Head Gasket Shot, or Bad Rings on 1.8L ?

[RacerM]

I have bad compression (70 psi) on cylinder #1. A cap of straight 30 oil in the hot cylinder brought it up to only 75 psi. The other cylinders were about 140 psi. I also have a lot of white smoke coming out of the oil fill cap. Also, when i put air pressure into cylinder #1 (at TDC), similar to a leakdown test, the air came out the fill cap. Is there any way to tell if the air is going past the rings, or through the head gasket? BTW, this car has only about 90k miles on it.

 

[killab443]

It's sounds like a head gasket to me. ANy smoke coming from the exhaust? You should check you coolant overflow for oil as well as you oil for coolant.

 

[RacerM]

Yes, I had some smoke from the exhaust--mostly white, but some blue.

I pulled the head today--I'm still not sure how the combustion gases were getting into the crankcase. The cylinders looks O.K., with some slight pitting that I can just feel with my fingernail. I hoped to see some indication of a leak through the head gasket.

Also, what is odd, is that there is a good distance between cylinder #1 and the oil drain hole. . .

Here is a link to a head gasket photo to illustrate. (cylinder 1 is the bottom left hole :

http://www.drivewire.com/mitsubishiparts/catalog/mitsubishieclipsecylinderheadgasket.html

Any ideas on this? I really don't want to put new rings in this engine BUT, I'd rather do it now than later if it is what I need to fix the compression.

 

[killab443]

The gasket wasnt broken at all? If you're blowing white smoke it is coolant and it appears in the pics that the coolant is the closest to the cylinder on the gasket. I dunno what to tell you about the combustion chambe tho,

 

[1.8laser90]

my 1.8 just did the same thing, but mine is defiantly the headgasket. it blows white smoke and shoots coolant out the overflow botttle or out the cap if u don't have it on. i just replaced my headgasket last year and had the head completely rebiult and shaved so its flat.. so i'm kind of confused on why it blew, i was hard on it at the time but nothing to do this. all i have to do is unbolt the head and its ready to pull off...

 

[RacerM]

I cleaned all of the gasket residue off of the block and head today. The block looked fine, but the head had circular gouges in some areas where the steel head gasket fire-ring sits. I am assuming that this is where the leak is, and I'll be OK without doing a re-ring. Any thoughts on this? Is this how head gaskets typically fail with an aluminum cylinder head?

FYI, the circular gouges were about .010" deep and about 2" long.

 

[1.8laser90]

take the head to get shaved to make the heads surface flat again if not u might go threw another headgasket.

 

[killab443]

Very tru. Alumium likes to warp with accessive amounts of heat. I would definitly get it resurfaced and maybe even do the valve seals too while its outa the car. And you'll get a bump in compression from shaving the head

 

[RacerM]

Yes, I'm planning to get it resurfaced. I have a local NAPA that does this for about $25. How much material should I have them remove without pinging on 87 octane? Will this alter the valve timing too much?

Also, is there any way of knowing how good my piston rings are at this point (with the head off) ?

 

[killab443]

Do you still see the factory crosshatching on the cylinder walls? The walls are the only way to really check without dissassembling the block

 

[RacerM]

Unfortunately for me, it appears like the crosshatching is gone on the bores, and now, on cylinder #2, I can see part of the top ring, because a very small piece of the piston is gone. I'm not sure now if I should rebuild this engine, or buy a junkyard engine. . . Rebuild kits with pistons appear to be $350+. If I could find some used pistons, it might make sense to rebuild, but I guess I will measure the bore to see if the standard size rings would fit. Thanks for all the input.

 

[killab443]

Id say swap it. You can get a junkyard 1.8 and change the timing components for less than 500*