Cometic Head Gaskets

Cometic Head Gaskets

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By Genuinerod - 9 Years Ago

Are Cometic head gaskets as good as the price (over $100.00) or are they over priced? Anybody run these?

By Cliff - 9 Years Ago

Over priced, I like if you can find the RED Detroit gaskets, I do not like any blue head gasket.

By miker - 9 Years Ago

The local engine builder swears by them, especially on small block fords. If they had been available when I rebuilt the motor, I would have used them. But, Mummert heads, and 10+ compression. Detonation is right at the edge, and blowing the fire ring has happened twice. Vern Schulman (sp?) used to sell a similar composite gasket. Never had a problem with them, either.

By Ted - 9 Years Ago

One problem with the Cometic head gaskets for the Y (unless they’ve addressed this just recently) is that the gasket only installs on the right side of the engine properly. Cometic failed to put two oil holes in the gasket and upon installing this gasket on the left bank with the correct rear water jacket orientation, then the left hand rockers do not get any oil. I’ve both phoned and emailed them in the past on this and still haven't seen a revised head gasket. I've had very good results using the Best Gasket head gaskets all the way up to 14.2:1 compression ratios without the sealing issues I've had with other gaskets.

By 57RancheroJim - 9 Years Ago

I used Best gaskets for the first time on my 292 rebuild. I only have 6000 miles on it but so far so good.. I don't know what the material used for the pan and valley gasket is but I like it better then cork..

By Ted - 9 Years Ago

Here is the page out of the Cometic catalogue showing the Y gasket offerings along with a blown up detail of the Y head gasket in question.

By DryLakesRacer - 9 Years Ago

Not a Y, but Best has served me well on my 302 GMC 6 with 14-1 compression. No other gasket works as good especially between the cylinders.. Good Luck.

By DryLakesRacer - 9 Years Ago

One other thing on Cometics. Ted may need to help on this answer. I was looking at different gasket thicknesses for our Dart block super stock dirt car and Cometic lists different ones to raise and lower compression ratios. They needed different finishes on both the head and block; I believe smoother but I don't remember the #'s given to it. Our machinist advised us to leave a finish he said was normal and to continue with the Fel-Pro we had been using which was .041" crushed. We use 11.8 to 1 comp on the engine.

By Ted - 9 Years Ago

DryLakesRacer (12/13/2015)

One other thing on Cometics. Ted may need to help on this answer. I was looking at different gasket thicknesses for our Dart block super stock dirt car and Cometic lists different ones to raise and lower compression ratios. They needed different finishes on both the head and block; I believe smoother but I don't remember the #'s given to it. Our machinist advised us to leave a finish he said was normal and to continue with the Fel-Pro we had been using which was .041" crushed. We use 11.8 to 1 comp on the engine.

The Cometic MLS head gaskets require a fine finish on both the decks and head surfaces. Having that fine finish does allow the gasket to slip and slide (by design) when the head and decks are of dissimilar materials such as aluminum and iron. Cometic recommends a 50RA or finer finish but I've seen nothing about different finishes on the deck and the heads on the same engine. Cometic also recommends no sealer but I’ve found that spraying them with CopperCoat does help as I’ve experienced water seepage with them when using them straight from the packaging.

When using the Best Gaskets composition head gaskets on the Y engines, I’ve simply been spraying them liberally with WD-40 before installing them. The use of WD-40 has allowed the BG head gaskets to be reused up to six times when doing extensive head testing on the dyno mule.