Super Jet Why do I keep blowing O-rings?

[torquen]

At the end of last summer I was riding and noticed that my pissers started sputtering and the water temps were hot. I pulled my Pro-Tec full girdle head and found that one of the O-rings on the bottom side of my dome was blown. I bought the whole O-ring set from Pro-tec and installed everything perfectly. Torqued down all the bolts like the show in the instructions.

Today I went out for the first time of the season with a couple of buddies. The first 15 mins the engine was running great. All of a sudden the pissers started sputtering again with hardly any water coming out. It was steaming and leaving exhaust on the side of my hull. So this is the same result as the last time.

What could be causing my engine to keep blowing the O-rings? Its a 701 super jet bored to 760. Everything is correct on the engine. The first two seasons everything ran perfect. Any help would be awesome!
G

 

[Matt_E]

Common causes:
Cylinder deck is warped
Sleeves have dropped
Head shell is warped (may not apply to Protec head)
Cylinder bore too big for the domes (Are they 701 or 760 domes?

 

[kevbo]

O-rings keep water from getting to the sleeve. Combustion is sealed by the chamber sitting directly on the sleeve. Lap the deck and get new domes.

 

[Waternut]

First off, get some o-rings from mcmaster carr so you don't spend another arm and leg for $1 worth of o-rings. Before taking drastic action, it is possible that you just pinched the o-ring during installation and not necessarily anything to do with your head or cylinder. Try one more set and see if the results are the same and in the same spot.

If they blow again, check where the dome touches the head and see if it's drastically worn. If so, you could add some very thin stainless steel tape between the two to help bridge the worn gap.

 

[torquen]

Little more info. I installed new domes the last time I replaced the O-rings. The domes are for a 760 so that is correct.

Ill defiantly order the O-rings through McMaster Carr as Pro-Tec rapped me the last time. 10 dollars shipping on the O-rings plus the over inflated price.

I will check for and warping on the cylinder as well as the head. I have access to a very nice mill and all the tools so I can take a couple thousands off to make it flat without a problem.
G

 

[luker]

is it a 2 peice head if so ive had a ada head that after years of abuse the domes actually wore into the head shell and the dome o ring wouldnt seal enough

 

[torquen]

Anyone know what size O-Rings I need for the domes? Its the Full girdle head from Pro-Tec. I have not had time to tear into the engine yet but would like to order the parts from McMaster Carr. Thanks,
G

 

[wydopen]

is it a 2 peice head if so ive had a ada head that after years of abuse the domes actually wore into the head shell and the dome o ring wouldnt seal enough

i had the same issue..i think it does that cause the motor is detonating...some 1211 on the orings fixed it....now i always use it as to avoid any problems even with a new head..

 

[chriselmore_1]

Protec heads are a 2 piece shell. Quick I actually like better then the ada 1 piece. If a sleeve drops. The dome chatters around, wears the ada shell and then its useless. With tge protec. Blowsion. Kommander style if that happens you can just getv the top piece of the shel decked and itscall good. Plus I like how the domes lock too

 

[torquen]

Ok so a update. I have blown two more sets of Orings. Its always the same cylinder "front". I bought a bunch of Orings from McMaster Carr so at least I'm saving some coin.

The last time I added the Stainless .002 tape that McMaster Carr sells. It was recommended here to shim the domes. I also added a very thin layer of Perma tec copper seal on top of the shims. Torqued every thing down and checked my compression with a Snap On compression tester. Both cylinders were exactly at 190 psi.

Went out to the local river and rode the ski. Everything was working perfect. Pissers had a nice solid stream coming out. About 30 mins into the ride I could hear the pisser starting to spit and pop. Looked down and I could see that Ive blown another Oring. I'm getting tired of taking this apart. What is the next step?

I have checked the sleeve and cylinder height. Both are perfectly flush. I called Pro Tec and they told me its probably from detonation. The domes have zero signs of any detonation. Should I take the head down to my buddies machine shop and shave some off? If so how many thousandths should I take off. And should I take the shims off the domes afterwords?
Garrett

 

[Crab]

Something is not flat...

 

[chriselmore_1]

That shimming only needs to be done on the garbage ada heads. Like i said. Just deck the top peice of the shell enough to make it flat post pics of the head in detail and the domes

 

[torquen]

That shimming only needs to be done on the garbage ada heads. Like i said. Just synch the to price of the shell enough to make it flat.post police of the head in detail and the domes

Say what?

 

[chriselmore_1]

Sorry edited lol