I think I found a Unicorn!

[DiDueColpi]

So, the cracked Rover blocks have been a problem for a long time now. And the ultimate repair solution has been a tophat liner repair.
This conversion works very well and fixes the problem for good. However, it also has a rather devastating effect on finances.
 I've never thought that the actual crack was the problem. The cylinder liner should seal properly to the head through the head gasket. Even if coolant made it's way through a cracked block in behind the liner, it shouldn't be able to intrude into the combustion chamber.
 What's happening is that the liners are badly machined. They have a very large taper at the top to allow easy piston installation. This taper is more often than not off center and removes completely any chance of a good seal to the head gasket.
The other issue is that the liner registers at the bottom of the cylinder bore. What this means is that as the engine warms up and expands. The aluminum block expands more than the iron cylinder liners. This causes them to lose contact with the head gasket and failure is just a stab of the gas pedal away.
Thinking that I was on to something I "O ringed" a failed block. I made a tool to score a groove around the cylinder liners just as they transitioned into the aluminum block deck. A  0.030'' copper ring was inserted into the groove and the heads were put back on.
That engine has worked perfectly for almost three years now. The only caveat was a very small coolant leak into the sump. I did something that I never do and put some block sealant into the engine. It's been perfect ever since.
After that success I realized that a little more work was needed on a long term fix. So with the next engine we pulled it apart and yanked out all the liners.
 The deck was milled 0.010" the liners were flipped upside down an re-inserted with locktite sealant and the deck was then again machined 0.005". This left the liners sticking proud of the block deck by 0.005".
The reason to flip the liners is that the bottom is flat. No taper has been machined in. You now have a nice 0.050" wide sealing surface. I still don't like the bottom register, but the taper is not an issue here.
I have four engines running this way for over two years now and no signs of failure!  
OK, so on to the Unicorn part.
As I said the tophat liner is the ultimate repair. Problem is I have too much Scotch, I mean Scot in me to pony up for them.
I have found a cheap tophat liner. It's from the chevy modular 4/5/6 engines. It's a melling part # CSL 356F and I just ordered 8 from Summit for $22.40 each.
They are 1.5mm bigger in OD than the range rover and come with an unfinished bore intended for 95.5mm. That means that they should accept the chev 305 piston nicely. Or use the modular piston with a slightly longer rod. The liners are also 10mm longer so they can be trimmed to fit. The best part is the tophat configuration. No more bottom register headaches.
Simply bore the sleeve to fit, provide the appropriate notch at the top of the bore to accept the tophat step and away you go!
With the liner now retained at the top of the bore, the block can do whatever dance move it likes. The head gasket don't care.
I'm thinking that an oring at the bottom of the bore would be a wise move. I will decide whether to machine it into the block or liner once the parts get here.

Live like you mean it.
Fred

[BlownMGB-V8]

Nicely done Fred.

Jim

[MGBV8]

I have found a cheap tophat liner. It's from the chevy modular 4/5/6 engines. It's a melling part # CSL 356F and I just ordered 8 from Summit for $22.40 each.
They are 1.5mm bigger in OD than the range rover and come with an unfinished bore intended for 95.5mm. That means that they should accept the chev 305 piston nicely. Or use the modular piston with a slightly longer rod. The liners are also 10mm longer so they can be trimmed to fit. The best part is the tophat configuration. No more bottom register headaches.

Thanks for that info, Fred!

[mgb260]

Fred, I mentioned flipping the liners a few years back. I know I had Todd check out a 4.6 block he had in his collection to verify they were flat on the bottom. Never made sense to have a taper at the fire ring. What interference fit for the top hat  liners will you use? What type or number of Loctite?  The top hat liners sound  like a perfect alternative.

[mstemp]

Fred,

Will the machining not easily surpass the cost difference between the liners? Looks like under $500 CDN between the Turner Engg ones and Summit, plus you could use your old pistons rather than buying Chevy ones if in good shape.
Hope my 4.6 L never starts to have issues so I can be left in the dark on this topic!

