GR33N GoblinM6

iTrader: (14)

K so im trying to chase down a tapping, or what sounds like a tapping.

I have a fairly stock 96 LT1, 1.6rr, xr270hr cam, stock heads.

im using the thinner stock GM head gasket (Impala gasket?)
and before rebuilding the engine i had the heads resurfaced, not too sure how much was taken off, but it cant be much.

Im using the stock push rods, 7.200 and im wondering if this is the cause?
I gone over the valve adjustment over and over and over..

other than the tapping or clicking at idle the car runs awesome, no isses on down power, or anything like that.. i was wondering if a collapsed lifter would cause this noise.. maybe not

i did find one of my header bolts loose, retightend it,, but didnt change the sound all that much but there was a change, im using Percy's dead soft aluminum gaskets.

it sounds like its mostly coming from one side(passenger) but i really cant be too sure on it.

any help or suggestions or tricks i can do? if needed i can get a vid on my iphone.

Fazz73jr

iTrader: (3)

Id start with replacing those header gaskets. I've had bad luck with those sealing up. Try felpros or mr gasket ultras.

Also are you running self aligning rockers? Using guide plates? Id grab a adjustable push rod and make sure those push rods are the correct length.

GR33N GoblinM6

iTrader: (14)

yeah they are SA rockers..

anyone have a link on how to use the pushrod length checker, and such?

GR33N GoblinM6

iTrader: (14)

ok, so i went out and removed a rocker, colored the valve tip, re-installed the rocker.. found zero lash, gave it 1/2 turn and locked it down. rotated the engine 2 times.. see results

looks like the pushrods not the right size



this is the driver side, #1 cylinder

thoughts?

defaultexistence

iTrader: (11)

Little too long, time for some 7.150's most likly ..aftermarket rockers and milling will require new PR's .. Did mine too.
Idk if that will cure the tick but.. Your stock ones need retired.
Btw sell your stock ones if u can.. Their hardened.

SS RRR

iTrader: (2)

It's not too bad. If the sweep is off center it is much better for it to favor the exhaust side than the intake. If you are able to get it towards the center yet the sweep becomes wider, go with what you have in that pic.

Speedy

Pushrods too long. Go with 7.1s or 7.0. Don't buy until you have checked with a pushrod checker to get the exact length you need.

Rob94hawk

iTrader: (1)

Looks like 7.1 but like others have said, measure. Mine turned out to be 7.15" after measuring. In this pic it was 7.2"

SS RRR

iTrader: (2)

Do you have adjustable guide plates? It doesn't look as though roller bearings on the rockers aren aligning on the valve tip properly.

WS Sick

You want tit as said to favor the exhaust side atthe top since it moves inboard as lift increases. You can allways get it perfectly centered, but my experience shows that the little off you are will not make valve noise. I would lean towards an exhaust leak or something else.

GR33N GoblinM6

iTrader: (14)

I have a compcams Pushrod length checker coming tomorrow, and all that I've read from comp cams and all the major head builders, is that using incorrect Pushrod length like I have, articulates the valves and puts stress on the valve guides, causing premature valve guide wear, resulting in oil consumption and power loss.

Thanks for all the help guys, very much appreciated

BALLSS

when you get the check tool, measure it's length to 7.150" and try that. if still to far towards exhaust than set it at a length of 7.100" and try again. to long/short of a PR puts strain on valve guides and they wear causing oil consumption and loss of power

I doubt the PR length is the tick....unless you have worn a guide to the point the stem has slop and making the noise.

exhaust leak or collapsed lifter more likely source of noise

defaultexistence

iTrader: (11)

I bet 7.150 would be damn near perfect..

WS Sick

If youre valve stem is so loose in the guide that it is making noise you got more problems than PR length...lol

I would like you guys to do a set of roller rockers on an all stock motor some time and take some pictures for me of the valve tip pattern.

GR33N GoblinM6

iTrader: (14)

k so i got my length checker.. started at 7.150.. about the same as 7.200.. took it down to 7.100.. still towards the exhaust.. 7.050.. dead center.

anyone else using that short of a pushrod? does that sound too short?

gjohnsonws6

iTrader: (12)

You are not using a solid lifter to check it are you? That's why you are not seeing a change in pattern you are just collapsing the lifter. I use a 7.050 but not one valvetrain setup is the same. Get a solid lifter then you will get the correct length.

Speedy

You're OK with that length of pushrod. The hydraulic lifter tolerance will be set by lash so don't worry about it. Double check that at that adjustment nothing is contacting anything that shouldn't.

airfix

iTrader: (30)

By any chance do you have emissions headers with a block off plate @ the egr tube?
I had this exact issue, and found the plate wouldn't seal properly with just the one bolt holding the plate on.

GR33N GoblinM6

iTrader: (14)

No I'm using sbc headers that ate not for LT1's. I'm thinking the leak is from my crappy bolts, just got some ARP's