symptoms of a blown/leaky head gaskey under boost?

Wheel House Motorsports · Oct 25, 2009

Alright, starting to chase down my problems... just throwing ideas out there to see what on earth my problem is.

i notice when i start my sled i got a little coolant in the exhaust... and when i build boost it will push a little out the overflow till it drains some, then it just pushes some air out.

when I installed a powerderlites shim i just split a gasket around it but i used a gasket tack spray on it.. if it was leaking could this be causing my crazy lean out as soon as i begin to build boost? just looking for symptoms of a blown gasket as if its not seated right this oculd be all my issues yes?

kinger9 · Oct 25, 2009

If your pressurizing the coolant system 90% of the time its a bad head gasket. Sorry bud this will need a tear down it appears.

zebiraross · Oct 25, 2009

Ski-Dooin it said:
Alright, starting to chase down my problems... just throwing ideas out there to see what on earth my problem is.

i notice when i start my sled i got a little coolant in the exhaust... and when i build boost it will push a little out the overflow till it drains some, then it just pushes some air out.

when I installed a powerderlites shim i just split a gasket around it but i used a gasket tack spray on it.. if it was leaking could this be causing my crazy lean out as soon as i begin to build boost? just looking for symptoms of a blown gasket as if its not seated right this oculd be all my issues yes?

Look at your plugs too. If you are pushing antifreeze you will see some green on the plugs. You can also do a compression test. Most times you can see if you lost a hg if you have a cylinder signifigantly lower then the others. Sometimes you can't find a leaky hg with a compression test though. When you do your head gasket do it dry. Also what did you torque proceedure did you use? What was your final torque? You shouldn't of lost a hg just dinking around in the garage unless you were lean poping it for extended periods of time. But like Kinger says, if air pushing into the cooling system that's most likely a head gasket.

SRXSRULE · Oct 25, 2009

More then likely its a blown head gasket.

Here is a simple way to check any internal combustion engine for a blown head gasket. Disable the ignition system so the engine wont start. Then fill the cooling system all the way full, you may need to plug off the overflow hose but fill it all the way to the neck. the crank over the engine and watch the cooling level. If it rises or has air bubble coming up you have a blown gasket or cracked head. When you start cranking you may see a slight rasie or drop in level but it should not change after a couple seconds of cranking. Dont be afraid to crank it for 15-20 seconds to give it a good test.

The rise in coolant level or bubbles is from combustion chamber gasses bleeding into the cooling system. Hope that helps. Eric

Wheel House Motorsports · Oct 25, 2009

thanks for all the advice, i may give it a run with the plugs all pulled and see if i get any bubles in the coolant jug... i also am gonna borrow a compression tester and give that a run when i do my other stuff.

as far as torque specs, i ran the ones ted jannety has posted over on TY somewhere, so there good methinks. always possible something weird gets stuck to it and doesnt seat right... im also gonna get some of the test strips from napa to test for gases in the coolant. coolant system seems to be better. but i dont know, still getting a little on anything but a really hot start in the exhuast... would be cool if thats all it was, but not so easy to pull a head in the RT.. whole top of the sled has to come off!

SRXSRULE · Oct 25, 2009

If you remove the spark plugs you wont see anything in the cooling system. bubbles in the cooling system would be combustion chamber gasses, Once you remove the spark plugs you have no compression.

Also a compression gauge will not do you any good to test for a leaking headgasket. I leaking gasket, depending on how bad it is, may only show up 5-10% down on compression. You could try and do a cylinder leak down test but not a cranking compression test. Eric

Wheel House Motorsports · Oct 25, 2009

i ment coils from the plugs. sorry, typing to many responses to try and figure it out!

SRXSRULE · Oct 25, 2009

Thats understandable. just want to make sure your headed in the right direction. Eric

4bangrboost · Oct 25, 2009

got any pictures of your sled?

Wheel House Motorsports · Oct 25, 2009

some over in my build thread in perf/mod but no recent ones.. i been lazy.

im thinking im having some huge jetting issues... so we will get back to the gasket theory when i swap larger jets in.

bigrhett · Oct 25, 2009

I feel your pain...and I think it's a head gasket too.

I didn't have coolant in my exhaust, but I was blowing out coolant when on boost. It didn't have any problems until it boosted, then it went to pot. I thought maybe I just needed more cooling, 'cause I didn't want to tear it down, but it was absolutely the head gasket.

And, I agree with Zeb... Absolutely clean surfaces, I used acetone to wipe down the surface and didn't touch it with anything after that. Then I torqued it down according to the procedure in this thread: http://www.snowest.com/forum/showthread.php?t=120396

That thread details my story and once I replaced the gasket and torqued the head according to the instructions...no more problems.

As an aside, I did NOT use new head studs and have not had any problems, so I don't think that is a necessary thing to do.

Oh, a compression test and a coolant pressure test didn't find it for me since it was only on boost it happened...standard cylinder pressure wasn't enough to make it leak so I couldn't find it that way.

