 is a typical modern sports bike that revs to 12,000 rpm.  Its engine has a stroke to rod length ratio of 2.12:1 which is suitable for high rpm use.  This can be compared to a Nissan SR20DE engine which revs to 7700 RPM with a rod to stroke length ratio of 1.58:1"
http://www.motoiq.com/MagazineArticles/ID/1996/Does-Length-Matter.aspx

I also saw where a 2.2 to 2.8 rod ratio is not uncommon in F1, along with a supposed quote from Smokey saying, "..use the longest rod that will fit...", and other engine builders who think shorter is better for reasons of valvetrain stability and better intake runner geometry. Many seem to think it is an unimportant issue.

So, back to your regularly scheduled program of trying to find a rod and piston to match the deck height. Best of luck.

Jim

I always thought the issue with the short rods was the rod angularity. Of course, it is always more complicated. There are pros & cons for both short rods & long rods.

http://www.stahlheaders.com/lit_rod%20length.htm

http://victorylibrary.com/mopar/rod-tech-c.htm

I have another theory on the cracking behind the liners. Wildcat Engineering ( actually from Des Hamill's Rover V8 book on Wildcat Engineering)had a excellent article on the later Rovers. Rover used .007 interference for the sleeves and when overheated cause the cracking below the headbolts. Most other engine sleeves use .003-.004 interference fit. At about 200 degrees F, iron and aluminum expansion is pretty close. When overheated aluminum can expand over twice as much as the iron liner causing tremendous stress. Wildcat have used straight sleeves up to 3.78 in the later Rover pink graded blocks. Why would the stock sleeve have a chamfer on top at the fire ring? I wonder if you turned the sleeves around so it would be flat on top?

https://books.google.com/books?id=gmSavy1RPxEC&pg=PA29&lpg=PA29&dq=wildcat+engineering+rover+engine+issues&source=bl&ots=nh5w4r6nvV&sig=eptPxPj-rYPVVj9nxDPIkFPaTko&hl=en&sa=X&ved=0ahUKEwjzor_mh_nMAhVEKlIKHY8iDbIQ6AEIHTAA#v=onepage&q=wildcat%20engineering%20rover%20engine%20issues&f=false

Did that apply only to the later Rover V8s, Jim, or maybe the 3.9L & up when it was bored to 3.7"?

QuoteRover, seeing the motor as its salvation for an aging product line, found that sand casting the block and installing press-in sleeves, (rather than cast in place), at a later point precluded any production problems or costs, but the beginning of longevity issues. This is where the liner issues began. In the Rover mass production techniques, the outer wall of the liner design was changed from a very coarse finish to a fine polished finish, for an easy mass production press fit. The thermal bonding in the cylinder cast in place assembly process, was eliminated completely. This allowed the smooth external walls of the new liners to provide easy installation but allowed the smooth walls to thermally expand at different ratios under the laws of dissimilar materials.

http://landroverforums.com/forum/discovery-ii-18/great-read-all-you-ever-wanted-know-about-land-rover-v8-engine-failures-31202/

Back to Dave (RDMG)

Land Rover has been accused of knowing about it & lying to cover it up.

This has been an issue for quite some time.  That is why "Top Hat" liner have been discussed & used in England for long time, now. The hotrodders figured out how to fix it as the Rover V8 is the SBC of the UK.

http://www.v8forum.co.uk/forum/

My Guess when they went to the newer style cross bolt block. The sleeves I've seen do look pretty smooth. This would be  an interesting experiment. Pressure test a block first. Heat block and remove liners. Hone aluminum cylinders for .003 fit. Wire brush  sleeves to roughen up.  Use Loctite on cylinders. Cool sleeves. Turn over sleeves. Press in. Torque head down with used gasket to set sleeve. Basically install as a repair sleeve as you would  in a iron block.  Still not a good idea to overheat any aluminum block with iron sleeves.

BOPR V8s have their share of problems, but IMHO Des Hammill has done our community a disservice by exaggerating them.

<font color="red">Caution!</font> Alarmist warnings cause anxiety and despair.

Jim B,

Your recommendations and experiences with the 215 then the 300 are very informative.  I think I'm on the same path, except the pick-a-part closest to me doesn't have any trees or brush surrounding the land rovers!  Same hills though.

