Engine Rebuild time!
 

With 293,000 kms on my 91 C2, I will be replacing the clutch and rebuilding the engine.

I've ordered Streathers 964 and Bentleys 964 manuals from Chapters arriving this week and made arrangements with my mechanic to start the engine rebuild this week.

He will allow me to document the whole process and i'll take a few days off to take pictures and try to explain step by step. I'm not much of a diy but i'll try my best. There have been some very good threads on Rennlist already. Is there anything specific that i can take pictures of for your viewing pleasure?

He is not a porsche specialist but spent 6 years rebuilding motors in Russia and has fixed a number of nagging little problems in the past year already.

I have gotten the credit card warmed up (who doesn't know theirs by heart?) and am planning the following:

Replace:

this is mainly the vertex auto rebuild kit:

Rod Bearing set
cylinder head gaskets
valve cover gaskets
valves - intake and exhaust
valve springs
timing cover gaskets
piston ring set
flywheel bolts
connecting rod/ nuts
timing chain
valve guides - intake and exhaust
Chain rails, left, right curved
Clutch kit
rear main seal

These parts i'm not sure until we open it up.

main bearings
flywheel pilot bearing
oil lines, seals, washers
oil return tubes
intermediate shaft bearing kit
transmission gasket set
fuel injectors and seals
timing chain tensioner
nose bearing #8
valve stem seals
front crankshaft seal
camshaft oil seal
through bolt o-rings
piston pin / connecting rod bearing

Here's where i could use some help....

Are there any items in my list #1 that do not have to be replaced?

Are there any items in my list #2 that are missing or are unnecessary?

Are any of these items duplicates with different names? ie: does the Rear Main Seal come with the Transmission gasket set?

Machine work: what needs to be done? Any idea how much this should cost?
Heads
valves
cylinder block

Typical # of hours that shops charge for rebuild?

I welcome your comments.

Most important thing, get Wayne Dempsey's 911 rebuild book!!! And check out my own 964 rebuild. It's somewhere here...maybe in the DIY section.

Second the Dempsey's book. It's not 964 specific, but is very detailed, and totally worth it. It's on Pelican Parts.

Look for the threads here where a number of us documented our rebuilds. You may want to strengthen the engine carrier, and replace the rear engine mounts.

Yep definitely will pick up Dempsey's book. Just read Kirk's rebuild again and will check out axl's rebuild. Thanks. Head is spinning from reading Kirk's. Then i clicked onto the Supercharger install ....

Rear engine mounts - i'll check them out.

Strengthen engine carrier: what's that?

engine rebuild
 

find the correct machine shop that is familiar Porsche parts. very recently there was a guy on here that had his heads milled and the were not square:nono:

the machining is very important, especailly the head work.


i would think you need a new oil pump too.

I don't want to be the wet blanket here, but if this mechanic has never rebuilt a 911 engine before, I would be nervous using mine as the guinea pig. 964 engines are quite complex and the parts are very expensive. Therefore the cost of failure is extremely high if something goes wrong during the rebuild. I went down this road about a year ago and looked into a several mechanics doing the rebuild including my regular wrench. My regular wrench is very competent, has rebuilt many engines, and like yours, has fixed many things on my own 964. But he had never actually rebuilt a 911 engine before (although he was confident he could do it). I opted to spend more money to have a well known 911 engine builder do it instead. And I was glad I did. When he got into my engine, there were a number of issues that he caught based on his experience that I doubt my regular wrench would have recognized or known to look for. Just my 2 cents.

Regardless of who builds it, spend the money on some very basic reliability upgrades such as ARP rod bolts, titanium valve spring retainers, and stiffer valve springs. You may want to consider Smart Racing (Jerry Woods) rod bearings also. But I'm no expert. There are several very knowledgable folks who were very helpful to me on this forum that can offer better advice. But if you are spending the money to do the engine, you would be wise to ensure that the guy building it really knows what he's doing and spend a little more to make it more robust than it was before.

Good Luck!:cheers:

engine
 

new piston and cylinders too, hate to say it.

Just stripped my engine - it had 170k miles and low oil pressure at hot idle. Im not a techie (being rebuilt by well known independent) but as a guide:
The crank needed work grinding I think .25. The bottom end bearings were worn and will be replaced along with all others.
Laser measure checked the pistons and cylinders for any wear. Mine were fine but if they were not, was seriously considering a 3.8 "Upgrade"
You might want to consider a new oil pump given the miles and if you had low pressure on idle.
Camshafts will probably be pitted and will need re-grinding/polishing.
I'm having the injectors sonically cleaned and seals replaced and tested. Will only replace if necessary.
Valves will again be cleaned, checked for damage and reground/ replaced. May re-use springs but will be checked.
Cylinders/heads? will be re-cut to allow post 1991 gasket to be installed. You may already have these.