[mgb260]

Mike, The Turner top hats will require machining too. The liners Fred found save you $500. Chevy Hyper 305 pistons are fairly inexpensive and allow you to build what you want for rod length and compression. There are different compression heights for 5.7 or 6" Chevy rods and dished for stock heads and flat tops for 300 Buick heads. I like his idea of flipping the liners. I'd use 4.0 pistons in the 4.6 and put larger valves in the stock heads.

[Blown v8]

We will be needing pictures to make this great thread even better !

[roverman]

FWIW., Loctite 620, "retaining compound", it's green and hi-temp. DO NOT get crazy with interference fit !  I would not go over .002", at room temp.  Remember the thermal expansion of alum. vs. steel ?  Get your re-sleeved block too cold and the aluminum can crack, from being over-tensiled.  Wildcat,(Wales), used to sell flanged liners. They were priced right, so I bought 3 sets.   Never could trace who "made" them.  
                                                                          Onward, art.

[roverman]

Fred, Since your now silently elected as "Rover V8 liner GURU", perhaps you could share your labor techniques ? Things like best method to heat the block, including temp ? Hyd. press/out, of the sleeves? Many Rover block "lives", are at stake....

[mgb260]

The Turner ones are made by Darton but, Darton won't sell them to you. They must have an agreement. Art, thanks for the info. I know aluminum expands about twice as much as steel when hot. At 180 to 200 degrees it is pretty close. Have you checked out the thread on Mgexperience on heat treating the 300 Buick heads?

[DiDueColpi]

I've used loctite 640 for all of the liner installations.
It's thinner than the 620 and cures slower giving you a little bit more time to get everything back in place.
For the flipped liners I just clean everything up with "Scotch Brite" pads ( because they just seemed proper)
Pop the block into my kiln @250'f ( the kiln is made out of fire bricks and an old oven. it's mostly used for powder coating. I can re-stack the bricks any way that I like for a particular part. works great.) and throw the liners into the coffee room freezer for a couple of hours.
Once everything is ready, I brush the loctite onto the block and just slide the liners in by hand. A couple of taps with a leather mallet seats them all the way.
Don't put loctite onto the chilled liners, it becomes unstable when it freezes.
As far as pulling the rover liners I use a home made puller. Its a simple bridge puller made from 1" thick wall steel square tubing.
I machined a plug that locates in the bottom of the sleeve. A piece of 5/8" ready rod connects the two together.
Mount the plug into the bottom of the sleeve, place the bridge onto the block deck, insert the ready rod and a couple of nuts and crank away. The liners come out easily on a cold block.
For the tophat liners I think I'm going to fit them fairly tight. The first engine that I'm going to try this on is the Lo-ver engine. I want some solid contact to the block for cooling and for locating the bolted on deck for the lotus heads.
0.0035" to 0.0040" interference fit is what I'm looking for.
Here's a few shots of the Rover and Chevy liners that I just pulled from some old blocks.


You can see how thin the sealing edge of the Rover liner gets.


And how much bigger the chevy is.

the rover becomes virtually razor sharp in places


Live like you mean it.
Fred

[Scott Costanzo]

I have no dog in this fight at all but this is a VERY interesting thread! Nice work Fred!

[MGBV8]

Find any cracked blocks, Fred?

I have read & seen pic where the block cracks behind the liner near the head bolt hole.  Seem there is not enough aluminum in htat area because of the increased 94mm bore.

https://www.youtube.com/watch?v=zlRkbeY7_IY

[DiDueColpi]

