L67 camshaft choice discussion

[immortality]

Noisy valve train, if older lifters try some of that Nulon Lifter Free stuff. Hydro lifters have the smallest orifice of any component in the engine, if crud is going to get stuck anywhere this is the most likely spot. Failing that, check the lifter pre-load. Some of the after market anti-pump up lifters that run stuff all pre-load also tend to be noisy. To say noisy lifters = stuffed lifters can be a very expensive exercise when it's possibly not the issue.

no where near 1k

http://store.yellaterra.com.au/holden-b ... ef-yt6649/

The reworked factory rockers are rubbish. They are welded and re-drilled and loose there case hardening at the rod seat and the rod crews the shit out of the rocker in no time.

I actually think it's the other way around TBH. Used push rods with re-manufactured rockers = fail unless the push rod tips are in perfect condition. Fairly much every ecotec I've seen has had some sort of wear on the push rod where it sits on the rocker and I believe this is because of the roller lifters which means the push rods don't spin. Our Calais was the same and was starting to get a slightly noisy valve train which on the ecotec has always been blamed on the lifters but I believe is in fact wear on the push rods causing the lifters to loose there pre-load. I fitted new rockers and push rods and she's quiet as now.

I have a set of worn 1.9 rockers here, push rod cup in the rocker has some wear but the push rods themselves are totally stuffed. I was going to try and clean up the rocker seats but the fuckers are still hard as fuck.

No this issue occurs with brand new push rods from crow cams. all rockers were chewed out but the push rods weren't even worn in, so that means the reworked rockers are too soft and just get mooshed like play dough from the hard push rods. I was able to dig at the rocker seats with a stanley knife to try trim off the burs.

Out of curiosity Vlad, how many have you seen like this? Can you be 100% certain it was mechanical failure due to a faulty component or possibly a poorly fitted one where the person didn't lube the parts before assembly?

The reason I ask is that over a few years I sold many a set of these types rockers and saw very few failures. I know there was a batch of bad rockers which if memory serves was due to a change in the manufacturing process but that was rectified fairly swiftly when the error was found. In those years I very rarely had customers complaining of issues with these rockers.

[vHell83]

Ah yeah I see. Ultralites will do then.

My lifters, with the remainder of the engine have under 10 thou since reco. The lifters were checked and found to be ok when going from na to sc, but the plan now is to use ls7 lifters that have far less tolerance.

[vHell83]

https://zzperformance.com/3800/zzp-1-65 ... -arms.html

Are these the ones you were talking about? Zzp rockers.

[vlad01]

Ah yeah I see. Ultralites will do then.

My lifters, with the remainder of the engine have under 10 thou since reco. The lifters were checked and found to be ok when going from na to sc, but the plan now is to use ls7 lifters that have far less tolerance.

Yeah thats the idea, all you need is adjustable pushrods for length checking and set the preload on the lifter hydrualic to I recall 2.09? mm

EDIT:

Thank buicks for google images. Been nearly 2 years since I found the page with this table.

part number of all LSx lifters from GM now end with 490 so yes, preload 2.09mm on base circle.

LSx Lifter Preload Update.jpg (57.02 KiB) Viewed 2972 times