Changing oil...Let it drain overnight ?

[BigJohn]

Cool thanks!!!

[Paul Workman]

Sitting here sippin my coffee, I just remembered that story from the HOTB book, where this gal was cranking up the brand new ZR-1s in sub freezing temps with the accelerator nearly floored. The result was a number of new ZR-1s with cam failures. So, it seem a quite plausible notion that most of the wear over time goes hand in hand with cold, dry starts, sans pre-oiling.

I too crank my Z every 3-4 weeks when in winter storage. My thought is to minimize the "drying out" of the bearings, and keep fuel residue from gumming up in the injectors (which actually happened to one of my motorcycles and a pressure washer left too long over winter w/o running). Pulling the injector fuses, IIRC, is easy to do, and would allow some pre-oiling/cranking for say 4-6 seconds w/o worrying about it firing up. (If it does fire, one would have to be wondering about a leaking injector.)

I knew this discussion was going to veer into something useful!

[Dynomite]

Originally Posted by Paul Workman

this gal was cranking up the brand new ZR-1s in sub freezing temps with the accelerator nearly floored. The result was a number of new ZR-1s with cam failures. The result was a number of new ZR-1s with cam failures.

Now you are scaring everyone.......

cannot tell what is meant by cam failure.

Was it due to gas pedal to the floor, freezing temps, or a brand new ZR1 that had sat for months on show room floor
Or.......something else entirely??

This discussion has just veered into something scary

[A26B]

Originally Posted by Paul Workman

Sitting here sippin my coffee, I just remembered that story from the HOTB book, where this gal was cranking up the brand new ZR-1s in sub freezing temps with the accelerator nearly floored. The result was a number of new ZR-1s with cam failures. So, it seem a quite plausible notion that most of the wear over time goes hand in hand with cold, dry starts, sans pre-oiling..................

That's just part of the story.

As related to me by Graham Behan.
Upon investigating this problem, it was discovered that the cam journal & corresponding journal bore tolerances were at fault, but certainly exacerbated by the starting procedure. All machining dimensions have tolerances, or a range of acceptable size. The size usually varies from tool wear and the machine tool accuracy. Such is the case here. As it turned out, clearance from the cam journal diameter at the large end of the tolerance and the journal bores at the small end of tolerance was insufficient. Revising the dimensions & corresponding tolerances solved the problem, right along with the cold start procedure.

[A26B]

Originally Posted by Dynomite

WEW......Thanks Jerry......was about to start tear downs of five or six LT5s to investigate the issues

It appears this was then a problem in the design of the first few LT5s that has long been corrected.
It also appears that such failure was not a locking of the camshaft between the cam covers and head but just a lot of initial wear of aluminum in the cam cover and head where the cam shaft was in contact. Or was this something more catastrophic????

I have noticed that on all the cam covers I have removed that some cam cover journals on the same cam cover have greater wear than others.

I have also noticed that the cam cover journal wear in general is the same on ALL cam covers no matter how many miles on the LT5.

This indicates some intolerance from the get go in the design of the cams/cam journals which seems to correct itself (quickly) by the wear indicated. In other words, once worn in the wear stops and the cams find themselves in a comfort zone for thousands (100,000 or more miles).

I am assuming that ALL the LT5s that came off assembly line with this initial Cam Journal intolerance were corrected in a call back??

And....what is the Cold Start Procedure??

About the wear pattern in the cam cover/cylinder head journal bores & similarity in different engines.
Think about the forces on the camshaft along the length of the cam. I think you will come to understand the wear pattern & why it is the same in other engines.

[A26B]

Originally Posted by Dynomite

Once in a while one will find aberrations in components like the Cam Lobes on one camshaft I found where there was wear on one side of the lobe as if the cam lobe was not cut parallel to the lifter (every lobe of that camshaft).

Supposed to be like that to impart rotation of the lifter.

[Fully Vetted]

Wow. Just...wow. Ok, you win.

[RussMcB]

I've found that if you play soothing music to your oil for two hours the night before it flows into the engine better.

[XfireZ51]

Originally Posted by RussMcB

I've found that if you play soothing music to your oil for two hours the night before it flows into the engine better.

Smooth Jazz or Classical?

I don't run my motor in the winter unless temps get to somewhere ~ 40F.

[A26B]

I think we have gone where no man has gone before........