I feel like I have now taken the MGB/BOPR swap to it's ultimate conclusion. Some finished specs like HP and torque will have to wait on dyno tuning, possibly next spring but as it currently stands the car is running with the following specs. As always, different builds may suit individual builders better:
Buick 300 block bored .030" oversized
TA Performance Rover heads, untouched ports
340/350 Buick crankshaft, 3.8" stroke
TA solid lifter Roller cam #TA264-74R .544/.274, .554/264, 112, 3
Carillo 6.2" rods
Wiseco custom forged pistons, 1mm rings, light weight floating pins 10.5 SCR, 8.3 DCR.
1.9/1.6" Ti valves, beehive springs
LS type adjustable roller stud rockers from TA
Eaton M112 blower
GM P-01 ECM ('411) with modded '02 Camaro tune
Projected redline: 7-7.5K, rev limiter currently active @ 5K during break-in
Boost levels observed this far: while driving 5-6psi, stationary at the rev limiter ~10. I have eliminated all the oil leaks finally. The pan and one of the big nuts on the oil pump needed attention but the front and rear seal are working flawlessly. I made a stiffener for the oil pan flange that finally did the trick. Oil leaks have been a big issue for me with these engines and it's nice to finally have it all sorted out. If there is enough interest I could start a thread on how to deal with those and hopefully others can contribute.
Oil pressure is good, using 5w20 dino oil for break-in but may not go high enough for the projected redline. It sits at about 30@1200rpm after complete warmup and limits at 45. Might need a stiffer spring or the TA adjustable cap. Warm idle has now smoothed out at 1200 and is not affected by PCV or the throttle plates so it should be controllable in software. Overall it's driveable but will need some fine tuning.
I think I can expect to see a minimum of 600 hp out of this engine. That might be conservative but we'll see. A typical stock 350 cid engine in the early 70's made upwards of 300, 10psi is 2/3 of sea level ambient pressure, so adding that to 300 gives 500 and I'm pretty sure the heads, cam and increased redline are good for more than another 60 which puts us at 600. Could be more, could be less but in any case it will be enough. It's entirely likely that I will have to resort to decreased ignition advance (already using that) and possibly liquid injection or even an E85 blend to avoid possible damage but those are feasible options.
The transmission is a Tremec 3350 in the GM case from Forte. Rear axle is Jaguar IRS, 3.08 Powerlok and ventilated Willwood rotors. Haltech now makes a standalone transmission controller for the Aisin AA80E so I have the option of swapping that back in at some point if I want to. Exhaust is custom full length fenderwell headers, 2-1/4" rebuildable cartridge glass packs and chambered resonators.
The car drives well. I'll be adding a hydroboost to the brakes to reduce pedal effort this winter. At present there are instrumentation issues I'll be chasing before really giving it a workout or driving very far. Looks like a power feed issue is most likely at this point, affecting my ammeter, wideband and rear stereo amp. So typical British car stuff right? Except there's not much British in those systems anymore. In any case it will be so nice not to have to worry about the car marking it's spot.
Now you might wonder why I feel I've reached the ultimate conclusion of the BOPR swap, and the answer is that the Buick 300 stands at the pinnacle of that series of engine's development, provided the right conditions are met. One is displacement. No other engine in the family is capable of more displacement except a marginal increase via overbore in the Buick 350 and that engine is not a very suitable swap candidate in the MGB. With the 340/350 crank and a .030" overbore it is a 5.7L engine, .7L larger than the largest displacement Rover ever built. It can use the TA-Rover heads, the best heads ever made for that engine family and competitive in every way with the best GM or Ford aftermarket heads. It weighs about 50lbs more than the late Rover but for this weight you get an iron block which is much stronger and has been proven in engines of over 1000hp output. All this and it fits in the car just the same as the BOP/Rover, has a MUCH cheaper bellhousing and mini starter, and can be installed under a stock hood. In the RB cars it is a bolt-in swap. Ergo, ultimate BOPR swap.
