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Car runs perfectly, screams to redline but is now leaking enough oil from the through bolt O rings onto the exhaust as to be a fire hazard, the resultant smoking a likely smog test fail too. Knowing this was coming I have spent a great deal of time talking to engine builders and machine shops all over the 14 western states, gauging upgrades for horsepower/torque and WYAIT efficiencies. There are a lot of choices to be made and you need to determine what the car is going to be used for. In my case mostly a street car with up to 6 track/AutoX days a year and weekly canyon carving.FWIW I have the complete breakdown from the machine shop (Competition Engineering), 4 pages, detailing what is and what is not useable again and the costs to repair. Once I get the costs to reassemble from Arredondo Motorsports I will have a pretty complete and up to date cost to rebuild a 964 motor, which I know from searches, many of us were trying to get a price on. Disassemble, machine as new, assemble with all needed new parts. Bear in mind, not all motors are the same, some will need heads, oil pumps, P&Cs, cams, cranks and more. Some of the rebuild threads over on Pelican have kept me awake nights, I have been very lucky, all of mine were either in spec of able to be brought into, other than the P&Cs which will be new Mahle 3.6.
Not refresh, not reseal, a proper rebuild to stock factory specs, all stock. A lot of time and research went into the decisions made on the motor; turns out, the factory knew a little bit about building 964 motors, there really isn't a lot of room for improvement unless you want to spend big money. Heads have terrific flow, cams are at the best all around setting, there are some small gains from LWF and a chip at reasonable prices, catback exhaust, but much more than that will cost much more. If there were some easy gains I am pretty sure the factory would have figured them out. The best speed enhancements are suspension/weight related as has been discussed here in some detail already.
As many of us start to face the reality of 25+ year old cars, a rebuild starts to look like a sooner rather than later decision; I hope to have a definitive west coast option to the dollar and from reliable, honest suppliers. Just a word to the wise, my car ran superbly, no inkling of what the teardown revealed; if it wasn't for the oil on the floor, I would be blissfully ignorant. A leaking, sub optimal 964 motor is still a great running motor.
Keep us posted. Always amazed how many P-Shops we have in So. Cal. and this is one I have not heard of. How many miles on the motor did you have? I'll be interested in the costs in today's dollars as I've been kicking it back and forth to re-build mine back to stock or possibly do a turbo.....
164,000 on the clock and was purring like a kitten, I have had it since 2008 and it has been very well maintained but also, driven very hard. The P&Cs were in spec at the limit of ovality but I don't want to do this again so will go with new.
Lots of threads here and elsewhere opining on upgrades; such and such cams, 3.8 bore in/slip in and on and on. But the best engine builders I have spoken with all say the same thing: We'll gladly take your money but the gains are very expensive for the relatively small increases in torque and useable HP. Each to his own but unless you strongly believe that you have a future as a race car driver, a new stock 3.6 is going to be a pretty delightful motor.
When finished, this should provide up to date costs for parts and labor to rebuild a 3.6, If anyone chooses to add personal upgrades or if they get unlucky and need an oil pump, or cams/heads etc. prices go up from here.
Not refresh, not reseal, a proper rebuild to stock factory specs, all stock. A lot of time and research went into the decisions made on the motor; turns out, the factory knew a little bit about building 964 motors, there really isn't a lot of room for improvement unless you want to spend big money. Heads have terrific flow, cams are at the best all around setting, there are some small gains from LWF and a chip at reasonable prices, catback exhaust, but much more than that will cost much more. If there were some easy gains I am pretty sure the factory would have figured them out.
Excited to follow along. Went down the same decision path last year. The whole "if I spent X modding my 964 so the car must be worth 2X train of thought is laughable." Porsche is not prefect but they got their NA motors 95%+ buttoned up.
Thanks for putting this thread together! I especially appreciate the fact that you are talking about an actual split-case, full meal deal, stock specification, rebuild as people bandy about terms that confuse people such as overhaul, top-end rebuild, reseal, etc... I always tell people the only way to really know what was done is look carefully at the parts lists, what vendors were used and who did the final assembly. I always chuckle when people say their motor was rebuilt and I see the parts list and its missing 80% of what a "rebuild" actually is. Usually their version of a "rebuild" included pulling the motor and replacing a few gaskets....
Keep us posted. Always amazed how many P-Shops we have in So. Cal. and this is one I have not heard of. How many miles on the motor did you have? I'll be interested in the costs in today's dollars as I've been kicking it back and forth to re-build mine back to stock or possibly do a turbo.....
There are a lot of P shops here in Socal, I spoke to quite a few of them, as well as Steve Weiner up north and Frank Beck in AZ, both of whom I would gladly drive to but have fairly long wait times. One of my requirements was that Competition Engineering (Walt Watson) do the machine work and that eliminated a few shops. Others I found dirty and disorganized, shocking in some cases from major names bandied about here. If your shop is a real mess, and shops aren't operating theaters I know, are you sure everything you took off my motor is mine and is going back on properly? Cause it looks like some here and some there, and some over there.
That is possible sure, Tony Callas quoted that figure to me, Steve Weiner was $20-25k depending on what is found once the motor is apart. Frank Beck was just a hair under $20k with new Mahle P&Cs. But if the ceramic is gone off the ports, cams shot, new oil pump the parts list can add a lot of $ in a hurry.
Would you please share the thought process in splitting the case at 150K miles? There have been bottom ends split at 280-300K which looked great.
Because the motor ran so well my hopes were to just do the top end but the main leak was from the case through bolt O ring, no other way to fix that (properly) than to split the case.
Also, not to call anyone out but I am very leery of 300k miles motors being untouched prior. More knowledgeable folks than me can chime in but unless that car was in the same ownership all that time, who knows what was done prior? The bottom ends on these cars are fairly bulletproof, the O rings are not sadly. If someone has 300k miles then it seems to be the luck of the motor, each is subtly different as are the driving habits of the owners. Prior to my ownership my car was used as a commute between Austin and Palm Desert, gentle miles. I then bought a car in 2008 no one else wanted for my daughters to learn AutoX and track skills so as not to blow up my 73T. We all drove the car hard once fully warmed up, and it was religiously maintained; 164k miles seems fair, during research I see case splits at 80k. Mr. 300k should count himself lucky if no one rebuilt the car before he got it. Or she.
Well now, haven't seen a stock rebuild documented in, well maybe ever? Best of luck with the process. I'm obviously interested to hear more. Fingers crossed for best case scenario for the rest of your build.
Case through bolt O ring. Although there were other leaks that was the main culprit. FWIW it is clear there was no prior major top or bottom end work done.
Case through bolt O ring. Although there were other leaks that was the main culprit. FWIW it is clear there was no prior major top or bottom end work done.
FWIW You don’t need to split the case to replace those o-rings but you might as well given the number of items taken off the engine to replace them.
I rebuilt my ‘92 C2 a little over a year ago. Only had approx 150,000kms (92,000miles) however I found a could of metal slivers in the oil that looked like they’d been through the ringer plus multiple oil leaks. The metal slivers came from 2 broken valve springs - really interesting how they break and splinter off a piece. Anyway, inside the case everything was perfect. Bearings all looked good (except the secondary shaft bearings being down to copper - which seems to be normal), the machine shop said the cams and crank were excellent and just needed a polish, and the oil pump was like new. As some have already commented, these engines as astonishing well (maybe over) engineered. I replaced all bearings, installed ARP connecting rod bolts, and replaced all case studs. Probably over did it but I want to hand this car down to my kids one day and “whilst you are there” is the cheapest time to do things.
05-11-2021, 11:37 PM
1992 C2/5 rebuild engine
