Carrera 3.2 complete (was: top end) rebuild
 

Hi everyone,

Back in April of this year, I finished tearing down the top end of my 3.2L carrera motor. It had been performing OK, but leaking quite a bit of oil, and consuming a little bit as well. The motor has almost 150k miles, so I figured it was a reasonable time to do the work.

I sent the heads, rockers, and camshafts off to be reconditioned. The heads came back nicely media blasted, with new hardware, valve guides, and intake valves. The cams were reground to 964 specifications, the rocker faces were reground, and the rockers were rebushed. I'm planning on getting a Steve Wong chip as well to go with my new Fabspeed premuffler and M&K 1 in 1 out muffler.

Here's the beginning of the reassembly. I've got the cylinders, heads, and cam towers back on. I did end up taking off the cylinders to make sure I had no broken rings or other weird looking issues with the pistons; there were none.

I'll use this thread to document progress and ask for help if any issues or questions come up. Glad to have the help of all contributors, frequent or seldom alike.

Thanks,

Preston

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The work looks top notch. Just one thought: Reusing Alusil cylinders with 150,000 miles on them is a gamble extraordinaire.
The nature of the 3.2 engine suggests that the rod length to stroke ratio creates excessive side loading on the pistons. This side loading causes wear beyond the wear you might find in other Porsche engines.
Good luck:).

Henry is giving good advice there... Did you do a compression and leakdown before this work? If not, I'd do one afterwards just to see where you're at.

Looks like you're doing a nice job!

Looks great Preston. Keep it up!

As for the Alusil re-use, ask Superman on this board about his experience. His came out fine. Good luck!

As did the re-ringing of my p/l's a few months back......my comp check was 190 post
with about 2500 miles since.....

Currently have about 114k on the speedo....

Nice looking work!

Henry: How did you know these were Alusil cylinders? I thought the 3.2's were Nikasil.

I had the same question, I thought they were Nickies too.

No, I didn't do a compression test before teardown. It was running "fine" aside from the mess.

Thirty years of looking at Porsche cylinders tells me they are Alusil.
It's just a picture so of course, I could be wrong.
Good luck

Henry,

How can I (or others) discern the difference between Alusil and Nikasil? Is there something I could look at in particular? I know the picture could be misleading because of lighting, flash, etc.

Edit: Upon searching, I found the following:

Nikasil cylinders have a yellowish internal coating, and the oil control ring on the pistons is not plated.

Alusil cylinders have no coating, they are just raw aluminum. The oil control ring on the pistons is chrome plated.

I definitely have coated cylinders and unplated oil control rings, so I think I can safely say I've got a set of Nikasil P&C's.

the milky white appearance of the bore suggests alusil. what's the brand? mahle or kolbenschmidt (KS)?

I think in all cases for 3.0 and 3.2 cylinders, KS will be Alusil and Mahle will be Nicasil. Nicasil cylinder bores will be magnetic while Alusil will not be.

Your pictures look like Alusil to me.

OK well now you guys have me nervous. The pistons have the following stamped at their bases:

13
U5B

If they are indeed Alusil, am I totally gambling to reuse them when they have 148k miles on them? I don't want to have to pull the motor back out in 20k more miles to replace more parts that I should have dealt with today, but I'm not too keen on shelling out $4500 for a new P&C set. I'll do it if required for reasonable longevity though.

Nikasil will be very slightly magnetic. Alusil will not be magnetic at all. A magnet is the only sure-fire test, because Mahle did make some with Alusil. I recommend a low-mileage used set of 3.2 P/C, of course within specifications, as they are a pretty good value...$5-600 for a good set. I personally would not re-use Alusils at 148k, but I'm not you.

Scott speaks the truth, take it to the bank.

I tested the cylinders with a magnet this morning -- not magnetic. Crap.

Anyone have a low mileage set of used Nikasil P&Cs available? If not, suggestions on who to call? Seems like a much more economical route than a brand new set. This is my daily driver, not a race car.

Thanks for all the help everyone.

Post a 'want-to-buy' in the classified section. Someone will have them.

Preston

I think I have one more set of used 3.2 Nicasil piston and cylinders left.

PM me if you are interested.

HI try hear for some cylinders,

http://stores.ebay.com/QSCUSA

or

http://www.supertecperformance.com/

regards mike

I spent about an hour and a half last night pulling off the head assemblies, then the cylinders, and cleaning them up. They look pretty good to me, I could even see the factory crosshatch pattern in all of them until I scrubbed them out lightly with a medium scotchbrite -- that put its own pattern in the bores. Despite reading the whole million-page alusil thread, and believing the cylinders are probably reusable, I've got this nagging fear in my heart that when I check the pistons for tolerances, they might be out or at the limit. My motor does have almost 150k on it. Of course, the controversy isn't settled.

But as I've said, this is my daily driver and peace of mind that I won't have to pull the motor again in six months is pretty important, so I'm going with a set of QSCs and JEs. 3.4, why not?

Do you think I'll have to split the heads/cam housings when I install the new cylinders? I assume so because they might have minute variances in height compared to how the old alusil cylinders sat. Or will the torquing process compensate for any variance?

They should all be the same height if they are machined and rebuilt, so no need to disassemble the heads/cam housings. The case must also have the cylinder seating surface flat and level, which it probably does, being aluminum.

Make sure to measure the piston/cylinder clearances very carefully.

Not a deal-breaker IMHO but some people feel strongly about chamfering the edge of the head combustion chamber to 98mm when they upgrade the pistons/cylinders.

Well I may be going with 95mm Nikasil Mahles after all, stay tuned.

You should be setting the deck heights identical, using copper shims on the base if necessary.

I took it all apart
 

Blame Henry, he told me I should do it.