I mentioned evolved. That's because this car has seen a wide variety of BOPR engines, all GM incidentally not that it matters much. First engine back in '88 was a Hi-Po Buick 215 with the hottest cam you could buy and a 650 Holley carb, the current headers and a set of glass packs. That combo was a little tricky just off idle but it would absolutely scream all the way up to 7 grand, but I ran it very hard and it had a limited lifespan as a result, eventually cracking a piston skirt and wiping out a rod bearing. Next came a couple of Olds 215's including the turbocharged Jetfire running a 2" SU with 6 pounds of boost and an Eaton M90 supercharged Olds with a heatpipe intercooler that exceeded 16psi of boost. After those came an M112 boosted long rod 340, an almost completely stock low mileage iron head 300, and finally the current engine. The 340 and iron head are still in good shape but I wanted to build this particular engine specifically for the car. I think it is likely to be the last one, but if it's not the 340 stands ready to serve, with a few improvements. Note, the 340 is NOT a good choice for an MGB conversion but once done it works well.
My car is a bit radical and that's old hat but for an MGB I've come to the conclusion that for a new BOPR conversion you can't do better than the Buick 300. It's hands down a better, stronger and more reliable engine than the other options and easier to drive. Even as an iron head it makes a great swap and it's inexpensive. As for availability for an MGB conversion, with about 525K MGBs made in total and perhaps 400K 300's produced the chances of finding a Buick 300 engine are about as good as finding an MGB and certainly much better than finding an MGB that needs an engine. With it's 9:1 CR the iron head 300 2bbl is a great candidate and does very well indeed on regular gas, having no trouble at all keeping up with the pack.
Jim
Good write up Jim.
On the pan oil leak front, I've been battling that for a while. It wasn't horrible, but enough to cause some drips on the shop floor and annoy me. I tried some of my usual tricks, straightening the pan, different types of gaskets and sealer, etc. It would be good for a while, then slowly it would start leaking again.
I think that I have it figured out though and have traced it down to a couple of things.
My block has been line-bored, and it is standard practice to remove some material from the main caps. Then the caps are torqued in place, and the block/caps are re-machined round again. Upon closer inspection, I noticed that the rear main cap (which also serves as the rear engine block close out) was recessed .020" from the oil pan rail edge surface of the block.
Also, my oil pan rail edge wasn't in the best shape, probably due to age and to many R+I attempts. I ended up cutting of the old mounting flange off the pan. Then I fabricated a new one-piece flange out of 1/4" thick steel plate. Fortunately, I have a spare engine block, so I was able to weld the new flange to the pan, with it bolted to the spare engine block. The flange/mating surface was machined flat using a combination of a large stationary belt sander, straight edge and files.
To address the recessed main cap, the plan is to make a .020" "shim" out of gasket material. Then I think I'll use ThreeBond RTV instead of an oil pan gasket.
Hopefully this will do the trick, as I am on a mission now!
Bill
I expect that will work Bill. In my case I have a 3/16" thick stainless stabilizer plate stacked between the pan rail and the pan so there are two layers of sealant. I'm using black Gasket Maker, I think a good quality sealant is needed here but something like Right Stuff would be a mistake. (BTDT) Dropping the parts in place and coming back in a day for final tightening is the usual drill as you want the sealant to make good contact all around but also want to compress it a bit. Again in my case a two stage process as torquing the main caps is part of the procedure.
Ordinarily you would think that attaching the pan this way would be good enough and sometimes it is. But sometimes it isn't. The right amount of sealant is important, I aim for a bead of about 1/8" but that's hard to achieve uniformly in practice. I go around all the bolt holes, I think none of this is really new. Surface cleaning is absolutely crucial as any slightest small smear of oil will create a leakage path. If the sealant does not immediately adhere in any place it will end up leaking. It doesn't have to be blemish free polished metal by any means but the sealant has to stick and I think this is where most of us find trouble as we inevitably find that spot 3/4 of the way through applying the sealant and don't want to stop. Ideally we would have a primer of some sort that we could brush on both surfaces and check for bad places but I don't know of one. Chances are good it exists though. Anybody?
The flange is a problem of course. Nothing that flexible is going to mate perfectly except under ideal conditions and this is where the old cork caskets came in. However, they are subject to improper torquing and drying out. Almost nobody torques them properly near universally overtightening, the flanges deform, and they were never intended to last past the warranty period which at the time was 2 years and a little over 20k miles and that was stretching it. Not exactly what we are looking for here. So the gasket maker sealant has become the replacement but it isn't as perfect when it comes to filling gaps as we would like to think and sometimes needs a little help. What tends to happen is that all the sealant gets squeezed out at the bolts, the pan rail flexes and bends, and gaps form between the bolts, especially at the corners. A stringer or spreader somewhat like you see for tin valve covers would help but it would take so many of them that you might as well have a single piece of thicker steel.
