350$ 944 contiuned

vdubr928 · 05-10-2011, 10:59 AM

So if you all remember I purschased an 87 na pretty cheap and it ended up having a spun #2.

I was going to rebuild the engine and figured I would need some parts ie a rod an maybe a crank so I picked up a core motor at my local pull and pay cost $250. Turn out this motor is probably good. It has a blown head gasket and looks like a fairly recent rebuild inside. Im thinking about using the bottom and having the head done. I have a spare if this one is cracked. Questions.

What should I do while I have it apart. I was planning on getting a front engine seal and head seal set. Pan gasket. Rear seal. What else.

Ps. Before I pulled the engine apart I ran compression ere are the results.

#1 130
#2 175
#3 180
#4 180

There was leak down into water system in #1 so let's assume a straight head and a gasket will correct #1.

I think this motor may be usable. Let me know what you all think.

running_cold924 · running_cold924's Garage

for that price i'd run it and try it out, with a new headgasket of course

Rudeboy42 · Rudeboy42's Garage

Do the rod bearings while you have it out. They're cheap insurance and it's very easy to do when the engine is out of the car. Maybe even get a crank scraper and oil pan baffle if you want to go nuts.

vdubr928 · 05-10-2011, 06:09 PM

Can I just change them out? Shouldn't the rods be machined and the studs replaced? Wouldn't I have to unseat the rings?

I figured id seal it up and check the endplay. Put in a scraper and timing belt + pump and see how many miles I can get. I think I will have somebody grind the valves and put the new seals in. Just wonderin if im way off base with that.

vdubr928 · 05-10-2011, 06:09 PM

Oh, and how do I ensure I get the correct rod bearings? They may not be factory size.

Rudeboy42 · Rudeboy42's Garage

Rod Bearings - Porsche 951 - www.texasblake.com here's a write up on how to replace the rod bearings. It also says how to tell if they are standard or oversized.

It sounds like you're on track with everything else you said though. Have a good machine shop check out your head and see what they say needs to be done.

vdubr928 · 05-10-2011, 06:36 PM

Ok. I have just never changed a set without sending the rode and the crank to the machine shop. Should I do the mains too? Or are they pretty bullet proof?

djaychela · djaychela's Garage

I've changed rod bearings on my Skoda several times (being a rally car it gets quite a lot of abuse), it's always helped the oil pressure and in the main the wear has been to the bearings, not to the crank; In fact the only time I've needed to get the crank reground has been due to loss of oil pressure leading to damage.

Generally mains will survive better, and also it's usually more difficult to do them in situ because you need the crank to move a bit to allow the mains to come out. Again I've done them in situ on the Skoda because a) I really needed to - it was the weekend before an International rally and b) because it's a 3-bearing crank the middle one in particular takes a hammering. It's NOT easy to get them located correctly when doing them in situ, and correct location is of paramount importance. But it is possible on some engines. I've stripped a 944 engine, and the main caps all being one block may make things harder for you in this respect - there's a large piece of metal to come out to allow access, so it may be that just changing the big ends is an easier idea.

Having said that, I'm not 100% sure what you're doing - if it's out of the car then changing the mains will be straightforward as the crank can easily come out, and it's easy enough to get it measured to see if it is in spec and will need machining or not...

As for finding out the current bearing sizes, just measure the journals. Regrinds are 0.25mm (usually) increments, so easy enough to measure them correctly, even with just a vernier caliper.

vdubr928 · 05-11-2011, 08:54 AM

Yeah. Its a short block and out of the car. Can easily drop the crank and do mains. I think ill let my endplay decide but I can also spot check. So reuse the rod studs or replace? Aren't they stretch bolts? I used to reuse them on old mercedes alm the time but those motors don't usually see the abuse this one surely will.