1:7 to 1:8 rockers
1:7 to 1:8 rockers can i swap my factory 1:7s to Crane 1:8s on stock heads, valve springs, cam, etc? got the guide plates and studs and bla bla bla.
More specificaly, whats install height, coil bind, operating range, and net lift of the stock valve springs? what about open and closed seat pressures?
got the arms used along with crane pushrods 7.250 inches. all 16 arms have slight damage from the studs b/c the rods are too short, idiot.
im building up a set of 706's i just bought so if the rockers wont work with the springs theyll just go on the new heads and be on the car in a few months. Im kinda hoping to put em on real quick tho. thanks
More specificaly, whats install height, coil bind, operating range, and net lift of the stock valve springs? what about open and closed seat pressures?
got the arms used along with crane pushrods 7.250 inches. all 16 arms have slight damage from the studs b/c the rods are too short, idiot.
im building up a set of 706's i just bought so if the rockers wont work with the springs theyll just go on the new heads and be on the car in a few months. Im kinda hoping to put em on real quick tho. thanks
You will have valve float at the top end with the Crane roller rockers and stock springs, better springs are required.
Concerning pushrod length, the Crane rockers REQUIRE a shorter pushrod due to the design. Standard LSx pushrod lengths don't apply to Crane roller rockers.
Concerning pushrod length, the Crane rockers REQUIRE a shorter pushrod due to the design. Standard LSx pushrod lengths don't apply to Crane roller rockers.
Last edited by 405HP_Z06; Feb 17, 2009 at 11:27 AM.
affirmative on the new springs, how high will it go before valves start to float? also how are the performance gains? I picked up the full set at a swap meet so im getting an idea of what ive got.
Crane rockers have a lower pushrod cup location compared to stock. That is why the shorter pushrods. If you have stock lifters and heads, then the 7.250" pushrods are fine. With something like a Morel, which is a taller lifter, then a different (shorter) pushrod length is required. I ended up with 7.150" when I ran my Morels with the Crane rockers.
PS: If you need a set of 7.150", I have a set for cheap since I have an entirely different setup now.
PS: If you need a set of 7.150", I have a set for cheap since I have an entirely different setup now.
thanks Vettenuts, ill keep that in mind. at that swap meet i also got a set of 706's that im building out. im not just sure if im gonna do just the heads then cam later or all at once but my best friend is a machinist, were gonna clay the pistons new lifters etc. if it comes up ill let you know
thanks for all the info yall. much appriciated. I still wonder why all the rockers rubbed their shafts. maybe the kid just cranked em all the way down?
for several reasons we are 100% postive something went wrong and he toasted one pushrod, one guide plate, and pretty sure one rocker. theve been replaced obviously but still.
his loss my gain!!! 800 bucks worth of crane valve train for 150 dollars. ahhhhhh sweet success
thanks for all the info yall. much appriciated. I still wonder why all the rockers rubbed their shafts. maybe the kid just cranked em all the way down?
for several reasons we are 100% postive something went wrong and he toasted one pushrod, one guide plate, and pretty sure one rocker. theve been replaced obviously but still.
his loss my gain!!! 800 bucks worth of crane valve train for 150 dollars. ahhhhhh sweet success
Expect somewhere in the 12hp+range in rwhp, and stock valve spring WILL NOT work with these rockers, you would be lucky to get part 5800K untill the valve train starts gettting unhappy. Use a Crane dual spring kit #144309-1 to match up with them. 7.250 is correct length for that rocker kit, aslong as everything is ALL stock with the engine, cam, heads, gaskets, etc...
