<VV> oily engine forensics

[djtcz at comcast.net]

snipped and bottom posted 

-------------- Original message -------------- 
From: BobHelt at aol.com
Subject: Re: <VV> forensics on my rampy engine.
N2VZD at aol.com writes:

i took  it apart and found lots of oil showing on all 6  
cylinders. rings  were in positions so i blame it on the bore / hone job i 
got 
locally to  save  costs. it ran very good , but ate oil like gas. everything  

else looked ok. 


Tim,
It would be interesting to find out more about this problem. If you are  also 
interested, please remove the rings on one or more pistons and
1) check the clearance of the pistons in their cylinders.
2) check several rings in their cylinders for the amount of ring gap and  
also for whether there might be any incorrect contact with the wall. (Put ring  
in cyl and look for light showing between ring and cyl)
3) What kind of wall surfaces are there? Are the honing cross-cuts still  
there? Are there any grooves or scores on the walls?
4) What rod bearing clearances do you find? (question: could there possibly  
be 10 u/s bearings on std journals?)

Please let us know what you find.

Thanks,
Regards,
Bob Helt

A couple of things I'd add to Bob's list would be:
- the position of the "pip" marks on the top and second rings (up or down). Upside down rings pump oil.
- the condition of the ring faces viewed with 10-20X magnification. The faces should not be worn  to 100% contact.  No scuffing or scratching (also true of cylinder walls, and the reason scrupulous cleanig with soap and water scrub is SO important
- The "side clearance" should be less than 0.006 inch. http://www.autozone.com/images/cds/jpg/small/0900823d80086611.jpg
- The grooves' top and bottom faces should be smooth. The time honored tradition of Cleaning out carbon with a broken ring carries some risk  Bill Grumpy Jenkins would not allow his ring grooves to be bead blasted because it compromised ring seal in his race engines.
- Oil ring expanders not overlapped (impossible with some types) nor shortened to reduce tension.
- PCV type and condition
- Proper oil fill - I had a dipstick that jammed before seating on a poor suffering MGA.  That resulted in me Running it  X quarts over full, and created a nice 3000 rpm rev limiter, since it POURED out smoke if revved even a smidge higher.


Dan Timberlake 
Westford, Massachusetts, USA