I'm now at a point where I need to weigh the cost-benefits of liners in a rover block vs rebuilding a 300.  At the end of the day, once all the "might as wells" of putting in 96mm liners, new pistons and rods, a 300 crank, and 300 heads into a Rover block has been done, I'll basically have a slightly lighter, much more expensive, Buick 300 with a Rover EFI and bellhousing bolted to it.  Since acquiring a complete Buick 300 is the cheapest way to get the heads, crank, and front cover for that expensive Rover engine, I'll also have a spare Buick 300 block in the corner of my garage.  

Carl and Jim N,

Interesting articles, and I didn't catch the significance of the tapered ends of the liners in the rover blocks.  Grasping that issue now, it really doesn't seem wise to invest much time in fiddling with gaskets on a block with my somewhat troubled history, unless I commit up from to re-linering the block.  I expect it's very likely the last round of head bolt tightening cracked the block, or that the next round will.  I can't understand why Rover engineers would sign off on the idea of tapering the liner ends.  It appears that may have been done to only the final years of production?  The TTY bolts seem to be a mistake too.  

Jim B,

Elsewhere on this site, you've mentioned "wet sleeves," as a risk that people with Rover over-bores have to accept.  What are the issues there?  An overbore increases the odds of cracks behind the liner, but as long as the coolant goes no further, all is well, I think?  I've seen a Turner Engineering flanged liner for sale with silicone o rings at the bottom.  Hopefully that would be the ideal solution?  I priced the sleeves and the install costs at about $2500 for a bare block.  About $200 more for oversize liners (same bore, thinner sleeve, no o rings).  

Dave

Dave, any year 300 gives you everything except the heads and 4bbl intake. The '64 4bbl with the aluminum parts is getting hard to find but the later iron engine is still fairly common. TA heads are expensive at about $2500 complete, half that bare but the best heads you'll find, look at Dan's flow testing results. That's where I'd spend my money. (But obviously I didn't since I mounted a blower... but the heads weren't available then.) Smaller chambers than 300, might be good with low compression pistons though. Worth looking at if you plan to use cast pistons. Iron heads will also work quite well and you can upgrade when you are able. You'll pick up another 50 lbs but it won't matter. The iron heads have very good ports compared to any stock aluminum heads. They are huge by comparison, possibly flowing nearly as much as the ported TA heads.

On the intake you have a number of options. You can use a BOPR intake if you fit a lifter valley pan and use spacer plates at the ports. I think TRS sells those parts but they aren't hard to fabricate. Stock 4bbl intakes show up every now and then, as do stock aluminum 300 heads. According to Mikey, the stock aluminum 4bbl intake puts the carb at the same height as the BOPR if I understood him correctly. Using the Rover EFI with spacer plates may result in hood clearance issues, so a scoop or bulge may be an issue you'll need to deal with. Thankfully a quality glass hood is available to solve that problem.

The bell and flywheel are cheap and available. Use BOPR headers and engine mounts, 300 water pump. The guys that have them really like these engines.

That Rover crack, in the photos I've seen it runs horizontally and it's obvious from looking at where it is that deformation of the deck and stud boss is the reason for it. Proper design would have the stud boss tapering down past the end of the hole to blend with the cylinder wall. Seems pretty obvious they didn't do that, but just truncated it below  the hole. All metals deform when stressed and that is a high stress location. Cast does not take deformation well and is prone to cracking. So it doesn't take a lot to see what is happening there.

The chamfer on the liners was in the category of "Very Bad Ideas". I would agree that the chamfer probably was intended to go down, not up. Somewhere there was a mix-up.

The wet liner comment had to do with very large bore Rover engines, which begin to approach Dixie-Cup status. An engine designed for wet liners tends to be heavy. Either the deck is reinforced, the studs go all the way to the bottom of the water jacket, or both. The liner cylinder does nothing to add rigidity or stability to the engine block, unlike a dry liner engine. So when you remove most of the liner enclosing bore material you substantially weaken the block and deck, without any very practical means of getting that strength back. Everything then flexes more, and the big bore engine has a short lifespan. We had one guy on here build one of those and apparently it didn't make it past the dyno testing stage because we haven't heard any more about it. I hope I'm wrong about that but I have my doubts.

