Jsulli

Im in the middle of a TBF rebuild on my 86.5 and am wondering rather or not to hone the cylinders. Searches turned up many mixed answers so I would like to get a few answers from you guys.

I read something about the cylinder walls being incredibly hard, so I'm assuming if done it needs to be done by a machine shop?

The pistons have a ton of carbon on them, not sure if this is more reason to hone or whatnot.

Thanks!

Mrmerlin

you can clean the pistons off with simple green just soak the ring lands in it it may take a while ( 12 hours or so) clean out the lands with a tooth brush. Dont try to scrub the skirts they should have a dull green/gray coating that is chromium.
Check the ring gaps in the cylinders push the ring down the bore with the piston so it is square.
Usually the bores are left alone, no honing

mark kibort

dont touch the bores unless you do the slicon paste process . Its nothing like a hone job
as long as the bores look dull and matted looking with no real scratches, they willl probably be ok

86'928S MeteorGrey

DO NOT HONE THE CYLINDERS. The 928 cylinders have a crystaline structure process (Alusil). The only alternatives are to sleeve the cylinders:

http://www.928motorsports.com/parts/...er_sleeves.php

or this Nicasil process (or similar) shown here:

http://www.928motorsports.com/services/uschrome.html

Both are absurdly expensive. But if you've got money to burn, or are building something extra special (like oversized pistons), these will do. Are your cylinders scratched badly?

Jsulli

Nah I dont think they are that bad, just kinda want to do whatever I need to while its all apart.

mark kibort

If you got it apart, just re-ring if the engine is old and re-assemble. post some pics of the cylinders, as its pretty easy to see if they are bad. most are just fine. as long as there are no scratches that are deep enough to catch a finger nail, you are probably fine not to touch them.

mk

docmirror

No honing. Look for a dull green/gray surface. If you see pits, you have other problems.

David L. Lutz

No honing, just wiped with oil.

Jsulli

I would like to get a new piston ring set, does anyone have experience with any certain ones? If I get new rings I assume I still wont need to hone anything, I will post some pictures of the cylinders because they are scratched, I just dont really know what "bad" is. Is it necessary to replace crankshaft and rod bearings?
Also I need a gasket set...if I could get some reviews from you guys that have been down this road that would be great.

Thanks again!

David L. Lutz

I got mine from Roger at 928sRUS. Below is a quote from a thread.

Roger?

http://www.928srus.com/

I now stock 951 piston rings for $228 a set of 8.
Chrome face, correct bevel and spring - a real must for the boost club.
Form an orderly queue please 8>)

David L. Lutz

Also for the gasket set, but the complete set its much cheeper even if you don't need all thats included.

Jsulli

Sounds great, I suppose I need to get in contact with Roger.

Thanks for the info

Mrmerlin

please post pictures of the bores B4 you buy any parts

Jsulli

Ok heres a shot of the damages, what do you guys think?

They do kinda catch your fingernail as he said...whats the best trail to take from here?

mark kibort

probably boarderline. sometimes the Sunnen process can clean up some of the light scratches, but these might be a little deep. I dont know. all the blocks ive taken apart look better than this shot.