Engine Swap 1.A, first question

Padrino · 03-20-2004, 01:42 PM

I have a 1970 P-Car with webers and with a 901 tranny. I need to do an engine swap. Not wanting to go through great exspense with a swap to a 915 tranny also, what engines would be the best for me to look at?? Finding another 2.2 seems more than difficult so I imagine going upward to maybe a 3.0?? Would that work with my 901 tranny?? Would I be wasting my time with a 2.7 swap? What troubles would I run into?? Ken

chuckw951 · 03-20-2004, 04:29 PM

Quote:

Originally posted by Padrino
I have a 1970 P-Car with webers and with a 901 tranny. I need to do an engine swap. Not wanting to go through great exspense with a swap to a 915 tranny also, what engines would be the best for me to look at?? Finding another 2.2 seems more than difficult so I imagine going upward to maybe a 3.0?? Would that work with my 901 tranny?? Would I be wasting my time with a 2.7 swap? What troubles would I run into?? Ken

A 2.7 or 3.0 will bolt right up to a 70/71 transmission. Both motors will have more torque so go easy on first gear. This is what I did with my car. The 2.7 is a fine motor if the right updates are made to it. In my view the easiest swap would be to get a 2.7 or 3.0 and install the webers from your 2.2 on the bigger motor (you'll need to rejet them and perhaps different manifolds, I'm not sure). You will have to address ignition system issues as your car probably has a 3pin rather than a 6pin CD ignition box. If you get a 78/79SC motor the distributor will work with carbs as is, otherwise with a 80-83 motor you'll need to recurve the distributor. Not sure about the distributor on a 2.7 motor perhaps that works without modifications. If you want to use the 2.7 or 3.0 motor with the CIS things are a bit more complicated but doable. The fuel lines would need to be adapted (and perhaps run a return line to the tank, you might need a different tank too) and you would need a different fuel pump. Your car has the 14 pin engine harness connector so that will simplify the wiring to some extent, but you will need wiring diagrams for the early car and later motor. Oh, and then there is the alternator. Early motors had external voltage regulators and the 80+ SC motors had internal regulators. The oil lines will need to be adapter or you could choose to mount an early engine oil cooler on the 3.0 motor (not sure about 2.7 motor engine oil coolers). In terms of exhaust you could bolt on the 2.2 exhaust to make a bit more power on the 2.7 or 3.0. You can also use the engine tin and heat system parts from the 2.2.

RallyJon is working on a similar swap...check out the summary of issues at the end of this thread.
3.0 into '71--coupla little questions

This might be more trouble than just dropping in a motor and going, but you would have more power. 2.2 motors pop up for sale occassionally...if you get a one with a good history that would be easiest. Or you could rebuild what you have. What is your budget? If your car is a 911S with the original S motor then I'd recommend rebuilding the S engine.

onewhippedpuppy · 03-20-2004, 04:35 PM

If you re-use your Webers, you can use hotter cams with a 2.7/ 3.0 and get more power out of them than with CIS, you'll have to re-jet, etc. like Chuck said. For the price of rebuilding your 2.2 you could probably easily get a fresh 2.7, the stigma associated with the motors makes them a bargain, but if properly rebuilt they can be a great motor. Either way, the more powerful motor with the shorter gearing of a 901 will be a rocket, fun stuff!

Padrino · 03-20-2004, 04:47 PM

Great info guys!! The exisiting motor was rebuilt to "S" spec's back in 1991. I spoke to the mech who did the work and he remembers the cams were S but also remembers he might have done the pistons/cyl. It's been a rocket ship until the recent problem which makes we want to replace it. I'll most likely start to look hard at Chuck's recommendation and find a 78-79 3.0. I'll also keep my webers as I love that sound when you put the foot on it. The 2.7's seem to be the best price right now however.

Will appreciate more info......

SteveF_911 · SteveF_911's Garage

The 2.2 S is one of the sweetest little engines, the short 66mm stroke lets them just rev and rev.

My 2.0 S keeps up with most 3.0 SC's on the track. If it was me and the rest of the car was in good original condition I would rebuild the S engine.