Yep, all the time Carl.
I'm still not convinced that the bigger bore is the culprit though.
The cracks are usually in cyls two and five. The head bolt bosses in those cyls, as in most of the others, aren't connected to the cylinder bores until you get to the underside of the deck. The cracking occurs much further down. And never on the outside of the block where the bosses are connected.
To me it's a combination of a more brittle block. The later blocks appear to be much harder than the earlier ones. Torque to yield bolts. and possibly harmonics transferred up from the stiffer cross bolted bottom end.
To get around this I generally bore the head bolt holes down much further. You will break through on most and will need to use sealer on the threads. I then use head bolts from the Volvo " white block" or 850 engine. These bolts are far too long and need to be cut to fit. But that's an easy task. They are also 12mm thread so the block needs to be retapped for that.
Now you have far superior thread engagement much further down into the block.
On the Lo-ver engine I've gone all the way and bored the head bolt holes all the way down to the bottom of the cylinder bores.
This requires some inventive sealing and custom studs. But relieves the upper deck and cylinder bores from any untoward stress.
Here are the Rover and Volvo head bolts side by side.

And here is the home made sleeve puller.


Cheers
Fred

[roverman]

Fred, Thanks so much for this sharing.  I hope the new press fit works out. Last pic, is that an "early" RV8, that the puller is resting ?  Have you used studs, on any re-sleeved RV8's ?   art.

[DiDueColpi]

Thanks Art,
Could be, it has the same cracking problems! ( it's actually a Merc flathead v8 / showroom coffee table.)
I don't use studs unless the engine is coming apart regularly. Too much hassle for no real return in clamping.

Cheers
Fred

[BlownMGB-V8]

So Fred, on the Lo-ver you're tapping the studs into the main web? You've got me really curious about that. Would you care to share more of the details?

Jim

[DiDueColpi]

Yep, made sense to me to move as much of the clamping load down the block as I could. It eliminates any side load distortion from the cylinder bores. And it takes the load down closer to the crank where it is more useful. Also if you remember | milled the deck off and replaced it with an aluminum plate. This helps to sandwich everyone together.
Several, actually quite a few of the studs exit and re-enter the confines of the block. I've made provisions for Orings but whether that works remains to be seen. I really should dig the motor out from storage and post some pics. That would explain a lot.

Cheers
Fred

[DiDueColpi]

My new liners arrived today!
The unfinished bore measures out @ 094.625mm which opens the door to a few more piston choices.
I'm going to strip down a 4.6 and send it off to get machined for them and see how it works out.

Yep, I chickened out on doing the Lo-ver first.
Too much time and effort into it to experiment that hard on it.

[mgb260]

Perfect for the 305 pistons!

[DiDueColpi]

Got 4.6 block stripped down and pulled all the liners.
It's off to the machine shop on monday.
Going to use 5.3 ls pistons and rods. That gives me a nice modern piston and 6+ inch rod combo at a reasonable cost.
It also lets me destroke the crank slightly to 03.096" to get a 0 deck.
That stroke with the 96mm bore still works out to a 4.555 L engine.
You could also use the 4.0 crank with this combo and deck the block very slightly to get the same result.
Fingers and toes crossed.

Cheers
Fred

[mgb260]

Fred, Wow! 3.78 bore! How thick is the remaining liner? Do you have to mill the rods big end on one side like the SBC rods to get the right offset? What is the compression height of the piston and rod length?

[DiDueColpi]

The liners are 3.920" od. so I'm pushing the limit a little I think.
The 4.6 liners measure out at 0.072" so based upon that I should be ok.
Yep the big end needs to be milled. Will do 0.050" per side so that the Chevy bearing will still fit.
Compression height is 1.3140" and rod length is 6.0980".
The difference between the Rover rod journal and the Chevy is 0.0850" so I have 0.170" stroke variance to play with.
You could even get away with the Rover 4.6 rod as the pin is the same @24mm.and the length is close @ 6.110"  but it would mean milling the piston and until I have one in hand I don't know how feasible that is.
I know that the compression ratio is a little whack but the heads are the 300 ones so not too much work to cc them. The pistons have an 8cc dish and should be up to at least a little massage as well.

[mgb260]

Thanks, Fred!

[BlownMGB-V8]

Sounds like a pretty good combination.

Jim