Casey96SS

I have been working on finding my pushrod length for my h/c swap. Read a few how to's. Set up #1 cyl with check springs and adj pushrod. 7.150" gives the narrowest sweep slightly favoring the exhaust side of the valve. This was the same for the intake and exhaust valves on #1.

I was having a hard time getting a consistent mark on #1 exhaust. The rocker was only marking the inner edge of the valve tip towards the intake valve. I then noticed the rocker was not centered front to rear (of the car) on the valve tip. So I loosened the studs and pushed the guide plate all the way towards the rear of the car which seem to center the rocker better. I retested both valves and 7.150" still looked the best but I am still not getting a real flat mark on the exhaust valve.

I did a little more measuring and saw that the center to center spacing is different between the valves, studs, and rockers. I got 1.905" valve to valve, 1.793" stud to stud, and 1.560" lifter to lifter.

So I guess the rockers are designed to be pointing slightly away from each other? It seems like this would not allow the roller tip of the rocker to sit perfectly flat on the valve tip unless the valve guides are drilled slightly at angle so the valves were angled towards eachother to accomodate. Any idea if the factory drilled them angled or are the valves parallel to each other?

This is all kind of hard to explain through writing. Just wondering if anyone else has experience with this? It's a little concerning that I am not seeing perfect contact between the roller tip exhaust valve.

guppymech

iTrader: (7)

Did you try swapping rocker arms on #1 cyl to see if the unevenness followed the rocker arm? Check some other cylinders to see if they're the same. Did you have a valve job done on the heads? Maybe that valve stem tip is not square.
Oh, I am no way a expert, just tring to help.

Casey96SS

Yeah, tried a few different rockers. Heads are new LE2. That's a good idea to check another cylinder just to see what it does and and if the same pushrod length looks the good.

wht97ws6ta

If the valvetip wasnt square, rotating the valve would show a change in pattern. If its in the rocker arm that would be as simple as trying the rocker from the intake valve that produced a square pattern. If its still off try swaping the rocker studs. If that shows no change the rocker stud hole wasnt drilled straight or that guide isnt straight up anymore. Has it had guide liners installed?

BALLSS

Many, including me, run ISKY adjustable guide plates so you can line up individually I/E RR to be dead nuts centered (LtoR) on the valve tip

The PR length is then set by measuring with a PR length check PR until you get the narrowest sweep centered or "slightly" favoring exhaust side