27 thou head gasket cometic : V-Twin Forum: Harley Davidson Forums

Booggerbe · 11-08-2009, 10:25 PM

Anyone had any experince with the cometic 0.027 thou head gasket. Was running some compression numbers and could up the compression this way. just wondering if it would hold up or blow out. Thanks for any knowledge. booggerbe

JustDave71 · 11-08-2009, 11:29 PM

please excuse my ignorance but when you guys talk about this stuff are you talking putting a slightly different thickness gasket? what effect does that have? is it something that can only be done on certain motors/builds?

06roadglide · 11-09-2009, 07:13 AM

I ran them in my 95" without any problems. Have you checked your deck height? I wouldn't run them if your piston is higher than -.003" . You could get away with it at a bit tighter but you'd have to be careful until fully warmed up.

aharp · 11-09-2009, 04:10 PM

I'd make sure things are VERY square on those surfaces

Ozroder · 11-09-2009, 06:03 PM

I have not run .027" head gaskets, but I dont think you will have any issues if the pistons are running up to zero deck height.

It would not hurt to check piston expansion (if you can find this out from manufacturer) and piston roll over at top of stroke to see how much the piston is intruding into head space...........obviously a loose piston will have more roll over than a tighter fitting one....

Ozroder

msocko3 · 11-10-2009, 01:04 AM

I've got 20,000 miles on a set but I'm only at 10.1 compression.

Booggerbe · 11-10-2009, 06:34 AM

Thanks to all, I was just thinking of a easy way to raise compression but i no better.LOL. Just never heard of anyone running the 27thou. Thanks booggerbe

springer- · 11-10-2009, 10:04 AM

Quote:

Originally Posted by Booggerbe

...Just never heard of anyone running the 27thou.

We offer a .021 and a .026 (not cometic). These are good for when the deck height is low. If your piston is say .008" down in the hole, a .026" will get you to .034" squish. We don't recommend running them with a zero deck height.

tmwmoose · 11-11-2009, 09:02 PM

Who makes the .027 gasket and is it available in 4.125"

TXCHOP · 11-11-2009, 09:07 PM

http://www.bigboyzheadporting.com/showthread.php?t=140

If ya want copper? click link. .026

PhilM · 11-11-2009, 09:24 PM

Quote:

Originally Posted by tmwmoose

Who makes the .027 gasket and is it available in 4.125"

Cometic will make anything you want, if ya get the right person on the phone. They made me several custom sizes when I was prep'ing for my 120 build.

route66paul · 11-11-2009, 10:01 PM

headquarters has some .027 gaskets.