puffin04

Since the serach engine sucks *** since it never works i have a couple of questions on my rebuilt engine. It is a 83 944 track car and it has aittle over 100,000 miles on it. I pulled the engine out( actual from the top which was a plain in the *** so never doing that again). Pulled and labeled all the pistons and what not and there is a few scratch here and there but not bad. I am ordering new rings which i was wondering if i can use 951 rings since i heard they are better. Also going to do all the bearing and was wondering do i need to take the crank to a shop. And if so do i have to buy different size bearings? What else should i do beside new gaskets and what not. Is there any stress points that i can grind on like my 350 LT1 engine? Thanks

Steffen Sparks

HyKlas

Definately take the pistons, rods, and crankshaft to a reputable machine shop to get everything checked out. They'll line bore the rods to make sure the holes are round, inspect the pistons, install new pin clips if you ask them to, and mic the crank to see if it's within spec. If the crank journals need grinding they'll let you know what was done and what size bearings you need.

Also make sure to hone the cylinder walls to get a fresh cross-hatch for the new rings to seal on. And a new oil pump is always a given when you have an engine apart.

The rest I don't know about...

PennyWise

Unless the cylinders are scored... don't touch them!!!!!!!, just put new rings in.... this is NOT an iron block.....

puffin04

The cylinders look pretty good actually a few scrapes here and there. I cleaned up the pistons and notice slight pitting on the outside wall on almost all of them. The 4th piston from the front had copper coming up. Do i need to replace them. Also the top of the pistons have a little damage where you can see something has hit it. Thanks

Steffen Sparks

KuHL 951

The OE Goetz rings you buy today are all the 951 model anyway so yes they will work. At 100K I would decide if you need them though. Is there any ridging at the tops of the bores signifying wear? If the ridging is minor, I wouldn't bother. One thing I was surprised about was the endplay on a 91K Turbo crank that showed excessive end play. I attributed it to bad clutch manners when I saw nothing but copper on one side of the thrust bearing. I have the curse of an engine on a stand where the temptation for a full rebuild and reseal is just too tempting to ignore.Were the marks on the piston anything like this?

StoogeMoe

NOOO! Do not do anything to the cylinders. If you hone them, you will ruin them. I rebuilt my engine (after much pondering) that had a few nasty scratches and it has been just perfect.

A new oil pump should not be necessary, especially at 100k.

Just as a point of reference, I rebuilt my engine last year. It had about 140k miles on it. The machine shop measured the journals and everything was about mid-way in the tolerance range. So I just had it polished and used standard bearings. But definitely measure everything before ordering parts. You never know.

Mongo

I did. Honing the block is important. It helps the rings seat better.

DO NOT rebuild an engine without having the bores mic'd. This tells if the bores may be out of round. Chances are though, at 100,000 this is unlikely, but don't take any chances.

This is an alusil block. To hone the bores requires a special stone; not the stones that are used on cast iron engine blocks. Be sure you let the shop know that since it's very important! PM me if you need any tips on rebuilds.

sharky47

You ABSOLUTLY DO NOT hone these engines - DO NOT DO IT!!!!!!!!!!

You need a special machine to etch the alumasil material that these blocks are made of, if the cylinder walls are not scratched/gouged - don't touch them, they are fine. Also, the oil pump is bullet proof - don't need to change it unless there is actually something wrong with it.

Mongo

Daniel, I had my engine honed, but with a special stone to polish up any small indentations. Are you sure you are not confusing this with Nikasil, a coating in the cylinder bores? My bores were perfect afterthe honing. It's NOT and I repeat NOT! the conventional honing everyone thinks of. Contact 928 Motorsports who repairs and HONES 928 engine blocks, which are the same Alusil material as the 944s. They also can replate the bores with a Nicom to strengthen the aluminum-silicone matrix and make it even more resistant to scoring or scratching.

Calmchaos

Honing can be done only if it is done right. Everyone says not to do it because if you just took it to any old machine shop they would hone it any old way and it would end up ruining the bores.
The silicon is NOT a coating; it is weaved in (which no one here seems to disagree on).
But IIRC, after the special honing, the walls need to be exposed to some chemical to dissolve away the aluminum and leave only silicon.

I was going to have it done to mine but I could not find a place that would do the alusil engine within 100 miles of where I live. If I could have gotten it done like Andy seems to have had. I would have done it. But the engine seems to be perfectly fine with the bores left alone.

Btw silicon is hard as all hell, and silicone is what boobies is made of .

And and +1 to what sharky said about the O-pump just replace the sleeve.

Mongo

You're right! I forgot to mention the catalyst to expose the silicone after the honing process. My block had small gouges (not even deep enough to require a bore) in it until the honing process was completed.

Mongo

On a side note, there are not many shops that know properly how to hone an alusil block. Be sure to check around for machine shops that have done, or have extensive knowledge in the Alusil matrices our blocks are made of.

sharky47

If you did it with 928 motorsports, then they should have used the Sunnen machine - which is the ONLY way to do it right.

Calmchaos

+1 to post number 12.

^Sharky^ Good to know the name of the machine... that will make it easier to ask next time my engine spins #2. LOL

And please.... silicon.... NOT silicone...

Mongo

I didn't do it at 928 MS. I did it at a local place in Chula Vista that has rebuilt 911, 928, 944 and various muscle car engines for 40 years. My Dad used to goto highschool with the guy. He has EVERYTHING needed to do an Alusil bore hone correctly.