MLS gaskets

[EtienneGignac]

Opening the can or worms...

So how realistic is it really to use a MLS gasket on a non-machined block and expect it to seal properly ?

Would copper spray compensate for any imperfections in the block surface ?

[nbskyline]

What was wrong with the engine?? No compression due to headgaskets failure??

[EtienneGignac]

Yup. Headgasket not sealing. Not sure if it was because of the assembly or what...and I do have a oem one lying around that I could use...

[nbskyline]

This is sounding very familair... I had boiling/bubbling coolant and low compression in #5 and #6 after I did a headgasket. The air would not bleed from the system. I am thinking mine is the same thing. I used a Tomei one and had the head skimmed?? Did you actually get it running to see where it was leaking?? Can you tell by the headgasket you took out that it had failed?

[EtienneGignac]

I just took the head off and the gasket looks in top shape. No idea what the problem was. It's like the head wasn't torqued down strong enough. Weird. Anyway I put a non-MLS gasket and put the head back on. Sis a leakdown test and everything seems much better now.

By the way is it normal to have air escaping through the exhaust valves eventhough I just got a valve job ?? It's not major but I can definitely hear it in the exhaust manifolds...

[JD74]

How do you expect to build cylinder pressure on the compression stroke if there are airleaks ? Yes, it's a problem.

[EtienneGignac]

Well I've heard new engines having 50% leakage so....obviously a certain amount of leakage is normal.

[JD74]

Well I've heard new engines having 50% leakage so....obviously a certain amount of leakage is normal.

That's crazy... 50% ? I just can't believe that.

[M13]

Did you skim the head?

[EtienneGignac]

Yes I did.