Yanmar 1500 head gasket

[Dr M]

i am sorry but i don't know what torque to yeild is??
Dave

 

[normde2001]

i am sorry but i don't know what torque to yeild is??
Dave

I never heard of it either, but assumed it meant torque until the bolt fractures, (yields). Must be a S. Africa terminology.

 

[pruntyc]

I believe what he was talking about, is the bolts will get longer with the torque, and when you reuse them, they will not torque up to the proper torque, and as a result will not pull the head down tight enough. I have heard that this does sometimes happen.

 

[Dr M]

I believe what he was talking about, is the bolts will get longer with the torque, and when you reuse them, they will not torque up to the proper torque, and as a result will not pull the head down tight enough. I have heard that this does sometimes happen.

can i use an additional washer or shim just to make sure the head is pulling down correctly?? when i get the head back i can check to see how much is left on the threads.

any thing else i should look out for??

Thanks again.
Dave

 

[HGM]

[/URL]

I never heard of it either, but assumed it meant torque until the bolt fractures, (yields). Must be a S. Africa terminology.

Nope, good ol' American terminology(well, who really knows)....

Anyhow, Torque to yeild is an engineering design for the bolts to stretch a predetermined amount when tightening.. This magnifies the overall torque applied... Picture a bungy cord stretched nearly to max vs a rope... The bungy will constantly me restricting, trying to maintain tightness while the rope is just tight... Its a very comon design of bolt used nowadays... You may have noticed some torque spec that asked you to tighten the bolt to "x" lb ft then turn 90*.. These are tq to yeild bolts and are not reuseable because they actually stretch and will not retorque properly..

Hope that helps... or check this site

 

[HGM]

can i use an additional washer or shim just to make sure the head is pulling down correctly?? when i get the head back i can check to see how much is left on the threads.

any thing else i should look out for??

Thanks again.
Dave

I seriously doubt the bolts are tq to yeild, but I was hoping someone else might know for sure.... I would run them down in the block to see how deep they go(by hand so you dont damage the block) mark them, then set them in the head to make sure you have tightening room.. I would expect the bolt to go at least 1/4" further into the block than needed to allow for gasket compression..

 

[Eddie]

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Nope, good ol' American terminology(well, who really knows)....

Anyhow, Torque to yeild is an engineering design for the bolts to stretch a predetermined amount when tightening.. This magnifies the overall torque applied... Picture a bungy cord stretched nearly to max vs a rope... The bungy will constantly me restricting, trying to maintain tightness while the rope is just tight... Its a very comon design of bolt used nowadays... You may have noticed some torque spec that asked you to tighten the bolt to "x" lb ft then turn 90*.. These are tq to yeild bolts and are not reuseable because they actually stretch and will not retorque properly..

Hope that helps... or check this site

That's why I like this site. Always learning something. Thanks

 

[kenmac]

as old as these motors are he may want to see what the cost would just to replace these bolts. When I would go through my race engine I would order a new set of head ,rod, & main bolts. AS much compression as these engins produce,It may not b a bad idea to replace them while he's there.
(Just an idea)

 

[normde2001]

"Hope that helps... or check this site"

Can't help but notice, that's an Australian web site, inhabited by the same folks that inhabit S. Africa.

 

[Dr M]

[/URL]

Nope, good ol' American terminology(well, who really knows)....

Anyhow, Torque to yeild is an engineering design for the bolts to stretch a predetermined amount when tightening.. This magnifies the overall torque applied... Picture a bungy cord stretched nearly to max vs a rope... The bungy will constantly me restricting, trying to maintain tightness while the rope is just tight... Its a very comon design of bolt used nowadays... You may have noticed some torque spec that asked you to tighten the bolt to "x" lb ft then turn 90*.. These are tq to yeild bolts and are not reuseable because they actually stretch and will not retorque properly..

Hope that helps... or check this site

I'm always learning....
the block has 6 stud bolts....so there's not any head bolts, just the nuts to pull the head down. i don't know how to get the studs out of the block and really didn't want snap one or do any damage. i think there is plenty of thread for torqueing the head down. should i be doing anything different??

The machine shop called and said they had to take .010 off to get the head straight. he said thats a lot for such a small head??
I'm learning a lot.....i have wrenched on a lot of things but, this is my first time playing a "Yanmar mechanic".


Thank's again to all the help.
Dave