I have a 3.2 upgrade on my car....it is a 930/03 engine (European 3.0) and I have the 9.8 compression Mahle 98mm P/C's on it. It got a gentle port/polish, stock cam and valve train, stock Euro CIS, single plug, SSI's, factory '74 muffler.

Been running the engine for about 13 years now, only about 30k km, on it, it runs like a clock on the 91 CLC gas we get here in Canada. Never heard or suspected any detonation anywhere at any time.

Probably the only question I have about it is whether the plugs I run in it are too cold...W3CS....tempted to try W4CS, but I am a little chicken.

I am at about 1000m altitude (Calgary) which buys you a bit of octane relief.....

Dennis

Dennis:
Before the rebuild, I researched thoroughly various issues.
JW recommended that I stay with W5DC for the ss 3.2 and that worked fine, no issues.
You'd be surprised with a 964-profile on your stock cams and springs:
A real kick after 4000 RPM exactly like Camgrinder described.
Cam-timing is 1.4 mm per JW's suggestion.
Very happy so far.

No issues with fuel delivery because a '79 already has the larger intakes and corresponding FD and WUR.
Other pioneers have done this so many times that it was easy to just copy the formula.
I am not into carbs.
I like CIS, especially the '78-'79, it's reliable and the mixture is easily adjusted.
Costwise, I liked the fact that one can stay with stock springs for the 964-cam.
If you go with carbs, you can try a hotter cam with upgraded springs.
What CR for the MM P/C's?
9.8 is o.k. for single plug.
Tried to reply your E-mail but it came back: Cannot be delivered.

How true.

Before the rebuild, I asked a lot of questions about what to expect re: HP for a ss 3.2 with 964-cams and SSI's.

http://forums.pelicanparts.com/showthread.php?s=&threadid=318251&highlight=short+ stroke+3.

As you can see, many gurus felt that 230 HP was quite doable with my description of all the components.
I have another stock 3.0 liter and the difference is so very noticeable.
Just as Camgrinder told me: The 964-cam will kick in after 4000 RPM, and it does!
I wouldn't have gone through the trouble without getting an extra ~50 horses and the experts confirmed beforehand.
If it's only 46.9, that's fine with me!
It all started with buying a running stock 3.0 and then making a ss 3.2 out of it while keeping my other 3.0.
It was a nice experience and I am very happy so far.
Like JW suggested, I use W5dc plugs and 1.4 mm for the cam timing. 9.8 : 1 CR is no problem for single plug.

Of course, one usually wants more power but I guess I am the modest type? Even 40+ extra HP make me happy.

Anyway, for anyone facing a rebuild with concerns about costs, I highly recommend making a classic ss 3.2 out of a 3.0 for about the same money.
Whether you end up with 45, 50 or 47.5 extra horses is then left to the experts who can pick it apart. :D

After reading through the link it seems the consensus is that there is no consensus.

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Mark:
If you want to do your '78, go for it; you'll love the extra horses.
You already have the larger intake and heads.
98mm P/C's with 9.8 :1 CR, 964-cams and SSI's..............
Would I do it again? Absolutely; very cost-effective and fun.
I like CIS but lots of people will argue for carbs.
For that matter, lots of people will argue no matter what you do and pick it apart. :rolleyes:

Enjoy. :)

Gunter,
Thanks for the reply. Afraid that in the People's Rep. of Kalif. I cannot go to SSI's...no room for cats. Carbs would be out too. Smog Nazi's are serious down here. With 148K on the clock I wonder if I should figure on splitting the case anyway....hate to. It runs great as is and leaks no oil....but I'd love the extra horses.

If it runs great and leaks no oil, don't split the case.
I would just take out the cams and have them reground to 964 using the same springs. Cam timing 1.4 mm.
Do not feed new chains on to old chain sprockets on the I-shaft!
Keep the old chains.
For an easy DIY distibutor service, and maximum advance timing, I posted both procedures with good results. Do a search.
Like many other engines, the unknown factor is P/C's when splitting the case. If you find KS Alusil, a serious decision has to be made.