Any kind of flex is a bad thing in an engine block. For aluminum to resist flexing forces the remedy is to use more material. This makes the block heavier, and this is the reason the Chevy LS block is as heavy as the iron 300 block. So for a given strength, often the weight advantage of aluminum is much less than you'd think. The iron Buick block has been proven up into the 700 hp range, well above what the BOPR is capable of. This means it is more rigid, more stable, and more reliable at any power level. The deck height increases by 9/16".

Jim

Not sure where you are located (I'm near St. Louis, MO) but, if you decide you want to go down the Buick 300 path, I have a disassembled 1964 Buick 300 that I'd sell.  I also have bare and rebuilt 1964 aluminum 300 heads and matching 2 and 4 barrel intake manifolds.  I might even be persuaded to sell the ported Buick 300 heads (1.775" intake and 1.5" exhaust Stage 1 Buick V6 valves, roller rockers with shaft end stands) and matching Huffaker single plane intake.

Dan Jones

Dan,

I'm not on the market for a 300 yet, but will reach out if I get there!

Jim B,

Regarding the de-stroked 300, would using the small-chambered TA Performance heads solve the piston/rod problem?  They would reduce combustion chamber volume quite a bit, perhaps permitting more piston/rod combos?

ON one hand it helps, on the other it hurts. The lower volume, as you say, gives options. But, it also means you have to either move the piston down in the bore which means no squish area, or you have to use a piston with a large dish. Common dish is around 13cc, you'd be looking at something around 35cc I think.

Jim

Just another observation on the Rover liner issue.

Over the years, I have not heard any issues with the Rover 3.5L engine. I think this whole mess started when they took out more aluminum to insert a larger diameter liner for the 94mm/3.7" bore engines (everything but the 3.5L).  I guess there was enough meat in the block for the 3.5, but not really enough for a bigger bore.

Sure is nice to have a Buick/Olds 215 with a cast-in cylinder.  :)

Hi Carl.

I was recently thinking along the same lines - my Olds block has cast-in liners, so, in spite of its smaller bore, feels like a safer bet than the 4.0 I have sitting in the corner of the shop. I'm thinking a 260 stroker Olds is the way to go for now.

Someone mentioned vibration caused by low rod/stroke ratios. I'm wondering if that vibration can be balanced. I realize that the vibration is proportional to the engine speed, and that it occurs somewhere around 45 degrees ATDC. I suppose balancing it means calculating the moment of the force at some average RPM, such as 2200, and using that in the calculation of the counter-balance forces. A good excuse to brush up on calculus and physics.

Paul

The cast in liners are a very good thing, however that really doesn't make the BOP engines any more reliable IMO. From what I have gathered the Rover castings *may* be denser and therefore have more strength in areas like threads where the Olds and Buick blocks really do fall short. I have yet to see an Olds or Buick block that would comfortably take full torque on either the head or main bolts without at least a feeling that the threads were pulling or stretching, and that's not a feeling you want to ever get when putting an engine together. Every time I built one of those engines I had to stick to the low end of the torque specs.

So while I agree with Carl's assessment of Rover engines and their troubles, I do not feel the US versions have any real advantage. In fact, the 3.5L Rovers could very well be the most reliable of the lot, but if building for power that isn't saying much.

Which again explains why I went to the iron block. First there is the bore size: 3.750" standard and a .050" overbore is generally going to be OK. (sonic check the walls) The threads will not pull out and torque will be firm and positive, a wonderful improvement. Then there is the possibility of stroke increases or decreases. For this you pay a weight penalty of 80 lbs. Big deal. You're at the same weight as a 5L SBF swap. Plus maybe some fiddling to get the intake you want. But all BOPR heads fit so that's a big plus.

I'm still convinced there is a rather large cross section of owners who value the corporate stamp of legitimacy, in that MG installed Rover engines so any MGB with a BOPR has a direct connection with implied factory approval. That is right and proper and as it should be. Not to denigrate any other engine conversion, but only the BOPR V8 fits this category. However, the 300 is the same engine. It has an iron block, somewhat taller decks, and a 1 piece intake rather than using a valley pan but is otherwise identical, and most people would not be able to differentiate between the two without a magnet. (Interestingly, the Australian  P76 version also had taller decks.)

Jim

Well, the Rover blocks are reported to be heavier.  I have a bare Rover block that I can weigh.  Anybody have a bare Buick 215 block to weigh?

