SBF valve adjustment question

I'm changing the cam in my 302 and while putting the roller rocker arms back on I noticed that when I took all the play out of the rocker/pushrod, and went to tighten the rocker approx 1/2 turn the valve spring compressed. This happened on 2 exhaust valves. Is this normal or should I be concerned?

 

Hyd SBF is 0 lash, not 0+

 

I should have been more specific. These are roller lifters.

 

What year 302?Most had studs that have a stop on them,you just tighten the rocker down.Do you have hydrolic or solid roller lifters?You may need to change to screw-in studs in order to have an adjustable valvetrain.Another thing,do the valves stick up thru the retainer about 1/4-3/8 inch?If they do you need "Rail" type rockers.You may also need to change the pushrod length when going to a roller cam. ROY

 

was the cam rotated on base circle for every valve you tightened??

 

Are you using a previously run set of roller lifters? I had a similar problem in a SBC recently. It was a new factory (ZZ4) roller cam and I reused the stock Hyd roller lifters. Turns out that what little oil was in the lifters wouldnt bleed out. I finally had to take each lifter apart and let the oil drain out. I put it all back together and had no problem adjusting the valves and it runs like a charm.

 

are you sure you have the cam in the right spot when your adjusting them? sounds like your adjusting the valve when the lifter is on the lobe.

 

I've got the cam on the base circle when I adjust each rocker. Its easy for me because the intake manifold was off the car when I did it and seeing the postion of the lifter is easy.The lifters are hydraulic rollers. I am reusing them. As far as the studs, the car originally had press in studs, we pulled them out and put ARP threaded studs in.

 

Watch the pushrod seat in the lifter as you tighten down the rocker nut and see if it depresses in the lifter body. If there is no movement, Id pull one lifter apart, clean the oil out, re-***emble and try again. Easy to do and if it doesnt work, you have eliminated one possibility.
When this happened to me on my SBC I tried leaving them all cranked down (slightly lifting the valves) over night hoping that the lifters would bleed down, but no luck.
This was the first roller cam motor I had ever worked on, so I dont know if this problem occurs fairly often or not. Ive had std hydraulic lifters before that were pumped up and all you did was pump the plunger with a pushrod forcing the trapped oil out. The hydraulic roller lifters must have really tight internal tolerances for this not to work. As a last resort I ended up pulling them all apart, cleaning them out...then everything worked as it should.

 

It isn't normal. Check out chop32's post for the "how to" on the fix.