As you all said, intermediate shaft bearings are shot, main bearings have some minor wear.

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and to think that all you "wanted" (thought) to do was freshen up the heads. This happens to most.

Actually, only the ones who really care about doing the job right!!

Just think of the peace of mind you will have when you are all done. Basically a brand new engine AND hopefully no more oil leaks!

Best of luck! You can do it! Especially in that spotless and cool looking garage. ;-)

Bob

Preston,

You are exactly where I am at right now. I pulled the engine/ tranny for a clutch replacement and now I have the case split :-) I too had Alusil P&Cs and I was not too thrilled to find that out (190k miles, 3.2). They are also well worn so time to replace. Cry once, right?

Good luck,
Bob

I've reused several sets of Alusil's some with original rings and others with new rings. These are on Toyo spec race motors (240 HP) and I have not had any problems with them. If you want the increased power of the 3.4 by all means use them but I wouldn't be afraid to reuse your old set if they measure up. Especially if the rings are still good and you keep them in the same locations. IMO the Alusil's got a bad rap from being associated with the 2.7 engines.

-Andy

For those of you leaning this direction I have many Alusil piston and cylinder sets that I would be willing to sell at a reasonable price.

You plop down your money and roll the dice.

but Henry, don't all of your "USED" parts come with a money back guarantee of 30,000 miles or 2 yrs? ;-)

Listen to Henry here or roll the dice "WITH YOUR MONEY"!
BOB

OK! It's finally going back together
 

I sent my rods off to Henry @ Supertec to be resized and cleaned up, and ordered a bunch more parts. Started re-assembly last night.

Rods look great, all balanced with the new ARP hardware in place. The crank was cleaned and polished locally, it was still well within limits. I got the rods back on the crank, and torqued them down last night. As per ARP's recommendation, I torqued and backed off 5 times on each bolt, and then did a final torque to 35 ft-lbs. Well guess what, that isn't enough, at least on my torque wrench (calibration might be iffy, need to have it checked before I continue reassembly) to get to 0.012" of bolt stretch. I don't have a stretch gauge, but I can use a micrometer. I mic'ed each bolt before and after, and all the nuts needed a bit, and sometimes more than a bit of extra twist to achieve the recommended stretch. I'd say between 40 and 45 ft-lbs, as measured by my torque wrench, which is nothing fancy.

Work will continue tomorrow or Saturday, I hope to get the bottom end put back together.

-- Preston


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OOPS! This last one is a picture of my other hobby, i.e. other time sink. Hopefully I'll have this one together in far less time than the Carrera motor has taken me.

P&C solution
 

Also, this is how I dealt with the piston and cylinder solution:

I bought a low mileage set of Nikasil P&C's from Supertec that Henry and/or his crew cleaned up and balanced. Very fair price. Very. Then, I took my old Alusil cylinders and sent them to EBS racing, who gave me store credit, again for a fair price. The net cost to me was low (relative to Porsche parts prices!) and the peace of mind more than makes up for it.

More reassembly tomorrow.

What is a reasonable price for a part that you strongly recommend not to re-use ?

Preston, I just noticed what appear to be Dilavar head studs in one of the early pics you posted. With all the beautiful work you are doing, those should at least be replaced with good ol' factory steel.

I replaced the whole lower row of studs with new steel ones from Porsche (OEM). The top ones on my 3.2 are supposed to be and appear to be steel already.

I got the mainshaft and oil pump/intermediate shaft assembly placed in the right half tonight. Can't seal anything up until I get some Yamabond 1104/1194, I ordered some but it hasn't shown up. I may get impatient and use Loctite, because I have that. What's the main advantage of the Yamabond? Increased working time? I've used the Loctite on the 356 engines I've built.

-- Preston

I used the Locktite 574 in a single bead, and had no issues. I did not put anything on the mating surfaces of the main webs.

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Case halves back together
 

Well, after a pretty stupid screwup which damaged the #7 plain bearings and required both time and money while waiting for a new set, I've got my case halves together. I used Threebond 1194 on the perimeter, Loctite 574 on the bearing webs, and Threebond 1211 for the #8 bearing seat. Everything went together smoothly. The 1194 is quite different than the 574 -- it tacked up but remained soft long before I joined the case halves. I hope that is how it is supposed to perform. It looks a lot more like RTV than the Loctite as well.

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Congrats Preston, that's a big first step.

The two short case perimeter bolts were different lengths. Which one was supposed to go in the front and which one in the back? I guessed, and it didn't appear to make too much of a difference.

Seems I've been here before. :) Just wish I had more time to move the project along. Things will hopefully proceed faster now. My plan is to work on the valve train and timing chain case stuff tomorrow.

I did want to verify that I could install the heads as I did. When I originally decided to pull off the old Pistons & Cylinders, I simply removed the heads and camshaft housing as two assemblies, rather than removing the cam housing and then pulling off the individual heads. So I put on the new pistons and cylinders, and simply installed the two head units, and torqued the head nuts back down. No need to do anything else I hope.

OK Ed, maybe you can't eat a banquet off my engine like you can with yours, but at least its clean enough to not be embarassing anymore.

And let's hope no leaks either.

Any answer to the case perimeter bolt question above?

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finish installing the cam and all the rockers and shafts first, them install them as an assembled unit. turn the cams so the keyways face straight up and set #1 and #4 pistons to TDC before joining things up. then you can hang the sprockets, chains and tensioners, slip in the timing pins, snug the cam bolts and then it's ready to set the cam timing.

I used yamabond on my last rebuild on 930; it never leaked once, ever where I used it - used no locktite at all. I also put a very, very light coat of lithum grease on several o-rings - especially on oil return tubes o-rings.
munchovie.