I don't buy the denser, stronger Rover casting.  i had no problem pulling the threads out of one of my 3.9 Rover blocks when torquing the ARP head studs.  They let go right at 50-55 lbs.

I made a "test coupon", from a 215 block. It tensile tested higher than what aftermarket, T356 blocks were . 215's density is grater than Rovers, because they were semi-permanent mold vs sand cast.    roverman.

The Rover block question is not as simple as it has been made out, there were considerable numbers of block/liner failures in these engines. As I understand it the 3.5 gave no problems at all and the same with the 4.2 but they started with the 4.0 and 4.6 engines. The bigger bore of these engines left very little metal behind the liners, the bores were ultrasonically tested for thickness and were graded accordingly. I think a dab of paint was put on the valley to distinguish the three thicknesses, 4.0 engines received the thinnest and medium and the 4.6 received the thickest and mediums if needed. The idea being that the longer stroke could cause the liner to shift so all thick bore walls went to the 4.6.
That was not the only problem that the Range Rover had, the top coolant hose was prone to airlocking, causing the engine to overheat and this in turn caused the liner problem. Of course the vast majority of owner did not know or understand the overheating problem and the engine then got its bad reputation.
If you read the information to the top Rover V8 engine modifiers they will confirm that their replacement top hat liners will cure the problem of liners, but it should not have existed in the first place. It is typical of the engineers/ management that lasted for the best part of four decades where cars were released for sale before sufficient testing was performed on them. There was virtually no car made by the Leyland group where the motoring press and the public were not critical of the quality. Those of you in the USA were spared the Allegro whose new owners were told not to jack it up or the windscreen could pop out!

]quote]As I understand it the 3.5 gave no problems at all and the same with the 4.2 but they started with the 4.0 and 4.6 engines[/quote]

The 3.9, 4.2,  4.0, & 4.6 all had the bigger 94mm bore.  Glenn Towery had first hand issues with the 4.2 block.

I have now found the reference from Des Hamill's book "how to power tune rover V8 Engines". He states that in 1993 Land Rover were aware of the problems with the variation in wall thickness in 4.2 engines and later  4.0 and 4.6. The wall thickness of the bores varied between 2.1 and 3.0 mm. After 1997 blocks were given one of three grades blue minimum of 2.2, yellow 2.5mm  and red 2.8mm a daub of the appropriate colour was put onto the valley of the block. Until 1997 4.0 engine were made from 2.2mm to 2.5mm blocks and 4.6 engines 2.5mm and above. after 1997 4.6 engines were only made from red blocks ie 2.8mm and above unless there was a shortage of thick walled blocks. Some pre 1994 blocks left the factory with as little as 1.2mm of wall thickness.
He also states that in the P38a Range Rover  a combination of top radiator hose failures and a coolant running temperature caused the rise in the number of failures.
I think a conclusion could be drawn that if you have a sound 4.0 or 4.6 and control the water temperature then there should be no failures. I also accept Curtis's remark that Des Hammill exaggerated the problem, but that problem must be real otherwise we would not have so many companies offering different  liner solutions in the UK. Obviously with the increasing age of these cars (the youngest is now 14 years old) the majority of them are long since gone to the scrap yard.
Philip

Reviving an old thread, but I posted some more details on my bargain 4.6 on my build page, and thought you guys might be interested.

I'm still not certain if the block is cracked, but I'm totally certain the engine needs to be completely disassembled and cleaned, with new bearings all around.

Next step is a pressure test, hopefully this weekend.

The head bolt holes are shot, and will need helicoils or time-serts all around, but that might be the *only* defect in the block casting.  The new gaskets didn't appear to be leaking, and the liners all seem to be in place.  All cylinders still have clear cross-hatching too.

The front cover gasket was prob the factory original, and it was in terrible condition.  there were suspicious sludge "trails" on the outside of the block near the front cooling passages too.  

I may be a hopeless optimist, but it's still technically possible that coolant was entering the crankcase at the front cover, and that the block isn't cracked behind a cylinder, and that the head gasket replacement didn't correct the problem, and that the questionable decision by the mechanic to torque all headbolts again likely ruined his ability to cheaply repair it.

The oil filter pieces are a mystery though, to me anyway.

I think Phillip's comment that by now most of the 'bad' engines have been recycled is valid and even more apt when applied to the 215's which also had porosity issues. You never hear of that these days because those engines are gone. However that doesn't mean one won't occasionally show up.

