hiltsy855

iTrader: (35)

Ok. This thing is driving me crazy. New LS1 motor, specs in my sig, dual springs, stock rockers, ticking bad at 2000 rpm. Great oil pressure - 55psi at idle. Geoff recommended 7.375 pushrods due to LS7 lifters and heads shaved .020. I used the "turns to 22 ft-lbs" method at initial assembly and they ranged from 1 turn to 1 3/4 turns. All over the map but I went ahead anyway. Had some ticking at startup so I got a PR length checker. While measuring I found the guy that did the valve job didn't grind all the seats & valves the same so the valve tip heights are all different. So I bought a set of 7.350 PRs and mixed & matched so now I have a few 7.350s installed but mostly 7.375s. Pre-loads were all calculated from the PR checker between .063 and .081. Still seems noisy as hell, mostly on the driver's side, I can clearly hear it from inside the car. Thinking back to the assembly stage, I measured and found the spring installed height to be about .030 too short (I don't think I checked them all) using Geoff's steel retainers and spring locators. Back then I called Geoff and he told me it should work fine since I only have a .600 lift cam. Is it possible the short spring is causing this noise? I wish now I'd gone with beehives - less pressure and the installed height would have been closer to correct. Let me know what you guys think - Please help!!!!!!

A.R. Shale Targa

iTrader: (2)

I think the stock length pushrods are 7.385 and a .600 lift cam will have a
base circle thats about .070-.075 smaller than a stock cam. I've read that
the factory lifter preload can range from .080-.110 however most guys try
to acheive between .050-.080. Also consider that milling the heads .020
doesn't exactly simulate a .020 longer pushrod because the valve-tip
height also moves south. It sucks that your tip-heights are all over the
place and it certainly doesn't help simplify the issue. I know dual springs
are a bit more noisy than beehives and too much valvespring pressure
could be collapsing the lifter plunger but I doubt thats your issue here.
Some say the ls7 lifter has a taller plunger height and others say thats a
myth. If you're thinking the springs are way too stout you could just take
the inners out to reduce the pressure and test run(not permanently) @ low
rpm just to see if it reduces the noise. I'm kinda thinkin longer pushrods
though perhaps 7.400.....hope some of this helps

kevin kuether

iTrader: (1)

Personally With a cam .600 or bigger I would never use gm lifters. I have seen too many threads on this forum about noisy valvetrains and everyone says it's normal. I don't buy it and I'm sure a lot of people will disagree but I just got my 427 up and running using the comp short race style hydraulic lifters and I have 0 valvetrain noise. I am also using the crane rollers because I had researched and they are supposedly the quietest. I wish I could post a vid because I am very happy I have none of the noisy sewing machines like a lot of vids on here. Maybe I just got lucky too but if I'm spending money I'm not gonna go half way only to be disappointed by trying to save here and there.

kendogg

iTrader: (2)

Intersting.

hiltsy855

iTrader: (35)

Guys - Thanks for your info. Going to longer pushrods puts pre-load over .080 and I thought I read the valvetrain is quietest with around .060. I didn't really think about spending more on the lifters because I read the LS7 piece is decent. Maybe they can't handle the extra load from the tight duals? That's the only thing that makes any sense. Again, I appreciate everyone's insight.

hiltsy855

iTrader: (35)

I forgot to add - When I installed everything with the matched pushrods I also double-checked using the "turns to 22 ft-lbs" method and they're all between 1 and 1 1/4 turns.

DMM

I have .600" with .650" duals running LS7 lifters and it is almost quiet as stock after changing the preload to around .60" from .100". The lifters are fine for this size cam and I would not worry about running them.

The LS7 cups are def about .50"-.60" higher in the lifter body than stock but that shouldn't matter if you are measuring. FYI - they seem to only have about .200" travel total, I am wondering if .100" lash would lead to collapsing the lifter with stiffer springs. (can anyone confirm this?!?!)

How much time do you have on the motor out of curiosity? I think mine may have gotten a little quieter after a few heat cycles.

hiltsy855

iTrader: (35)

DMM - Thanks for your info on the lifters. Glad to hear yours quieted down, I read other instances where reducing preload made things a little quieter. I still have a couple that measure over .080. Maybe I should change them to 7.350s and get preload to .055?

I have about 600 miles on the new motor.

garygnu

what rockers did you use,after market or stock?

hiltsy855

iTrader: (35)

Stock 50k rockers. I was thinking about the Comp trunion upgrade. If I get a consensus opinion on here I'll change whatever + the trunions and take it apart just one more time. Ya, right. I've had the valve covers off so many times I can do it in 5 minutes.

kevin kuether

iTrader: (1)

DMM, I didn't want almost as quiet. To each his own. The comp short race lifters are set to 0 lash plus an eighth of a turn and no more. Maybe the adjustable rockers help with the valve train noise too.

*02WS6TURK*

iTrader: (13)

Can you post up a video? I'm running the same EPS cam with Pac 1518 springs and it's got a little noise to it, but not a lot. I'm using Trickflow stock length pushrods Geoff sold me too.

kendogg

iTrader: (2)

Whats the deal with rockers as noted above? Is there an issue with stock rockers?

*02WS6TURK*

iTrader: (13)

Stock rockers are more then fine. I'm running them, tons of my local buddies are running them on their H/C packages. Never once heard of anyone local or on here running into issues with them.

hiltsy855

iTrader: (35)

I'll try to get a video up tomorrow. What lifters are you running? Stock I assume, I followed your build thread and ordered my cam somewhat based on that. When I ordered the cam from Geoff we talked about PR length and since I had LS7 lifters (higher) and shaved heads (lower) he recommended 7.375s. They would have been spot on if my machininst would have made the valve height consistent. Some valves sit higher in the head requiring shorter pushrods.

Damn I wish I'd got PAC 1518s like you did. I think my short spring install height is caused from the steel retainers + the thick spring locator from EPS (I think they were .050 or more). With the 1518s I know I'd have 1.800 install height using stock retainers and the thinner (.040) seal/spring seat.

So my current thoery is that the noise is caused by short spring install height (added seat & open pressure), dual springs which are heavy and add pressure, and the heavy steel retainers. I have to go back thru my math but 1518s reduce seat pressure by 20#, reduce open pressure by 50#, and are lighter + allow use of lighter stock retainers.

hiltsy855

iTrader: (35)

I can't imagine stock rockers are an issue. I was considering the Comp trunion upgrade just for good measure.

hiltsy855

iTrader: (35)

Interesting reading here. The EPS cam profile was originally designed for use with beehive springs.

ls1 1990 VN

Adjustable rockers will sort your valve heights, or like me, have a machine shop skim the tops so all valves are the same length.
Measuring with an adjustable pushrod sorted out the correct length pushrod for me.
I also changed from dual Patriot golds to Pac 1518s.
Engine picked up an extra 500rpm & is quiet as far as sewing machine effect is concerned.

hiltsy855

iTrader: (35)

Good info, thanks. What lifters are you running and what did you end up with for pre-load?

Patrick G

iTrader: (14)

.060" pre-load is too shallow if you want quiet. You need it closer to .080-.100" for more quiet. Of course, that's not the only source of the noise. High spring pressure (as noted) is hurting your here too.