'89 964 Rebuild, no cylinder update?
01-08-2006, 08:39 PM
#1
Three Wheelin'
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'89 964 Rebuild, no cylinder update?
This weekend I managed to take the heads off and have a look at the cylinders.
It would appear my 964 never got the cylinder head gasket update.
So the question is what to do about this?
Should I rebuild the engine and do nothing about it, or should I send the cylinders / heads off somewhere to be machined? Or try and find an updated set of cylinders / heads somewhere?
Who does this kind of machining and what does it cost? I imagine it will be some place in the US.
Opinions / Recommendations?
Thanx
Kirk
It would appear my 964 never got the cylinder head gasket update.
So the question is what to do about this?
Should I rebuild the engine and do nothing about it, or should I send the cylinders / heads off somewhere to be machined? Or try and find an updated set of cylinders / heads somewhere?
Who does this kind of machining and what does it cost? I imagine it will be some place in the US.
Opinions / Recommendations?
Thanx
Kirk
01-08-2006, 08:47 PM
#2
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Kirk, I'd send them to Ollies Machine in LA.. They have a real nice fix for your heads and Liners. They can also install new valve guides and do a valve grinds while there..
01-08-2006, 10:46 PM
#3
Nordschleife Master
The first thing I'd do is to measure the pistons and cylinders. Due to the large bore, the pistons rock in the bores and scuff the cylinders. If the piston skirts are worn smooth then you need new pistons. If the cylinders are out of round and scuffed, you need new cylinders. I'd start there first before I made a determination about what to do. All new cylinders have the new design and all you'd need to do is have the heads machined for the update along with any head rebuilding that is required.
From the picture, it looks like the #1 cylinder has been leaking, but the others look pretty good. This is consistent with what I've seen with #1 and #4 running hotter than the other cylinders. Most likely if you measure the head, it will be warped by a few thousanths.
From the picture, it looks like the #1 cylinder has been leaking, but the others look pretty good. This is consistent with what I've seen with #1 and #4 running hotter than the other cylinders. Most likely if you measure the head, it will be warped by a few thousanths.
01-09-2006, 01:38 AM
#4
Burning Brakes
I agree, get the p/c's mic'd but if it's been taken care of they can last 300K miles - as can the crank, case, lot's of stuff.
I just took all my parts to Ted at German Precision. Every expert has their own solution - but just FYI - some of the later gasketed ones leaked so machining the head for a gasket (and ditching your existing p/c's if you go that way) isn't guaranteed to not leak. This was not the first gasketless head/cyl porsche design, just the first one with significant seepage.
I was ready to leave mine alone but Ted cut me a deal on his procedure since he had 3 other sets to do and had the jigs/tools or whatever all set to go. His approach is to remove the angle from the cylinder tops. They are not 90 degrees to the cylinder - they are higher on the inside than the outside. He makes them 90 degrees, resurfaces the heads (not enough to alter CR), and since he gave me a deal I said what the heck let's give it a shot. I'll let everyone know if i ever notice any new gunk.
Steve at Rennsport Systems and Henry at Supertec also have procedures (different) for this. Ted's list is about $500 to do the cyls and heads - uses your existing stuff and no gasket. The shops the other guys mentioned on this thread are pretty reputable as well. Whoever you pick, act like the leak really isn't worth x amount of bucks and see if they cut you a deal. For me it wasn't an act - yeah what you see looks bad, but that's a lot of mileage and chances are it's only at warmup and cooldown, and I seriously doubt that could ever make a drip on the floor. It's more of an aesthetic / neat freak thing than anything else.
I just took all my parts to Ted at German Precision. Every expert has their own solution - but just FYI - some of the later gasketed ones leaked so machining the head for a gasket (and ditching your existing p/c's if you go that way) isn't guaranteed to not leak. This was not the first gasketless head/cyl porsche design, just the first one with significant seepage.
I was ready to leave mine alone but Ted cut me a deal on his procedure since he had 3 other sets to do and had the jigs/tools or whatever all set to go. His approach is to remove the angle from the cylinder tops. They are not 90 degrees to the cylinder - they are higher on the inside than the outside. He makes them 90 degrees, resurfaces the heads (not enough to alter CR), and since he gave me a deal I said what the heck let's give it a shot. I'll let everyone know if i ever notice any new gunk.
Steve at Rennsport Systems and Henry at Supertec also have procedures (different) for this. Ted's list is about $500 to do the cyls and heads - uses your existing stuff and no gasket. The shops the other guys mentioned on this thread are pretty reputable as well. Whoever you pick, act like the leak really isn't worth x amount of bucks and see if they cut you a deal. For me it wasn't an act - yeah what you see looks bad, but that's a lot of mileage and chances are it's only at warmup and cooldown, and I seriously doubt that could ever make a drip on the floor. It's more of an aesthetic / neat freak thing than anything else.
