Why 2 head gaskets?

[forcenine]

Dear Don, et. al.,

If I am experiencing low compression, why can't I just use one head gasket instead of 2? My marina mate who helps me is dying for me to use only 1.

Lisa

[msauntry]

I've wondered the same thing. The compression on these engines seems EXTREMELY low. Anything that can get it a little higher can't hurt. I don't think you'll have any clearance issues by running only one gasket.

If you go for it, please post some results on this site.

[forcenine]

Don-why Two?

HI Don,
I'm still curious about your take on the use of 2 head gaskets, esp with my low end compression, and the rate I'm going through heads (!). Do you consider it essential and why?
Lisa

[sunnnnseeeker]

Note from Don that I had seen he posted some time back.

[Don Moyer]

Lisa,

Please see attachment. I thought I had responded to this question
previously, but I don't see it in your recent thread so perhaps it got lost
in cyberspace.

You can see in the second attachment that the Atomic 4 was designed with a
relatively long stroke versus its bore diameter (referred to as an "under
square" design). This really unique design of the Atomic 4 produces its
famous smoothness and long-lasting reliability across a wide range of RPM
using fuel from the lowest to the highest octane.

Artificially raising the design compression ratio of an engine to overcome a
loss of compression is almost exactly the same thing as whipping a tired
horse to pull harder on the plow. Even if you get a momentary boost in
performance, it will be short lived as blow-by increases through bad rings
and valve seats and all you will have done is screw up the wonderful and
unique "personality" of the Atomic 4.

Don

[Greg]

Why Victor gaskets & 2 of them ?

I'm a new Atomic 4 owner and we lost the #3 + #4 cylinders yesterday after purring away for 60 miles. It was my luck that I had asked my mechanic to help transport my boat with me. We pulled the head and found the infamous green gasket. He feels it was the offender. His questions now are
1) why the Victor gaskets ? Are OEM gaskets still available ?
2) Won't 2 gaskets invite cylinder leakage between the 2 ?
3) Did the factory recommend lubing the head studs on re-installing or cleaned and dry ?

I've read the posts to him from the 2 gasket pdf Don provided, but he's still not convinced.

Thanks .. I'm very thankful for this forum.

Regards, Greg
Ericson 32
Sirena
Isleton Ca

[Don Moyer]

Greg,

I spoke to a mechanic about this subject last Friday, I don't recall his name, so I don't know if it was your mechanic or not.

In terms of using one or two gaskets: in designing the thickness of the steel reinforced graphite gaskets which are currently in use on the Atomic 4, the engineers at Victor Gasket Co. concluded that the "crush factor" on the graphite gasket material would result in approximately the same thickness as the original copper-clad asbestos gasket - if they are installed in pairs and properly torqued to 30 to 35 foot-pounds. In this way, the original compression ratio of the engine could be maintained.

Universal also recommended the use of two head gaskets, not only for the reason explained above, but also because they felt that a head could be removed more easily if two gaskets were used. While we have no evidence from our own experience that heads come off any easier with two head gaskets, the design thickness of the Victor gasket has apparently worked out rather well in terms of compression ratio, since compression values tend to be around 90 to 110 psi on engines in average condition (depending mostly on variations in the depth of combustion chambers in the head). As a point of reference, the original design compression value for the Atomic 4 was 95 psi.

Westerbeke, which came to table somewhat later than the rest of us in converting to the Victor gaskets, chooses to sell the gaskets singly (for approximately the same price the rest of sell them for in pairs). While we acknowledge Westerbeke's OEM status with respect to the Atomic 4, we disagree with their position that it's OK to use the Victor head gaskets singly, and we have been following the advice of the manufacturer and of Universal since these gaskets were introduced approximately twelve years ago.

Regards,

Don Moyer

[Greg]

Head gaskets

Thanks Don,

The explaination sounds good to me. I'll talk to my mechanic tomorrow and order up the parts.
Do you happen to have an opinion on the dry -vs- oiled studs ?

Regards, Greg