Header Bolts

[Silverback51]

Has anyone used Percy's locking header bolts?


Percy's 20004 - Percy's Split-Lock Header Bolts - JEGS

[Tom Wells]

Silverback51,

I tried them on my aluminum SCJ heads. I almost ruined one bolt hole.

Two things happened that I didn't like:

1) More than one of the setscrews fell out after the car ran through several heat/cool cycles.

2) The bolt itself resembles a tap; in trying to remove one of them to go back to the Stage 8 bolts, the bolt tried to tap one of the holes oversize. It apparently didn't collapse to its original shape when I took the setscrew out. Yikes!

Having said that, they may be OK for iron heads. Definitely not recommended for aluminum.

I told them this at PRI year before last and thought they were permanently withdrawn from the market. Maybe not.

I now use the Stage 8 bolts. They are a hassle to fit, but they seem to be compatible with the aluminum heads.

Hope this helps,

Tom

[vanoochka]

Sorry for this slight hijack...

Tom,

I bought of Stage 8 bolts and am planning to install them when my headers come back from ceramic coating later this week. Do you have any installation tips?

Thanks,

Chuck

[Tom Wells]

Chuck,

It's been more than two weeks since I put mine in

I recall having to take my time and study each little retainer individually. Some seemed to fit "as-is" and others required a bit of grinding to get them on snugly. If they weren't ground down a little, some of them would not go on at all. This is part of what I meant by "hassle". The other part is getting the C-clips on - I had to use the Braille method and some real contortions

One other thing I did was to mark each one so if I ever had to take them off, I could get them back in the same spot; this means marking them so I knew which side faced the head. I did do this once and (mostly) got them back on satisfactorily.

The good news is they were harmless to the heads, and I could R&R the headers if I had to. A real PITA.

All in all they were worth it because header leaks are few and far between now, where they used to happen every other week especially if I abused the car a bit by taking it to the track.

I tried good quality header bolts early on, and they just wouldn't stay.

Tom

[Silverback51]

Thank you for the input.

[rdorman]

Try safety wire after a retorque.

[undy]

Go with the Stage 8s. I had the "split bolt" ones in some aluminum heads I had on a 383 SBC. If they weren't loosening up, then they were galling the threads. If there were no expansion, contraction and/or vibration they'd work fine..

[sllib]

I agree with rdorman. ARP makes a nice set of pre-drilled stainless header bolts ala NASCAR.
Bill Stradtner