Rebuild advice needed after teardown
 

Ok, I tore my 80' SC 3.0L down today, and I was suprised at what I found. I expcted to find Aluisil cylinders, when in fact I found Mahle Niki's. The part number is 95ZN1W4, which I can't find anywhere. I'm guessing they are standard 95MM niki's for 3.0L, here are the pics:

http://home.comcast.net/~sramnit/rebuild/piston1.jpg
http://home.comcast.net/~sramnit/rebuild/piston2.jpg
http://home.comcast.net/~sramnit/rebuild/piston3.JPG
http://home.comcast.net/~sramnit/rebuild/piston4.JPG
http://home.comcast.net/~sramnit/rebuild/piston5.JPG
http://home.comcast.net/~sramnit/rebuild/piston6.JPG

Now, I'm dropping these off at the machine shop to have them checked out for round and such. But, what should I do? Have them honed a bit and replace the pistons? Compression was down across the board, 120 ~130 and two cylinders with 35%+ leak trough the rings. It appears that the jugs were replaced, but not the pistons. What would you do?

Next... I found that all of the lower studs are Dilivar according to Wayne's book. They are not magnetic, and they are of the correct color. The uppers are steel, and one of them pulled out:

http://home.comcast.net/~sramnit/rebuild/engine1.JPG

Do I do any replacement on this stuff? Other than the upper that pulled out? It's very clear to me that the engine has been gone through on at least one occasion, which direction so I go?

I think those need a re nichol job ( EBS ) not a hone. do they have a slight yellow hue to them ??

Yes, slightly "gold" in places. They are old no doubt about it. What's a "nichol" job?

Scott,

I would replace all the dilavar studs while you have them out with steel. The dilavars will break at some point. The 993 steel studs are around $10 each. I replaced the lower 12 when I did my rebuild, due to two broken dilavar studs. Cheap insurance! See how the measurements come out on the P & C's.
Afterburn was talking about having the cylinders replated with Nakasil. If they are in spec you should just be able to clean the cylinder up with scotchbrite (do a search on scotchbrite in this forum, lots to read about nikasil cylinders) and re-ring the pistons.
Are you looking at just rebuilding or are you looking for more HP?

Interesting...never seen a stud pull out of an aluminum case before.

The stud did not pull, the barrel nut is still on it, it simply unthreaded from the case rather than having the nut come off. Looks like the locktight is just old.

EDIT: Forgot to mention four of the lowers three on one side and one on the drivers side are already steel studs. Looks like headstuds were the nature of the original repair.

You do not ever hone those, Like Diamond blue says ,a cyl rebuild is in order EBS might be a good choice ,all new studs will make you sleep better...............

Ordered the studs, going with the steel option. The cylinders were just dropped of at my p-car wrench along with the heads to have everything checked. The cams are off to "Camgrinder" tomorrow when I get them back from my wrench, he wanted to see every part, even the pieces he's not rebuilding.

On to the lower end, what prompts a lower end rebuild on a 3.0L? I'm on the stand down to the case right now, I'm just worried that I'll never get the surface to reseal. Wayne's book makes it seem like it might be something I would mess up. The rods all seem great, bushings are within spec... What should I do?

you are 2 hours away from a complete inspection.......it will open the way for more stuff...new chain and sprockets, crank polish, rod rebuild, rebalance....etc

I know, I know. I have a new set of chains already, came with my tesioner kit that I installed last year. I don't mind spending the money for a Magnaflux check and a rebalance. Just not sure about the case sealing thing, everything else I've done before, bearing and such. Man this whole project is such a huge can of worms.

If your pistons are in spec, you could have the skirts coated and then re-plate the cylinders + match hone. This is as close to new as you will get with your oe P+C's. You could also put in JEs, but I don't think it's worth spending the extra money since the cylinders can't be opened up for 98s reliably with the sealing grooves. EBS Racing does this (as do I), or you could go with new P+C's in a 98mm bore and get some more displacement. There are lots of choices. Do a search.

will you replate aluisil as well and at what cost?

Yeah, I've done alusils as well. The only quesion there is ring compatibility with the re-ring on the original pistons on nikasil, but i'm sure it's been done.

What I am thinking of doing is replating my aluisil cylinders and buy JE pistons

That would work too. For what it's worth, as long as the original factory cylinders are in ok shape (not overheated or severly out of spec), they make great candidates for a re-plate.

For example, I won't replate a set of half-finned 97mm turbo cylinders, regardless of condition - they are a bad design to start with.

Thanks Charles, depending on what my mechanic says about the cylinders I may contact you for the plating.