Powerplant transplant(s) - 3.8 for a 3.2

[tdw28210]

It's been awhile since I've done any heavy wrenching but I found something that has me motivated. I sort of fell into a nice running 964 motor beefed up to a 3.8 complete with cam and PMO 50's in a 1970 911 tub. It runs really nice, sounds great and comes with a freshly rebuilt/reinforced 915 transmission. I really love the old school look of it and the 285 HP's should be cool too.

Here's what I want to do.

I am going to pull the 3.8 and the beefed up 915 and swap them into my Mexico Blue car that currently has a stock-ish '85 3.2 and 915. I've only ever dropped 3.2 motors and never a 3.6 or a carbed 3.8 motor and I certainly haven't swapped one into another car.

I've done some reading but still have some questions (below) and I certainly don't know what I don't know:

1) Should I pull EVERYTHING out of the 3.8 car, including fuel lines and fuel pump and swap them? Or will the existing fuel lines and pump supporting the current 3.2 suffice for the 3.8?

2) What about the wiring harness? Does that need to be pulled out of the 3.8 car (hope not) or can I use the existing one I am using with the 3.2? And then vice versa (3.8 harness work with the 3.2)? I feel like getting the harness form the carbed 3.8 to work with the stock 3.2 may be a challenge. Yes/no?

3) I feel like I've read that the 3.6 (3.8) motors ride lower in g-body cars (mine is a backdated '77) than the 3.2 so the exhaust can look oddly exposed. Yes/no/depends? I plan on sticking with the existing headers and 2 in/2 out exhaust. If yes (it hangs low), then what's the fix?

4) ECU - I am guessing I want to pull that from the 3.8 car too.

5) I've got Boxster front brakes with turbo master cylinder (23.8mm) and Carrera rear calipers on the Mexico Blue car now but no brake booster. The car stops fine now, it just need a little more leg effort but it looks super clean up front. Do I add the brake booster back or not necessary?

I am 100% sure I am missing at least a 1/2 dozen other things, but as I said, I don't know what I don't know.

Fire away with your responses and thoughts. Thanks in advance.

[tdw28210]

the 3.8 in question...

And to anyone who might read this, what is the best source for individual screens to go on top of those ITB's? I don't like the look of the rain hats and won't likely be driving in the rain ...ever. Thanks.

[Bill Verburg]

Originally Posted by tdw28210

It's been awhile since I've done any heavy wrenching but I found something that has me motivated. I sort of fell into a nice running 964 motor beefed up to a 3.8 complete with cam and PMO 50's in a 1970 911 tub. It runs really nice, sounds great and comes with a freshly rebuilt/reinforced 915 transmission. I really love the old school look of it and the 285 HP's should be cool too.

Here's what I want to do.

I am going to pull the 3.8 and the beefed up 915 and swap them into my Mexico Blue car that currently has a stock-ish '85 3.2 and 915. I've only ever dropped 3.2 motors and never a 3.6 or a carbed 3.8 motor and I certainly haven't swapped one into another car.

I've done some reading but still have some questions (below) and I certainly don't know what I don't know:

1) Should I pull EVERYTHING out of the 3.8 car, including fuel lines and fuel pump and swap them? Or will the existing fuel lines and pump supporting the current 3.2 suffice for the 3.8?
not sure what chassis you are putting it in , I see 3.2 references and assuming it's a 3.2, w/ stock 3.2 fuel pump & associated plumbing you should be fine w/ that, actually cis 3.0 up is good

2) What about the wiring harness? Does that need to be pulled out of the 3.8 car (hope not) or can I use the existing one I am using with the 3.2? And then vice versa (3.8 harness work with the 3.2)? I feel like getting the harness form the carbed 3.8 to work with the stock 3.2 may be a challenge. Yes/no?
again wiring depends on what's in the new chassis, w/ PMO the only real issues are fuel pump relay and ignition, What's in the old car should be used in the new

3) I feel like I've read that the 3.6 (3.8) motors ride lower in g-body cars (mine is a backdated '77) than the 3.2 so the exhaust can look oddly exposed. Yes/no/depends? I plan on sticking with the existing headers and 2 in/2 out exhaust. If yes (it hangs low), then what's the fix?
There are several ways to mount the engine, w/ 964 and 993vram the Intake is quite tall and so the rear of the engine is usually spaced down by ~1.25", This is the primary cause of the droopy drawer exhaust look, w/ PMO spacers won't be needed due to that problem, but another reason for spacers is the 964/993 tin. I've been investigating this for my 993 in 1976 and the solution appears to be.
3.2 engine mount console instead of the 9964/993 version
3.0 or 3.2 cross bar which needs to be bent
custom f/g tin replacements, Roger Sheridan has some nice appropriate pieces.
smaller crank pulley, I use a 993RS one that would work but that won't work on a 964 crank, so some smaller single sheave crank pulley, will be needed.

I'm still not 100% sure that is the final solution, I'm waiting patiently for installed pics
of this setup


4) ECU - I am guessing I want to pull that from the 3.8 car too.

not sure what ECU is used but whatever is in the old car needs to go to the new, there has to be some ignition controller and timing control, but I haven't a clue what's in there now, stock ECU and harnesses a sensors control fuel and spark, but w/ PMO you only have some sort of spark control


5) I've got Boxster front brakes with turbo master cylinder (23.8mm) and Carrera rear calipers on the Mexico Blue car now but no brake booster. The car stops fine now, it just need a little more leg effort but it looks super clean up front. Do I add the brake booster back or not necessary?

That depends on you, the slave/master ratio you have now is 32.91 right where I'd want it to be w/ non boosted brakes, it does take some leg but shouldn't be that bad. Non boosted down in the high 20s is where I'd look into boost, but the you whipper snappers likely would still be ok w/ that.

I am 100% sure I am missing at least a 1/2 dozen other things, but as I said, I don't know what I don't know.

Fire away with your responses and thoughts. Thanks in advance.

****

[winders]

Screens? Do you want the motor to look good or do you want it to live a long life? Screens will let large enough particles through to hurt the motor. You want to put some actual air filters on top of those ITBs...I'd look at ITG.

[PeteKz]

Foot stomp on what Scott said. Don't drive it without air filters.

[RobFrost]

Is the 1970 a T?

Sent from my SM-G988B using Tapatalk

[LJ851]

That looks like a carbureted engine with a mechanical distributor that doesn’t have an ECU at all.

[tdw28210]

Originally Posted by Bill Verburg

****

Thanks Bill. Super helpful. Especially appreciate the details on the brakes.

Originally Posted by RobFrost

Is the 1970 a T?
Sent from my SM-G988B using Tapatalk

I'll need to check the serial again. I'm not near the car though. Traveled to a graduation for a family member.

Originally Posted by LJ851

That looks like a carbureted engine with a mechanical distributor that doesn’t have an ECU at all.

Yeah, I've come to same conclusion. A lot of little fiddly screws and knobs on those things.

And I hear you all on the screens. I just took off the rain hats and K&N's and ran it for all of about 60 seconds. No actual road time.