Padrino · 03-21-2004, 01:19 PM

I'm kicking around another alternative. I've located a 2.4 block and crank which has been rebuilt (w/case savers!). I'm thinking of transfering the externals (pistons, cyls, heads, cams, etc) to this unit. That would give me a 2.4S with the 2.2 higher compression pistons. Unfortunately, I loose the short stroke crank of the 2.2.

Also, I've located an aluminum flywheel/pressure plate which should really allow it to rev.

rich22 · 03-21-2004, 01:54 PM

If it has a non-counterweighted "T" crank and an "S" top-end that generates "S" power, you could be asking for longterm problems.

Padrino · 03-21-2004, 05:56 PM

it is a non-conterweighted crank. As a S conversion it already has about 100k miles on it and it isn't the reason I'm swapping engines, that problem is with the intermediate shaft.

I've heard from a number of people that this T crank is actually better due to it being lighter. I would suspect there is a reason Porsche used a counterweighted crank with the S's and non with the T's. But right now I'm getting about 75% response saying the T crank is the better way to go.

HELP!!!

onewhippedpuppy · 03-21-2004, 06:43 PM

If I'm remembering Frere's 911 Story correctly, the T crank was non counterweighted as a cost cutting measure, as the T didn't need it due to it's lower revs. I think they also had different cylinders (cast iron?), and something else, if I wasn't lazy I'd look it up, but I'm sure someone more certain will chime in.

Zuff911 · Zuff911's Garage

I beleive Porsche counter weighted the S crank because of the higher RPM limit on this engine. The T could make do without the counter balance because at lower RPM the non-balanced forces are smaller. I would not use a T crank if you plan on reving the engine hard to redline a lot. The small gain in acceleration from less rotating mass is not worth the risk. The 2.2 is an excellent motor and fits the personality of early 911s so well. Less power but more character. I would rebuild the engine, but that is my opinion. Either way the car should be fun.

-brad

Padrino · 03-21-2004, 07:28 PM

everything on the engine has been swapped to S spec's except the crank and she's running webers. All p/c's are S as are cams, distrib, etc.

I've found a lonnnnnnng running thread elsewhere here on Pelican on the topic of the 2.2 vs 2.4 cranks. The 2.2 T's were a cast crank, non counterweighted. The 2.4's with a longer stroke were forged and only the S's were couterweighted.

I have no intent of ever taking this thing to a redline....again. No need to risk it all when there's enough kick without going that far.

Only question remains, will it be noticable in how quick it revs to stay with the 2.2? The aluminum flywheel is still at question.

Raymond · 03-21-2004, 07:36 PM

chuck, that was a great post. good job.

Raymond · 03-21-2004, 07:50 PM

not to confuse the issue, but the 2.2T non-counterweighted crank isn't cast, it's forged. there has been some debate to this issue, but there were some scans from technical porsche books that indicated it was forged steel.

i have a 2.2T with some internal mods like yours, and that thing revs SO quick, it's amazing. i must have airport gears, because i get about 1 second before i shift into second... i get another 2 seconds before third and such.

it revs so fast, it's very difficult to accelerate seamlessly. i have the dogleg 5-speed 901 and a short shift kit.

all that said, i'm also thinking of pulling my engine, dropping in a hotrod 3.0 and rebuilding my 2.2 at my convenience.

i don't want to alter or cut too much. i don't really want to do anything that i can't put right back to original stock condition. no way i'd ever take a torch to the body to put on something that wasn't put on by the factory. the engine's one thing, but the stock body is of paramount importance to me. when i read of guys cutting their cars apart to make them RSR clones, it makes me happy. our original cars are becoming more valuable each day. keep cuttin 'em fellas!

Padrino · 03-22-2004, 07:30 AM

Nice longnose Raymond!

Long hours researching lastnight, new demand I have the car on the road without the down time of a rebuild. I'm now going back to plan "A", pull the 2.2 and drop in a temporary substitute (2.7 maybe) and rebuild the 2.2 on my own time also.

I do love the rev's I get from the thing and want to keep the originality of numbers, etc.

end of story!