Gunter,
Can you elaborate on this? I'm pretty green when it comes to engine rebuild stuff but willing to learn. What decision/options?

Re-ringing Alusil P/C's is a gamble that many people don't do.
Do a search on this issue.
Since you don't intend to split the case, leave it alone; just do the 964-cams.

Gunter,
I see what you mean...just looked up cost of new P/C's....yikes ! That is a serious decision.

3.2ss
 

I have a 78 3.0 with high millage and some oil leakage but good leakdowns. I have no history on the engine so I am considering a rebuild before anything lets go. I like the sound of the engine that you built. When doing this build are there any problems with the rods or rod bolts with the larger pistons (6,500 rpm max)? Also when building stroker motors of the V-8 variety the piston pin height changes. Is this a non issue for porsches I have not seen it mentioned so I assume not. But if anyone can tell me for sure I would appreciate it. Also if it does not have an effect why? Thanks for any help.

Hi Gunter,
Thanks for posting a lower cost solution for 3.0's.
This addresses smog issues for those for which it is a very real problem.
There is always a more powerful update to any engine, usually accompanied with a significant increase in cost.
So much of what we do on this board is to come up with cost effective modifications of varying degrees.
Most just want a bit more than we currently have.
We all admire Henry's engines and his knowledge, however not everyone wants to or can afford to go that direction.
In fact if money were no object we'd all be running the newest, best that Porsche offers.
Thanks Gunter,

To answer the stroker crank question, if you change the crank from 70.4 (3.0) to 74.4 (3.2) there is a wrist pin issue. The wrist pin height is different (heigher in the 3.2) and the pin in the 3.2 is 23mm where the 3.0 is 22mm.

Thank you,

So if you go with the 98 jugs you have to specify that you are using the 3 liter crank to get the right piston pin location correct? When I see these sets sold I do not see it called out.

Forget about the crank-stroke and wrist pin location.
The 98 mm P/C's for a 3.0 are bolt-on; no modifications required.
The ss 3.2 was popular from day one with SC owners and has been proven over time; it's simple and cost effective; no machining required on the heads if you have a '78-'79.
All you specify when ordering is that it is for a 3.0, the CR you want, and maybe the dome-shape for the pistons.
If you stay with CIS, you'll order the CIS dome.
As for CR, 9.8 : 1 is still good for single plug.

Send out the crank for checking/polishing, send out the rods for re-bushing along with a new wrist pin, send out the heads for a valve job, replace the head studs (Exhaust side).
Have the rockers re-furbished along with new shafts if necessary.
Have the cams re-ground to a 964 profile if you stay with CIS. (That way you can use OEM springs)

In short, follow the excellent instructions in Wayne's book.
Get the book and read beforehand to get answers to your questions.

It's just a little more $ than a regular re-build to make a ss 3.2 but, you'll feel the results.

Most professionals will tell you that 9.8:1 compression on a large bore CIS engine is pushing your luck.

It is important to remember that it is not uncommon to see detonation issues with CIS engine 80-83 US versions. These engines were only 9.3:1
I can't tell you the number of times I have disassembled an engine from these model years that had a broken piston from detonation. This is caused by many factors, not the least of which is the quality of fuel available in the US.
The other factors are, lean running as the result of the lambda control system (smog). Another important issue is the nature of the hemi head found in all two valve 911 heads.
Large diameter hemi heads detonate by the very nature of their design.
If you intent to run 9.8:1 there are a few good ideas.
Order 7 pistons when you purchase your pistons.
Guarantee good fuel quality 93 octane or better
Euro fuel distributor
Control head temperatures (big cooler)
Recurve the ignition distributor
Pray
Good luck

Good stuff there, Henry.

Euro FD because of higher capacity to deliver fuel?
I assume that the FD from a US '78-'79 is about the same as a Euro '78-'83 since both have the larger intakes?

I understand detonation to mean combustion much before TDC? Or?

Higher octane means advanced combustion?

Recurve the ignition distributor to achieve more retard at higher RPM? Or?