Alan Mackin over on BuickV8.com (AMACK) makes a very nice set of 1 piece spreaders for the tin valve covers and I've mentioned that one for the pan might be a good idea. It uses a 1/2" strap set edgeways with tubes for the bolts to go through so it concentrates the clamping force on the inner edge of the flange. He just missed getting me a set of the valve cover clamps in time for the BV8 annual auction but they will be there next summer. By then it's possible he'll have the pan piece done if he sees the need. It's something we all could use and I hope we get it. That could already be available as the Buick 350 uses the same pan but the BOPR is different.
Another crucial upgrade is at the oil pump cover. Typically not enough attention is paid to this area and it's just assembled as an afterthought without much of an understanding of how it works. The key consideration is that this unit is a hydraulic pump. As such it is at it's core a precision assembly and should be treated as such. As with all such pumps the gear end gap is crucial and should be held to the absolute minimum necessary running clearance. If that number approaches .005" it is way too much and poor oil pressure will be the inevitable result. As for leaks, careful work here is required and 3 areas need attention. The spacer shims, the cover bolts, and the big nuts/fittings. Once the end gap has been established each surface of each shim and the housing and cover should be properly cleaned and sprayed with a sealant before assembly and promptly assembled and torqued, followed by a rotational check. Absolutely no Vasaline should be allowed to touch the mating surfaces under any condition. The cover bolts should ideally have a flanged head. Copper sealing washers should be used under the cover bolts. The bolt threads and internal threads should be cleaned and degreased and a quality sealant liberally applied to the threads on the bolts that break into or are situated inside the internal cavity, all the bolts can be thus treated, the sealant will act as an anti-seize at disassembly. The big nuts should have a proper sealing washer or o-ring and be tightened suitably. I prefer copper washers, YMMV. If a fitting is used or an adjustment screw, steps should be taken to insure an oil tight seal.
At the rear main cap, I have taken to injecting sealant into the side cavities with a caulking gun and a short stub of plastic tubing, a needle if you will, making sure the sealant comes out the sides at the root where the corners of the cap have been beveled and filling the side groove all the way up. That and a smear of sealant on the parting line over to the main seal seems to do the job. The seal ends should be offset from the parting line and treated with sealant where they mate. The use of sealant in the main seal groove is a good option but don't overdo it. The two piece rubber main seal works if the hash marks have been ground off of the seal journal. This reduces the diameter by around .005".
I don't think that having the main cap sunk .020" below the pan rail is a problem that can't be overcome by the sealant but that's a judgement call. A filler piece could help provided the surfaces are well prepped, otherwise I could see it getting dislodged.
Make sure there is a clean surface for the front main seal to ride on of course, and the same processes applies generally to the front cover of course. Having narrow bands where it contacts the block, extra care is required. Some consider the gasket essential here, some do not. Your choice, both can work.
Finally, the intake. Much here depends on the fit of your intake at the front and rear of the block and the closer that is the better. Rubber seals were used to allow for surfacing of the head later on and you can use those and most do I think. Some have had success with building up a large sealant bead here. I think the only ideal solution requires fabrication and on a production intake the idea would be to add pieces that will constrain the seals to the area they are intended to serve, both inside and outside of the lifter valley. I am not yet aware of an ideal solution but don't feel it would be hard to do. In my case a custom intake removes the issue. On the BOPR you have the lifter valley pan and the neoprene coated Rover part is a good one. The aforementioned spreaders made by Alan Mackin handle the valve covers if you are not using cast aluminum ones, and the last consideration, well two really are oil level and PCV. Do not overfill the pan.
Jim
Yeah, that's the other concern that I have been working on, excessive oil in the intake manifold. When I had the supercharger off, to have the rotor pack rebuilt/coated I noticed a significant amount of oil in the intake manifold.
After seeing this, I ran a bore scope through the spark plug holes and there was a lot of carbon build up on the pistons due to the excessive oil in the intake. Suspecting stuck/carboned up piston rings, I performed a leak down test and found several cylinders at about 20% leakage. This of course only compounds the problem, due to excessive crankcase pressure.
To de-carbon the engine, I like to use GM top end cleaner. My preferred method is to use an oil squirt can with a piece of vacuum hose and fill the cylinder with top end cleaner so that it covers the piston. Then I will let it soak overnight. The next day I will insert a length of 5/32" fuel hose connected to a cordless drill through the spark plug hole. Basically, I'm using the drill to flop the hose around to splash the top end cleaner around. Then let it sit for a couple more hours, after that I'll suck the top end cleaner out with a brake vacuum bleeder. After the fluid is sucked out, then I re-inspect for carbon with the bore scope. This process works best with piston down and the oil pan off. (it allows you to capture the top end cleaner in a drain pan)
The process is slow going and it takes a few days, but the pistons look like new. Once the pan is back on and it has oil in it, I'll crank it over with out the spark plugs installed to clean out any remaining top end cleaner.
