I was looking for a link on more information about Ray Pampena's 3.7L and 4.5L stroker kit. I know he was talking about this last year some time, but what is the status on this? Anybody have a link?
Ray Pampena's 3.7L and 4.5L stroker kit
GTOVR4TT
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This is what I am also waiting for.306GTO said:
I have heard that these motors can put down 1000hp+ with a much better torque curve than stock motors.
That has me salivating.
Yes, yes!!! The DR DBB 1200 is definatly fueling my desire!tonygold said:
Lotsa, lotsa money I know.
But if your not willing to throw down the cash, and lots of it,
then this is probably the wrong platform for you.
Daniel
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This is so super fantastic, I am in heaven.
Good idea with selling the crank. I can source other parts cheaper so the kit kinda cost me more than I'd like when including pistons, and rods.
Good idea with selling the crank. I can source other parts cheaper so the kit kinda cost me more than I'd like when including pistons, and rods.
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Will the 3.7's be available a year or so from now, thats when im doing the motor in the 99 and this would be bad ass, would have to do heads/cams later, but this shorty would make my E3's happy and id bet theyd spool hella quick and still make all the power i could ever use....thats what i say now anyway:muahaha:
Jason
Jason
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Zombie thread
Never saw a good response about rpm limits. I would size turbos to maximum engine capacity.
Looking for reasons to not LS my starlet. 4.x liters at 8500 - 9500 rpms can move the same air as most 6.0Ls.
Custom cranks made with no consideration for sfi dampers? Sfi parts are something that really bothers me when using a non Cookie cutter engine. No proper dampers, even the recent custom group buy is not legit.
I would use a 75 block cause they fit the right way in my fwd and my rwd don't care.
Also, what stroke was planned? 99mm bore 98mm stroke? Guessing 4.5 liters is optimistic cause 4mm overbore is probably too much. Sonic tests do show 74 and 75 are only ~.01 different in wall thickness. I am not scared to partial fill. Not sure if Nelson or the Russians ever did that
Never saw a good response about rpm limits. I would size turbos to maximum engine capacity.
Looking for reasons to not LS my starlet. 4.x liters at 8500 - 9500 rpms can move the same air as most 6.0Ls.
Custom cranks made with no consideration for sfi dampers? Sfi parts are something that really bothers me when using a non Cookie cutter engine. No proper dampers, even the recent custom group buy is not legit.
I would use a 75 block cause they fit the right way in my fwd and my rwd don't care.
Also, what stroke was planned? 99mm bore 98mm stroke? Guessing 4.5 liters is optimistic cause 4mm overbore is probably too much. Sonic tests do show 74 and 75 are only ~.01 different in wall thickness. I am not scared to partial fill. Not sure if Nelson or the Russians ever did that
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RPM limit is due to bearing limitations too. Being that our bearings are prone to suck, I wouldn't get your hopes too high with spinning the crap out of a big stroker motor.
I have the 74/75 combo (3.75L) and spin it to 8000, but don't want to go too much higher. I used a piston speed calculator and did some research to see what I thought would be safe. I should be pretty safe still. IIRC, ray balanced my assembly to like 10,000 RPM.
There's also something to be said for our cams and head flows. I haven't seen cams (not even the new 280's) that will keep power even to 8000...
I have the 74/75 combo (3.75L) and spin it to 8000, but don't want to go too much higher. I used a piston speed calculator and did some research to see what I thought would be safe. I should be pretty safe still. IIRC, ray balanced my assembly to like 10,000 RPM.
There's also something to be said for our cams and head flows. I haven't seen cams (not even the new 280's) that will keep power even to 8000...
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6G72 MIVEC cams have 300 duration and stupid lift, wish there was more data on them.
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Cams, thats because nobody wants a race car. Its really easy when you step up to a camshaft that actually hurts low rpm performance. I have a 12 valve 300 degree cam with pretty aggressive profile that idles....at cruise rpms.
Want to go bigger. Venders also sell camshafts with big ADV #'s that are not very aggressive because in reality people don't want what they think they want. Just because the valve opens doesn't mean its opening quickly. I have never really seen a bearing problem, just an oil supply problem. When Ray was high reving, he had valvetrain issues (plus you can't shift the 3/S manual) and Matt eventually lost a stock used rod bearing after almost hitting 10k rpms through the traps. Probably stretched the cap fasteners and that killed the big end. Then I see a million guys with dented pans, worn pumps, low oil levels killing bearings.
2JZ's with terrible piston speeds stock still run 11k rpms and still love their strokers.
I am more interested in the engineered RPM limits. Sometimes there is something "wrong" up there with the crankshaft that we have to avoid. Also, maybe his rods won't like it, etc. 10k rpms would work great for making power and a good powerglide would eat that up. Ability to make more power or rev high would open up the value of the custom billet crank product. I know a guy running a dry sump oil system 12 valve 6g72 in an endurance car so its not like legit race engine mods don't happen when you go outside the 3/S box.
