Okay, installed new rockers, pushrods, etc. after heads being rebuilt. When rotating the crank it looks like the valves do not travel as far as the specs on the cam card.

My spring installed height is 1.700. So I took the measurement when the pushrod has the valve at max lift. I subtracted the two measurements and I am no where near the valve lift indicated by the cam card.

I am assuming the hydraulic lifters affect the overall measurement due to its internal piston movement??

Need the proper procedure to determine this.

Thanks
d1

 

Installed height has nothing to do with valve lift. With the valve closed set a dial indicator on the valve retainer and zero it. Turn the engine slowly and watch the needle on the indicator, it will indicate max lift and then start to drop. There are other ways.

 

Used the dial indicator and got the same measurement (more accurate mind you than caliper I used in the first method I used).

Basically, intake valve lift based on cam card is .494. I am getting .205 using the dial indicator method.

I verified the lobe lift by measuring the lifter movement.

So, I am guessing I have the wrong length pushrod? If so, will someone please tell me how to accurately measure this length?

I used a pushrod length checker and measured the distance when both valves were closed and ensured the roller tip of the rocker contacted the valve stem tip correctly at base circle, mid lift and max lift locations. I got 8.350. I added .050 for preload and used 8.400 pushrods.

I tried lengthening the adjuster and got an overloaded condition so I backed it down 8.350 and everything seemed good to go until now.

d1

 

Put the dial indicator on the lifter, should be around .308. If you're getting that there and not .494 at the valve then your lifters are not full. I would worry about it as long as you're getting the right measurement off the lobe.

 

Measured the lifter with dial indicator and averaged from .305 to .309 for lobe lift. Measured from starting at max lift and starting from base circle. Starting from max lift seemed to be the more accurate way to measure as those measurements were closer to the cam card spec of .309.

There is so little movement in the valve train, that is why I was concerned the valves were not opening to their max lift.

Thanks for the help.

d1

 

.305 X 1.6 rocker arm ratio = .488

 

I had to go back and remeasure. I did edit my original post. Thanks for looking out.

 

If you're measuring it at the rocker you have to remember the valve spring is compression the lifter plunger. Without the engine running you have no oil pressure to keep the lifter pumped up and it will bleed down.