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StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Hey Guys,

I've got the engine head and block separated right now as I think the mating surface is warped. (had a small oil leak at the back corner of the head gasket.)

First, what is the best way to clean gasket residue off the block?

Also, if I have to pull the pistons and crank out to have the block machined, do I need to replace the main bearings with new ones? I rebuilt the engine literally 1500 miles ago, and I would rather not have to spend a bunch of money on that again. If I do end up having to take the rotating bits out, I'm gonna have them balanced, and the crank knife edged. Are there any other tricks I should have done while its at the machine shop? I'm planning on getting a light weight fidanza flywheel as well. I just want to have a bullet proof engine that is much more 'exciting' than stock. I've already got euro pistons installed, a header, and a set of webers for it.

Thanks in advance,
Ryan
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1978 924 NA
-250lb lowering springs, Euro Pistons

Joes924Racer · Posted: Sun Apr 17, 2011 5:18 am Post subject:

Seems you know what you have to do just deck the head after pulling valves ... and look at your bearings on the bottem end. Most shops have a price list for work done ...you want to balance the bottem end and maybe what knife edge the crank. Besides striaghtening the head mating surface you might want to go for a 3 angle valve job. Thats all i can think of .... I dont know if theres any holes to enlarge on the crank for better oiling ... i dont think so.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

MikeJinCO · Posted: Sun Apr 17, 2011 9:06 am Post subject:

I once worked for a piston ring company. The rings are probably fully seated by now. If straight cast iron for sure, if chrome plated or moly/ceramic coat and the block was honed on a Sunnen type honing machine for sure, if not honed that way then maybe not. Ask the machinist who did your work the first time. If you have to pull it apart, I would get the bores re-honed with a machine that can give a rough enough surface to reseat the rings and reuse everything exactly the way it came out, nothing is going to wear out in that kind of mileage. Mains should be good for another 20 years.

I'd seal every hole in the top of the block and use a gasket scraper to clean it up then get the surface checked for warpage by some one with some precision straight edges. and If no problem not take it apart. If the head is warped it might be easier to find another one than go thru the headaches of loosing the crank center to cam center spacing by surfacing it. Other people here have had a lot of experiencess with than, myself I have had none. just my opinion.
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Hey Mike,
Could I get around the cam to crank center spacing by using one of those metal head gaskets that Ideola sells? I saw that they come in different thicknesses, but I guess I don't know the thickness of a regular gasket. Also, when the engine overheated this winter, I immediately took the head off and took it to be resurfaced, which it needed, and reinstalled it with a new head gasket. The car ran okay and everything, but since it had that small leak I wanted to get it right. So I'm thinking the head will be okay, or at least very little material will need to be removed.
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1978 924 NA
-250lb lowering springs, Euro Pistons

MikeJinCO · Posted: Sun Apr 17, 2011 9:19 pm Post subject:

I don't really have any opinion on resolving the head resurfacing/ c-c problem. Ideola, the racer guys, lots of people here have the answer to that. I'm not the person to ask, sorry.
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Mike

'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

924RACR · Posted: Sun Apr 17, 2011 9:45 pm Post subject:

Re: cleaning the block - scraper will be just fine on the iron block, but I recommend a green nylon scrubbie for the aluminum bits (head etc).

I agree, the mains should be just fine as-is (assuming a visual inspection reveals no surprises).

Regarding the cam-to-crank spacing. Well, realize that if you make no other changes, the decked block will give you a slightly higher compression. Not necessarily a bad thing! Your machine shop should be able to work out with you how much.

Dan will have to speak to the thicknesses available of the Cometic head gasket, but the main concern would be cam timing... which can be fixed with an adjustable cam gear or an offset cam key.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Hey everyone,
Thanks for the input. I dropped the engine off today at a reputable engine builder. He mainly works with high end V8's and the like. Dewco is the name of the machine shop. Evidently the guy there is well liked for his ability to put together a strong rear-end for drag racers.
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1978 924 NA
-250lb lowering springs, Euro Pistons

gla924sem · Joined: 08 Nov 2002 Posts: 405 Location: Taylor, Michigan

Hope your engine rebuild goes great

Can't say that about mine

Still in pieces.......no comment on my shop

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Thanks,
It seems that machine shops never really have a very fast turnaround time. Last time I had my engine redone it took over a month to get it back. It's whatever I guess though, Im in no rush to get it back together. Gives me more time to save up for a lightweight flywheel!

Ryan
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1978 924 NA
-250lb lowering springs, Euro Pistons

StienbargerR · Joined: 28 Oct 2005 Posts: 1362 Location: Richmond, IN

Hey all,

I've got a few more questions about my engine build.. It's been a slow process to say the least.

-Can I do the honing myself? I've seen some tools that you can attach to a drill to do it. I would imagine I just need to deglaze the walls.
- Also, are there any brands of piston rings I should avoid? I decided I should probably get new rings just to be safe. Are total seal rings worth it?

Thanks in advance
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1978 924 NA
-250lb lowering springs, Euro Pistons

Grenadiers · Posted: Tue Jun 19, 2012 8:55 am Post subject:

I sent my 931 block out recently for professional honing. Include the main bearing caps as the machine they use attaches to these. Somehow. I wouldn't do this myself. Anyway, got the block back in a couple of days, and am almost done putting the engine back together. I bought new rings from Dan, and they were easy to put in. I reused the crank and rod bearings, since they looked like new. Engine has had a total reseal, new seals, newer oil pump I had, new gaskets, new turbo bolts-not sure where I got those, Flosho's rebuilt turbo, small crack welded in exhaust manni, I did myself, nice.

I'm having more trouble with remembering where shit goes after having the car on the lift for two years. Need to source out a rubber elbow, the skinny tube one for the deceleration valve. The two I have are fubared. hmm, I might have to keep this car! Good luck!
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands