3.2 rebuild delimma - NEED ADVICE

I need some input, so here is the story. I pulled the 3.2 out of my '88 with the intention of a complete rebuild. The engine has 110K miles and has been regularly maintained, but had the bad smoke on startup and oil consumption issues we have seen discussed often here. Oil pressure and operating temps have always been perfect.
After I got into the top end I realized that the engine was in exceptional shape - just needs the guides replaced and maybe the rings. The question is, should I stop there? I know what Bruce Anderson would say, but I think this engine is an exception, yet I don't want to cut corners unless I am spending money needlessly. The cost is not the issue at all, just 'practicality' if nothing else. So, I need some opinions asap!
Thanks in advance.
Tom

Tom,

First, a couple of questions:

1. Are the cylinders Alusil or Nikasil?

2. Do you have the spec book for your car?

If the cylindersz are KS Alusils ... don't plan on doing ANYTHING to them or the pistons or rings ... just put them back in the same location they came from, assuming they measure within specs! If the cylinders are Mahle Nikasil, replace the rings with OEM, not Deves, per Bruce Anderson!

My recomendation is to replace the 24 head studs with a set of 24 steel OEM 964 studs, commonly called 'Micro-ecapsulated' ... this may seem extreme, but Dilivar studs are dying and breaking all over the world!

In addition to the valve guides, I vote to replace the 6 exhaust valves, and just get the intakes reground, assuming that the stems measure within spec.

Be sure to use Loctite 574 or 518 around the base of the cylinders, after cleaning the base mating surface thoroughly with degreaser, then use Loctite 'Locquic Primer N 7649' following the instructions. A 24-hour curing time for the Loctite is recommended for best results

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Warren Hall
1973 911S Targa

Warren,
Can you determine whether the cylinders are Alusil or Nikasil w/o having the engine out?
Thanks
Mrdi

You may want to upgrade to sport valve springs from a source such as Andial. Designed to minimize valve float at unintended over revs. Also gain 3-400 rpms safely.

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8 9 9 1 1, The last of the line.

smoking is pretty normal on startup unless it's obviously excessive. oil use on carreras is generally worn guides, worn valve stems and broken or hard stem seals. if it has nikisil cylinders i would be tempted to leave them alone at this mileage. alusil cylinders don't last as long and perhaps you should consider replacing them w/nikisil. don't hone alusil cyls if you decide to ring them. replace exhaust valves for general principal, mic the intake stems for excessive taper, and use phosphorous/bronze guides, and white old style stem seals. the newer orange stem seals worked too well, and that's what started all this stem and guide wear.

mrdi,

Near the base of each cylinder, right next to the crankcase are mfr marks and tolerance group markings ... maybe not so easy to see if there is oil leakage or dirt in the general area, but you can look at both cylinders 1 & 4, and perhaps wipe brush off the bottom 1/4" to 3/8" band where the marks are. I believe Mahle spells out their name on each cylinder and Kolbenschmidt uses an overlapped 'KS' ... so I guess the answer is yes, but not necessarily very easy!

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Warren Hall
1973 911S Targa

The pistons and cylinders are KS Alusils. I have the spec book, but my plan was to send them to EBS along with the heads and let them completely go over everything. I will recommend they change the exhaust valves and check the intake stems. The advice about the white seals is good, as noted, the orange were 'too good'.

Now the final questions is: Do I open the case at this point to replace all bearings??

Thanks for all the valuable insight and suggestions.
Tom

being that i'm not a pushy rebuilder, i would not generally recommend a complete on a 110K engine. they are pretty strong engines, and if it was properly cared for with oil changed regularly, the top end fix will get you another 100K. that mileage on a chevy would require a complete o'haul, but 911s are such a fine piece of engineering, they last way longer. money hungry rebuilders won't tell you that, though.

Tom,

No, it doesn't sound like there is any reason to go into the crankcase!

And, yes, be sure to use the 'old' white Teflon 'Perfect Circle' style valve guide seals, as they allow just enough oil past to keep those exhaust valve stems lubricated, and not visibly smoke, yet be within the 'normal' oil usage guidelines!

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Warren Hall
1973 911S Targa

Thanks for all the great advice. I am sending the pistons/cylinders and heads to EBS tomorrow for refurbishment. If the pistons are out I will replace them along with the cylinders. Heads will have a standard valve job, new exhaust valves and 'white' stem seals. May also install the new studs, but I will not go into the crankcase afterall.
Tom

IMHO pull the rods off of the crank and look at the bearings, if everyting checks out there bolt it back together and use ARP rod bolts.

Randy Jones
1971 911