After de-carboning the engine, I performed another leak down test and all cylinders are coming in at 2% to 3% leakage, so I'm feeling pretty good about that!
Getting back to how the oil/carbon got there in the first place. It appears to be sucking it in through the PCV. I have a catch can on it, but it doesn't seem to catch much oil.
I suspect what may be going on is that there is too much oil being retained in the windage cloud. A problem that only got worse when the piston rings carboned up.
I'm going try a couple of things to see if I can improve the situation.
Although I did have a horizontal baffle in the oil pan, I decided to make a better one that has more coverage. Also, I raised the baffle up about a 1/4" to make sure that it's slightly above the oil level, when there is 5 quarts of fluid in the pan.
Since I don't have a windage tray, I have a crankshaft scraper coming (should be here today). Supposedly there is a slight horsepower gain by using a scraper. I'm more concerned about controlling the quantity of oil retained in the windage cloud for oil control purposes, than I am about trying to extract every last bit of horsepower.
Once it's back together, I'm interested to see how de-carboning the engine and having better oil control effects the EGT readings. I would think that with better ring seal and less carbon build, that it will equalize the cylinder-to-cylinder readings somewhat. If it does, then most likely I will go in and adjust my injector fuel trim settings for optimal performance.
Sounds like a good plan. What I've learned about the oil level is this. If the oil level is too high, the crank assembly will whip it with the results being about what you would expect. It doesn't take as much as you would think. Disregarding the filter the '65 Buick 300 had a pan capacity of 4 quarts. We tend to run a much smaller filter on our cars than one that will hold a quart so if we put in 5 quarts at oil changes it overfills the pan. Your dipstick may or may not reflect this reality.
Here is my experience. With the stroker which has that 3/16" thick pan spacer and umbrella exhaust valve seals, after putting in 5 quarts of initial break in oil to the clean engine, it smoked, and it didn't quit smoking until after I had done an oil change and then removed almost a quart of oil to get back closer to that 4 quart figure. And then it was perfectly happy. Most of that smoke was coming from the passenger's side so think about how the windage was occurring. My best guess is, too much oil thrown up into the cylinder bores and overcoming the rings but it's hard to say for sure. That oil could then migrate into the intake by reversion so the PCV may not be entirely to blame. In any case it's clear that windage and whipping of the oil will increase the oil sucked out by the PCV regardless of where or how it's plumbed in.
It's perfectly safe to run 4 quarts as long as you aren't losing too much oil pressure in the turns. One quart low in the pan means the engine has 3 quarts of oil available to it, actually a little less when you consider the configuration of the pickup. And that's the point at which we are expected to add oil. Might not be the best practice for a Buick engine but it hasn't resulted in any exceptional number of failures. A public skid pad (Roundabout) is a reasonable place to test. So this is a pretty easy check to make.
One might think, being a stroker that the crank would be closer to the oil and that's right, but not by much. The stroke increases between the 300 and the 340 from 3.4 to 3.8 inches meaning the crank swings .200 further down but then you have to subtract that 3/16" stabilizer plate and that leaves only .012" which isn't enough to make a difference.
Jim
Makes sense, I forgot to add that my pan has been modified to increase the capacity. Basically, the notch for the exhaust cross-over was removed and replaced with a rear section from another pan. It's been a long time since I did it, but I think I used a section out of Ford Y block V8 pan, if I remember correctly.
I remember poking around in the wrecking yard for quite some time, trying to find one that was the correct width to match the 215 pan!
Bill
Well then Bill, you might try running a half quart low and see how it works.
Alan sent me his email link if anyone wants to check with him on his stiffeners:
fullperimeter@gmail.com
He's working on a web site.
Jim
Way back in the day, I put a 7 quart Moroso oil pan on the 350 in my Camaro. I ran 6 quarts in it.
I think that I probably will Jim. When I welded on/replaced the oil pan flange, it moved it down 1/4" effectively making it 1/4" deeper. Which is one of the reasons I moved the new horizontal up 1/4". Since I'm going to have to re-mark the dipstick anyway, I'll adjust the "safe" range accordingly.