Carl, please do weight your bare block. I weighed several 215 blocks and they came out to 60 lbs. Precise actual should be within a pound or so of that, with the main caps and bolts. If as you and Art say the metal is not more dense then certainly sand casting would have added more metal. Another oddity is that I have heard of some Rover head bolts being torqued down to as high as 90 ft/lbs. That strikes me as very odd given your and my experience.

I completely understand the desire to build a light engine. However, bear in mind these were never expected to last even 100K miles. At the time of their design expected engine life before unacceptably high oil consumption and other issues was around 50-60K miles. Warranties, when they did begin to appear, were for about half that. Timing chains regularly failed at 30K. Modern engines, designed for 200K+ are engineered for great rigidity in the block and other components. This minimizes distortions and harmonic vibrations that cause wear and other failures, and that's one of the biggest reasons for the increased service life, along with cleaner gas and better oil. Buick addressed this problem by switching back to cast iron and their subsequent engines became renowned for exceptionally long service life despite their remarkably light weight for a skirted block. Rover did not really address the problem, stretched out their production run with band-aids like the cross bolted block, and eventually replaced the engine with something more reliable.

What I find very interesting is that the iron block Buick and the Rover *are the same engine*. The only fundamental difference is the material they are cast from. Anyway, I can say from working with both that Buick's choice was the right one. From an engine builder's perspective the iron block is so far superior to the alloy one that they simply are not even in the same League. Yes, you do take an 80lb hit on the weight. But it is SO worth it.

Jim

I have bare Buick and Rover 215/3.5 blocks that I can weigh tonight.

Tim Bland

Amendment to my previous post.

After further checking I have two Rover blocks and not a Buick block.

These vids I took say it all...

https://www.youtube.com/watch?v=d6G1Ojv3I20

The Later 4.6's seem to have the "loose liner syndrome" (not to be confused with "cracked block behind liner" or the earlier "dropped" liner issues). These are simply that there appears to be insuffient interference, especially on the centre four liners, for the liners to hold in place, especially at higher temperatures.
Pinning is the easy fix for what is otherwise a plenty servicable engine. If you do proceed, I'd go ahead and simply pin them all anyway, as its so easy to do with the engine on the bench, in pieces.

The "first 6 month production" 2003 4.6's had the well known issue of the dowel holes in the block for the front cover being machined in the wrong place (interestingly the bolt holes and even the countersinks for the dowels were right, someone just mistakenly offset the dowel holes). This is easy to see as the pump gerotor is likely broken when you pull it out, and ALL the bolts are biased to one side in the holes in the front cover. Fix for that is to simply pitch the dowels, align manually such that the gerotor gear "floats" and can be slid forwards/backwards using a magnet thru the oil seal, and drill a few 1/8" holes and knock in a couple of roll pins for holding that location.  Just because it came out of an '04, don't assume it was an '04 motor. You'll see the countersink offset around the dowel very easily if it is there. If it looks ok, it is ok.

Finally, if you do pressure test the block, I recommend setting the block on your grill, and warming it up, at least to 180 deg. If it doesn't leak at that temp, you've definitely got a goodun.

Loctite should fix that also.

Jim

Warning: If you convert to head studs, reduce your torque # by 30% ! 20 tpi vs 14 tpi.  Just about any cast aluminum thread will fail,if 30% too much torque is applied . FWIW, roverman.

Well, my levels of optimism are now much lower.

A pressure test through the coolant passages passed at 30psi for 24 hours, and I thought I was a brilliant finder of decent RV8 engines in the wild.  Just for kicks I pumped up the pressure to 50psi, and within a few minutes cylinder four sprouted orange, oozing, bubbling stuff all around the top of the liner.  Definitely looking at a cracked block.  Center head bolt hole is stripped too, and I think that's not coincidental.  I haven't yet tested the crank journals for wear, but I will.  Heads just had a valve job, so they should be ok.

My only leads on a replacement used engine are from suspect trucks: either from no-body-damage Landys in the junkyard for about $300, or from a guy parting out his Rangie after an "interior burn" for $1500.  No way to test either before buying them, so it feels like a real dice roll either way.  All are high mileage and likely need rebuilding anyway.

I'm inclined to invest in the block I have, to be reasonably sure it will last a long time.

