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art leong 12-23-2007 11:45 PM

2 Head Gaskets???
 
Has anyone tried doubling up on MKS headgaskets. Two of them would give me .080 thickness.
I'm trying to be able to change compression ratio with out doing the machine work all over again.

Woodro Josey 12-24-2007 11:18 AM

Re: 2 Head Gaskets???
 
Art, you can get Copper Head Gaskets in about any thickness you need, stacking gaskets, i wouldn't reccomend that! Sounds like you have a lot of compression!

Tom Goldman 12-24-2007 11:40 AM

Re: 2 Head Gaskets???
 
Art, ditto on what WJ said. .... I run a .085" Hussy copper gasket on my Super Gas BBC 522@ 15 to1 and have no problems...The Hussy people are great to deal with for custom applications too...... I've had the best results sealing the water passages with either Permetex Super 300, or the brush on type blue Hylomar sealant. ..... Tom

Glenn Briglio 12-24-2007 02:20 PM

Re: 2 Head Gaskets???
 
Art, Try looking up Cometic head gaskets for the correct thickness or call them. If you have any questions call me at the shop next week (516) 599-7182. B&B Auto Machine.

Run to Rund 12-25-2007 01:12 PM

Re: 2 Head Gaskets???
 
From the cometic website, www.cometic.com

Can I order a head gasket with a different thickness than you have in your catalog?
Yes. Call Cometic with the engine type or Cometic standard part number (search online or in our catalog) along with the thickness you would prefer and we will create your custom gasket. (800-752-9850 or 440-354-0777)


Can I order head gaskets with a different bore size than you have in your catalog?
Yes. Call Cometic with the engine type or Cometic standard part number (search online or in our catalog) along with the bore size you would prefer and we will create your custom gasket. (800-752-9850 or 440-354-0777)

savoyracer 12-25-2007 05:44 PM

Re: 2 Head Gaskets???
 
Quote:

Originally Posted by art leong (Post 51652)
Has anyone tried doubling up on MKS headgaskets. Two of them would give me .080 thickness.
I'm trying to be able to change compression ratio with out doing the machine work all over again.

Ditto with SCE, I use a .093 custom made gaskets.......no troubles at all

goinbroke2 12-25-2007 10:05 PM

Re: 2 Head Gaskets???
 
ok, I'll ask the obvious. Doesn't having .080 or more clearance kill your quench? Or is there other factors to make up for it? (like the afforementioned 15:1) Huge domes, hemi with no quench to speak of...or am I right but this is a band aid?
(and sorry, I don't mean to be belittling a huge dollar well prepared race engine or offend by calling it "band aid")

Dave Goob Cook 12-26-2007 04:01 AM

Re: 2 Head Gaskets???
 
Quote:

Originally Posted by art leong (Post 51652)
Has anyone tried doubling up on MKS headgaskets. Two of them would give me .080 thickness.
I'm trying to be able to change compression ratio with out doing the machine work all over again.


How much compression do you want to lose?

What are the bore/stroke, dome cc's, chamber cc's you're working with?

Solid or hollow domes?

I would never run a naturally aspirated engine with that much piston to head, unless it were a flat head or Hemi as mentioned.

You can work a chamber shape and volume, lose some dome (best option), sink the valves or use a tulip style.....????

Help us out here with as much specific information as possible....

art leong 12-26-2007 10:10 AM

Re: 2 Head Gaskets???
 
Quote:

Originally Posted by Dave Goob Cook (Post 51843)
How much compression do you want to lose?

What are the bore/stroke, dome cc's, chamber cc's you're working with?

Solid or hollow domes?

I would never run a naturally aspirated engine with that much piston to head, unless it were a flat head or Hemi as mentioned.

You can work a chamber shape and volume, lose some dome (best option), sink the valves or use a tulip style.....????

Help us out here with as much specific information as possible....

Bore is 3.484, stroke is 3.976. 7.5 cc dome, flat of piston(not dome) 0.010 above deck Head cc's 49.5. Stock head gasket is 0.040.
Using the stock gasket I come up with about 13.5 to 1 compression. The piston was sent back to the manufacturer to cut the valve reliefs as much as possible and shave the dome.
With the stock gasket I'll only have 0.030 piston to head clearance. 0.60 piston to valve with the smaller of the cams that are available to me at this time
Using an .080 head gasket will lower my compressiom ratio by over a point, give me 0.70 piston to head (quench area) and allow me to use a couple of larger cams.
The next motor I build I'll have a piston made without these froblems. But for now I'm going with these.
Called Cometic today and ordered a gasket from them 0.74 thick. I'll yrt 2 gaskets after I get the the running and dialed in. For now It's one less thing to worry about.

Dave Goob Cook 12-26-2007 12:12 PM

Re: 2 Head Gaskets???
 
I see, it's a clearance issue more than compression.....

I get a difference of near 2 (1.9) points adding .040" on the gasket.

Gotta do what ya gotta do, watch your tune up on that one.

Good calculator tools here.... http://users.erols.com/srweiss/index.html#jcalc


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