I did make a 1/4" thick spacer for the oil pick up tube. When I checked the pick-up to pan clearance, it comes in at 1/4 to 3/8".
On a related topic, my nephew has my dad's 78 MGB V8 conversion (BOPR) that he built before he passed away last year. Jake (my nephew) commented that he had been having oil pressure issues while driving. Since my dad had bought the engine already fully assembled. I suggested that he pull the pan to have a look. Jake sent me some pics and something didn't look correct with the pick-up tube. I had him send me some more pics from a different angle, and you could see that the pick-up was bent upwards about an 1" to 1.250"!
Jake replaced the pick-up tube, and all is good now. He asked me if grandpa ever had any oil pressure concerns and I told him that I didn't recall my dad mentioning it. But then I reminded him that the difference was probably because he drove it like a 86-year-old man, vs Jake who's in his early 40's and tends to drive more aggressively!
Bill
Then of course once you have taken the engine itself as far as you are comfortable doing it we come to fueling and controls. But first, a word about where that line should be drawn.
When you're working within the B series' limitations you tend towards seriously considering any and all possible ways to increase the output of the engine. That gets top billing with durability somewhere further down the line if it's given any thought at all. Upgrade to a larger engine and that all begins to shift, curiously enough. By the time you get to the 300 and it's more powerful variants like we have here the focus changes more to reliability, durability and even economy which is natural enough but not at all obvious going in. The reason is quite simple though and harks back to the old timer's advice when buying a car to get the largest engine available in it, or stated more colorfully, "There is no substitute for cubic inches".
This has much broader meaning than just performance and I'll give two of the most important examples here. First, even though experience and service records might not do much to support the concept the larger engine is understressed compared to it's smaller counterpart and for that reason alone will tend to present it's owner with fewer and less expensive issues during it's life. Even if it doesn't last any longer (it probably will) it won't be pushed to it's limits nearly as often and we all are aware that race engines, a highly tuned and highly stressed example, have short lives. So it's an investment in the long term. The second example, again not immediately obvious is that the larger engine makes the car easier to drive, not harder. This is primarily because of the surplus of torque which makes the driver a lot less likely to reach the edges of the performance envelope where bad things happen. And as has always been the case, alternative power adders as they are called always come with an added cost and complexity, need extra room, and may hurt durability and economy. Yes it's true that a turbo four might get over 30mpg cruising the highway. It's also true that it might get 7mpg or even less in strenuous driving but we never hear about that. Just another hidden cost.
But the bottom line here is that once you have achieved the upper limits of your own personal horsepower goals there is no point in going any further. Then attention shifts more towards durability. Might be nice to take a winter off, yes? So if your selected power plant can meet your goals in an unmodified form from it's factory configuration you can well expect to exceed factory warranty limits as well and sometimes by a spectacularly wide margin depending on the engine's record.
Here the lowly Buick 300 particularly shines brightly, and the cheapest of the cheap, the base engine with a 2bbl carb, iron heads, and 9:1 compression is admirably suited to match the typical MGB owner's loftiest dreams of power. Ask an MGB owner what they'd like and you'll hear numbers like 120 as being ideal. Maybe 150 if it wasn't too expensive and involved. But the dream number? Ah, that is 200. Always has been. With 200 hp the average MGB owner can only imagine what he might do.
And there you have it. Not only does the base Buick 300 put out not 200 but 210 hp in unmodified form, it does it on regular gas and delivers 310 ft/lbs of torque while it's at it. All this in a very understressed package that was renowned for durability long before one was ever installed in an MGB and to top it all off is more than capable of being swapped into the RB car over a weekend. And if you don't think that makes an MGB easy AND fun to drive it's only because you have never tried it. Yes it does add 50 lbs or so to the front of the car (when using the alloy heads and intake, 100 lbs with iron). Practice has proven it's well worth it. And as the least expensive engine option out there this is a proven winner. Also there were roughly the same number of Buick 300 engines built as there were MGBs so finding one is about the same level of difficulty. They are there if you look in the right places.
This makes a very strong argument for drawing that imaginary line right at 200 hp, and that number puts the MGB right in the thick of today's cars out on the highway, a bit towards the upper end but obviously not in today's "performance" brackets. It will do fine, but it isn't going to fare that well against a modern Corvette for example. Still, as the above example illustrates, if that's the goal it is within reach and all the traditional methods are available. Next post will likely get into some of that, starting with engine control options.
Jim