-
Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.
If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.
Enjoy.
3.5 stroker Cologne?
- Thread starter socorob
- Start date
MikeH
Diamond Level Sponsor
I don't guess that the Chrysler pistons would work with the 2.9 crank.
How did you come up with the stroke value?
MikeH
Diamond Level Sponsor
I've read that with just the 2.9 crank conversion that the piston skirts need to be trimmed.
MikeH
Diamond Level Sponsor
Answer please.
I don't guess that the Chrysler pistons would work with the 2.9 crank.
How did you come up with the stroke value?
Answers
Hi Mike!
Sorry I couldn't respond sooner. Long day at work, followed by a late night washing machine repair.
According to my sources, the stroke of a 4.0L is 3.32". That's 1.66" up and 1.66" down. When calculating compression height, you use half of the stroke, or
3.32 / 2 = 1.66
plus the rod length, subtracted from the nominal deck height. In my limited experience, deck heights are usually higher than advertised. This was true on a 400ci Chevy and a 292 Ford.
So, we're talking about a 1.66 vs 1.35 half-stroke. Less than one third of an inch increase. .31" that has to be clearanced from pan rails, piston skirts, etc. Sounds reasonable. If I can arrange for a truck, I'll go get the 2.8L and 4.0 Ranger engines this weekend. (I already have my Mustang II engine.)
Jim, I'm willing to at least try to fit that 4.0 crank in there. The payoff is just too big not to try. 25% bigger engine means 25% more torque. That's huge. And if a fella has to resort to custom rods to make it work, well, that's an opportunity to stroke it even bigger using 2.0" rod journals to get another .125" of stroke; another 8 cubic inches, or 130 cc's. 3.6 liters total.
It's been done before, and maybe it's not so bad. But all this is a lower priority than getting my Sunbeam on the road this year. I pick up a transmission tomorrow.
Hi Mike!
Sorry I couldn't respond sooner. Long day at work, followed by a late night washing machine repair.
According to my sources, the stroke of a 4.0L is 3.32". That's 1.66" up and 1.66" down. When calculating compression height, you use half of the stroke, or
3.32 / 2 = 1.66
plus the rod length, subtracted from the nominal deck height. In my limited experience, deck heights are usually higher than advertised. This was true on a 400ci Chevy and a 292 Ford.
So, we're talking about a 1.66 vs 1.35 half-stroke. Less than one third of an inch increase. .31" that has to be clearanced from pan rails, piston skirts, etc. Sounds reasonable. If I can arrange for a truck, I'll go get the 2.8L and 4.0 Ranger engines this weekend. (I already have my Mustang II engine.)
Jim, I'm willing to at least try to fit that 4.0 crank in there. The payoff is just too big not to try. 25% bigger engine means 25% more torque. That's huge. And if a fella has to resort to custom rods to make it work, well, that's an opportunity to stroke it even bigger using 2.0" rod journals to get another .125" of stroke; another 8 cubic inches, or 130 cc's. 3.6 liters total.
It's been done before, and maybe it's not so bad. But all this is a lower priority than getting my Sunbeam on the road this year. I pick up a transmission tomorrow.
socorob
Donation Time
If you do it, please document and take pictures if you can. With the alpines weight I always thought it needed around 250hp. That would at least put it in the ballpark. The junkyards here are full of 4.0 explorers so the crank should be cheap to get. I also thought that the 3.7 dodge was their 4.7 V8 with 2 cylinders cut off? Maybe that would Be another option for pistons?
MikeH
Diamond Level Sponsor
Thanks, I'd gone though this before with info I found on the web, but didn't remember how to do it. So then the rod length+stroke+compresion height is compared to the deck height? As I recall I calculated my piston to deck height with pistons having a 1.511 compression height, a 2.9 crank, and 2.8 rods at 0.0155. Does that sound right?
Also, you would need to mod the snout of the 4.0 crank to accept the 2.8 timing gears instead of using a timing chain which would reverse the roation of the cam. I had to do this to my 2.9 crank.
Also, you would need to mod the snout of the 4.0 crank to accept the 2.8 timing gears instead of using a timing chain which would reverse the roation of the cam. I had to do this to my 2.9 crank.
Mike, I think you have the idea; 1/2 stroke, plus rod length, plus compression height minus deck height gives you how far down the hole, at least in theory. Compression heights and deck heights can vary from design and even vary by design. I think it was common practice for piston manufacturers to have a less-than-design compression to avoid trouble when decks are milled.
Yes, the snout would have to be milled to 2.8 specs. Good catch.
Rob, I would happily document the whole process if/when it happens. Yes, the 3.7 is a 4.7 less two cylinders.
Yes, the snout would have to be milled to 2.8 specs. Good catch.
Rob, I would happily document the whole process if/when it happens. Yes, the 3.7 is a 4.7 less two cylinders.
Questing for Mike H.
Hey, Mike. Quick question for you; your 2.8 has a 2.9 crank in it.
I wasn't planning to do that, but yesterday I bought a 2.9 crank, rods and pistons for $75. The pistons look very good, so I think I can actually save money by fitting that up to my 2.8, assuming that my 2.8 needs pistons. The money I save on pistons will pay for the machining needed to fit the 2.9 crank.
