Apex head gasket replacement?

Modedmach1 · Jan 24, 2013

Gotta do mine this weekend anything I should or shouldn't do?? I have a Manual. It is a OSP motor, no head shim.

One thing I need is the torque specs for 10mm head studs..
Thx Josh

gunnerthesnowman · Jan 24, 2013

Modedmach1 said:
Gotta do mine this weekend anything I should or shouldn't do?? I have a Manual. It is a OSP motor, no head shim.

One thing I need is the torque specs for 10mm head studs..
Thx Josh

Do you have a replacement gasket , if its a OSP engine , he does not use a stock Yamaha gasket , is the block closed deck ???

Modedmach1 · Jan 24, 2013

Not sure I haven't tore it apart yet.. As far as I know its a stock block & head w/head studs rods & pistons. I didn't have the motor build the guy I bought it from did. What gasket do they use?? Thx

gunnerthesnowman · Jan 24, 2013

Modedmach1 said:
Not sure I haven't tore it apart yet.. What gasket do they use?? Thx

I take it you did not have this engine build , did you buy it already done ? He does different level of mods , do you know what pistons are in it , stock Or lower compression ?

Modedmach1 · Jan 24, 2013

gunnerthesnowman said:
I take it you did not have this engine build , did you buy it already done ? He does different level of mods , do you know what pistons are in it , stock Or lower compression ?

It has 10:1 Wiseco's. Yep bought the sled with the engine done..

It is pressurizing the coolant system under boost & losing coolant out of the vent line. The thing that has me a bit confused is it isn't burning any coolant & there is no coolant in the oil.. Guess I'll figure it out sooner or later..

gunnerthesnowman · Jan 24, 2013

Modedmach1 said:
It has 10:1 Wiseco's. Yep bought the sled with the engine done..

It is pressurizing the coolant system under boost & losing coolant out of the vent line.

OK , if it has 10:1 piston in it , it is not one of his full mod engines , should have a stock Yamaha head gasket.

What kind of boost you running ? may be a cracked head! , but more then likely the gasket.

Modedmach1 · Jan 24, 2013

gunnerthesnowman said:
OK , if it has 10:1 piston in it , it is not one of his full mod engines , should have a stock Yamaha head gasket.

What kind of boost you running ? may be a cracked head! , but more then likely the gasket.

I have only rode it twice. Ran around 15lbs both times..
The guy I bought it from said he ran it around 17lbs. I hope its not the head but, we'll see.

Duke · Jan 25, 2013

Is it blowing alot of the coolant or just a little? I always check my coolant at the end of the day when the sled is still warm. Then it's good for the next ride. If I have any amount in the main coolant bottle (when cold) it will expand out the overflow. Guess that's why they are supposed to have an overflow bottle. Head gasket will have a violent boil over under boost.

sledfvr · Jan 25, 2013

Duke said:
Is it blowing alot of the coolant or just a little? I always check my coolant at the end of the day when the sled is still warm. Then it's good for the next ride. If I have any amount in the main coolant bottle (when cold) it will expand out the overflow. Guess that's why they are supposed to have an overflow bottle. Head gasket will have a violent boil over under boost.

Mines the same as Duke's. They like to have very little in the reservoir. Mine will push coolant out if its over 1/4 full in the res.

Modedmach1 · Jan 25, 2013

It seems like it a fair amount.. I pressurized the cooling system to 16lbs last night, it lost a pound in 20 minutes. Would a leak down test tell me more???
I am a mechanic by trade. It just doesn't make since to me that if the head gasket is bad, I don't have any signs of a bad head gasket. No water in oil, no oil in water ect. Not saying it isn't possible just want to be sure before I tear my motor apart. Thx for the replies. Josh

kinger9 · Jan 25, 2013

Be carful with the ARP head studs and TQ'ing there is a process that is different then the factory manual. I followed the factory manual using ARP head studs and it would lift the head on boost and blow coolant out, then seal up when idling/pressurizing. I put back stock head studs and followed the manual and been running 10-11 psi for 4 years now since then.

I think you even have to cut the ARP bolts down and the TQ is somthing like 50 ft-lbs which is right at the break strength of the threads. A engine builder would know all this. My only take away was its not as easy as just replacing the studs with ARP.

gunnerthesnowman · Jan 28, 2013

How did you make out , what did you find ????

BigFish BC · Jan 28, 2013

Modedmach1 said:
It seems like it a fair amount.. I pressurized the cooling system to 16lbs last night, it lost a pound in 20 minutes. Would a leak down test tell me more???
I am a mechanic by trade. It just doesn't make since to me that if the head gasket is bad, I don't have any signs of a bad head gasket. No water in oil, no oil in water ect. Not saying it isn't possible just want to be sure before I tear my motor apart. Thx for the replies. Josh

it sounds like you are lifting head only under boost so no coolent gets in the cylinders it just pressurizes the coolant system & pushes coolant out the overflow.then when you are off boost it seals back up,sounds like the head may not have been torked proper & some of the studs may have loosened up,or there has been deto which will lift the head.

Modedmach1 · Jan 28, 2013

Well I got it changed, time consuming but, it is done now. I am guessing it had what Bigfish said, happening. No obvious defects in the gasket & the head wasn't warped. I am guessing that that head wasn't torqued properly when it went together, or maybe when I had it way to rich something happened.
Took it out and test ran it after getting it together &I adding a overflow tank. At 14lbs it didn't push any coolant into the overflow tank so, I think I got it fixed. I torqued the head in steps to 45 ft lbs (per powderlites) then backed them off 1/4 turn & retorqued. Gonna take it out this weekend for the real test. Thx for the replies & suggestions. Josh

BOOSTD · Jan 28, 2013

Glad you got it done bud, have fun on it and let me know how it goes.

Modedmach1 · Jan 28, 2013

BOOSTD said:
Glad you got it done bud, have fun on it and let me know how it goes.

Thx for the tips. Not sure I would have done it without talking to you.. :tea:

BOOSTD · Jan 28, 2013

No problem josh, anytime you have questions you know where to find me.

BigFish BC · Jan 29, 2013

another thing to consider is a retork at the end of the season always a good thing on a turbo motor after some hot cycles.:thumb:

yamahajohnson220 · Jan 30, 2013

Mines the same as Duke's. They like to have very little in the reservoir. Mine will push coolant out if its over 1/4 full in the res.[/QUOTE]

My turbo phazer on 13lbs is the same way with the coolant

allaboutdaz · Feb 18, 2015

Any one have DIY instructions for head gasket replacement?

Apex head gasket replacement?

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