COLDLZ

I have built a stroked 6L, a 402. All appropriate machine work was performed by a well known engine builder, forged rotating assbly, new AFR heads. stainless roller rockers, a new moderate EPS cam, new OEM lifters, and I ended up with an obnoxious valve train rattle. I changed lifters to Lunati thinking the OEM weren't up to a .600 lift. No difference. What am I overlooking? It sounds like a 1977 Olds 350 diesel. Thanks for any advice.

JOHNNY59

iTrader: (398)

did you torque the rocker arms down correct to 22 lbs? I would pull the covers and see if you have any abnormal play in any of the rocker arms. I would also re-torque them again.

COLDLZ

Yes, that's been done twice. Also made sure of correct length on push rods. The motor runs strong, just clatters like it's worn out.

Mercier

iTrader: (15)

How is oil pressure? Did you make sure the rockers were good and centered on the valve tips? How much have you run it so far? I had noise on my cam swap a week ago and then popped the valve covers, made sure to center the rockers before re-torqueing. It seemed to help a little immediately but then after a few heat cycles(testing thermostat and steam port setup) it seems to have really quieted down..so.much so that there is no more valvetrain noise than the normal ticking of the injectors firing.

COLDLZ

I'm old school, thought the rockers would automatically center. Has plenty of oil pressure, it's a fresh build. Been thru retorq 2 times. Motor is very strong, just can't listen to the clatter. Not all lifters are so loud, sounds like only 2 or 3. Guess the motor has 50 miles on it. Thanks for your help.

Mercier

iTrader: (15)

I figured they should auto-center...and maybe they do. Seems like once my stock lifters got used to pumping up a little more it was all good. But I specifically had this cam ground to be a max-ish cam on stock LS2(6) valve springs.

So what are full cam specs and valve springs?

I like your reference to the Olds diesel. I have actually heard one of those long ago. Loud, loud. Would be funny to see one of those blowing big black smoke.

COLDLZ

I don't, at this moment, have the exact cam specs. The lift is right at .601 and .609 and the duration is .270ish. It's a custom grind by EPS. Really good cam for my app, torqie, 6000+ rpm. The springs are what came matched on a new set of AFR big bore heads, should be good for .650 lift. Appreciate your time to respond, I'm a racer from the sixties and and highly deficient on technology. Hard to adjust to the idea that I can't just open the hood, turn a couple of screws and make it all better!!!

Mercier

iTrader: (15)

The hydraulic lifters should take up the slack within reason. How were your pushrods chosen and what at they and what length? I know you said they were done right but it occurs to me that it's going to be lifters, rockers, cam lobes worn, installed height of springs off, pushrod length. Of those, the most likely is the pushrod length and easy to check if you have the right tools Is that 270 number total or @.050? I'm guessing the former.

Or bent pushrod(s)? Or some wrong length? Did you check them all for exact length and roll them on glass to check for straightness like a pool cue?

COLDLZ

I put a new set of Lunati lifters in, checked for proper push rod length with an appropriate tool, both of which were ordered from Summit, I did ck for straightness. I can't imagine lobe wear on a new roller, plus the noise was there from first fire. I've been told it might be from the ramp design on the cam, hard to believe. The heads were out of the box AFR, torn down and cleaned thoroughly, reassembled, put on top of new cometic head gaskets on a studed block. The duration is about 270 total. As I've already said, the motor is very strong, just sounds like hell from the front, sounds like heaven from the rear.

Mercier

iTrader: (15)

Could be the ramp rate. Doesn't seem likely but a cam can sling the lifter up so fast/hard that it can jump off the lobe. Usually that's super wild cams though.

(Geoff? @)EPS has a good rep around here. Have you sought advice there? He/they would know what to expect with the cam if he spec'd it.

When you say you checked pushrod length, did you measure every pushrod? I know you established needed length on one lobe but once you decided and ordered the pushrods, did you ensure that all the pushrods you received were the right length? I haven't heard of getting a set with some rods short but it's theoretically possible.

COLDLZ

I haven"t called EPS, my next move. I measured only one push rod, hadn't thought of that. I put about 80 miles on it today, still hate that noise but I may just have to get used to it.

Mercier

iTrader: (15)

I wouldn't have thought of it either unless discussing with you. (I'll be checking my next set though since it's easy insurance) It does seem fairly unlikely but when you have a couple of guys cranking out a thousand pushrods in a day, they could get mixed up. Also the machines that make them eventually wear..and often that wear isn't noticed until a part is identified as "wrong."

Is the noise actually loud enough to be obvious sitting in the vehicle(what kind of vehicle)?Me, I fixed all the rattles and squeaks in the CJ with mufflers. And then the radio. . But a ticking might drive me a little nuts...how do you know when a /real/ tick starts?

COLDLZ

The noise is heard at idle or driving. The vehicle is a 99 z71, reg cab, swb, step side. It has been tuned, performs surprisingly well for a 4600lb truck.
The exhaust is obnoxiously loud, just the way I like it. I live in a rural area, so far I've gotten away with it. I run Brad Penn 10w30 break in oil. Wonder if more viscosity might help.

2001_Z28_FUN

will you change the oil and filter after the first 200 miles on that new built motor? I would put a Quart of Lucas oil additive that helps everything quiet down, when I had a LS1 5.7L I put a MS4 cam kit in with double Valve Springs and chrome molly push rods and swapped the timing chain from chain drive to gear drive only.... the motor sounded like a Sewing Machine for a while.... but quieted down a little after break in and oil change with Lucas Hope I helped a little bit

Mercier

iTrader: (15)

This sounds like a good idea. Didn't realize you were still on break-in oil(should have figured). I always used Lucas in my Can-Ams(4 wheelers) and even after flipping over, sinking entirely, and filling the crankcase with mud and sand, changed the oil a few times and didn't even smoke. Ran like a top. Maybe that's more of a bump for BRP than Lucas but I ran those bikes very hard in 4 feet of mud and always got compliments on how strong they ran. Quiet, too.

Doing first oil change in the Jeep next weekend since the swap. Going to make sure to remember to put some in there. As I mentioned earlier, I still have a little noise but it's about at normal injector level..just deeper tone.

COLDLZ

I normally use Lucas oil treatment and will when I change oil. I agree, seems to work well, especially in moded engines. I really appreciate the responses on my noisy motor. Brother Mercier, have enjoyed conversing with you, I will update as I get this thing under control, thanks.
COLDLZ

McGinnis

What weight oil are you running, to thin might cause more racket when warmed up fully?

RevGTO

iTrader: (12)

I would take a vid of it and send it to Geoff at EPS for consultation. You might want to post it here as well.

Mercier

iTrader: (15)

Figure anything out?

RockinWs6

Probably a leaking-damaged oring on the pickup tube