any one on here using an aftermarket head that uses o-rings to seal ? Im looking to machine o-ring grooves into a stock head...but want to know what sort of size o rings they use in aftermarket ones! Cheers
Logan has an o-ring girdle head which will be coming off shortly (when he gets around to it)... His engine seized down at Pauanui. Its in Howick too so not too far away. And my RIVA head is rubber o-ring? (I think his are some alloy compound)... Its off already. But one question... Why? They seem more trouble than good to me! All I ever hear about is people replacing them!
Some of the reasons I can think o-rings would fail are, head or cylinder surfaces are not true, o-rings in bad condition, and maybe the main cause could be detonation..... just my thoughts. Ok..... on the ADA website they say they use a 043 viton oring, "viton" is the material it is made of, more heat resistant than normal "buna" o-rings. http://www.adaracing.com/viewitem.php?i ... watercraft then you go to http://www.mcmaster.com/ and search that page for "o-rings" click on that. Then from that new page select the drop down menu near the top and select "043" or just 43 in this example, that will give you the spec of the o-ring. According to this thread Riva use a 153 viton : http://www.pwctoday.com/showthread.php?t=43074 Here is a pix of a standard head that is o-ringed: that head is off ebay: http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0136371549 You may have to machine your squish band, on a 701 engine 0.045-0.050 inch seems to be the suggested SAFE size. How to measure your squish: http://www.x-h2o.com/showthread.php?t=2681 If you go ahead tell us how it works out...... I have not read on a forum anyone actually doing it but it seems a good way to check on your engine without having to spend money on head gaskets, I have heard that only genuine yamaha head gaskets should be used as cheap aftermarket ones actually can absorb water and then cause corrosion between the head and cylinder surface. Dean.
i want to raise the compression......so figure i can either machine the head down a bit .....or put in o-ring grooves and use o-rings...that way you loose the thickness of the head gasket (hence raising compression) .... what sort of problems do you hear about? blowing them out etc?
and after all that we still need someone to measure the depth of their o-ring groove so we know how much crush to apply to the o-ring..... ha ha.
yea i saw that head on ebay.....thats what gave me the idea of putting grooves into the stock head... I think there is also silicon o-rings availble now too ...they mite hold up better?
I would think removing the gasket and using o-rings would reduce the squish band to a dangerous level, which is why that head on ebay has had the chamber reworked.
give roger parker at jetwerx a ring. he mite be able to help or send you in the right direction. but im sure he would advise against this.
o ring heads seem to be a pain in the ass. i have a removable dome head but i dont use orings i use a stock head gasket. more reliable.
The head currently on my ski is standard, with a skim to 180psi... And i am using a standard gasket... How high do you want to go? I wouldnt recommend going much past 190 for reliability / engine life...
Not certain but i thinks by raising the compression it increases power by increasing the vacuum force in the cylinder and also raises rpm. :roll:
the love o ringed heads , ive never had a problem running them even when my engine was running 220psi off compresion . when i was building my engine and trying to tune i was takeing the head on and off at the lake all the time checking the pistions ans such , cant do that sort off thing with gaskets .
