mchicia1

iTrader: (5)

Before typing why I am asking, yes I am going to measure.

Ok so, I already have lifter tick with these stupid LS7 lifters despite going with the lightweight valves, ti retainers, and cam motion cam at low rpms. Clears up at 2k, but its getting louder at low rpms so I want to swap them out before they eat my cam. I feel dumb for skimping now.

The problem is this is my DD and only car right now, so I need to do the install in 1 day. Does anyone know the difference in cup height of the two lifters? I plan to order like 3 sets of pushrods and then return 2, but I need ballpark figures first.

Right now I have LS3 heads milled .030", .040" cometic and the pushrod came out to 7.375" which gave roughly .050" preload or so.

A.R. Shale Targa

iTrader: (2)

Not saying the noise would be completely non existent, but it's my understanding that the factory/LS7 lifters work best with more preload
Something in the .090"-.0120" range

mchicia1

iTrader: (5)

I mean I could spend the $100 and try a longer pushrod too, but the tick wasn't there at first and it showed up later. That is what has me concerned.

It's not the loud, constant tick when a lifter is already toast. It's definitely the lifter bleeding down because it clears right up with throttle. It's not constant either. So MAYBE more preload could solve it.

Worth a try? I could throw the stock pushrods in to check, but they're only .010 longer than the current ones.

MuhThugga

Throw some 7.400s in there first.
.050" of preload isn't enough.

mchicia1

iTrader: (5)

Before I do that, have you experienced noisy lifters get quiet after adding more preload?

I'm thinking if I have .050, I may only have .025 when warm and that is when it is loudest. It sounds fine when cold.

mchicia1

iTrader: (5)

Just remeasured zero lash on 4 valves.

Intake: 7.262. Count the turns was about 7 or slightly less.
Exhaust: 7.275, maybe slightly less. Count the turns was 6+.

Obviously, count the turns is not as precise, but it almost matches up, so it was a good sanity check.

So with 7.375" pushrods, I have too much preload. Could this be the cause of my intermittent ticking?

I must have measured wrong since the lifters were new, they were probably moving down with the weight of the pushrod.

Rare96LT1Formula

iTrader: (32)

In my experience, many of the LS7 lifter failures and/or valvetrain complaints have been directly a result of improper preload setup and/or incorrect length pushrods.

I've seen many vendors sell what I would refer to as "cookie cutter" camshaft packages with 7.400" pushrods as if they're guaranteed to be the correct length. This is not the case in many instances, which can potentially lead to situations such as yours - which I'm in no means insinuating what has happened. I mean, I can legitimately have my wife order 5/16" or even 3/8" custom spec pushrods, so why not spend the money on a quality tool to ensure you have your ducks all lined up? If buying pushrods on an LS is this this easy, I feel we owe it to ourselves to at least spec them out correctly.

Measure twice, cut once, right?

From what you've explained - I believe you've answered your own question, although I am interested in knowing - is your camshaft ground on an 8620 core?

mchicia1

iTrader: (5)

I did measure them before ordering, but I fucked the measurement up because I was depressing the freshly installed lifter plunger down. It goes down with very light pressure. I was a bit rusty as it had been a couple years since I touched an LS motor. Funny, looking back at my old threads, I made the same exact mistake with the same exact pushrod size on my old vette build lol. But that resulted in bottoming out the LS7 plunger and the car would not even start. I must be a C hair away from bottoming out the plunger in this case.

My cam is ground on 8620, yes.

I ordered 7.325" pushrods, will report back after they're installed. If the ticking is still there, the heads are coming right off. Nothing is worse than that low rpm tick. I hate it. And the last thing I want to do is have to take the cam out too.

MuhThugga

Yes, I have. I have also seen lifters get quieter with less preload when the pushrod is too long.

If you ordered 7.325, then you are still only going to have ~.050" of preload. I would order 7.350s.

mchicia1

iTrader: (5)

.050 on the exhaust, .062 on the intake

Will report back tomorrow.

mchicia1

iTrader: (5)

Installed the shorter pushrods. The off beat tick went away, so it was definitely pushrod intermittently bottoming out.

But the VT is louder overall, but at least it is harmonious now.

I was concerned installing the shorter rods, because 4 of the lifters were not coming up with the spring inside. They seem to be ok but I will keep an ear on them.

mchicia1

iTrader: (5)

Same tick came back, the lifters can't stay pumped up below 2k rpms. They're coming out.

MuhThugga

I still say you aren't running enough preload at .050/.062.

mchicia1

iTrader: (5)

I doubt it will make a difference if .100 was terribly loud as well. I just think there is something up with 1 or 2 lifters in the batch I got.

I did order 7.350" pushrods to go with my Morel 5315 lifters that I ordered, so it may be worth a shot to put those in before pulling the heads just to see.

A.R. Shale Targa

iTrader: (2)

Ever considered the possibility of larger lifter bore clearances bleeding off pressure that would help the plunger deal with higher spring pressures
Tried once back in the day to put a hydraulic can/lifters in an iron block that had previously run a solid roller cam. Very noisy lifters. The bores were wasted and I ended up junking the block. Different fresh block. Same hydraulic cam was quiet

mchicia1

iTrader: (5)

Doubt it since the valvetrain was dead quiet for the first 1,000 miles. Now it still sounds like this video, except you can clearly hear one or two lifters randomly ticking. And when they tick, the engine idle gets a little bit rough. They are bleeding down, I am sure of it.


Here is first weekend of cam, quiet.