AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I can't watch. With no changes, I see no different outcome.
Head Gasket experts...check in....
- Thread starter 70aarcuda
- Start date
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Let me think about this overnight.....yes..if I order them tomorrow they will be here on Thursday....hell..it is only money...lol
Since the the block is bored .040...do you order a .040 bore gasket?
Since the the block is bored .040...do you order a .040 bore gasket?
Krooser
Building Chinese Free Engines since 1959...
My block and heads are o ringed but those were not installed after the last rebuild. Not sure what I may use this time.
famous bob
mopar misfit
I bought 4.380 cometic for my 4.350 bore. After compression, the fire rings are out pretty even with the cylinders . Cometics can be used more than once . Nothing special on the finish, took just a .003 clean up to square mine , didn`t know I was going to use cometics when it was in the machine shop.---------
Forgot , I`m no expert !!
Duane
Well-Known Member
When I bought my gaskets from cometic they told me that after extensive testing, they have become less strict on the surface finish. They now recommend
Ra 50 is acceptable.
General machine shops can achieve this.
The potential issues with cosmetics is usually water seepage. At the recommendation
Of another member I put some hylomar around each water hole on the gasket. That is the same stuff Chrysler used to sell at the dealerships.
Mls is derived from the Diesel engine industry. They can take the cylinder pressure.
Duane
Well-Known Member
I think cometic told me .030 bigger than bore size.
Duane
Well-Known Member
What changes do you suggest?
He is asking opinions.
Time to o ring the block?
Hey Duane...............................
Duane
Well-Known Member
A change to An Mls gasket has made o ringing and the associated cost not required.
A 6 bolt block is the best fix but we have to work with what we have.
OK, my opinion is poor intake manifold fitment and lifting up on the head; it explains why gaskets only failed on the upper side towards the valley.......if it was because of the fact of only 4 bolts around the cylinder, you would have blow out along the bottom also......do we have that???? Gaskets didn't show me that.
I know people have a hard time "imagining" that ill fitting intake can lift the head.......it happens.....ask yourself, how much of the clamp load has to be relieved in order for the gasket to squirm out. That was why in my first post asked questions about how the intake fit on the china walls and what the actual deck height measurement is, they relate to one another.
At the moment, I can't find my MP engine book that gives the details, there is a brief 2 sentences in the block machining section that states for "x" amount removed from the deck surface of the block , you remove "x" amount from the china walls........think about it
They pretty much all failed. Cause?
Duane
Well-Known Member
Those are all valid points.
Only Tony can answer those fitment issues.
My comments were directed towards it being a tuning issue or a detonation issue or bad camshaft selection. The suggestion being to bleeds cylinder pressure to make the gaskets live.
But his motor is a drag motor with the intention of making maximum steam.
The 1008 gasket works very good for most people. But in some instances it is still not good enough and the Cometic is the answer. Most other small blocks have 5 bolts per cylinder.
Before the release of the fel pro
1008 the sbm was plagued by head gasket failure in very high compression/ high cylinder pressure situations. I am not saying some installation issue was not to blame, only that 11.8
Is getting up there and for a standard 4 bolt block, there is a better choice now. I inspected my manifold fit and port alignment with a bore scope down through the carb mount.
Great tool to see this. My end spacers are .120 though thick.
First engine: 360, .030 over, SIR rods, KB107's deck height 9.580, home ported "J" heads, 60cc chambers, M-1 intake. They failed in the first 3 seconds of the first run down the track with the engine, brand new.
When I got the car home and apart, found the gaskets, it became a 2 1/2 year search for a reasonable explanation about what happened. Very first thoughts were that it was detonation however, I ruled that out because if it was detonation, detonation that severe would most likely shattered the 107's or at least I would have seen evidence on the crowns of the pistons, they looked just like what they were, brand new pistons with felt tipped writing on them, rod bearings were still tight in the big ends of the rods. I measured head thickness, and head bolts 4 times to convince myself head bolts hadn't bottomed out before clamping down. I even sent the gaskets out to a "professional" for his opinion, he came back with detonation or head lift. I then had a lot of people tell me no way could an aluminum intake with 3/8's bolts pull against an iron head with 1/2 inch bolts.
Thought more about what stuff looked like when I pulled engine apart........I had noticed that bead of RTV was super thin (started life as average bead ) on front china wall, rear wall bead was just as thin, came to the conclusion that intake bottomed out on the china walls and pulled on the heads. To get passed the commentary about aluminum intake and 3/8 bolts pulling against iron heads and 1/2 inch bolts I remembered something I read in "Ripley's Beleave it or Not" that a common hose fly can cause measurable deflection on a 1 inch dia solid steel bar; is it significant deflection? No it is not, it's measurable.
So how much does the clamping force of cylinder head bolts/studs have to be up set in order for for the gaskets to squirm out?????
Krooser
Building Chinese Free Engines since 1959...
Has anyone here used 0-rings with a MLS gasket? How about the 1008 or even copper?
My 383 was originally built before all these fancy gaskets were around (1993) so I would imagine that's why it was o-ringed.I'm not pro or anti any gasket. I might just use copper with the o-rings or???
W-2 heads btw.
It will be some time before this thing gets screwed back together... $$$ is pretty much non existent right now.
My 383 was originally built before all these fancy gaskets were around (1993) so I would imagine that's why it was o-ringed.I'm not pro or anti any gasket. I might just use copper with the o-rings or???
W-2 heads btw.
It will be some time before this thing gets screwed back together... $$$ is pretty much non existent right now.
Watch what you say about orings, you might get the big red X.
No offense intended, just casual observation.........you seem to be doing alot of talking for Tony......I'm curious as to what Tony has to say
Duane
Well-Known Member
I am not talking for Tony other than to say the car runs low 10,s
In a car that is not a featherweight, and that takes some power. All I am saying is sometimes sbm pushing the limits have head gasket trouble
for the main reason of 4 bolts.
There does not always have to be a mistake in tuning or assembly to have trouble.
Duane
Well-Known Member
Here is a excerpt from the striker small block book about the sbm and head gaskets.
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