Lightningmcnulty

Hey guys

So I finally have all the stuff together to rebuild but I have run into a couple of sangs.

First, how do I get the woodruff key out of the crank?

second, I have found some scores on my bores, see pic, I think it may have happened when I wans moving the engine to tdc (not happy) what should I do now, I really want to avoid further work at this point and one day in the not so distant future i'd like to do a 3 liter anyway.

Question is can I get away with this for now, the scratches are not horribly deep but you can deffinately feel them. should I try to smooth them out with some 1200 grit sand paper or let the rings take care of it or is this destined for failure?

Really need help on this one guys

thanks

Kim

Prime320

I'm going with failure. I'll let the other guys decide though.

morghen

My old audi diesel worked ok with far more and i think worse scratches. The guy i sold it to showed me pics and then he put it back the way it was and drove it for two more years before selling the car. The car still runs with those scratches. In your case it might drop compression..if the rings are not broken and the scratches are not deep that might work for a while. Why not show the blck to a machinist? He could measure the scratches.

badcoupe

A pair of side cutters works well for removing the key from the crank. I have scratches like that in these motors plenty as well. Are you pulling the pistons? If so make sure you don't have a broken ring. The bores are so soft that they scratch easily. Bolting the head down and running a leak down test will be very beneficial. You don't need the cam tower on to run a leak down test. The cylinders need to be close in leak down percentages, within 5-10% of each other.

944Ross

A broken ring wouldn't scratch up that high. What do you mean, "when moving it to TDC"?

Lightningmcnulty

Ok cool,

When I took the engine apart it was not at tdc because the timing belt had snapped so then I had to rotate the engine to tdc and rotate it for cleaning purposes

They are deep, maybe half a paper thickness!

is it worth bolting the head on then compression testing it.

If I have to buy a new block because it blows smoke then I will but I would like to get it running first.

Luckily I brought the cometic head gasket and a full gasket set from LR so i have a spare HG


thanks for your responses guys

Kim

944Ross

What I meant was, how did you turn it to TDC that you think it caused the scratch? Could there be some debris from the TB failure in there? Can't imagine a piece of valve broke off

Lightningmcnulty

No but there could be debris from it sitting with its head of for nearly 2 months waiting for LR

944Ross

It would have to be metal to do that kind of damage. Otherwise I'd suspect it's been there a while.

StoogeMoe

Why is the top of your piston all scratched up? You shouldn't clean the pistons while they're in the block. And you shouldn't use something abrasive. Some of the debris will fall down between the piston and the wall. Maybe that's how you got the scratch. I hope you didn't do any "cleaning" on the bores.

That one scratch looks ok, the other one, um not so good. Whatever you do, don't try to sand out the scratches. You will only make it worse. This may be ok for an NA, but maybe not for a turbo. I had multiple scratches in mine, that looked like your ok one. I took it to an experienced 944 builder, and he told me to "Just build it and run the heck out if it. After a while, you will forget they are there." Well, after 80k miles of daily use and three years of track duty, it is still running great, with no oil loss during street driving.

You should probably remove that piston to see if something is lodged in there or maybe something is wrong with a ring.

Lightningmcnulty

Huh, I did not know that, I'm sure thats what caused the issue, I think i'm just going to build it and see what happens, I can only get a gasket set deeper into it than I already am and one day I want a 3.0 so why not.

Thank you for your help, I will keep you guys updated

StoogeMoe

I was thinking about this more on the way home and could think of the reason why that gouge got in there. Was this engine rebuilt at one time? The gouge starting at the very top of the cylinder is the clue. It looks like like someone installed the piston without fully compressing the rings. Then they hammered the piston down into the cylinder causing the scratch. If that's the case, then that was there for a while. So maybe you'll be ok. Just blow out any debris that may have got down in there from your cleaning.

944Ross

^^^ or do these piston pins have circlips?

Only other thought was a whisker from a wire brush, hard to believe tho.

Lightningmcnulty

yeah, I don't know but I would think that I would still be able to see the debris if that was the problem.

I will see what happens when I put it back together

Kim

Lightningmcnulty

Ok results of the leak down test, I only had a hf tester so it's hard to get accurate measurements.

I got between 10 and 20% on all cylinders but 25-30 on cylinder 3 it's still in the green per the tester so we might be good for now.

What do you think

Thanks Kim