ARP head studs M30 or M90. How to retain the rocker shafts.

[lynnbilodeau]

Sorry to double post, but I think my question got buried in my old thread (originally about piston selection).

Again, running M90 block, S38 factory (Goetz) head gasket with B35 head. Just bought the Isky Groove o-matic (sounds stupid, but it works) to "O" ring the block, since my machine shop of choice no longer does "O" ringing. Figured with all I am doing to make this thing bullet proof, may as well go with arp studs. Here is the question:

This is for the guys running arp studs in either an M30 or M90 block. My understanding is that the top part of the stud is thinner than the factory headbolt, and it will therefore not be a tight fit against the retainer groove in the rocker shafts. What are you guys using to make sure the rocker shaft does not move?

[Hit Man X]

Check on mye28, lots of M30 guys there with ARPs. I still have bolts on my M106, was just trying to have the car going when I had the head off... did not even do a valve job. Stupid, eh?

Todd would know who supplied your modified K27.

[Hit Man X]

http://www.mye28.com/viewtopic.php?t=121062

[lynnbilodeau]

I posted a solution in that thread Eric.

I believe I have found a suitable solution. Here is my solution. Just drilled and tapped 4 holes on an old cracked junk head, one for each shaft. An 8-32 allen head set screw gets a good 6 to 8 threads to catch. I see no need to drill the shafts themselves. Just install 8-32 set screws with heavy duty thread locker.

If you want to make SURE the shafts never move, just drill a very small hole where the set screw "sets".

Of course there are guys saying there is no problem using ARP studs without anything to lock the shafts in place. There are many reasons the shafts may not have moved. Doesn't mean they won't. Also doesn't mean they won't on another engine. They need to be locked in some way.

[Hit Man X]

Awesome solution.

[gixxerboy]

Good info & reference here. The ARP's 'can' pose an issue. I just assembled a new head. While sitting on my workbench one of the rear shafts slid out on its own. This is in part due to zero tension on 3 side-by-side rockers during rotation of the cam in addition to the outward pressure the rocker springs create. I'd imagine this is more of non-issue on old non-disassembled head as the shafts tend to stick in place.