Mcxnytro blown headgasket

[pgtm8]

Hey question for yall, my head gasket blew out on me yesterday just down the trail. Nasty oil and anti-freeze cloud coming out of the exhaust pipe. My dealer thinks i should have the head decked due to warping before putting it back together but the gasket didnt blow under any sort of boost at all. After last ride it wasnt smoking or acting funny at all. What dp you think?
mcx 240 @14#

 

[boost mod]

My brother’s nitro head gasket took 18/19 psi be for it blew. Did your dealer torque the head properly?

 

[pgtm8]

I dont know why the gasket blew out. The motor has had 2000 plus miles @ 14# boost since the turbo was installed with no problems. I really want to know if the head could be warped though.

 

[M5-]

Was it really the head gasket or the shim. I've seen 3 shims go all right around the 2500 mile mark. Regardless put a new shim in it when you rebuild it.

M5

 

[Duke]

I think Impulse sells a stainless shim. Thats what i'd run if you can get one...

 

[SylvanLaker]

when you get a sudden failure that lets out a lot of fluid it usually is a failed bolt or stud. Normally it is a slow failure where the coolant system takes on cylinder pressure from the gasket wasting. Bet you broke a bolt / stud..

Dave
REDLINE Engine Performance
403-396-1443

 

[SylvanLaker]

oh and PS there are tricks to get them to seal properly. You don't need a SS gasket. but like I said there are tricks. feel free to call us. I done a few motors in my days and ours has 4 years of 20+ lbs on it. I run a 80 thou alum 5051 gasket and no issues...

 

[pgtm8]

Makes sense, I will know tonight. Anyone know where to get arp studs from?

 

[pgtm8]

Looks like a head gasket was the least of my worries. Detonation has eroded the sh*t out of the head and the gasket was burnt enough to finally let go. 2 pistons are burnt, valves on one cylinder are burnt. When I bought it the dealership they told me it should run 17-18# on 91 octane at elevation to make 240 LOL. I discovered 2 months later that was wrong and I changed it to make 14# but I guess these are the results. Thanks __ Yamaha!

 

[summitboy]

What elevation ? If you are talking the 6500-7000ft altitude that 17-18 psi was a little high for the 240 map. It should of been around 15-16. Not sure if 1 psi over 16 would do that much damage unless your fuel or fueling was messed up. Sorry. That sucks ! Thats why a guy should use the TCV lol ! Turn key and go ! Those Nytro motors don't seem to like deto as much as the Apex mill, i hope LOL. Lightly used Apex for sale, ha ha !!

 

[Thistledoo]

I got a good used head if you need...where u at?

 

[pgtm8]

Yea 5000-7000 elevation and my fuel is always fresh 91

 

[summitboy]

18 psi at 5000 is too much imo. That should of been maybe 15 max imo. Get the Nytro God to chime in, he knows all !!

 

[pgtm8]

Smithers BC. Does the head have all the valves amd stuff in it still and,how much. Dealer says I should do rods and rod bearings because of the deto. What do you guys think.

 

[M5-]

Smithers BC. Does the head have all the valves amd stuff in it still and,how much. Dealer says I should do rods and rod bearings because of the deto. What do you guys think.

Might as well while you are in there, build it for 20+ lbs and run the 270 setup should be bomb proof. I have the 240 map in my Nytro 14-15 lbs at 6500 ft and just watching the wideband I've always thought it was a lean map. I always run that Chevron 94, guys say the Shell 91 and you are good to go but a couple of points of extra octane can't hurt I figure. So far so good, touch wood.

M5

 

[pgtm8]

Are carrillo and JE pistons worth it if im only gonna run 14-15#? or should i just replace everything with OE.

 

[Thistledoo]

Are carrillo and JE pistons worth it if im only gonna run 14-15#? or should i just replace everything with OE.

not worth it IMO

Find a set of take out pistons and rods and rebuild it and get back on the snow....

Head is complete off a engine I parted out.....is yours junk then?

 

[pgtm8]

Yea my head is toast and one valve on one cylinder is toast aswell. I will take that complete head off of you for the right price. You dont have pistons and rods too do ya?

 

[Thistledoo]

no pistons and rods...talk to Chuck at Lakeside motor sports

14037463119 he will have or know someone who does....he is in Benalto Alberta

pm me you offer for the head

 

[M5-]

You are really only talking about the difference between the cost of the JE and stock stuff. Seems crazy to me not to upgrade if you are going that deep into the motor plus you won't need a shim which will save a few bucks and be one less thing to go wrong.

M5