lifter adjusting

kwplot34

Heart Attack
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Mar 24, 2008
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Liberty,Mo
Need a little input here on lifter adjusting.
flat tappet cam,jeg's 1.6 roller rockers.
this is on THeiskel's 383 he just put in his 69 vette.
the lifter are clattering pretty good so we took the v/c off to tighten them up,but noticed the rockers were hitting the v/c,so he ground down the v/c for clearance,but they are still clattering.
they are not hitting the v/c any more,i think he needs to adjust them down a little more,but Todd said he had already given them one full turn already.
Are they still loose? or is there something else we should be looking at here??
 
if they keep loosening up the cam is most likely toast

Thats a concern that we disscused today. but after adjusting them down a little more the clatter never got anybetter. wouldn't they progressively get louder if the cam was eating it's self up? plus we turned the motor through by hand to look at all of them,and they all seem to have a very good range of motion.
 
Need a little input here on lifter adjusting.
flat tappet cam,jeg's 1.6 roller rockers.
this is on THeiskel's 383 he just put in his 69 vette.
the lifter are clattering pretty good so we took the v/c off to tighten them up,but noticed the rockers were hitting the v/c,so he ground down the v/c for clearance,but they are still clattering.
they are not hitting the v/c any more,i think he needs to adjust them down a little more,but Todd said he had already given them one full turn already.
Are they still loose? or is there something else we should be looking at here??


umm, it`s been years since I ran a flat tappet cam but don`t you have a cam card that lists what the valve lash is supposed to be?
redvetracr
 
No Todd does not have anything on the motor,he got this motor from his brothers,they built it some time back,but they do not have any of the info on it,can't even idetify the Alum heads on it,other than they were purchased from comp products,but no paper work with them.
I have been talking with Tim on the phone,he said to first make sure they hydraulic lifters,and also i was thinking maybe this motor has the wrong push rods in it,but i have no idea how to tale if they are to short.

I also need to add this motor was neve run untill recently.
I'm going to see if i can talk Todd into letting me to try an adjust them with the motor running and see if i can make any headway.
 
i was thinking maybe this motor has the wrong push rods in it,but i have no idea how to tale if they are to short.

The correct push rod will "center" the wiping motion on the valve stem top. Ideally, when at 1/2 lift, the rocker should be contacting the center of the valve. If you were to coat a valve stem top with bluing, then run the engine, you would show a wear/rub mark "centered" on the stem.
 
i was thinking maybe this motor has the wrong push rods in it,but i have no idea how to tale if they are to short.

The correct push rod will "center" the wiping motion on the valve stem top. Ideally, when at 1/2 lift, the rocker should be contacting the center of the valve. If you were to coat a valve stem top with bluing, then run the engine, you would show a wear/rub mark "centered" on the stem.

Thanks Jeff. :beer:
 
I wanted to post this to let you guys know what we found. What it ended up being was the rocker arms hitting the valve covers. I used tall Cal Custom finned valve covers and they needed some massaging. It's running strong now, but I did want to say thank you guys for your input. I feel a bit better now that it's quieted down and not sounding like it's wiping a lobe.:eek:
 
I had a problem with loosening rockers a while ago and I learned that you can NOT reuse the rocker nuts a few times :cry:

One full turn is quiet a bit, back them off, feel the "zero play" and give them 1/2 turn, that should be enough preload.
 
make sure its not an exhaust leak. I have spent more time than I want to admit chasing clattering rockers only to find out there is an exhaust leak.
 
Todd's motor is all nice and quiet now and running very strong. What we thought was lifters out of adjustment was the back of the rockers hitting the side of his valve covers. We had found that problem earlier while running the lifters and Todd took some material off of the valve covers,but when we put them back on the car and refired dammit if the noise was still not there,so we gave up for the night (actually his wife said we have been playing long enough and it was late) but Todd pulled the covers the next day to find out that the rockers were still hitting his covers :banghead: but he fixed that problem and all is well now :trumpet:
 
I backed all the rockers off a ½ a turn and all still quite.

I was about to set fire to the thing, but then I realized I would still need to clean up the mess. :banghead: So fixing the rockers was the easier of the two alternatives.
 
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