pa951

Just took the head of my 86 turbo with 305k km on it. Thought it was using oil due to a worn valve guide but now i ca see some scratches in the cilinders.

Would this be the cause of my oil consumption?

And what to do? Sleeve it nikasil it or just leave it and fix the turbo. The turbo has to much play.

blade7

Have you worked out the cost to plate or sleeve it ?.

YZ250

Check out this thread:

https://rennlist.com/forums/showthre...ferrerid=51861

333pg333

You might be able to get the block honed and just go oversize pistons. You need to find someone qualified that can hone an Alusil block though.

JustinL

Nikasil is great, but a ton of work getting all the steel out of the block. I think it's a good long term solution. How bad are the scratches? Can you catch a fingernail on them? How much oil consumption are you seeing? How do the valvestems look? Is it the original turbo?

Laust Pedersen

The scratches are in an “unfortunate location”, different from where dirt and debris normally accumulate and get squeezed by the rocking motion of the piston. There should be no piston-cylinder forces in the longitudinal direction.

There is a high probability that you have S-shaped connecting rods, created by a “mild hydro-lock”, where the cylinders and con-rods “battle to give” (cracked cylinder or bent con-rods).

Laust

Fredrik H

If the rest of the block is ok, sleeves are really tough and will give you a lot of options regarding pistons. But not cheap in the short term

Dougs951S

I've never had a motor sleeved but if you were dry sleeving, you are basically pressing a cast iron liner into a bored out factory bore. That being said and depending on what your goals were build wise, would it not be possible to use ductile iron sleeves meant for a sbc (even if they had to be cut to fit) and use 101.6, 102.36mm or 103.12 mm pistons? Sleeves can be had for a SBC for a bargain, it would probably cost more to have them installed. Just a thought, I dont know if this is possible.

refresh951

Sleeves for my stroker were like $30/each and installation cost was about $100/each IIRC.

Dougs951S

Shawn, the ones I am looking at are ~80 each from darton, which sleeves did you end up using? Did they have to be cut down in length to fit the porsche deck height?

Sorry for stealing all your build secrets, but I drool over your motor

BC

Then why does everyone say a sleeved block is 1000s of dollars?

Dougs951S

Because everybody uses Darton MID wet sleeves which ARE 1000's. There are other options though, most porsche guys shy away from using stuff not "built for a porsche." What is an acceptable sleeve wall thickness after boring? I found some other sleeves that are a 4.0" bore with a .125" wall so after final boring, wall thickness would be .095" which seems more than thick enough. The particular sleeves I'm talking about have a 5.875" height.

Edit: ^^^if you had 0 piston clearance

Actually with a .035 piston to bore clearance that would make the wall pretty thin at .06". Some sleeves with a 4.031 bore would probably be a good compromise between not making the wall too thin, and not having to bore the factory cylinder too thin to fit the sleeve.

333pg333

Doubt many people are using MIDs. There are about 2 people that I know who use them.

Paulyy

There are a few MID sleeve users. however they're not cheap as people have told me.

refresh951

The key in my view is to find the right machinist to partner with on a build. I talked to some guys at local race shops to find the right machinist in my area. No substitute for experience and really good equipment.