So here's the question; is turning the snout of the crank all that you had to do to fit that up to the 2.8? I'll start tearing the 2.8 down as soon as I finish this post.
Oh, and that T5 I thought I was going to get? It was an M5R2 Mazda transmission. What is the problem with using that kind of transmission in our Sunbeams? I think there is a M5R1 that has a bellhousing that fits the 2.8, and I know that Ford put the M5R2 behind the Thunderbird Super Coupe (supercharged 3.8 V6 making more than 200 hp.) So it must be suitable for passenger cars as well as trucks.
Jim, you bet that if I get to that stroker 3.5 project I'll write it up for the British V8 web site.
Paul
Hey, Mike. Quick question for you; your 2.8 has a 2.9 crank in it.
I wasn't planning to do that, but yesterday I bought a 2.9 crank, rods and pistons for $75. The pistons look very good, so I think I can actually save money by fitting that up to my 2.8, assuming that my 2.8 needs pistons. The money I save on pistons will pay for the machining needed to fit the 2.9 crank.
So here's the question; is turning the snout of the crank all that you had to do to fit that up to the 2.8? I'll start tearing the 2.8 down as soon as I finish this post.
Oh, and that T5 I thought I was going to get? It was an M5R2 Mazda transmission. What is the problem with using that kind of transmission in our Sunbeams? I think there is a M5R1 that has a bellhousing that fits the 2.8, and I know that Ford put the M5R2 behind the Thunderbird Super Coupe (supercharged 3.8 V6 making more than 200 hp.) So it must be suitable for passenger cars as well as trucks.
Jim, you bet that if I get to that stroker 3.5 project I'll write it up for the British V8 web site.
Paul
Hi Paul,
The Thunderbird Turbo Coupe used a version of the T5 that was used behind the four cylinser cars. I don´t know of any other transmission used in the Turbo Coupe. The only other transmission who´s bellhousing bolts up to the 2.8 V6, is one from a Ranger pick up. That one is a Japanese mad transmission, which I don´t recommend for this conversion.
Jose
The Thunderbird Turbo Coupe used a version of the T5 that was used behind the four cylinser cars. I don´t know of any other transmission used in the Turbo Coupe. The only other transmission who´s bellhousing bolts up to the 2.8 V6, is one from a Ranger pick up. That one is a Japanese mad transmission, which I don´t recommend for this conversion.
Jose
The M5R2 was used in full sized pickups behind the 300 inch six and 302. Also was used in the Super Coupe. Unfortunately, all applications used the V8 pattern and I think an integral bell housing. Pretty much screws the pooch.The truck application has the shifter sprouting out of the gear box, while the Super Coupe application had the shifter coming out of the tail housing. If this tranny is from a Super Coupe, let me know. There are guys on another Forum that would be interested, even if its a junker.
There are two versions of the R1 that will bolt to the 2.8, they have differing ratios. But they bring their own problems to a swap. The shifter is too far forward and the mount location will not work with Jose's mount. In addition, Jose goes ballistic when they are discussed. Sort of like "He who shall not be mentioned" in Harry Potter.
Almost forgot, there are a couple of '80's era 5 speeds for the 2.8 that are pretty much bad news, especially for this application. Noisy, poor ratio selection and notably weak. Do not even consider them. Too bad, the shifter location is perfect and the size workable. However, I have read their removable bell housing can be adapted to use a T5.
Bill
Bill, thank you for the detailed explanation. I just didn't understand why a transmission that was used in a supercharged Thunderbird wouldn't be a suitable choice for another car.
Yes, I believe the M5R2 was from a Super Coupe. I think it's in good repair. The fully dressed supercharged 3.8 is sitting about 10 feet from the transmission. I even verified that it's a real 3.8 SC block - it has the SC cast into the front of the engine.
Curious, why is there interest in that particular transmission? Is it the shifter set-up?
Yes, I believe the M5R2 was from a Super Coupe. I think it's in good repair. The fully dressed supercharged 3.8 is sitting about 10 feet from the transmission. I even verified that it's a real 3.8 SC block - it has the SC cast into the front of the engine.
Curious, why is there interest in that particular transmission? Is it the shifter set-up?
Yes to the shifter. Guys building Locosts (home made Lotus Sevens) are very interested in the Duratec engine, but a bell to use the T5 costs $500 and the M5 shifter location is a problem. There are a couple of guys that are interested in the concept of grafting the R2 linkage to the R1. Currently, no one knows if it can be done. If you are not interested in this tranny, could you give me the particulars that would allow them to track down this puppy? If you do not wish to do it here, send me a PM.
Bill
MikeH
Diamond Level Sponsor
I don't have my engine together yet. As far as I've I know, from what I've found on-line, the snout is all that needs to be modified on the crank. I don't know what you would gain by using the 2.9 pistons though as they are dished on top. I read that the pistons for the 1974 2.8 had a higher pin placement than the later ones and might provide enough deck clearance. I also read that the piston skirts would need to be trimmed for clearance. The dimensions for the snout machining were found here:
http://pwp.att.net/p/s/community.dll?ep=87&subpageid=117777&ck=
socorob
Donation Time
http://www.cologneengines.com/3.5 litre v6 cologne power chart.htm
It looks like you can get 50 or so hp over a standard built up 2.8.
It looks like you can get 50 or so hp over a standard built up 2.8.