I still don't know why Nelson kept losing main bearings with his dry sump and 11k+ rpms. Not sure if he fixed that or dropped rpms.
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Necro resurrection for 2021.
New years resolution, make a 4.5?
What happened to the 4.5?
My own calculations show that you can get close to 3.5 out of a 72 block depending on bore but 84 mm stroke is about the max that's when the rods hit the underside of the bores and you've got to start grinding things for clearance. Really the limit is 3.4.
A 74 block can go to about 4.1 litre, 95 by 95 mm gives about 4040. That's easy, use 75 pistons. Stroked 75 crank and rods of the right dimensions .I've got one dummy assembled for now.
A 75 block , might be able to go to 99 by 97 for about 4.5 litres?, 4480 cc, for the absolute max, filling the bottom of the block to support the cylinder walls. That's using readily available off the shelf parts that have been modified rather than custom built one off parts.
Mitsubishi actually built Dakar 4 litre V6s, they would have been 97 by 95. The 75 walls seem to measure a bit thicker that the 74 walls so a 75 block at 99 mm should be no weaker than a 74 block at 95 mm.
Bore and stroke?
A 3.7 is easy, it's just a 75 crank in a 74 block, no way it's ever going to happen in a 72.
New years resolution, make a 4.5?
What happened to the 4.5?
My own calculations show that you can get close to 3.5 out of a 72 block depending on bore but 84 mm stroke is about the max that's when the rods hit the underside of the bores and you've got to start grinding things for clearance. Really the limit is 3.4.
A 74 block can go to about 4.1 litre, 95 by 95 mm gives about 4040. That's easy, use 75 pistons. Stroked 75 crank and rods of the right dimensions .I've got one dummy assembled for now.
A 75 block , might be able to go to 99 by 97 for about 4.5 litres?, 4480 cc, for the absolute max, filling the bottom of the block to support the cylinder walls. That's using readily available off the shelf parts that have been modified rather than custom built one off parts.
Mitsubishi actually built Dakar 4 litre V6s, they would have been 97 by 95. The 75 walls seem to measure a bit thicker that the 74 walls so a 75 block at 99 mm should be no weaker than a 74 block at 95 mm.
How?
Bore and stroke?
A 3.7 is easy, it's just a 75 crank in a 74 block, no way it's ever going to happen in a 72.
I have to ask how much experience you have with over stroking engines and more specifically with the 72 and 74 blocks. I ask because of some comments you've made here and other threads concerning engine stoking, which makes me wonder if you understand all points correctly or just not stated in way that I was able to interrupt clearly. I’ve never tried to stroke one of these engines, but have stroked many American made V8’s, which makes me wonder if those engine are enough different than these.
You mentioned above about grinding on block for clearance and needing to fill in water jacket area because of that. I’ve installed 1/2 in. and 5/8 in. over stroked cranks in V8 engines, which required grinding notched areas in both sides of cylinder bottom to clear rod bolt/bossed sides. In the case of longer stokes that was a lot of material removed, but with the amount of material extending below water jacket area to bottom of cylinder bore, the water jacket or block strength was never compromised even without partially filling block area. Do you know from experience this is not same case with the 72 or 74 blocks in these cars?
Somewhere else you questioned shouldn’t rod length be the same, I wasn’t sure if you meant rods used should all be same or if you meant rod lengths should be the same between stock and stroked cranks. Also you mentioned pistons contacting crank counter weights, which most familiar with stroking understands how this is handled. In both cases it might have been just me not correctly following your comments, since that might not be the case I’ll explain below how these are normally handled.
With stock piston/rod combination and a stroked crank, the pistons will be pushed out top of cylinder block the same amount of the over stroke. To correct, a piston/rod combination must be used to accommodate the over stroke. In most cases a shorter rod and piston with altered wrist pin location brings piston top back down for proper deck height. In cases of the longer stokes I’ve even had pistons where the wrist pin hole had to be raised high enough, that it actually opened a small section at bottom of oil ring gland groove on each side of piston. The pistons also had shortened bottom skirts to clear the crank counter weights when at bottom of stroke, some also had radius sections removed on each side of the shortened skirts to clear counter weights on the longer over strokes. Do you know from experience that these piston/rod combinations for over strokes, does not exist for the 72 or 74 blocked engines?
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The cut down 6G74 crank shaft fits fairly easily in a 72 block. I've been using one for about 7 years. Ray cut and balanced the crank. I am using stock length BC rods and Ross pistons with an altered wrist pin location. The main girdle requires some grinding to clearance the rods, but that is it. It is 85.8mm stroke.
At some point I will be changing to the BC billet crank, which is 84mm stroke and will require either different pistons (most typical) or longer rods to make up for the 1.8mm stroke I lose.
