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Quote:

Originally Posted by Marcellus (Post 13968403)

Sounds like too much synthetic too often to me. Imagine washing your hair 5x a day for 2 months. Detergent at too high a level is always bad.

Edit: And I am literally just saying what comes to mind. Thats a lot of oil changes at short interval for no reason.

That's interesting. Never heard of that but I suppose makes sense.

I assume with the low miles this guy was just doing oil changes about every 6 months regardless of miles?

Quote:

Originally Posted by SAUTO (Post 13968388)

We are in the process of cam swapping an 01 2wd reg cab short bed 5.3

Pulled the cam this afternoon and the front cam bearing is brass over halfway around on the pressure side.

I was shocked. Truck only has 61k on it and it's hard the oil changed 24 times with Mobil 1 synthetic. Older guy that owns it bought it new.

Any thoughts?

Normal, every LS I’ve been into has had healthy cam bearing wear. My 6k mile LSA was about the same.

Quote:

Originally Posted by lewdog (Post 13968414)

That's interesting. Never heard of that but I suppose makes sense.

I assume with the low miles this guy was just doing oil changes about every 6 months regardless of miles?

Like I said that was just a thought that popped into my head for some reason after seeing the oil change interval. May be nothing like MIA is saying but I did a quick Google search and found this which is kind of along the lines of what I was thinking.

Quote:

Generally, there is a parabolic curve that is associated with wear rates. The are slightly higher initially, drop down to nearly nothing, and then escalate again after the oil is compromised past its point to deal with contamination.

The “uptick” in wear is due to the tribochemical barrier being removed by the “fresh” detergent package upon installation. Yes - believe it or not, too much of a good thing is a bad thing. Now, DO NOT read too much into this; I’m not saying it will kill any engine. But what I am explaining, and what is abundantly clear in UOA data as well as supported directly with the SAE article, is that the wear is HIGHER upon the initial OCI, because the cleaning additives actually remove the boundary layer that protects the metal parts. Don’t believe me? Read the whole article. And review my “normalcy” article as well; there is CLEAR data that shows the wear rates drop the further out you get from an OCI event."

I haven’t seen the SAE article, but it seems to be based on used oil analysis, showing metal particle content.
I posted there once suggesting that since UOA is an indirect way of measuring wear perhaps something else is going on.
I think it’s possible the rapid increase of metal particles in fresh oil comes from being “washed off” of various surfaces in the engine, not from increased wear.
Of course my idea didn’t get a warm reception.
I think the only way to conclusively show the short OCI’s increase wear would be to run two or more engines under identical conditions but different OCI’s, tear them down and measure the wear.

OCI means "oil change interval" I am pretty sure.

Quote:

Originally Posted by Marcellus (Post 13968403)

Never thought of that.

Quote:

Originally Posted by MIAdragon (Post 13968421)

Normal, every LS I’ve been into has had healthy cam bearing wear. My 6k mile LSA was about the same.

Ive never seen it like this before.

You swap in new bearings every time you swap cams?

Quote:

Originally Posted by Marcellus (Post 13968435)

I'd be interested in reading that article and the sae one mentioned if you happen to have a link

Quote:

Originally Posted by lewdog (Post 13968414)

That's interesting. Never heard of that but I suppose makes sense.

I assume with the low miles this guy was just doing oil changes about every 6 months regardless of miles?

Every 3k unless it sat an extended period. We always cried when we drained basically brand new oil out of it.

Quote:

Originally Posted by SAUTO (Post 13968462)

Every 3k unless it sat an extended period. We always cried when we drained basically brand new oil out of it.

So realistically what do you really recommend for a car that is driven low miles when using fully synthetic? Were you recommending he change that often or was he?

Quote:

Originally Posted by SAUTO (Post 13968449)

Ive never seen it like this before.

You swap in new bearings every time you swap cams?

Unless it’s bad to where you can feel the grove with your nail I run them. I’m not easy on my motors either.

Quote:

Originally Posted by MIAdragon (Post 13968375)

Don’t go too low, the LSs’ like compression. I went too low on my first 427 and it was a pig on the street.

ill be 9.8:1 on 317 heads with .051 head gasket, i have flat top pistons etc.

Quote:

Originally Posted by lewdog (Post 13968465)

So realistically what do you really recommend for a car that is driven low miles when using fully synthetic? Were you recommending he change that often or was he?

He was insisting.

I go 5 on my truck and it still looks new coming out.

Quote:

Originally Posted by SAUTO (Post 13968460)

I'd be interested in reading that article and the sae one mentioned if you happen to have a link

Took a wee bit of digging but here it is. Interesting stuff.

Shouldnt be surprising oil companies want us to change oil as often as possible :D

https://www.sae.org/publications/tec.../2007-01-4133/

Quote:

A fleet of three vehicles was run in Las Vegas and oil samples were collected at various drain intervals from 3000 miles to 15000 miles. As in the previous study, the results showed that the aged engine oils provide lower friction and much improved wear protection capability. These improvements were observed as early as the 3000 mile drain interval and continued to the 15000 mile drain interval. The composition of tribochemical films formed on the surface with the 3000 mile drain interval is similar to that formed with the 12000 mile drain interval as seen before. These findings could be an enabler for achieving longer drain interval although several other factors must to be considered.

common failure points of an LS

1. rods
2. rod bolts
3. cam bearings

cam bearings is what killed my truck motor the first time around. At the same time I have zero intention on swapping cam bearings in the TA going to a turbo cam, unless we open it up and see something egregious.

Quote:

Originally Posted by MIAdragon (Post 13968475)

Unless it’s bad to where you can feel the grove with your nail I run them. I’m not easy on my motors either.

It's got a lip.

We're pulling the motor tomorrow. Shit the timing chain had almost a 1/2 inch of slop. Heads will have to come off now. I'll take it to the machine shop and have them install bearings.

Quote:

Originally Posted by SAUTO (Post 13968487)

It's got a lip.

We're pulling the motor tomorrow. Shit the timing chain had almost a 1/2 inch of slop. Heads will have to come off now. I'll take it to the machine shop and have them install bearings.

WTF?

Sounds like premature wear.