Motor rebuild diy project

[Swerve951]

Hi all, this is my first post and I thought I would share my little project to see if anyone had any advice or comments on it. This is my first time rebuilding a motor and I'm still fairly new to the 944 so please bear with me.

I bought the car (1988 944 turbo) with a blown motor which the previous owner suspected to be a spun rod bearing. Upon trailering it home and disassembly I found that the rod on the #2 cylinder had been snapped in half. I've included some pictures if anyone has an idea of what might have caused this feel free to share, I told the previous owner about what I had discovered and he said that the motor must have hydrolocked. Anyway, it became clear to me that I could not reuse the block or pistons, but fortunately the previous owner had given me with the car a spare NA motor and extra 944 turbo connecting rods. Looking around a bit I decided to go with wossner pistons as oem ones would be close to 3000 dollars and I'm not made of money. Using the spare turbo rods as well as the block and crank from the NA motor, I assembled the short block about a week ago. Included are some pictures of my progress so far. I am currently waiting on new front and rear seals for the balance shafts and that will be my next move. As I said before this is my first motor rebuild so if anyone more experienced has any advice to share feel free. Glad to be a part of the forum

[Darwin]

Be careful with the Wossners. They changed their coatings a while ago, and also were sending out incorrect rings. I would thoroughly double check everything with them, or maybe even swap.

[Tom]

Welcome to Carpokes, and great first post!! I would heed Darwin's advice and do a little investigating. I don't have first-hand experience with the PC-9 coatings on those pistons, but there are some here who do and might comment, like @BuchananAutomotive and @Gregbbrd. Looks like you are pretty far down the path, so hopefully they'll do ok. Did you have the cylinders prepped for these specific pistons and/or otherwise confident with the clearance? The walls look kind of shiny, unless that's just the picture....? Piston to wall clearance is pretty critical, regardless of coatings, so hopefully you (or a machine shop) obsessed on that adequately. If you are using the block from the blown-up motor -- be ridiculously thorough cleaning it out -- shrapnel can get everywhere/anywhere. In general when assembling a motor, I try to keep everything as clean and debris-free as I possibly can. I got that from a number of books by well-known builders -- i.e., clean everything at least 3 times until you are 100% sure it is clean; then clean it10 more times!

My view has always been that if you need a stock-ish motor and are on a tight-ish budget, you can't do better than finding a solid used motor known to run well. They are cheap in comparison to building a motor, and eliminate all the risks of the unknown. You can reseal them before installing too, for a tidy, leak-free car. Just a thought if still helpful. On the other hand, if you are building the motor for fun and the satisfaction that comes with the job, then I get that too -- and welcome to the club.

balance-shaft-preep.jpg (634.9 KiB) Viewed 1755 times

This is how obsessed I get with clean and tidy assembly space....

[Tom]

By the way, I'd nominate this for the @52Megahertz b/s spacer give away!

[chris white]

Hard to see in the pics but the cylinder walls look extremely clean, hopefully you didn’t hone them. Alusil doesn’t work that way!
The Wossner piston have been good in the past but I had some issues with the rings.

Good luck!

[Darwin]

Hard to see in the pics but the cylinder walls look extremely clean, hopefully you didn’t hone them. Alusil doesn’t work that way!
The Wossner piston have been good in the past but I had some issues with the rings.

Good luck!

This guy knows his stuff when it comes not only to building engines, but using Wossner specifically!

[Swerve951]

Hard to see in the pics but the cylinder walls look extremely clean, hopefully you didn’t hone them. Alusil doesn’t work that way!
The Wossner piston have been good in the past but I had some issues with the rings.

Good luck!

I did some research before hand and didn't hone the cylinders. Would you mind sharing what issue you had specifically with the rings? Considering how the shortblock Is already assembled I would rather not tear it apart to replace the rings unless I really need to. Have any thoughts on that? Thank you!

[chris white]

I had some issues with a couple of motors and found that Wossner had supplied the same rings of Alusil, Nikasil and steel bores. They claim this is fine and the same rings will work in all types, that’s not what all the other ring manufacturers believe

[Tom]

Was looking for something else and found this thread. How's this motor coming along?