01-09-2006, 05:55 AM
#6
Check'em first as others have suggested. If you need new P&C's then the cheapest option is probably some used 993 items. I did't want the headleak so I used 3.8 Cup pistons nut then this was part of a much larger project. Good luck and look forward to hearing more!
01-09-2006, 05:59 AM
#7
Check'em first as others have suggested. If you need new P&C's then the cheapest option is probably some used 993 items. I did't want the headleak so I used 3.8 Cup pistons but then this was part of a much larger project. Good luck and look forward to hearing more!
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01-09-2006, 03:16 PM
#8
Three Wheelin'
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This weekend I will have the time to finish dismantling the motor, and I will mic the cylinders and look at the pistons. I don't expect to find any significant wear. (But ya never know) My motor only has 200,000km on it. The only reason its apart is because the oil leaks were so bad. (steady drip from cylinders 1-3 and a slow drip from 4-6) however most of my leaks were from the cylinder mating to the block, not from the head to the cylinder)
Do you guys have the full contact info for:
Ollies Machine in LA
Ted at German Precision?
If I send the heads/cylinders in I will have them clean/prep/valve job/guides and clean up the bore in the cylinders. (If I am going to ship the stuff from canada I might as well get it all done)
Kirk
Do you guys have the full contact info for:
Ollies Machine in LA
Ted at German Precision?
If I send the heads/cylinders in I will have them clean/prep/valve job/guides and clean up the bore in the cylinders. (If I am going to ship the stuff from canada I might as well get it all done)
Kirk
01-11-2006, 02:39 AM
#11
Three Wheelin'
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I don't suppose anyone happens to have a nice set of low mileage heads & cylinders lying around that they are anxious to sell for a low price?
Kirk
Kirk
01-11-2006, 03:33 PM
#13
Three Wheelin'
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If someone had a factory set of heads & cylinders from 1991 +, that has the provision for the seals that would be a way for me to solve the problem.
I have to decide whether to:
A. Leave it alone, reassemble the engine without the gaskets, and hope for no leaks. (Machine the mating surfaces, lap them together and put in some raceware head studs to hold it all together)
B. Have my existing heads / cylinders machined to accept 930 style fire rings
C. Try and find a replacement set of heads/cylinders from a later year car and use them instead.
The downside of option B is that I don't think the machining will provide the same gasket as was applied to the later year cars, due to a difference in the cylinder/head castings. It will allow me to put a 930 style ring in. (Unless I am mistaken)
So out of curiosity I was wonder if someone had a set of heads/cylinders available. (Maybe from a 3.8 upgrade, etc)
I won't be home until the weekend to complete the dissassembly, at which time I will know for sure if my pistons & cylinders are still in reuseable condition. But I thought I would check if option C was out there or not.
From what I have read it would seem that the heads could be machined to be the same as the later style porsches but the cylinders couldn't? (Not enough material around the edge on the cylinders?) In which case that would allow option D, to replace the pistons and cylinders and have the existing heads machined to allow the standard head gaskets used in later years.
Anyone who wants to correct me on any of this please chime in now. Its a confusing topic.
Kirk
I have to decide whether to:
A. Leave it alone, reassemble the engine without the gaskets, and hope for no leaks. (Machine the mating surfaces, lap them together and put in some raceware head studs to hold it all together)
B. Have my existing heads / cylinders machined to accept 930 style fire rings
C. Try and find a replacement set of heads/cylinders from a later year car and use them instead.
The downside of option B is that I don't think the machining will provide the same gasket as was applied to the later year cars, due to a difference in the cylinder/head castings. It will allow me to put a 930 style ring in. (Unless I am mistaken)
So out of curiosity I was wonder if someone had a set of heads/cylinders available. (Maybe from a 3.8 upgrade, etc)
I won't be home until the weekend to complete the dissassembly, at which time I will know for sure if my pistons & cylinders are still in reuseable condition. But I thought I would check if option C was out there or not.
From what I have read it would seem that the heads could be machined to be the same as the later style porsches but the cylinders couldn't? (Not enough material around the edge on the cylinders?) In which case that would allow option D, to replace the pistons and cylinders and have the existing heads machined to allow the standard head gaskets used in later years.
Anyone who wants to correct me on any of this please chime in now. Its a confusing topic.
Kirk
Last edited by KirkF; 01-11-2006 at 04:47 PM.
01-11-2006, 04:01 PM
#14
Burning Brakes
A guy on pelican rebuild forum couldn't sell a set of 91 or 92 (newer) p/c's, stock 3.6L with 15K miles, for $750. It's his mechanic actually - might check with him if that's the way you want to go.