rocker covers and head studs

[jethro]

Somewhere I read a thread about putting in head studs from arp. if I remember correctly-
the fellow milled out some of the web in the underside of the valve covers- instead of milling off the rocker blocks.

Am I understanding the situation correctly ? Do the ARP studs simply prevent the covers from going all the way down to the gaskets ? that is they don't create any interference with the valve train its self ?

I would rather mill the underside of the covers than mill the valve train parts !
( I think I saw someone also sells a spacer which jack up the covers off the head about 1/2 inch.... )

Am I understanding the situation correctly ??????

Tim

[RCCUMMINS89]

Sounds like you should go with A1 studs..... Are you replacing the gasket at the same time?

[lz69]

I have the A1 studs on my truck and it's the stud and nut that interfere with the valve covers. I used a die grinder to remove approximately 1/16 to 1/8" of material right above the stud and nut to get enough clearance for the cover's to sit flush on the head.

It was a kind of a pain to do with a grinder and would see about getting them milled if I ever had to do it again.

[rollieD250]

I had my pedestals machined down, i think they were machines down .20in. And the stock valve covers fit no problem and the fit/finish is awesome.....a little more work now but worth it in the end

[jethro]

My gasket seems to be OK- but I would like the "insurance" of not having to later take the engine back out for a new gasket.
the engine is now on the engine stand. I am all most done with it- nearly ready to install.
I have the milling machine sitting about 15 feet away- and would much rather mill the covers (a non-structural part) than
the valve system parts. The thin cast aluminum covers will cut easy on the mill.

I was thinking of the ARP's but I didn't know there was another brand. I will google the other ones and see what they are .

Thanks !
Tim

[RCCUMMINS89]

I am a fan of A1 studs, over ARP. For the sake of argument... are they the same strength? Probably.

However, A1 is recommended to bottom tap the block (more block to stud contact), also have to grind the webbing out of the valve covers.

ARP.... drop in, but have to mill the rocker pedastals.

[jethro]

I will get the covers off this week end and see how hard it will be to mill the rocker pedestals vs. bottom tapping the block.
I was planning to not take the head off....
I would think there would be maybe 1/4 inch depth gained with a bottom tap ?
Will check the A1 studs now !
I have a 3 inch carbide fly cutter which I guess would cut the pedestals pretty good If I decide to go that way.
Thanks for the A1 tip !

PS- put in the Hungry Diesel fuel pump spring and the steel fuel line - it fell together like store bought !

Tim

[RCCUMMINS89]

Good to hear

[AHineman]

This is the paperwork that comes with ARPs.
I thought bottom tapping the holes was recommended for all stud installs but idk. We did back when my ARPs were installed.

[fatty]

That's what I thought too. The Cummins castings are pretty terrible and you are likely to have uneven stud protrusion if you don't

[RCCUMMINS89]

We've had a lot of folks run the A1 (which are longer) that didn't bottom tap and were still fine. Where as I had to with ARP studs.

[jethro]

I think I like the idea of A1's
Looks like the D11 are about 650$-700$, 1722 about 500$
Appears a bottoming pulley tap is about 50$

What would you say are the HP limits for the two different stud materials ?

Tim