Head bolts

Psychoframer · Apr 13, 2011

Everyday I work on my NAA I learn something new, yesterday I learned that I should have put my head bolts somewhere safer. My 4 yr. Old was out "helping" dad and I lost concentration for a second and knocked the canister they were in over. It wasn't a big deal, because I planned on buying all new head bolts anyway. But that was before: a new starter, wiring harness, air filter, welded manifold, paint, penetrating oil, engine overhaul gaskets, and carburetor rebuild. My tractor is basically going to be a work tractor, but I probably will tear it down again in two years to do a real restoration. I know that if you reuse the bolts they should go back in the same hole they came from originally. So my question is can I get two years out of those head bolts without risking damage to the head by putting them in different holes? Thanks.

rcurrie · Apr 13, 2011

Head bolts do not have to go back in the same holes that they came out of. If there are different lengths make sure they go in the right holes for the appropiat length. If the bolts are torqued using the torque turn method, meaning they are torqued to a certain torque then an additional number of degrees then they should be replaced every time. If the torque spec. is to tighten to a certain torque only then you should be alright to reuse them. I have been a licenced HD mechanic for 20+ years and have never replaced head bolts unles specified to do so in manual. Good luck on the rebuild.

Rob

Psychoframer · Apr 13, 2011

Rob,

Thanks for the advice. Unlike you, I don't have the experience or the training, consequently what I know is based on books, videos and friends. But no matter how well the books are written they can't cover everything or answer questions or build up your confidence.

Tom

Soundguy · Apr 13, 2011

replace any waisted bolts.

soundguy

VE6IAZ · Apr 13, 2011

Psychoframer said:
Everyday I work on my NAA I learn something new, yesterday I learned that I should have put my head bolts somewhere safer. My 4 yr. Old was out "helping" dad and I lost concentration for a second and knocked the canister they were in over. It wasn't a big deal, because I planned on buying all new head bolts anyway. But that was before: a new starter, wiring harness, air filter, welded manifold, paint, penetrating oil, engine overhaul gaskets, and carburetor rebuild. My tractor is basically going to be a work tractor, but I probably will tear it down again in two years to do a real restoration. I know that if you reuse the bolts they should go back in the same hole they came from originally. So my question is can I get two years out of those head bolts without risking damage to the head by putting them in different holes? Thanks.

I agree with rcurrie, it is not nessesary replace head bolts unless specified to do so. The only suggestion I would have is to take a striaght edge and put it on the side of the bolt and hold it up to the light to check that the bolt is not stretched. You can see this easily as a stretched bolt will show a narrow spot usually at the top of the threads. Also, I clean out the holes in the block with a good sharp tap and then blow them out with compressed air. Put a little engine oil on the bolt thread before installing them and then torque them down in step sequence starting in the center of the head working outward in an X pattern. Or follow the manufacturers sequence if you have it. Good luck with your overhaul. VE6IAZ

simonmeridew · Apr 20, 2011

manufacturers specify different head bolt torqueing figures if the bolt is dry(unlubed) or wet(lubed). (less torque if lubed) don't overtorque.
simonmeridew

LD1 · Apr 20, 2011

I agree with the others here, no problem re-using them and it dont matter the hole.

When it comes to engines, the only thing that really matters if it goes back in the same hole (aside from pistons obviously) are the lifters. They form a wear pattern with the cam and should always go in the SAME hole.