wheatjb

Hello,

I recently swapped out the LM7 in my suburban with a Junk Yard L33.
The L33 has 129,000 miles. I replaced all the gaskets and seals and cleaned the engine out as best I could when I had the valve covers, oil pan and front/rear cover off. There was a fair bit of crap in the oil pan but not too horrible. I have also cleaned out the lifters with B12 Chem-tool and performed a motor flush.
My question to other L33 owners is how noisy are these motors at idle?
This L33 runs great but I notice internal engine noise that I never had with my LM7.
It does not knock or make any really bad noises, but I notice valve train or lifters or something is louder at Idle than my old LM7. I also replaced the oil pump and pickup o-ring with new ones and have good steady 50-60PSI oil pressure.

Other L33 owners please chime in and let me know if you notice hearing the engine internals at idle on your L33.

Thanks

Aaron at SDPC

Original lifters though I assume? All things created equal and in good running order I wouldn't expect the L33 to have any more noticeable noise while running than the original LM7.

wheatjb

Yes Original Lifters.
I just thought maybe I was hearing more due to an Aluminum vs cast iron block?
Also I replaced the exhaust Y pipe while replacing the motor. The old Y-pipe had pre-cats directly after the flange where they bolt to the manifolds and the new pipe does not. My exhaust is slightly louder but not much. And it is not an exhaust noise I am hearing definitely internal engine noise.
Thoughts?

Aaron at SDPC

The difference in noise is not something in my opinion that you would notice. I would pull a valve cover make sure a rocker hasn't backed off, and if everything looks good there you might want to take a closer look at the lifter situation.

wheatjb

Could I be hearing the lifters?
I thought they would be more of a loud tapping sound?
This is more just like a crunching type sound at idle?
I guess it could be lifter noise?
I don't want to have to pull the heads to replace them though. I will just send the engine back and get another under warranty. Any ideas on how to determine what the source of the noise is?

wheatjb

I have pulled all the rockers and blasted each lifter with B12 and looked down at each one with a lite, they looked fairly clean?
I re torqued all the rockers back on to spec. and performed a motor flush.
Same noise still there, at idle only, when I rev it up it sounds smooth and I don't here it?

wheatjb

Maybe I am just being to picky, and I need to live with a little more idle noise than my old LM7?

Aaron at SDPC

Are you sure it is an internal engine noise?

wheatjb

Yea, pretty sure.
I have listened with a stethoscope and it sounds loudest around the heads.
I will listen again more this evening.

Michael Lamb

Hi there I have 2007 Silverado with the L33 with 107,xxx miles truck run super great, but I do also notice noice and I'm pretty sure it's lifter noice, could be lauded cause these engines run LS6 heads that are aluminum so the nice could be a little pounder, recommended and engine treatment and then do a good strong engine flush before your next oil change.

hope this helped best of luk

tull

yes my 06 l33 has noise sounds like the valve train