Ferocity02

iTrader: (59)

I did a head/cam swap on my 5.3L about 3 weeks ago. Heads are new stock 799's milled 0.022", cam is a new 212/212 0.561/0.561 114LSA, new dual springs and Comp 7.325" pushrods. I did not touch the oil pump or o-ring during the swap. There was a chirping/ticking noise once it got warm after the first start up, it lasted the whole 20 miles drive home but went away mostly the next day. I babied it for several heat cycles, then I changed the oil a few hundred miles ago from M1 10W-30 to Rotella 5W-40. The ticking noise then came back a few days after.

It's a metallic ticking/tapping sound coming from the block area around cylinder 5 and 7. It varies with RPM and appears to be tapping at about half the speed as the engine is spinning (idle in videos is 650 rpm). The tapping happens at all temps, but is louder when warm. It does not seem to vary much with load. The oil pressure gauge is fluctuating slightly at idle. It did not do this before the oil change, but I also messed with the gauges themselves so I could have hurt the stepper motor or something. I put the front on jack stands to listen and the tapping noise almost disappeared.

I thought it was an exhaust leak but I have none, checked by hand and smoke. Pulled the valve cover and saw nothing. Retorqued all rockers and checked the springs. Lifter preload is 0.075". The lifters are LS7's with about 40K miles on them, looked okay when I put them back in. Compression on all cylinders is 180-185psi, cylinder 7 was 170psi. Could be user error however. I did not notice any abnormal metal on the drain plug when I changed the oil.

Warm-ish idle:

Warm-ish idle (notice the tapping comes and goes, skipping a beat here and there):

Warmer/hot idle after driving home 20 miles (tapping is consistent):

WhiteX

I would probably attribute the shaky oil pressure to the cam lope.

The ticking is interesting though. I do notice a slight tick with my TR220/ported 706 combo that isn't there with a stock engine. I bought mine built so I can't really speak to the initial build. I also have long tubes and there's a definite increase in valve train noise. The tapping is also something that's talked about on other LS based vehicles that have had a cam swap.

I'm interested to see where this goes. Good luck!

TXSZ66AVLANCHE

iTrader: (7)

Why are your push rods so short?

Ferocity02

iTrader: (59)

Heads are milled 0.022" and LS7 lifters are 0.050" shorter. I measured with a pushrod length checker and a dial indicator. Preload is 0.07-0.08". If the pushrods were too short all of them would be making noise. Clearly only one part/thing is making this noise since the tapping is at half the engine speed.

I double checked the springs, rockers, and pushrods tonight on cylinder 5 and 7. Lifters all seem normal too. Only weird thing I saw was that the exhaust valve on cylinder 7 isn't as tall as the rest. Thus the preload on this one was only 0.05-0.06". I filled this cylinder with compressed air but didn't hear anything leaking out of the exhaust or intake.

But, even with the spark plugs all out on the drivers side, as I turned the crank by hand I still heard hissing sounds from the drivers side like air was leaking from somewhere. The passenger side was silent even with all of it's plugs in. Very strange...

Mangled03gmc

iTrader: (95)

The cups on the ls7 lifters sit higher then the ls lifter cup. That sounds like a lifter issue to me. It is not a rod knock.. Given the the 7 lifter is a direct replacement, drop in, I am not sure I would have knocked that much off the PR length.. I still believe the compressed height is the same, just a higher plunger..

Ferocity02

iTrader: (59)

The shape of the LS7 lifter cup makes the pushrod sit higher, that's a fact. I measured the preload about a dozen times on different valves using two different methods to achieve what I have been told is a good preload for these lifters. I ran these lifters with 7.350" pushrods with stock unmilled heads and they were quiet. I do have a set of 7.350's I could try, but that would put my preload above 0.100" on some of the lifters. I think that is too much.

I'm still not sure about the exhaust valve on cylinder 7, that baffles me.

I think tomorrow I'm going to use a stethoscope to try to narrow down the tapping noise.

TXSZ66AVLANCHE

iTrader: (7)

So why when I look up a newer vehicle with LS7 lifters from the factory....it uses the same part# push rods as a 99-06 5.3?

Ferocity02

iTrader: (59)

Perhaps they are designed to accept higher preloads. I'm not doubting what you're saying. I just used the advice I found on here and tech, and what my measurements told me. Some people, like WCCH, advise even lower preloads with these lifters around 0.050".

Mangled03gmc

iTrader: (95)

Who knows it could be a lazy lifter. But if the lifter has a higher cup height wouldn't you want less preload? For what its worth I am running 7.4 rods, with .020 off my heads, have no noise at all. But I am using the older style ls lifter. Couldn't even tell you where preload is set at, just no they felt rite to me.

Mangled03gmc

iTrader: (95)

I have even read some run .035..