classic_speed

iTrader: (3)

Built a new 6.0 motor. Decked heads, cam, ls7 lifters. Did the math wrong on the pushrods and ended up with a noise. Truck was driven probably 50 miles with 0.195" of preload. Replaced the pushrods with the "correct length" 7.300 0.058" preload. I still have a noise. Any suggestions? My thinking is the lifters are damaged but thats not what im hoping to hear.....

Darkman

iTrader: (2)

The preload you were running appears to about equal to the total travel of the lifter plunger in the LS7 piece. I say "appears" because in reading old threads I did not find reference to an absolute measurement, but did find "opinions" ranging from 1.66 to 2.00 inches.

classic_speed

iTrader: (3)

Right? I see so many different "accurate measurements out there. Am i possible still off on my preload? The 0.060 range should be on the money

Darkman

iTrader: (2)

I don't happen to run LS7 lifters, but based on what I read on this board 0.060 inch preloads is on the light side with most reporting 0.070 inch to just of 1.00 inch as their preload. Still I would not think 0.060 inch would be noisy if 0.070 inch is not.

A.R. Shale Targa

iTrader: (2)

If the plunger was bottomed out it would effectively have become a solid lifter. Without lash the valves would not be seating and the engine would hardly run. Your preload now seems a bit light. What lobes are on the cam ??
They may never be quiet if they're real aggressive. Lastly you may want to double check the oil pump O-ring on the pick up tube. If not seated right it can allow air in to aerate the oil causing a really loud valvetrain.

classic_speed

iTrader: (3)

The truck has 60# of oil pressure at an idle. Is it still possible the oring could be a problem?
Its a comp LSR cam http://www.compcams.com/Company/CC/c...csid=1400&sb=0
With Comp 918 springs, Stock valves, Heads decked 0.072, stock rockers,LS7 lifters and currently a 7.300 pushrod

classic_speed

iTrader: (3)

Is it possible I need dual spings?.....

Darkman

iTrader: (2)

Well Comp recommends their 926 springs, which suggests it is an aggressive cam to me.

TurboBuick6

iTrader: (2)

I don't think you need a dual spring. Opening and cloing ramps look slow.

Darkman

iTrader: (2)

From 2013 Comp catalog:

LSR
™
• Take advantage of today’s newer and better flowing aftermarket
cylinder heads
• Feature higher exhaust duration and overall lift to provide
broadest powerband and most top end power of
any COMP Cams® LS camshaft
• Unique grinds for both cathedral & rectangle port heads
• Require 26926-16 high pressure valve springs

TurboBuick6

iTrader: (2)

The catalog is always right.

I have 20 degrees more duration and 0.040" more lift on 145 seat pressure. Only reason I have a dual is because I dont want to push a beehive to .650" lift on a DD car.

classic_speed

iTrader: (3)

The noise gets louder as the engine warms up. First startup sounds tolerable. Once the engine is up to temp it becomes much more pronounced

Darkman

iTrader: (2)

Your current springs, even if the Comp Catalog is correct, should be enough to control that cam at idle. But I suspect that quiet operation may not be one of that cam's design parameters.

classic_speed

iTrader: (3)

This is beyond normal noise. I have oil flow at the rockers but it's very minimal. Trickles out at an idle. 60 psi of pressure on the gauge.

classic_speed

iTrader: (3)

^ from what I read however though this is normal...

Darkman

iTrader: (2)

If it were mine I would upgrade the valve springs to either Comp 921s or BTR LS Platinums; and increase the preload using some stout push rods.

99Bluz28

iTrader: (35)

This is one of the issues that periodically arise is that the LS7 lifters don't come in a flow matched set, so there's no guarantee regardless of how well you set the preload that you lifters will all be fairly quiet, since you could have a few that are bleeding down to fast.
So, have you checked to see if you can pin-point the valve train noise to any particular cylinders..?

Darkman

iTrader: (2)

Do you have an opinion as to what valve springs are needed for this cam?

99Bluz28

iTrader: (35)

I don't think that the valve springs are the issue, or where he set the lifter pre-load. I'm also running right about .059" pre-load on my LS7 lifters on a LSL/LXL lobe combo, and I've ran the preload higher at .084" and my valve train was noticeably louder. My valvetrain is by no means stock like, but I also don't think abnormally loud, I'm also using PAC 1521s dual valve springs.

I'd still recommend going with a set of dual springs with better spring rates for use with the LSL lobes.
I would go with a set of good dual spring, mainly because most beehive single springs just don't have near the spring rates to better control more aggressive, and higher lift of cam lobes like the Comp Cams LSL lobes. There's also the added security you get with dual springs incase of the "what if " happens. I'd recommend go with a set of the BTR dual springs. They have good closed and opened rates, and are a excellent set of springs, but for a budget price.

A.R. Shale Targa

iTrader: (2)

Sometimes it just seems that badass lobes make killer power, Badass springs
keep all the **** where it belongs, and GM lifters that are being asked to
tolerate nearly double of both forces are gonna let you know how unfuckin'
happy they are regardless of what pushrods and oil you put in there.
Maybe it's as simple as....GET BETTER LIFTERS !!!!....