1). The bigger stud means less surface area for gasket seal.
2). Bigger holes in the head also increase post torque distortion. Make sure you have it torque plate honed again!!
Did you try torquing the exsisting studs at a higher rate?? I bet you could get some chromolly studs from ARP that are the same size as stock and saved much time and money!!
Faster then Speedy Gonzalez, slower then the Road Runner!!! MEEP MEEP
100hp honda wrote:call a expert and get some real world advise. i dont recall Pstoffers mentioning his 45 shot lifting the head . maybe you have other issues brit
as i understand Pstoffers melted the piston due to oxegenated fuel being mixed with No2, but thats another story for different time.
i certainly wasnt making this a big deal and if bigger studs is what you want then go for it. i was simply saying, did something else cause this? high compression and a big shot will cause the head to lift and stretch head and base studs then blow the gasket, and it pops oring heads also (ive seen pictures of it 100 times on other sites). but your not running that much compression and a 20shot is pretty small. caarry on
100hp honda wrote:as i understand Pstoffers melted the piston due to oxegenated fuel being mixed with No2, but thats another story for different time.
EXACTLY
i certainly wasnt making this a big deal and if bigger studs is what you want then go for it. i was simply saying, did something else cause this? high compression and a big shot will cause the head to lift and stretch head and base studs then blow the gasket, and it pops oring heads also (ive seen pictures of it 100 times on other sites). but your not running that much compression and a 20shot is pretty small. caarry on
I replaced a stripped stud using 10mm fine thread rod.My thinking was that the fine thread would be stronger and more resistant to being stripped again.Helecoils suck because they require a huge hole to be drilled leaving precious little parent material behind.To drill the hole bigger in the gasket I sandwiched it between some plywood too keep things solid.Worked like a charm.
So far I've had no issues. Loctite on all the studs helps a lot.
Fins Rule!
Liquids drool.
"If the rule you followed led you to this of what use was the rule?" Anton Chigurh
I won't ever put a helicoil in a bike application, I eclusively use the pioneer insterts that are solid pieces, the 6mm case bolt inserts have a 10mm o.d. and are the best insert ever. i just had to put 6 10mm ones in some old 650 bike jug for a dude
Sorry for the late reply M.F.D.B. I thought about that and decided that since I only replaced only the one stud that I would set them all to the same spec. I couldn't see how size or thread pitch would change clamping force if they are all the same and I didn't want to distort my cylinder to the bigger stud. The torque wrench only knows where you set it and puts the same pressure on both fastners regardless.My theory.Would the bigger stud multiply or add more pressure then what it's torqued to?
What are your thoughts M.F.D.B.?
BTW took my motor last night apart to replace a bad bottom end gasket and my cylinder shows no signs of wear from distortion.
Fins Rule!
Liquids drool.
"If the rule you followed led you to this of what use was the rule?" Anton Chigurh
Torque measurements are designed to maximise the clamping force of the fastener based on how far it can be "stretched" before yeilding.
The thread pitch determines the "leverage" of the torque you are applying. If you torque a fine pitch thread nut and a coarse thread nut side by side to the same torque number, the fine thread will be applying a much higher clamping force. The diameter of the fastener is a large determinig factor in strength and appropriate torque number, but the biggest factor is the thread pitch...
Faster then Speedy Gonzalez, slower then the Road Runner!!! MEEP MEEP
. maybe you have other issues brit
EXACTLY
