Sounds like you are on the right track, compression ring seal problems.
Your manual should show the piston clearance. The measurement needs to be taken about mid way down the skirt, 90* to the wrist pin. Typically an air cooled will run around .008 to .015 clearance. Sounds like your engine has been bored .030 over, but the clearance specs will be the same. Go by the book, not what I say!
Other things to check is the ring to ring land clearance and the condition of the ring lands. Should be about .0015 clearance new, and the lands need to be relatively flat, parallel, not tapered.
And there is ring end gap. Should be around .012-.015 gap measured close to the top of the bore. Use an inverted piston to push the ring straight in the bore.
But all this is contingent on the condition of the bore. If tapered, out of round, or scored, the rings will never seal properly. The manual will give the tolerances allowed. Scoring is not good, but sometimes it has to be allowed unless it will be rebored.
There is a lot of info on this subject on the net, Youtube. A lot of it is race engine related though, just have to wade through and see what applies.
Upload one or more videos to your post. Photo filesizes should be less than 300K and Videos, less than 2MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Upgrading an Oliver Super 55 Electrical System - by Dennis Hawkins. My old Oliver Super 55 has been just sitting and rusting for several years now. I really hate to see a good tractor being treated that way, but not being able to start it without a 30 minute point filing ritual every time contributed to its demise. If it would just start when I turn the key, then I would use it more often. In addition to a bad case of old age, most of the tractor's original electrical system was simply too unreliable to keep. The main focus of this page is to show how I upgr
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
