Head Gasket Cylinder Overhang

[RBCharger]

70 440, .060 over, TF 270 heads

TF called for the FelPro 1009 gasket.

The gasket bores are not round. On the intake side (top) of the gasket it overhangs the bores.

So bore on the 440 with .060 should be 4.38". FelPro website says 4.41 bore size on that gasket.

I've got plenty of room on the cylinder head to piston - .013 avg in the hole. Gasket is .039, so .052.

Gasket overhangs the bore on the intake (top side of piston) by a few thousandths.

I don't think that's gonna fly. Any insight appreciated.

 

[Don67Satellite]

I have read about this before and you are right, I don't believe that is going to fly.

Search around the forums and I think others have said FelPro 8519PT-1, it has 4.505, and no overhangs.

I'm sure others will chime in.

 

[GTX JOHN]

I would not run a gasket with ANY overhang period.
I have used that gasket on a number of 440 plus 060
over the years. Edelbrock/Max Wedge/Product Factory heads
and have never seen your problem.

I wonder if it is an issue with the casting of the Trick Flow heads?
I have never tried them.

 

[lewtot184]

Over hang is the kiss of death.

 

[gkent]

I wonder if it is an issue with the casting of the Trick Flow heads?

If the gasket is overhanging the bore, how is that caused by the heads ?!?!?

OP: you need a different gasket.

As for TF's recommendation, they don't know you're going .060 over !!

If you have the proper finish on the heads and decks then you could use an MLS gasket. Contact Cometic and they can solve your issue. www.cometic.com

 

[RBCharger]

I went with those gaskets becuase of the tighter bore (4.41") and because TF recommends. My bores are .060 over which should be 4.38". Everything else lines up.

The other FP gasket will change the compression a bit. Was trying to stay in the 10.5 range.

It seems like all of the bores on the odd bank overhang. I got cranky and didn't check the other side. Better to walk away at that point. This is supposed to be fun, right?

The FP 8519PT1 gasket shows a 4.505 bore and 0.039 in. compressed. That will change the compression a touch, but may not have a choice.

I'll look at the cometic, but sheesh those are silly money for gaskets.

 

[gkent]

The change in compression is insignificant. Besides, unless you confirmed the compression with fluid and a burette - the compression is just an estimate !!

 

[lewtot184]

I like the 8519 gasket and use them on both my cars. I have used the felpro 1039 with success on a 4.375 bore. Don't nicpic small compression loss; worry about torching the heads and having to weld them up on a continual basis
.

 

[451Mopar]

I have used the 8519 at 11:1 compression without issues.
What ever gasket you use, make sure it will seal inside the bore chamfer and cylinder head. Bore size means nothing when it comes to sealing because the chamfer at the top of the bore is larger than the bore size.

 

[RBCharger]

I like the 8519 gasket and use them on both my cars. I have used the felpro 1039 with success on a 4.375 bore. Don't nicpic small compression loss; worry about torching the heads and having to weld them up on a continual basis
.

The bore on that gasket is 4.59". The 8519 boes is 4.505". I'm only a few thousdandths off on the 2009 so leaning toward the 8519. The other issue with the 1039 is the compressed thickness of .051".

The 1039 puts my compression to 10.1. The 1009 is 10.48. The 8519 10.14.

Has anyone used the 8519 with aluminum heads on iron block?

 

[RBCharger]

I have used the 8519 at 11:1 compression without issues.
What ever gasket you use, make sure it will seal inside the bore chamfer and cylinder head. Bore size means nothing when it comes to sealing because the chamfer at the top of the bore is larger than the bore size.

No sure what you are referring to here - chamfer on the block?

Update - I just found another tech article on the upper cylinder Chamfer on the B/RB blocks. WTF was the factory doing? This is becoming a headache. This is likely what I'm fighting.

 

[RBCharger]

Update...talked to FelPro. They want at least .010 away from the bore, no overhang. Kinda knew this.

So gasket options:
FP 1009 4.41 bore, .039 compressed. Have sliver moon hanging over top of cylinder, WON'T WORK
FP 8519PT1 4.505. .039 comressed. Clears Cylinders, won't work on aluminum heads
FP 17059 (marine gasket) 4.5 bore, .039 compressed. Likely still won't clear bores - only .09 larger than the 1009 or .045 back from edge

 

[lewtot184]

The bore on that gasket is 4.59". The 8519 boes is 4.505". I'm only a few thousdandths off on the 2009 so leaning toward the 8519. The other issue with the 1039 is the compressed thickness of .051".

The 1039 puts my compression to 10.1. The 1009 is 10.48. The 8519 10.14.

Has anyone used the 8519 with aluminum heads on iron block?

I do. No issues. 8yrs on them.

 

[BSB67]

The 1039 puts my compression to 10.1. The 1009 is 10.48. The 8519 10.14.

I think you have a math problem. If the 1009 is 10.48, the 8519 will be 10.44. They are both 0.039” thick

 

[gkent]

I think you have a math problem. If the 1009 is 10.48, the 8519 will be 10.44. They are both 0.039” thick

The larger bore decreases the CR - albeit by a negligible amount

 

[not so famous bob]

70 440, .060 over, TF 270 heads

TF called for the FelPro 1009 gasket.

The gasket bores are not round. On the intake side (top) of the gasket it overhangs the bores.

So bore on the 440 with .060 should be 4.38". FelPro website says 4.41 bore size on that gasket.

I've got plenty of room on the cylinder head to piston - .013 avg in the hole. Gasket is .039, so .052.

Gasket overhangs the bore on the intake (top side of piston) by a few thousandths.

I don't think that's gonna fly. Any insight appreciated.

it will be worse after tightening it down , I used 4.380 cometic gaskets on a 4.350 bore , came out perfect , reuseable for a couple times ...!!

 

[68-500]

If its just the odd bank you might think about offset dowel pins. The cylinder head may mot be properly centered also?

 

[malex]

I’ve used cometic 4.350 bore gaskets on a .030 over 440. Which is 4.350.
No issues.

 

[451Mopar]

Update...talked to FelPro. They want at least .010 away from the bore, no overhang. Kinda knew this.

So gasket options:
FP 1009 4.41 bore, .039 compressed. Have sliver moon hanging over top of cylinder, WON'T WORK
FP 8519PT1 4.505. .039 comressed. Clears Cylinders, won't work on aluminum heads
FP 17059 (marine gasket) 4.5 bore, .039 compressed. Likely still won't clear bores - only .09 larger than the 1009 or .045 back from edge

The 8519PT1 works on aluminum heads, at least the B1 BS heads. They are also really inexpensive, I think less than $20/set. I have been using Cometic MLS gaskets, but they are around $200 /set

 

[beanhead]

...Chamfer on the B/RB blocks. WTF was the factory doing?

It was all about making it easier for the line workers to slam the pistons into the bores...or so I've been told (by someone that actually did engine assembly for Chrysler in the mid-late 70s).

This is becoming a headache. This is likely what I'm fighting.

I think you're overthinking it a bit....which we all do sometimes.
Forget the minimal compression difference due to gasket bore, the thickness has the greater impact here.
And, any gasket I've used did not have perfectly round bores; that's just how they make them. No problem.

FP 8519PT1........won't work on aluminum heads

Curious as to why you say this?

Do a search on this site, try "gasket" for the keyword and in the "by: Member" box, enter IQ52.
In case you don't know who he is, well...."legendary Mopar engine builder" would be one description