reposting ringing the aq130c

Joined
Apr 19, 2009
Messages
20
HISTORY
IT all started when I decided to check the compression on my 73 aq130 which was in my opinion running... almost very well. It would load up easily at low rpms 1500 or below, but ran great at 3000 to 4000 and i assumed it would do it all day long. But upon examination it only had 125ish compression in 3 cylinders and 85 in the last one. ( it had a stuck center ring)

PROBLEM
I am assembling my AQ130c after having a valve job done and am replacing the rings. Problem one is the center ring grooves are measuring a little tight at .0015 shim there are tight spots. the spec. is (.0018 to.0028)
The ring grove that had stuck when I took it apart was very tight and needed to be lapped wider with some valve grinding compound and the old ring, just to get the ring groove wide enough to hold the ring with the minimum clearance. I have a ring groove cleaner and used it, but it doesn't cut the width, it is about .002 narrower than the groove spec., I had to go over the grooves with an old ring even after running the groove cleaner, it didn't get into the corners of the ring grooves
QUESTIONS
Should I run it with .0015 to .0025 ring grooves( A little scary)
Should I lap the ring grooves to spec.(Seems A little tedious, and uncommon)
wHY WOULD THE RING LANDINGS BE LIKE THIS Do they warp. there doesn't seem to be any significant carbon build up.
Thanks for any help.
Any reply should be helpful.
 

captmello

Captain
Joined
Jun 30, 2008
Messages
3,826
Re: reposting ringing the aq130c

I recall seeing your previous post. I've got no idea about ring and piston issues. Did you ask your machine shop guy about it? Did you have the block checked out by the machine shop as well?
 
Joined
Apr 19, 2009
Messages
20
Re: reposting ringing the aq130c

captmello thanks for replying. The machine shop just did the valve job didnt have too much to say about the ring problem. I didnt have them check the block because it looked pretty good overall, didn't have much cylinder tapper, wrist pins were tight, the bearings looked real good, cam looked good. when i took it aprt the oil pan was clean. the machine shop did not find any cracks or warping of the head, just one bad valve seat and he found the valve guides to be relatively loose. so I had them replaced.
Since then I decided to assemble it with the snugg ring landing clearence.
But know I have a bigger problem, please see my new posting about grey oil in the aq130
 
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