Rhett

SLY · Oct 25, 2009

Sounds like a gasket to me. I had one on my Nytro last season and it would only get air in the coolant when seeing higher boost over about 15. Was constantly purging it. Didnt show up with pressure testing cooling system or leakdown but I knew it had to be the gasket so tore it down and you could see where it had blown. Funny thing is that it was a dry gasket that went in and usually I spray them down with copper spray.

Wheel House Motorsports · Oct 26, 2009

well, guess im gonna order up not only some jets, but also 2 new gaskets to sandwich my powderlites shim. appreciated all the help on diagnosing the problem, gonna be the death of me if i didnt figure it out.

as far as gasket in, i cleaned the whole thing off good, but its so easy for a fleck of dirt to end up in it... just how things are.

and what do you guys put on the studs when you torque em down, i know i read somewhere something about putting some sort of lube on em so they fully torqued right

M5- · Oct 26, 2009

Ski-Dooin it said:
well, guess im gonna order up not only some jets, but also 2 new gaskets to sandwich my powderlites shim. appreciated all the help on diagnosing the problem, gonna be the death of me if i didnt figure it out.

When you do the headshim you only need 1 new Yamaha gasket. The stock Yamaha gasket is 3 layers thick. Seperate the three layers throw away the middle one and replace it with the headshim. I not sure why you would be ordering 2 gaskets but if thats what you did last time that's your problem.

M5

zebiraross · Oct 26, 2009

Ski-Dooin it said:
well, guess im gonna order up not only some jets, but also 2 new gaskets to sandwich my powderlites shim. appreciated all the help on diagnosing the problem, gonna be the death of me if i didnt figure it out.

as far as gasket in, i cleaned the whole thing off good, but its so easy for a fleck of dirt to end up in it... just how things are.

and what do you guys put on the studs when you torque em down, i know i read somewhere something about putting some sort of lube on em so they fully torqued right

It's called arp molly lube. ARP sells it with their head studs. You can also get it by it's self. It reduces friction when torquing so you can usually acheive around 10 ft/lbs more torque then using just oil. That being said, I ran all last year about 18 psi and my stock head studs did fine with 38 ft/lbs and using just oil. I installed some arp's this summer though because I plan on running a little more boost this year.

Turbo11T · Oct 26, 2009

Cam timing

If you have it apart might as well change the cam timing to powderlites specs as well. I think 114 degree lobe centers will get you where you should be. Also if you absolutely need to change the cam timing if you didn't before. Adding a thick gasket will put you off on cam timing and hinder performance. I am sure there are guys on here that can give more info on the correct cam timing and the importance of it with the head shim. I am a newbie to all this but have done a extreme amount of reading!

Wheel House Motorsports · Oct 26, 2009

Yeah, i guess seing as im going to be in it again, anyone want to let me in the know on how to adjust the cam timing on the rx1?

as far as the moly lube, ill just keep with the oil as im not going to be pushing the boost at all.

and I did forget the yami gasket was 3 layers.. just needs to be seperated, so only have to order 1 of em! i did split em last time, just think i kinda trashed em em when i went to install and got a poor seat on it.. the black stickey stuff between em was kinda trashed, so probably didnt seat well at all... after looking around even MORE at my sled i did notice I also had a tiny bit oil seaping out from around the head gasket under the carbs right by the cam chain tensioner.. so this definately says it didnt seat right.

Turbo11T · Oct 26, 2009

Become a member on ty4 if your not already. There is alot of info over there about cam timing and installing head shims. A few step by step right ups and everything.

bigrhett · Oct 26, 2009

Ski-Dooin it said:
and what do you guys put on the studs when you torque em down, i know i read somewhere something about putting some sort of lube on em so they fully torqued right

I just used engine oil, torqued them down in stages, then backed them off a quarter turn and went to the final torque like someone else posted: "tork in proper sequence, 10 lbs then 20 lbs. then 28 lbs. on the last tork turn back 1/4 and retork to 28lbs. in one motion as you go through the proper sequence."

Zeb is saying 38 lbs, I went to 28-30 lbs and have been fine. I only run 18-19 psi of boost max.

kinger9 · Oct 26, 2009

My head gasket did the same thing on a rebuild it ran fine idled fine but at 9000+ rpm it would blow past the gasket and cut out. Ended up a TQ issue I had ARP studs TQ'ed at facotry spec big no no. Went to Factory studs TQ'd per Ted janetty with moly lube and voila cured.

It may be worth a call to Dave at powderlites and just let him explain the process and pitfalls of using his spacer so this will be the LAST time you need to get that head off. Just find out what he does for the boost your running and go with it. I got too much advice on mine and ended up all crossed up. Now I just pick a tuner I trust and say what do you do, how many units are running like this, and when is the last failure. They normally always say do this, have 20-30+ with no issue. good enough for me! LOL

I feel your pain man, the only down fall on 4 strokes is getting that head on and off is a PITA.

symptoms of a blown/leaky head gaskey under boost?

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