701 w/ 31cc domes and a head gasket compression?

[blasterDrey]

I've looked through the forums and cant find any solid numbers on this. I bought a used riva head with 31cc domes for my 701 (61x). That would make 110 comp if using the head orings. I need to run pump gas (91 ethanol free usually). Could I run an OEM gasket (.050" thickness) with the riva head and what kind of compression could I expect doing that? Is there another gasket I could use that would get my compression to around 170? Would porting have an impact on compression in this case? Thanks for any input guys.

 

[eastcoastjumper]

I've looked through the forums and cant find any solid numbers on this. I bought a used riva head with 31cc domes for my 701 (61x). That would make 110 comp if using the head orings. I need to run pump gas (91 ethanol free usually). Could I run an OEM gasket (.050" thickness) with the riva head and what kind of compression could I expect doing that? Is there another gasket I could use that would get my compression to around 170? Would porting have an impact on compression in this case? Thanks for any input guys.

On stock cyl
31cc domes gets you around 210+
33cc 200 ish
35cc 180 ish

You can't use a regular headgasket with heads meant for o rings

You change the domes to change compression



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[blasterDrey]

I want to avoid changing domes to save cash. It looks like all the cooling ports on the head would line up with cooling ports on the stock gasket. Would a thicker base gasket lower my comp some?

 

[eastcoastjumper]

have fun

 

[AAlamo]

If you want to save cash, go back to the stock head and sell the riva. I'd buy it for the right price.

 

[blasterDrey]

I guess I'll just be buying domes. Thanks for the input guys


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[augustaf]

I don't think that's available.

 

[blasterDrey]

What's not available?


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[blasterDrey]

have fun

I don't think that's available.

Damn, those riva domes are impossible to find, huh?


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[Freakrider]

Get the domes cut by an engine builder.

 

[blasterDrey]

Get the domes cut by an engine builder.

Okay, I'll look into that. Thanks


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[Freakrider]

I had a pair of 31cc race domes cut to 33.8cc for 85mm pistons on 93 pump gas running Total Loss.

 

[blasterDrey]

Where did you have that done? Was it by someone on the x?


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[Freakrider]

Team Scream Racing in Clearwater, FL, Chuck's new shop.

 

[blasterDrey]

I decided to run the head with a gasket I bought from superjet-113. All of the cooling ports match up. The compression was 175 in both cylinders. It ran great for all three hours I ran it on Sunday. I think it's going to be okay.

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[badvinny]

Not much sealing area where the dome meets the seal ring. I am pretty sure I have a set of 35cc domes I would swap you for the 31cc.

 

[Freakrider]

Not much sealing area where the dome meets the seal ring. I am pretty sure I have a set of 35cc domes I would swap you for the 31cc.

I agree on the minimal sealing area being sketchy.

 

[blasterDrey]

Not much sealing area where the dome meets the seal ring. I am pretty sure I have a set of 35cc domes I would swap you for the 31cc.

If I blow the head gasket, I think I'll take you up on that offer.


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