1982 SC 3.0 Engine Refresh - Performance Bump Question

mercury26 · mercury26's Garage

I am getting prepared to have my engine removed and then torn down. The plan is to have the head studs replaced, since I have one broken stud (maybe more). The mechanic working on the car is going to check the condition of the valve/cylinder heads, cam shaft, pistons/rings/cylinders, rod bearings, timing chain, etc.

If I need to replace cams and/or pistons/cylinders, then I am considering the following. My question is whether this will work with the stock CIS setup.

Cam Replacement: 964 Cams
Piston/Cylinder Replacement: Mahle Euro 3.0 Cams (1980-1983) (95mm, 9.8:1 comp)

I did some searching on the forum, but did not see any info on Euro C/P with the US engine. I am looking for a street car with a minor performance boost. I prefer mid-range power, since the car won't be used at the track.

Thanks,

Chuck

FrankyV · 08-02-2011, 08:21 AM

My underdstandnig after going through a 3.0 Euro conversion is that everything that affects the fuel/air flow has to be changed to take advanatge of the higher 9.8:1 compression ratio: fuel distributor and lines, intake manifold and air box, warm up regulator.

As for the 964 cams, I understand you should be able to used those with no other mods for a nice performance bump.

Flat6pac · 08-02-2011, 01:07 PM

You already have 9.3 with the USA car and the injection is limited by the lambda and smaller injection. You need to get a 78/79 injection system and a fuel distributor for the euro 82/83 9.8 system and the warm up regulator to control the fuel pressure.
You gleen a couple horses but at what price. Do a valve job, install the engine and sell it out of the car and get a 3.2, then you have some performance.
Bruce

mercury26 · mercury26's Garage

Quote:

Originally Posted by Flat6pac

You already have 9.3 with the USA car and the injection is limited by the lambda and smaller injection. You need to get a 78/79 injection system and a fuel distributor for the euro 82/83 9.8 system and the warm up regulator to control the fuel pressure.
You gleen a couple horses but at what price. Do a valve job, install the engine and sell it out of the car and get a 3.2, then you have some performance.
Bruce

I am happy with the motor (beside the leaks and broken stud). Since the Mahle P/C kit costs are the same for Euro and US pistons, if I had to buy new P/Cs was wondering if I can get a bump at the same cost.

Sounds like cams (if needed) might be the easiest power bump, or moving the power to a different part of RPM range.

Thanks,

Chuck

trond · trond's Garage

it's my understanding after merely reading various postings (no hard dyno evidence or bench flow plots), that to benefit from 964 cams the narrow 2R runners/and small head ports should be replaced with the larger 78/79 4R runners/heads/airbox.

With the 964 cams the power band is shifted towards higher rpm range slightly, about 1000 rpm. That means you sacrifice some torque at the lower end of the rpm range (where most road cars spend most of the time) but with small port heads/narrow runners you won't gain enough at the higher end to justify it.

Higher compression on the other hand will help across the rpm range and retain the engines tractor like character.

fred cook · fred cook's Garage

If you are going to buy pistons and cylinders anyway, why not go with the 98mm P&Cs and build a 3.2SS engine. Cost would be the same. You could use the 9.5:1 pistons, have your heads redone, add in the 964 cams and have a nice engine. You will still be limited by the small ports and intake runners, but should still have a bit more power for the $$$ spent. If you are not in an area that has emission inspections, add the SSI exhausts. Good luck with your project.

mercury26 · mercury26's Garage

Quote:

Originally Posted by fred cook

If you are going to buy pistons and cylinders anyway, why not go with the 98mm P&Cs and build a 3.2SS engine. Cost would be the same. You could use the 9.5:1 pistons, have your heads redone, add in the 964 cams and have a nice engine. You will still be limited by the small ports and intake runners, but should still have a bit more power for the $$$ spent. If you are not in an area that has emission inspections, add the SSI exhausts. Good luck with your project.

So the 3.2 P/C are a drop-in, as in NOT requiring any changes on the CIS components??? When you mention heads redone, are you talking porting? Or more just new valve guides, cut seats, etc?

Unfortunately, I am required to do emissions testing every two years. No SSIs for me...

Thanks,

Chuck

Flat6pac · 08-03-2011, 07:55 AM

He s talking about 98mm short stroke 3.2 using a 3.0 engine. Its a righteous combination.
Bruce

mercury26 · mercury26's Garage

Quote:

Originally Posted by Flat6pac

He s talking about 98mm short stroke 3.2 using a 3.0 engine. Its a righteous combination.
Bruce

Does Mahle have a set of P/C? Or do I need to go to JE Pistons and LM Cylinders?

Thanks,

Chuck

lindy 911 · lindy 911's Garage

You did not mention how many miles are on your car. My '78 3.0 had 98,000 miles when we pulled the motor and the P&Cs looked almost new. I doubt you need these renewed on your freshen. The performance gain from a P&C swap is going to be minimal; I doubt you'll be able to feel it. Plan on $3500+ for new ones. Cams are going to move the power around a little in the rev range but again, minimal overall change. It's your car but if it were me I'd re-ring it, head job (guides, seal, grind, no port work) and put it back together. Without intake and exhaust mods, cam and compression changes won't do much, if anything.

mercury26 · mercury26's Garage

Quote:

Originally Posted by lindy 911

You did not mention how many miles are on your car. My '78 3.0 had 98,000 miles when we pulled the motor and the P&Cs looked almost new. I doubt you need these renewed on your freshen. The performance gain from a P&C swap is going to be minimal; I doubt you'll be able to feel it. Plan on $3500+ for new ones. Cams are going to move the power around a little in the rev range but again, minimal overall change. It's your car but if it were me I'd re-ring it, head job (guides, seal, grind, no port work) and put it back together. Without intake and exhaust mods, cam and compression changes won't do much, if anything.

My motor has 175,000 miles on it. Probably go with a re-ring and head job. The questions was asking, IF I have to buy new cylinders and pistons (due scoring, piston damage, etc) what should I consider. I am not planning on sinking a bunch of money on performance goodies. The thought was that if all things being equal in cost for P/C set, should I go bigger (compression, displacement, etc).

Thanks,

Chuck

lindy 911 · lindy 911's Garage

If you are forced to buy new P&Cs go with 98 mm and bump it to a 3.2. There will be a slight torque gain with the added displacement. Lots a folks have done this successfully. Look up "brad911sc".

mercury26 · mercury26's Garage

Quote:

Originally Posted by lindy 911

If you are forced to buy new P&Cs go with 98 mm and bump it to a 3.2. There will be a slight torque gain with the added displacement. Lots a folks have done this successfully. Look up "brad911sc".

Is their a Mahle kit of P/C for this change? Or do I need to go JE Pistons and LM "Nickies" Cylinders?

Thanks,

Chuck

mercury26 · mercury26's Garage

I do see two Mahle Sport Sets from Andial, second set seem to be better fit (in regards to compression differential to stock)

AND 103 983 98 98mm bore 3.0-3.2 CIS 70.4 stroke 9.8 compression

AND 103 985 98 98* mm bore 3.0-3.2 (alt to 984 98) 70.4 stroke 9.5 compression

mercury26 · mercury26's Garage

Quote:

Originally Posted by mercury26

AND 103 983 98 98mm bore 3.0-3.2 CIS 70.4 stroke 9.8 compression

I spoke to Peter at Andial and he recommended the set above for CIS bump from 3.0 to 3.2. He mentioned that pistons domed properly for a CIS injection setup. Also, told me that it would work well with pump gas (91 octane and higher). I might go this direction, IF I need P/Cs.