cylinder leaking oil at head

Just finished rebuilding the 1974 1600DP, and put it back in. Breaking it in, runs great, save a cracked fuel pump insulator and a couple of other small problems I had to fix. Noticed that my oil strainer cover is leaking a bit, I will replace that. But I also noticed that my cylinders appear to be leaking at the head joint. Not a whole lot of oil, mind you, just some drops, but there appears to be some coming out. I appears to be mixed with a bit of gas, since it is eating some of the tin paint. Is this normal? I have only put about 50 miles on it so far. Will it seal up on it's own after a while? Not all of them are leaking, I think it is just #2 and #4. Please advise.

Reply to
js
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I hope someone else can back me on this...

First the cyl's should leak anything, anywhere. Are the heads torqued enough ( something like 24 ft-lbs)? Also leaking oil from the cyl/head 'seam' would mean your rings are shot.

Reply to
Mel P.

Maybe you got some leaky push rod tube seals.

Reply to
Jim347a

Ok, I've been away from all of Usenet for ages and came over here to dig for info for my bug_farm... but while I'm here what da heck.

My first 'take' as an oil leak between the case and barrels. That would mean a paper gasket was left out.

Then I reset my brain and re-read your article.

My first guess would be that you might have forgotten to set the gaps in each ring to a different location. The "Idiot's Book" gives the correct info. I'm happy to say that this is one I've yet to muckup... but I'm NOT breaking my arm patting myself on my back. I've got More Than Enough Bad Muckups to my credit...

Now then, IF you have clear recollection of doing that to the rings, then take a hard look at the head cover where it joins the head. In fact, pop the clamp and take a good look at the gasket on it. It should be Clear of All Oil on both sides where it was clampped to the head by the cover. It it's got a slick of oil on it from the inside to out, that's probably the leak.

That too is a Been Thar item.

AR

Reply to
AR Ogden

i think there was no sealer put on the headside of the washers under the head nuts....that'd be my bet...

Reply to
Joey Tribiani

Hey, thanks for the replies. I actually did use some high tack underneath the washers (I think), but I will check again when I pull the engine to retorque the heads. The leaks appears to have stopped, so I THINK I/you may have been right about the oil passing the rings. I had originally arranged the rings inside of the top 180' of the cylinder, but I had to pull them back off due to a construction malfunction, and may have gotten them moved around enough to cause a leak. I think that now that I have put more miles on it, the rings have sealed up, might just be residue inside from the initial break-in. The engine seems to make a lot of "noise", and not just the leaking exhaust donuts ;-). It seems to be very tight sounding, if that makes sense. I assume this is a good thing, and I have checked my pushrods again and again, so I am assuming it is just the new cam and lifters. (anyone know a good way to make the donuts seal, save flanging the heat-exchanger/muffler connection?)

Reply to
js

if the oil made it past the rings that is bad.....if it made it past the rings *then* leaked out at the cylinder to head sealing surface, that is even worse...that means your heads are loose and the sealing surface can take a hell of a burning due to this.....this can trash a set of heads pretty quickly...

Reply to
Joey Tribiani

Ok, finally had the chance to check the compression. #1 137psi #2 138psi #3 140psi #4 140psi

Still a little bit of oil leaking down from around the barrels on #1 and #4. Retourqed the lower head bolts. I wonder if it is coming from above the barrels some how? Intake? Oil cooler? I am stumped. Very little oil, just enough to make a shiny coating in a few spots, on top of the tin. Nothing appears to be leaking from the pushrod tubes. The oil is very black, like it is burned or picking up the black paint of my cylinders. If my compression is good does that mean I can rule out leaking head to jug joints? Makes no funny sqeaking, just a nice smooth whistle going down the road, tail pipes I guess. Covering the pipe when the engine is cold will not stall the motor, however, so I think I do have a pretty good exhaust leak at the heatbox joints.

Reply to
js

Is there oil directly above where the cylinders join the case? Compression figures look good to me, but maybe leaking when the engine cools down, then resealing when it heats up and expands. I would clean it all off and check it when you start it up when oil pressure is high, then when it's warmed up and finally after about hour after a run.

--Steve

js wrote:

Reply to
Phatman

That sounds like a good idea. No oil where it joins the case, just at the head. Can't see the top though (tin), but I am going to pull the engine once I get my Fiero running and check it then. I don't know about you, but I am really curious about this. I would think that this would be a common problem, but I guess not. I did NOT lap the heads with the jugs, since I had read that this can mess up compression ratios, but I might do that if they actually are leaking. That is what I was thinking too, since I know that aluminum heats and cools 5 times faster than mild steel (136 BTU/hr vs 26 BTU/hr) I am going to tune my carb today (got a new tester with a digital tach yeah!) and when I do I will check compression after a run. I hate removing the plugs hot though, that is going to suck :-(

(Currently listening to the Jayhawks "Tampa to Tulsa")

Reply to
js

there shouldn't be oil in the cylinders to leak out....

Reply to
Joey Tribiani

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