Local top-hat install costs are $1200 labor, plus $500 cost of sleeves, plus $100 to tig-weld the crack.  The might-as-wells add $2000, or maybe much more.

I'm now wondering what to have the machine shop do:

1.  Stock bore (94mm ID liners) and replace all worn bits with new Rover 4.6 spec bits, or

2.  Overbore (96mm ID liners) and go with Chevy 305 or Ford 4.6 pistons and appropriate con rods.

It seems like option 2 gives me more power, a free-revving engine, and perhaps tougher and lighter pistons for the same labor?  Do I lose anything?  I'm guessing the parts and machining costs are similar either way?

I'd be looking for an iron block.

Jim

A different brand same idea...
https://www.hotrod.com/articles/sleeve-coyote-block/

Yeah, see with an iron block there's no messing with sleeves. No cylinder wall cracking. No threads pulling out, ever. And a 3.8" bore (96.5mm).

It costs you 80 lbs.
So worth it.

Plus a much cheaper bellhousing and a lot more transmission choices.

Jim

Hi Jim,

I hear you on the iron block, but I'm irrationally committed to the Rover aluminum block.  I had a chance to buy a 300 out of a remote junkyard about 6 months ago, but just couldn't go through with it.  I have so many pieces (bellhousing, coated headers, factory flywheel with ignition trigger wheel, EFI intake, etc) waiting to bolt onto my RV8, I can't bring myself to go another direction.  Maybe for my next project?

I am wondering what if anything I gain/lose by fitting 305-size pistons to the RV8 block.  I found a set of ICON Premium Forged Pistons, IC834-060, that have a
3.796" bore, 1.433" comp height, weigh 522g, that should work with a 6.11" 4.0 RV8 con rod inside a 96mm (3.78") liner from Turner Engineering.

On the plus side:
  Slightly larger displacement, maybe 4.8L
  Forged pistons with higher strength, allows for TA Perf heads down the road
  Slight weight savings (maybe)
 
On the negative:
  Totally custom approach, likely has higher failure risk
  Have to rebalance the crank, etc
  Overbore top-hat liners are thinner, maybe weaker
  Longer 4.0 con rod (6.11" vs 5.90") gives a slightly higher rod-stroke ratio 1.89 vs 1.83 (I think?)
 
Unknowns:
  Cost of set of 4.0 rods and machine shop costs to bush the wrist pin and reduce piston comp height a few thou, vs high cost for stock-spec forged pistons

Am I missing anything important?

Dave

Well Dave, you could still use your coated headers and EFI intake (have to use spacers though, and might not fit under the hood then). On the plus side you could use a 350 crank in it for 5.6-5.7L displacement. That flywheel might work with some machining and re-balancing but I expect that'd be possible without much difficulty. You need to thin it out some anyway I expect. And I'm guessing you are going with the Rover 5 speed?

But I do get it, you're in love with the light weight aluminum 4.6. It's clouding your judgement right now. Just consider that for what you are talking about spending to make it work, you can adapt your parts to the 300 (or sell and buy different parts) and possibly stroke the 300. And it will easily outlast the 4.6L Rover. I'd go with one of the 4bbl throttle body EFI's though myself. Simpler, easier, and looks better in my opinion. That doesn't help with your Rover transmission though, does it. Hmmm... What do those sell for these days?

It is basically a math problem on the face of it but with other factors. I'd definitely do the full cost comparison though before taking irreversible action.

Jim

Hi Jim,

Your argument is compelling.

I spent yesterday morning in the local pick-a-part, hoping to find another RV8 that might be sound, but the only safe bet was in a Discovery with 180,000 miles on it.  Full rebuild territory. For $500.  No thanks.  

If a 300 Buick falls into my lap, I may shift focus.  I'm ready to think a bit harder about the options.

I can't seem to find the "recipe" here for stroking the 300 block.  Is there a parts list or a discussion thread anywhere?  

I already have a decent Camaro V8 T5 and a set of aluminum 300 heads (need work).

Dave, 300 Stroker info:

https://www.mgexp.com/phorum/read.php?40,2598435

From BritishV8:
http://www.britishv8.org/Articles/MonsterMotor.htm

Perhaps you could ship a Turner top-hatted block over? A consolidator wouldn't charge you too much.
Maybe ask Real Steel; they use a consolidator, just in the opposite direction.

http://www.realsteel.co.uk/

Ivor

Dave, by now a few 300 strokers have been done, and much depends on your expected redline. To be completely honest, in an MGB a 350cid Buick does not need to exceed the factory limits unless you aim to race it somewhere. You can get an easy 375+ ft/lbs of torque out of it with the OEM build, and that's enough for great gobs of silliness. OTOH, a set of NASCAR take out rods and forged pistons are a relatively affordable route to 7500+ rpm speeds and ridiculous power levels.

So far there is not any one established formula. However if economy is the goal then the 340/350 crank main journals can be lathe turned to .030" oversized before going to the grinder. (1/2" overall reduction. Bear in mind that is like at least 10 complete full crank grinding jobs if the grinder does it all.) and then the 300 rods can be reused with suitable pistons of your choice. (Making sure to check the fit of the oil slinger in the 300 block.) The key to the entire thing is the rod and piston combination. The 300 uses a relatively long rod, the piston has a significantly larger than typical pin height, which only works due to the tall deck, and then the thing that makes the stroker work is that pin height. You can easily decrease that to accommodate the longer stroke without getting into the ring package.

So, for a performance build, start with the rods and plan on specifying custom forged pistons so you can get everything the way you want it, such as CR and squish area. This method allows you to minimize weight in the reciprocating assembly for a truly free-revving engine, and there is a LOT of room for reduction. The wrist pins themselves are 200 grams and that can be reduced by half.

For the near-stock build, use the 300 rods and either one of the pistons used in prior builds, any one that you find you like better, or custom. Note, piston crowns can be cut to modify deck offset, CR and dish plus there are a lot of things that can be done with piston pins if you feel like getting into that.

Bear in mind here that the difference between cast pistons off the shelf and fully spec'd out custom forgings is in the range of about $300-400 which may sound like a lot but you get a lot for that and spread over the life of the engine it is peanuts. Still, if I was being dollar conscious I would look very closely at the pistons that Chris used. That's been the latest development, and to my mind one of the most sensible. (Disregard Chris' whining, he's just a bit too much of a perfectionist. ;-) ) However we are yet to find the perfect rod/piston combo. Bear in mind also that early SBC rods with the large end narrowed are a valid rod choice and are available in forged rather than cast. This enlarges the piston options as well. The largest limitation to piston choices in fact is the 3.8" bore size, but expanding the search to non-American engines may prove fruitful. It takes a little math to get the pin height for the selected rod/piston combo but not that much. Deck height, stroke,rod length and then pin diameter to make sure you aren't into the ring package. You can use up to a 6.3" long rod with no worries. In fact I think it would be possible to squeeze in the longer 340 rods if the ring package was very compact.

So while it may sound complex, what you actually have is a great deal of flexibility. About 1/2" of leeway on rod length and the same on pin height. If you can't find a rod and piston that suits under those conditions either you just aren't trying or you are being too picky. Well, not you personally of course. There may even be some motorcycle pistons that would work just fine.

But again, for simplicity follow Chris' build. It's the easy recipe. Have your block sonic checked for core offset before you start (you can get an idea of core shift by looking at the cylinder roots at the crank end of the cylinders. If there is a great deal of visible variance it isn't a good sign.) and try to stay over 3/32" on the thrust side if you can, try to stay within .050" on the overbore and do the oiling mods. Since you already have the 300 heads set up an automatic search for a 300/4bbl aluminum intake and ask around. Any old iron block 300 will do the trick.

I currently have a 300 block on the engine stand with a turned but not ground 340 crank sitting in it. It'll be a slow build but my next step is to find the best rod I can at the best price. This engine will likely get Venolia forged pistons similar to my 340.

Jim

Many thanks Jim, Jim, Ivor, and Dennis,

I clearly have a lot of reading to do!  

The 300 is a really neat idea, but I'll admit the level of effort described in the mgexp thread is a bit overwhelming!

Some beautiful custom pieces in that car.  Particularly the motor mounts.

Dave

It can be done very much like a straight up Rover swap. Except no liners to deal with. Doesn't have to be a stroker, plenty of power as a 5L.

Jim

Mike Moor gets just over 300 RWHP with his stock stroke 300.  So, one does not have to go to the trouble of stroking the 300 for it to be a very good engine.