mike tkach

iTrader: (3)

to answer your question baja chicken,i see no down side to doing anything to help make the valve train more stable.imo shaft rockers are overkill for a 6000 rpm engine with a hyd roller cam,but it,s only money.

Panther

If you already have everything, the stud girdles are the way to go. But with a 525 cam, it's not crazy lift or spring pressure where the stability is that critical. You're also RPM limited. If you're starting from scratch, yeah the costs are similar so just go with shaft rockers.

GPM

Is it really overkill if it outlasts everything else on the market, stabilizes the valve train better than anything else, maybe.

mike tkach

iTrader: (3)

it,s kind of like using a L19 arp rod bolt on a 5500 rpm 500 hp engine that an 8740 bolt would be all you need at half the price.is the L19 a better bolt,yes but again it,s overkill,just my opinion.

MILD THUNDER

iTrader: (3)

I absolutely think shaft rockers are superior, and have their place in many engines.

I do always see that guys say that they are not that much more money when starting from scratch over a traditional bbc setup. How so? A T&D shaft setup is 1600-1700 dollars. A conventional rocker, like a Comp Ultra XD, Crower, are in the 400-600 dollar a set range. Then stud girldle kit, lets say another 250. Then another 75 bucks for ARP rocker studs. So, 725-925 dollars, you get a steel rocker arm thats good for up to 1000PSI of open pressure, 8740 rocker studs, and a girdle that ties it in all together, vs 1600-1700 dollars, for an aluminum bodied shaft rocker setup. 800-1000 bucks is a lot of dough per engine.

All that for a hyd roller that isnt going to see north of 6000RPM? I could see if we were talking about a 800 lift 7500rpm 55-60mm cam deal, but.....

Bajaroost, how much spring pressure are you running? What pushrods are you running? What rockers?

CDShack

I use the Comp Cams stud girdle. Always had good luck with it. Summit is like $250 per engine.

Baja Rooster

iTrader: (1)

MT, I’m running Comp cams untra pro magnums with their push rods as well using their 525EFI clone cam. They call for 928-16 springs which have open load at 383 and 160 on the seat. Seemed kinda light compared to Cranes 741which requires much higher pressure.

I don’t actually have possession of the cam yet. Just now getting the short block back.

MILD THUNDER

iTrader: (3)

Comp is doing alot of spintron testing these days. They do alot for the marine bbc guys. I follow one of their head guys on facebook. With their HUC series of bbc lobes, which are hydraulic, they found that with those lobes, a 11/32 valve, the valvetrain is stable to about 7000rpm using a spring such as the #935. That spring nets around 200lbs seat, and 525-550 open depending on the lift. Above 7000rpm , he says things start getting a bit more tricky.

while 7000rpm is quite a bit higher than you will ever see , i still would increase the spring pressure over what that 928 will provide.

im running a 954 spring, which also is in the 200/500 range, and it pulls cleanly to 6500 on the dyno without a hint of valve float or bounce.

Rookie

iTrader: (4)

My head guy would like those pressures, and those are inexpensive springs!

mike tkach

iTrader: (3)

imo the 928 spring is cheep and not a good spring,in my experiance they wear out much faster than the crane spring for the 741 cam.