Chattery valve train

[Impalaguru]

I recently installed some rebuilt double hump heads on my 327. I had to go with a longer than stock push rod as the valves were taller than stock. I did the check with an adjustable pushrod, sharpie marker on the valve stem, looked at witness mark, etc and came up with +.200". The wear pattern on the valve stem was difficult to determine since I have stamped rockers. I also didn't swap out for a solid lifter when I was checking as I hadn't thought about it until after the fact.

When I look at the little oil hole in the rocker I can barely see the hole in the end of the pushrod, when the valve is closed. On the 409, which doesn't have this problem, I can see more of the hole in the pushrod, when the valve is closed.

Do I need some shorter pushrods? Is there a better way to check this with my stamped rockers and hydraulic lifters? Was my hydraulic lifter compressing too much and throwing off my measurements? I still have the checking push rod. The intake is still installed on the engine.

Any help would be great!

Ross

 

[models916]

I use this

Use a hyd. lifter shimmed solid inside under the plunger to the height of the rocker preload you are going to use. I like 3/4 turn.




http://www.summitracing.com/parts/MAN-42132/

 

[Fathead Racing]

I recently installed some rebuilt double hump heads on my 327. I had to go with a longer than stock push rod as the valves were taller than stock. I did the check with an adjustable pushrod, sharpie marker on the valve stem, looked at witness mark, etc and came up with +.200". The wear pattern on the valve stem was difficult to determine since I have stamped rockers. I also didn't swap out for a solid lifter when I was checking as I hadn't thought about it until after the fact.

When I look at the little oil hole in the rocker I can barely see the hole in the end of the pushrod, when the valve is closed. On the 409, which doesn't have this problem, I can see more of the hole in the pushrod, when the valve is closed.

Do I need some shorter pushrods? Is there a better way to check this with my stamped rockers and hydraulic lifters? Was my hydraulic lifter compressing too much and throwing off my measurements? I still have the checking push rod. The intake is still installed on the engine.

Any help would be great!

Ross

You must use a solid lifter to check the valve train for anything and everything. The hydraulic lifter will compress and throw all your measurements off!

 

[58 Apache]

+.200 seems a little long but

:? I use a lot of push rods in the 8.0 to 8.1 range on small block race engines but .200 longer on a street engine with stamped rockers seems too long. Factors that that will change the lenght are the valve lenght of coarse, the head being milled and deck height of the block. Are you using offset dowl pins for raising the heads on the block? When measuring lenght for hydralic lifter the rule is to add .020 to the lenght over the solid lifter measuremnt for lifter pre load. One idea for rechecking for lenght with adjustable push rod is to use plasta gauge on the stem and look at the smear across the valve stem and the wipe across the rocker face.

 

[models916]

marker

I have used magic marker on the valve stem. The pattern will be the clean spot on the top of the valve.