thick or thin head gaskets?

[Mr Mike]

I'm going to be doing a valve job on my 60 Hawk. The engine is stock as far as I know, except for a Pertronix kit. My questions are:
1. How much do the thicker head gaskets change the compression ratio?
2. Would the lower compression ratio be beneficial with today's 87 octane regular unleaded fuel?
Thanks, Mike

[BobPalma]

1. About a half a point.

2. Yes. But I'd use at least 89 anyway. BP

[Mike Van Veghten]

1. Like Bob says...just under a half a point loss in compression.
2. If it ran well on 89 octaine gas before, with the steel shim gasket, I would put that type back in.

You'll be happier with the overall outcome....
A little more (as original) compression - a good thing
a little better gas - a good thing
Fresh valve grind (clean, well sealed valves) - a good thing

Mike

[Mr Mike]

Thanks for the input guys. Unfortunately, in my area (southeast So. Dak.), 89 octane is only available as a 10% ethanol blend and 92 octane is pretty much a thing of the past. Do those octane boosters work?
Mike

[studegary]

quote:Originally posted by Mr Mike

Thanks for the input guys. Unfortunately, in my area (southeast So. Dak.), 89 octane is only available as a 10% ethanol blend and 92 octane is pretty much a thing of the past. Do those octane boosters work?
Mike

In many areas you can not get any gasoline that is not at least 10% alcohol. This is okay, as long as you have changed the rubber/neoprene parts of your fuel system to modern materials, which you should do anyway.

Gary L.
Wappinger, NY

SDC member since 1968
Studebaker enthusiast much longer

[PackardV8]

FWIW, most Studebaker V8s other than R-series, had compression ratios in the 7.5-to-8.5 range and will run fine on anything out of the pump IF the ignition is properly set for initial and total advance.

In the metro areas of Washington state, we have had 10% ethanol in our 87, 89 and 91-octane fuels for a long time now. I have run my completely stock '55 E12 with the 224" V8 for many years with no problems. The ethanol does not have as much energy as gasoline, so it reduces fuel mileage by about 5%.


thnx, jack vines

PackardV8

[Mike Van Veghten]

Like Gary and Jack note...and again...the thin gasket and 89 oct. gas.
10% ethanol....most people don't even notice...neither will your engine.

Mike

P.s. - the more ethanol...the more compression that's required to make up for the lost power in the fuel.

Note - an alcohol burning, supercharged, 500 inch Hemi runs in the 13 to 1 range for compression.
By comparison, the same engine on race gas...will need to run in the 6 or 7 to 1 compression ratio.

[pszikszai]

I bought a car which had thin gaskets.
It leaked water into one of the cylinders.
It ruined an otherwise low mileage engine.
If you are going that route be careful to seal it well.

[53k]

quote:Originally posted by pszikszai

I bought a car which had thin gaskets.
It leaked water into one of the cylinders.
It ruined an otherwise low mileage engine.
If you are going that route be careful to seal it well.

Maybe the gaskets had been installed without using a gasket sealer (like copper). My dad used to just use ordinary paint as a head gasket sealer.


Paul Johnson, Wild and Wonderful West Virginia
'53 Commander Starliner (since 1966)
'64 Daytona Wagonaire (original owner)
'64 Daytona Convertible (2006)
Museum R-4 engine
1962 Gravely Model L (Studebaker-Packard serial plate)
1972 Gravely Model 430 (Studebaker name plate, Studebaker Onan engine)