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JoePA

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Discussion starter · #1 ·
I picked up a stock cylinder that was re-sleeved to a 310. I'm curious if a standard cool head will work or does the dome need to be reshaped? I have a cool head with a 19cc dome that I would like to use but checking to make sure it will work.
 
As long as the outer edge of the squish area matches up to the bore of the cylinder, that dome can be used. If not, then all it needs is for the squish area to be re-machined to match the bore.

Another thing you might want to think about, the OEM TRX cylinders sleeved out to a big bore, can be problematic keeping the head gasket area sealed when using just a gasket, so you might want to think about having the cool head machined so that o rings can be used instead of a gasket.
I will say, I've ran the OEM TRX cylinder big bores & used the gasket, but used Three Bond #1211 sealant on the gasket & allowed several days for the sealant to cure out before finishing the engine build.
Neil
 
Discussion starter · #3 ·
Neil,
Thank you for the reply. I use your 1211 sealant tip for all my builds as well as the head gaskets and it does work! Once I get the engine assembled Ill check the squish and go from there. I didn't want to go down this road but the price was right so i hope it runs well.
 
I picked up a stock cylinder that was re-sleeved to a 310. I'm curious if a standard cool head will work or does the dome need to be reshaped? I have a cool head with a 19cc dome that I would like to use but checking to make sure it will work.
Joe:

You need to make sure the dome CC's are matched to the larger bore piston, 72MM to 73.50 MM is typical for the 295/310CC BB sleeves in OEM cylinders. Note the Cool Head domes are not made for the BB 295/310CC sleeves, the use of the standard Cool Head dome (even the largest CC ones) are not enough volume for the Bigger Bores like 72 MM/73.50 MM....we usually machine the correct dome size based on the UCCR needed from a blank custom Dome for these set-up. You will also need to o-ring the sleeve & head, or run a special BB gasket....FYI

Carlos
 
If it were me Joe I would do as both neil and carlos said. But I would have the cool head have the oring grooves cut into it if it doesn't all ready. And if you can get a dome for your cool head recut for it thats what you should do to a 17cc dome for more compression also.
 
I think having a new dome cut, is the best way to go as well.
Because if you start machining on the old cool head dome, to get the CCs right for the 72 piston, it will probably cause the dome to be weak & could crack.
The cool head domes, has those fins machined into the outer part of the dome, so it dont take a lot of dishing out of the bowl area to weaken those domes.
Neil
 
Discussion starter · #7 ·
So is it better to machine the head or the cylinder for the o-rings? As far as what size dome. The best fuel I can't get is straight Sunoco 110 so it would have to be built for that.
 
Machine the head for the rings. LED used to make these modifications with the OEM resleeve to run with the GNCC guys like Bill Ballance back in the day. It might be worth it to give him a call to see what his opinion is.
 
So is it better to machine the head or the cylinder for the o-rings? As far as what size dome. The best fuel I can't get is straight Sunoco 110 so it would have to be built for that.
Sunoco 110 Is equal to VP110....good Race Fuel. Get the dome cut for the BB, oring or custom gasket, either way it is old school technology and should present NO problems.

Carlos
 
I think having a new dome cut, is the best way to go as well.
Because if you start machining on the old cool head dome, to get the CCs right for the 72 piston, it will probably cause the dome to be weak & could crack.
The cool head domes, has those fins machined into the outer part of the dome, so it dont take a lot of dishing out of the bowl area to weaken those domes.
Neil
Best advice yet on this thread yet from a real world experience guy.
 
is it better to machine the head or the cylinder for the o-rings? As far as what size dome. The best fuel I can't get is straight Sunoco 110 so it would have to be built for that.
One more point; If using orings, the Inner oring can be machined in the sleeve, the outer in the shell. Custom cut domes for the CoolHead shell prevent any dome failure.

Carlos
 
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