[grandville455]

What would make the gasket distort like this around the cylinders?

My car has been using coolant ,but i haven't been able to find out where , so i tore down drivers side tonight. This is what I found..Is it from not enough clamping force, not retorqued? 1016 Gasket. The #7 bolt wasn't very tight at all, and another one too somewhere on it, don't remember now, guessing that's what caused it to move n distort? It's been running fine, not hot or anything, i did a coolant pressure check it held pressure, nothing in oil, or coolant, thats y i was baffled. The one thing i did find was weird is it would hold pressure for 2-3 days before i could open rad cap. i just thought it was the griffin rad,lol.. guess not huh

[72pontiac]

only a guess but there's something about the finish left after decking a block and milling heads. forget whats its called. RA, roughness average I think. when too smooth it causes gasket creep. not even sure if that's with all gaskets or just copper. some one will explain better im sure.

[blueghoast]

With it being lose like that will let it move around.
I don't usually retork either, But I will from now on
After seeing that.

GT.

[screamingchief]

I've seen a couple like that.

It's a combination of the block deck contour along the lifter valley and the Fel-Pro 8518/1016 gaskets design.

From the looks of the imprint on the HG in the pic,were looking at the deck side,right?

If you look closely you'll see there's a "dip" in the deck surface right where that failed,and it's a weak area of the gasket with that long oblong cut-out right there,put those two things together,and this is what seems to happen.

IIRC this is kinda why JBP does'nt like the Fel-Pro head gaskets all that much.

They make those holes in that area of the head gasket a bit bigger than they really need to be to maintain the "universal" nature of their head gaskets.

I mean dont get me wrong,if a head bolt was'nt tight,that too could of contributed,but the ones I saw like that were definitely torqued correctly (studs) and re-torqued as SOP,so it was clear it was the gaskets fault and not anything else.

Might be time for some cometics...

Bret P.

[grandville455]

Bret
I believe thats the way it sits on the dck so the side your seeing is the side that was against the head. I have a pic of the head too i can put up.

[screamingchief]

Got a pic of the other side of the gasket?

Anyhow,that really does'nt matter much,the problem area is pretty obvious.

IIRC that long "oblong slot" is there for the older heads w/rocker stud oiling,and on these later engines it's not needed,and the thing is it kinda leaves that area of the gasket more-or-less unsupported,which is bad because the head bolt is right there,so when that bolt for the head is torqued,that area can "squish around" and deform somewhat.

And if you look at the block,you'll see that "dip" area along the deck surface by the lifter valley that I mentioned earlier,that's usually right where that part of the gasket is as well.

The old gasket should've left a nice imprint on the block where you can see that too.

Like I said,I believe this is why JBP does'nt care much for these head gaskets.

Bret P.

[grandville455]

I can take one tomorow, but yes I agree i ordered another one to just get back running for rest of yr, but i will think about after season if i am going to open them up, then i may go to cometics too

[screamingchief]

It's a thought,that's for sure.

Dont get me wrong,I use these #1016 head gaskets too,so yeah I try to keep this stuff in mind when using them,but for a while I have seen certain trends with regards to these head gaskets too,so I can't ignore it completely either.

But for me,I'm still using iron block & heads and not making a ton of hp,so it does'nt seem to be that big a deal for me yet.

But planning to use some nitrous later on,so HG life keeps this deal on my mind.

Been thinking some,so I may do a few changes before I do that though,likely just gonna run it NA till then.

GTG

Bret P.

[grandville455]

Here's 3 more pics from the deck , u can see where it was leaking on #5 around fire ring and water jacket, also look at the impression between 1-3, then look at at 3-5 no impression, think it was cross leaking there too? 5-7 look like 1-3. The head has a Black spot in between 3-5 if u look at the picture also. I am going to get head checked for any warpage this week, hopefully today after work.

[steve25]

If the finsh on the deck suface on aluminum heads is not near mirror smoth when using the 1016 gasket it will fail in time just from the shearing forces of cooling and heating / expansion and contraction.

On a freinds 455 motor with a 671 blower running 10 psi of boost and cast heads and block we ran the 1016 gasket for years with no problem, then just 6 months after plopping on aluminum heads and placing some 80 heating and cooling cycles on the motor a gasket failed!

The cast iron motor ran with head bolts, and the re-build with the aluminum heads got studs which helped not one bit with the couse deck finsh on the new heads!
Its been 5 years now since the heads where resurfaced on a wet stone type mill (which is the only way to get a polished finsh) with the last 3 years of use during summer time being a daily back and forth to work driver and if I had to guess the motor currently has some 400 start up and cool down sessions on it with no problems.

Your high cooling system pressure after shut down for two days was from cumbustion gases getting in as they do not go away when the system cools down.
Your lucky you where not blowing hoses off of the motor!

[grandville455]

So How Do I clean up the surface now since its off, before i put it back together? Some of those bolts i got loose with my snap on cordless impact others i used a breaker bar, i think they lost their torque over the last 3 years since motor was built and allowed the head to walk just enough over time.

[fastekibeast]

I´ve same issue, but passenger side! same place like you... just make me wonder!

[ponjohn]

Darby how did you isolate it to DS or was it luck?

Are you sure the other side is ok?

[grandville455]

John
Plugs were easier to get at,lol.. So I thought why not ... Here are pic's of the pass side plugs, they look perfect.

[wheelspin]

Darby, you have a pm.

[PunchT37]

Looks like not enough clamping force to me. Bolts or studs?

[grandville455]

Originally Posted by PunchT37

Looks like not enough clamping force to me. Bolts or studs?

Bolts, Kinda what I am thinking too, my snap on cordless is good to about 80 ft lbs and it broke some of the bolts loose others needed a breaker bar and pipe on it to pop them loose.

[J.C.you]

Butler told me one time the Fel Pro gaskets should be called Fail Pros.

[Blued and Painted]

What's the coolant temp peaks looking like before gasket failure?

[65nss4spdGTO]

I would question the flatness of the deck surface after the block or heads were machined.

Calvin Hill
Hill Performance
708-250-7420