These engines work to tight tolerances. You should ensure your rebuilder knows what the safe tolerances are.

I think a top end rebuild comes in at about 40 hours but I am doing it on a fixed sum. My guys do lots of these so know how long it takes.

If you are photographing, why not get some comparison pictures of the "worn bits" and the new. There doesn't seem to be much on Rennlist of this. If I had known what to expect at certain mileage, I would probably have done the rebuild sooner and at least have had a better idea of potential cost.

I am sure there will be some others along soon with more good advice.

The engine carrier bolts to the pulley end of the engine, and then to the engine mounts. It tends to crack and bend near the ends.

You might want to PM Geoffrey... in one of his recent threads I asked about what to change/improve during a rebuild for the street... here is what I got:

For the steet I'd simply blueprint the engine using stock parts with the exception of valves, valve guides, valve springs, and valve spring retainers which I'd get aftermarket ones. Also use aftermarket racing rod bearings. And ARP bolts.

That is exactly what my engine builder did. For rod bearings, we went with the Jerry Woods bearings. He also cc'd each head to bring them up closer to 11.3 comp ratio. And I agree that Geoffrey is a great source for information on engine building. He helped me out with some great advice when I was having mine built.

Alex, the parts that I highlighted in red should not be check and see items. If you tear the engine down far enough to look at them, they should be replaced. I really don't like to reinstall crankshaft bearings after they have been torqued, especially if they already have ~190k miles on them. I wouldn't open the bottom end up unless you intend to refresh it completely, and at your mileage I would highly concider the full rebuild. It may be fine for some time, but who knows for how long. You will have a decent amound of money wrapped up in the the top end alone, it would be a shame to have to go back in there again any time soon.
As far as machine work goes; I am in the process of completing a 3.2 overhaul, and I sent the cylinder heads to anchor atlantic in New Jersey. The workmanship was TOP NOTCH, and I can honestly say the heads look nicer than the brand new cylinders I sat them on. You should also remind your mechanic that Porsche cylinders are not your run of the mill parts. I believe all 964's have Nickasil cylinders (someone please correct me if this is not true), which means there is a very thin sepcial coating on the bore. You must not machine through this coating, or you will have new problems and will have to replace or send out the jugs. I am not an expert on Nickasil, as I have never dealt with them before. You should do some research on re-ringing these engines, as it will pay dividends to know at least as much or more than your mechanic in this area. If for some reason your cylinders are Alusil (like I said, I doubt this), you will have very little luck finding someone who is capable of preparing them for new rings.

Good luck with your project!

Great advice fellows. I am going to have to print out this thread and work through the list.

Not sure what 'blueprint' the engine means.

Now considering a porsche specialist rebuilder although my mechanic has rebuilt 3.4 litre 996 and 3.2 litre 911 motors.



Pistons and cylinders - need to be replaced? What dies on these two parts.

I will be in touch with Darth who is also rebuilding his motor locally so we'll compare notes.

For machine work, i will definitely send them out to someone very knowledgeable on Porsche.


Sundog, for the engine carrier bolts, can you suggest a good manufacturer / supplier.

I'll do the best i can to take pictures of before and after machining / blasting etc.

Okay, the story begins:

Back from the mechanic's shop today.

Engine and Tranny have been removed and split.

Transmission has leaks in 2 places. Will replace seals.

Engine tray has lots of rusty / non existent tin and several places where oil is seeping and has attracted lots of chunky dirt

Clutch looks old and will be replaced with Vertex Performance Friction kit.

Engine Mounts look okay... no leaks even though i recently jacked up the car to do the rear brakes by taking the advice of p-car's jack under the motor trick. Then went on to read that this is a very good way of busting them and having to replace them with the OEM $500.00 parts....

Will remove intakes and fan related parts and prepare for machine work.

Can anyone recommend a good shop in Toronto specializing in Porsche? I am familiar with the local specialists: GTek, Bestline, Mantis, Hunter and Pfaff. All expensive but as all my friends say, 'what dya expect? It's a Porsche' :crying:

smokin' TR6 - i will replace all the stuff highlighted in Red... 'while you are there'....

I'll upload some pictures as soon as i figure how to...

Alex

Bronko's was recommended by a local Pelcanite.

http://www.bronkos.com/

If you need to do any crankshaft or camshaft work Canadian chrome

Hope this helps
Bill