1992 964 Engine rebuild - progress...
 

Hi all, RE: 1992 Porsche 964 Engine Rebuild

Considering we are not looking for high horse power or spending a lot of money, What input would you offer for our project?

Background:
We are in the process of rebuilding a 1992 964 3.6L engine for my son's 1978 911 race car. The car has been running a 3.2L Aase built stock spec engine for about 5 years - it is still very strong and a class winner for 2 years. But, we need more torque and minor HP increase to still be competitive within the NASA PTA Class. Based on our weight HP is limited to 248 RWHP and torque lower than HP.

Findings:
We purchased a used 3.6L and have disassembled it to inspect and measure. The engine had a known leak down test indicating rings - but we also found valve issues(Edit( no problems with valves - just appearance)) in #5 & 6 and #5 rod bearing excess wear. Cylinders are out of tolerance spec also.

Approach:
After discussing the issues with our local Porsche Indi shop and Don at EBS(and researching the Forums) we have decided to:
1. send the cylinders to EBS for refinishing and increase to 102MM -- Done
2. send heads to local racing engine machine shop for reconditioning-guides,grind,etc. -- Done
3. send crankshaft and rods to machine shop for reconditioning and microfinishing -- Done
4. send cams to Webcams for regrind to 20/21 - and maybe rockers for recondition --Done
5. replace with JE 12.5CR 102MM piston set -- Done
6. replace with ARP rod bolts --Done
7. replace with EBS racing valve springs -- Done
8. replace head studs -- Done
9. replace rod, main and IS bearings -- Done
10. replace flywheel with Patrick 964/915 custom conversion ---DONE
11. replace front pulley with single belt -- Done
12. clean and flush case and valve carrier oil passages -- Done
13. reassemble by Porsche Indi shop -- 7/20/2012 Start date -- DONE
14. wiring conversion by Indi shop -- DONE
15. use existing 915 custom built and geared transmission - rebuilt last year -- DONE and changed 5th to 0.82 Stock
16. use existing custom 1.75" header system ---DONE
17. use 964 stock intake and DME ---DONE
18. when conversion to 3.6 is complete take car to Steve Wong for dyno custom chips --- NEXT

I will be posting this thread on several different places for feedback.

Thank you for your time to respond.

Sincerely,
Roy Turner
Phoenix, AZ

A picture of the UPS brown Porsche race car ---

http://i158.photobucket.com/albums/t...UPSGoodPic.jpg

Your list looks pretty comprehensive, but I'd add a couple of things for your consideration. I had these things done for my 3.3L rebuild, so not sure about the 3.6L needing them, but if it does then you may wanna crossdrill crank for better oiling and add fire rings to heads and cylinders mating surfaces for better seal.

Uh, oh, now a torquey 3.8L in PTA here in AZ:eek:

Slippery slope. Trying to keep it under 248 rwhp might be a challenge. But ballast is relatively cheap if you go over...

Can't wait to see the finished product. Let me know if you need any hands on help in the build process. See you guys soon.

Erik

CaptainCalf,

Thank you for your reply!
I am considering the crankshaft oil passage cross drilling and will talk to the machine shop when they have the crank in their hands and have evaluated the 20 year old part.

I have heard the term "fire ring" but am not sure exactly what it is? Does it replace the standard cylinder/head ring?

Thanks again.
Regards,
Roy T

Erik,

Thanks for the boost! We have a couple of other things to reduce points for PTA also besides weight - front splitter changed and dial back the tires -- Brian will have more straight line speed and a bit less cornering speed.

I think we will ask DJ to put the engine back together so we don't have any DIY puck ups...and never ending oil leaks...

We hope to see you on the track at Firebird, still with the 3.2...

Take care,
Roy T

Hi Roy,

Here's a few pics of the fire-rings on my build;

http://forums.pelicanparts.com/6686616-post76.html

Essentially 2 machined channels into the mating faces of the cylinders and heads, which house/sandwich a ring. Used a lot on higher spec turbo engines, as you do get the heads lifting under boost. Porsche got around the problem by welding the cylinders to the heads on (iirc) the 956/962's :D

Thank you for the photos of the fire rings -- now I understand.
I see "Turbocraft" written on the cylinders - did they do this machine work for you?

Regards,
Roy

Does someone have an idea why #5 is worn and not others rod bearings??
 

We have the engine apart and are puzzled by the wear on #5 rod bearing.
Does anyone have experience with this unusual wear?

Thanks,
Roy T
http://forums.pelicanparts.com/uploa...1337543943.jpg

http://forums.pelicanparts.com/uploa...1337543995.jpg

Hi Roy,

No, I purchased them though Chris @ TK, but the machining work was done by the guys at LN, then shipped directly from them to me, to save the transit time....I guess that's why they have TurboKraft written on them, as the job was commissioned by/through them.

