roller rockers

[phat01]

i have a Vt 304 stroked to 355 10.1 comp and crane roller rockers. They are adjusted to no lash and half a turn are noisy and seem to set of the knock sender.I think this is to tight and with about 0.020 clearance it would be quieter .Any ideas?

[delcowizzid]

email crane and ask for the lifter proload setting it varies between manufacturers a lot some being next to no preload others being 0.060".sometimes the tie bars rattle bad on some lifters and if the springs arnt upto the task they will bounce off the cam very easy setting off knock sensors they require more spring than flat tappet cams due to weight of the lifters as well

[Holden202T]

im assuming this is with a hydraulic lifter ?

I am not sure how the crane rollers compare to stock, but most things I've seen suggest 1-1.5 turns after 0 lash ... it may be you need more preload on them ?

[HQ355]

Is it stock cam ? If it's not gave the valve springs been upgraded to suit ? What rpm range does the knock occur ?

[vlad01]

I've head 0.070" preload on hydo roller lifters. Don't know if that's correct or not. Best contact the cam or lifter maker for specs.

[krusty]

Need to identify what lifters they are. Required preload will then be able to be worked out.

[krusty]

You also say that 0.020" clearance may be quieter? I'm assuming you're running a hydrualic roller lifter due to being VT or have you gone solid flat tappet?

[Holden202T]

talking about lash clearances is solid lifter speak, anything with a hydraulic lifter usually never has a lash setting, and its more like screw it down till the pushrod takes up then go another half to one and a half turns down (and this is how I've always done hydraulics) but solid is normally .010-.020 lash etc then lock the rocker adjustment at this point.

this is why I asked the original poster if its a hydraulic or solid cam....

the other thing you need to keep in mind with solid lifter cams, when the motor is cold you might have .020 lash then once its up to temperature, block and head growth from head can add another .005 - .010 to that number and this all depends on cast iron or alloy heads too!

[Charlescrown]

I am surprised phat01 hasn't come back. A lot more info is need so perhaps replying might help the diagnosis to head in the right direction. Questions I have is it a new cam installation? is the engine noisy at idle or as the RPM increases. As far as hydraulic lifters go as 202 said 1 to 1.5 turns and leave it alone. The manufacturer decides the setting to be a good position to allow for metal dimension changes with temperature and slight variations over time but as long as it's got no clearance it will work without noise. We used to set them to only 1/2 a turn so that when the engine valve bounced it took less time to recover after the RPM dropped other than that more info is required.
I recently had a 350 Chev that made some serious valve train noises when the RPM was increased above idle. New cam and lifters only a couple of months old. Guess what the cams lobes had been ripped of due to poor run in procedure but that was flat tappet not roller.