I don't mean to post the 'same' Q in two rooms over time, but this is going into lifter theroy... Internal/advanced discussion...

From what I know and understand, also from what I have heard..... You cannot adjust lifter preload on stock lifters. -W/o modification of lifters.

We did an MS4 H/C install on -=Modified=-'s car. LS6 Stage 1 heads, stock .054 GM head gaskets (I'm pretty sure on the thickness) TSP also did this on a stock 02 LS1. -=Mod=- duplicated that setup, exactly. We rotated the engine over multiple times before we fired it up. No PTV clearance issues. The tick is still on the same side. Driver's side. We also just changed the oil to get all the assembly lube out of the system.

We started w/ 7.400 PR's... Ticked like crazy... TSP said we needed 7.425's... we installed them.. Still ticking. We just installed 7.3-somethings tonight... STILL TICKING!!!..LOUD!

This time, it was quiet until it warmed up, it was babied until it warmed up then a couple small pulls w/ it... (SMALL pulls).... then the ticking started again.

Lifter preload could be established w/ longer pushrods, correct? If they are shorter than the length that is needed, the rocker can only be tightened to a certain point. THe way they are now, we can spin the pushrods, but no vertical play. The rocker tip can be slightly lifted off the valve tip by hand. Prolly 1/16".. not even (WTF is the point of HYD lifters then?!?! Make up difference in valve lash w/ hydraulic pressure. ~.020, tho.). then you can feel the lifter plunger getting tight. How much trow do the lifter plungers have anyway?? 1/2"??

What makes sense in my head, longer pushrods would push the lifter plunger into the lifter for the needed preload, before the rocker fulcrum is TQ'd to spec (seated, tho)... -Was advised on another board... (similar terminology)


THis is taking every bit of theory I can dig up in my head from school to try to figure this damn problem out! It's getting really old! Wouldn't stock length push rods work w/ stock head gasket thicknesses?? Lifter preload should be accounted for w/ pushrod length and rocker TQ specs... .... ???..

 

Is it possible that one (or more) lifter could be defective?

 

I'm starting to think that. It's only on the drivers side. #3 or #5 cyl.

How can a lifter just 'go' like that?? Could it be related to not soaking them in oil when they were out?

 

Occasionally new ones don't "just go," it's more like they were never there. If they are new that wouldn't be a shock. If they were previously used and worked OK, it could have simply collapsed. You might try taking it apart to see if it was getting enough oil to pump up. How much valve spring pressure are you running?

 

No idea on the pressure.. PRC dual gold springs. The lifters have 37k miles on them. I think one is just not getting oil. We're going to tear his car apart again today. Lifters and PR's coming on wendsday.

 

I have an 11-1 350 in my 81 camaro and the motor is fresh. I also have a tap on the passenger side that won't go away. It's cylinder 8 I think. The lifters were new, but I replaced them again anyway thinking one may have collapsed. I tried putting the stock rockers back on with no luck. I also swap the push rods around. I am stumped, I think it may be something in the head. The heads are camel humps, but were rebuilt. the motor maybe has 500 miles on it. oil is coming out of all the push rods evenly, It doesn't do it cold, once it warms up it starts tapping.

 

Could the problem be related to the heat in the motor causing the oil to thin out thus allowing the lifter to leak down?

 

Who's heads? I've run into this before....

 

TSP LS6 Stage 1 heads. I've heard of a couple people having problems w/ thie heads. -Not many, just a few.

Could be the problem... I never thought of that actually.

 

That's what I thought...

A customer of mine who got a cam and heads from them had the same issue on a $125K+ custom '69 Camaro. He played with the pushrod lengths forever and finally put in a set of adjustable rockers on it (Comp Pro Mags) to get the noise out of it... A LS1 has to have the valve job seated heights close to get rid of this noise with stock rockers.... when they are not they clatter like this constantly. It's just down to bad QC on the valve jobs. You have to either get a new real valve job on them, swap heads or put a adjustable rocker arm in there.

Also just changed the cam over to a more streetable cam and I'm excited to see the dyno results. I'm expecting the same peak HP but just improving the whole TQ curve and making it much more drivable.

Bret