head gasket 440

[DAVE14]

I intalled my new fmf pipe today & upon start up what I thought was an octane ping (12.5:1) 440 was front right corner of my head gasket ,blowin out after probably a 3 month rebuild it has gt thunder studs cometic gaskets ,xr head gasket etc. it was good for a while & I used the right stuff the only real concern is one of those studs was put in with a helicoil other wise a have another cyl. I can restud & sleeve without thread damage & start all over again or if its just a gasket is there a really good gasket available for high comp 440s ?

[cals400ex]

cosmetic makes a gasket for the 89mm bore. are you sure the stud is pulling or could it just be a loose head bolt?

[DAVE14]

i still gotta take the rocker cover off to get to the head bolts I just noticed this morning ,but Im assuming the worst it was all torqued to spec when it went together I never really heard of them loosening afterwards but a machine shop put the gt thunder studs in & im sure the cyl. had to be straight etc. the last rebuild when it was a 400 was just a piston/sleeve job with a stage 3 cam on top but the one stud had the helicoil & it just makes me nervous !

[Big - D Racing]

run a stock gasket bored out too an 89mm, Duncan racing makes them for $40 and there is nothing better. The strength of it from blowing out is many times better than cometic gaskets, especially with high compression.

[Eddiesanders250]

for reliability use honda gaskets

[F-16Guy]

Originally posted by DAVE14
...but a machine shop put the gt thunder studs in & im sure the cyl. had to be straight etc...
Did they use a roll form tap? That's where a lot of the strength comes from. A roll form tap compresses the aluminum to make the threads instead of cutting material away. This makes the metal more dense which increases it's strength.

[DAVE14]

I just got the rocker off & ill half to re torque the bolts to see if it seals & if that doesnt work Ill do it again from scratch with my other cyl. gt thunder studs etc. & that sleeve or another 440 sleeve in the other cyl. I have its too bad too because it was a beatiful day the bike sounded like a powerhouse with the new pipe I was gonna richen the mixture & take off but i noticed the pop from the cyl.& new I was screwed so mo ridin today !