Re your #5 rod, have you checked the rod bore diameter and shell thickness? I.e., are they all original shells (with the Porsche triangular hallmark) and/or has any previous centre-centre correction been performed on your rods?

Cheers
S

Thank you,

I am pretty sure these are the original rods and bearings.
So far the consensus is the engine was run on low oil and over heated the #5 bearing.

We will have the rods reconditioned and the crankshaft checked before we reassemble the engine.

Cris at Turbo Kraft has a good reputation here in Tempe.

Regards,
Roy

Yup, am a very big "Chris fan", nothing but positive feedback from me, and has steered me in the right direction a number of times with my late-night (from the UK) phone calls after an evenings tinkering!

6-13-2012 Progress report

Cylinders back from EBS along with new JE 102MM 12.5:1 pistons , rings & light weight pins, ARP rod bolts, steel head studs, and EBS race valve springs

Cams sent to Webcams for 20-21 grind and cut off power steering piece (?)

Parts to local speed engine machine shop: recondition heads with new exhaust valve guides and 3 cut valve seats, recondition rods, check and polish crank; balance crank, rods and pistons.

Thanks to Don Jackson Enterprise in Phoenix for the Excellent technical assistance and future engine assembly.

Thanks to Don at EBS for your excellent service!

This is a slow process -- but we have plenty of time -- Granddaughter born this past Monday so driver will be out of the car for a bit...:)

http://i158.photobucket.com/albums/t...0608-00017.jpg

Is there anything more beautiful than new pistons?! Besides the granddaughter of course :)

Looking good

Crankshaft Issue feedback??
 

7-05-2012 Progress Report

Heads, rods and crankshaft done and balanced.

However, there is a very, very small pothole on the #5 rod journal in the center near the oil hole - it is about half a pin head in size. This is the rod bearing that had the damage. The journals measure spec -- no wear.

We have about decided to not turn the crank and run as is. I don't have a picture - but it is so small I'm not sure you can see it anyway. As insurance we can send oil to the lab and keep an eye on the bearing wear.

This will be a race engine - but limited to 6200-6500RPM with most running between 3K and 6K.

Your feedback on this crankshaft issue is appreciated.

Regards,

No problem. Think of it as holding a reserve pocket of oil:)

Porshaah --

Thanks for your reassurance.
A similar comment was made also - which makes this dimple different than one
on a camshaft that will continue to degrade and loose metal around the edges.

And, from a very old and experienced Porsche engine builder -- "...seen a lot of these, no problem, put it back together and run it."

The machine shop did polish the bearing surfaces and they look like mirrors.
And, the measurements showed no wear.

Now its time to reassemble...

Regards,

Engine assembly...
 

The 1992 964 engine is being put back together - here are a few pics --garage porn!!

Crankshaft (magnafluxed and polished) rods (reconditioned - big end recut to round and size, new bushings) and ARP bolts added -- plus all balanced...

http://forums.pelicanparts.com/uploa...1342817040.jpg


Heads reconditioned, valve seats 3 angle grind, new valves, new EBS valve springs and TI retainers...


http://forums.pelicanparts.com/uploa...1342817187.jpg

Case halves cleaned
(shop is Don Jackson Enterprise, Phoenix, AZ)
Porsche Independent Repair Specialists , VW, Audi Service


http://forums.pelicanparts.com/uploa...1342817405.jpg

And...a broken head stud X2...why would only one stick and break?
Oh, well --- ready for the assembly of case halves, heads and cams...

http://forums.pelicanparts.com/uploa...1342817500.jpg

Oil pump was disassembled and examined - no issues -- heavy grease and assembled.

Next will be the cam timing process --- next week...

Porsche really designs and builds the most fantastic engines and cars!!!

Regards,

7-31-2012 Progress report --

Case halves together with new head studs and Patrick single pulley --
Had to replace one through bolt - wouldn't hold torque
Next -- pistons, cylinders, heads and cams
...sorry for the blurry pics...
http://forums.pelicanparts.com/uploa...1343773178.jpg

New chains and all new bearings - sprockets are OK, no wear

http://forums.pelicanparts.com/uploa...1343773453.jpg

http://forums.pelicanparts.com/uploa...1343773257.jpg

Regards,

Are the studs in the above post photo being used? Just curious, as the P/N on the bag indicates an older vintage 911?

Porshaah -- good eye!!

Yes, the bag does say 911... not 993 or 964...but they work and were sent by EBS
(Engine Builders Supply) in Reno, NV.
I think Porsche does some very interesting swaps with their parts -- the through bolts are 959 part numbers...

Maybe some more knowledgeable folks would have a good explanation for this Porsche parts numbering system??


Regards,