Longer stroke custom cranks have been produced by Ray and used, most notable in Dynamic Racing's 8 second race car, which displaced 3.54 liters with a 72 block and 91.5mm pistons, barely larger than stock. IIRC 3.7 would've been the displacement with 93mm bore.
There have been some 4.0 liter 6G74 based engines built with Ray's Sonny Bryant cranks, but I have no seen any results of their builds.
A 6G75 crank wouldn't be a good idea in a 72 block because by the time the main journals were ground down to 72 size there would be no rod/main journal overlap and it would be too weak.
At some point I will be changing to the BC billet crank, which is 84mm stroke and will require either different pistons (most typical) or longer rods to make up for the 1.8mm stroke I lose.
Longer stroke custom cranks have been produced by Ray and used, most notable in Dynamic Racing's 8 second race car, which displaced 3.54 liters with a 72 block and 91.5mm pistons, barely larger than stock. IIRC 3.7 would've been the displacement with 93mm bore.
There have been some 4.0 liter 6G74 based engines built with Ray's Sonny Bryant cranks, but I have no seen any results of their builds.
A 6G75 crank wouldn't be a good idea in a 72 block because by the time the main journals were ground down to 72 size there would be no rod/main journal overlap and it would be too weak.
Good info, but how much block material is left at bottom of cylinder bore. Any chance there’s enough that it can be ground away enough to clear the rod main journal without grinding on journal itself?
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The 74/75 main bearings are larger in diameter, so the crank has to have the journals ground to 72 size. You can not reasonably line bore the block enough to fit the 74 bearings.
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The max stroke you can put into a 72 block is 84 mm.
That's why the billet cranks are 84 mm.
The pistons to go with the 84 mm billet are the same ones for the cut down 74 crank.
As it is with 84 mm there's grinding to do. The side of the no 1 conrod hits the bottom of the no 2 bore. The side of the no 2 conrod hits the bottom of no 1 bore, same goes for 3,4 and 5,6.
Not only that but the counterweights have to be cut down to fit the block, the rod bolts hit the sides of the girdle so the girdle needs grinding too.
For the effort involved to go from 3.0 to 3.4, that's only 12.5%, not really worth it if you could go to 4 litres or more for about the same effort.
There's a lot more work required to make a 74 crank fit a 72 block compared to just stroking a 74 or 75 crank by an extra 5 mm or 7 mm.
That's why the billet cranks are 84 mm.
The pistons to go with the 84 mm billet are the same ones for the cut down 74 crank.
As it is with 84 mm there's grinding to do. The side of the no 1 conrod hits the bottom of the no 2 bore. The side of the no 2 conrod hits the bottom of no 1 bore, same goes for 3,4 and 5,6.
Not only that but the counterweights have to be cut down to fit the block, the rod bolts hit the sides of the girdle so the girdle needs grinding too.
Did you measure your stroke?
For the effort involved to go from 3.0 to 3.4, that's only 12.5%, not really worth it if you could go to 4 litres or more for about the same effort.
There's a lot more work required to make a 74 crank fit a 72 block compared to just stroking a 74 or 75 crank by an extra 5 mm or 7 mm.
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Its a stock 74 stroke, 85.8mm. People have run a little more. The extra displacement makes a huge difference in response.
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Really not that much grinding once the crank work is done:
![292144]( "292144")
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(389) My Stroker motor info | Mitsubishi 3000GT & Dodge Stealth Forum (3si.org)
3.5" stroke or 88.9mm
3.5" stroke or 88.9mm
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OK so the 72 stroker that's at 3.7 is 94 mm bore by 88.9 mm stroke, That seems to work out about right.
A 94 mm bore in a 72 block is 2.9 mm oversize.
I've got some measurements somewhere of wall thickness but was a bit concerned about going from 93 to 95 in a 74 block, must be OK then?
88,9 mm stroke, that's 4.9 mm over and above the 84 mm stroke that needs a fair bit of grinding.
That means that whatever grinding you do for 84 mm stroke, you need to do the same but go 2.5 mm deeper in the same places and maybe more grinding in other places as well.
Probably only 2 of them ever made?
A 94 mm bore in a 72 block is 2.9 mm oversize.
I've got some measurements somewhere of wall thickness but was a bit concerned about going from 93 to 95 in a 74 block, must be OK then?
88,9 mm stroke, that's 4.9 mm over and above the 84 mm stroke that needs a fair bit of grinding.
That means that whatever grinding you do for 84 mm stroke, you need to do the same but go 2.5 mm deeper in the same places and maybe more grinding in other places as well.
Probably only 2 of them ever made?
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Maybe that's the other difference using standard rods compared to Pauter rods.
Mine is 84 mm and had to grind under all the bores to make the conrods fit.
Then I swapped over to Pauter rods to find that they're shorter and had pistons hitting the counterweights .It lowers the compression a couple of points too.
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