Farm Equipment - D-17 S IV Gas Overhaul Q

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D-17 S IV Gas Overhaul Q

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=202968
Printed Date: 23 Nov 2024 at 9:41am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: D-17 S IV Gas Overhaul Q

Posted By: KY D-17
Subject: D-17 S IV Gas Overhaul Q
Date Posted: 31 Aug 2024 at 4:03pm

We have the gas engine out on a stand. I bought it from the original owner so I know it was overhauled sometime around 74, but he doesn't remember much. The sleeves/inserts have a 4 1/8" bore and I have read it came out with a 4" bore.

1. Should I go back with a 4 1/8 or 4?

2. Is there someplace better than others to order parts (engine overhaul Kit, etc.)?

We have pulled the rod bearings and they do not appear to be AC, at least we don't see an AC stamp. We also can't tell if they are oversized. We will put a micrometer on the crank Tuesday. (They have an Fm inside a circle, and one has the member 241166 and under that 1 74, another has what appears to be two letters -maybe SS followed by 1-123) Does that mean anything to anyone?

Replies:

Posted By: DrAllis
Date Posted: 31 Aug 2024 at 4:27pm

Original engine from the factory had 4 inch bore pistons at 7.25 to 1 compression ratio. Many after-market overhaul kits are 4 1/8" bore and some are lower compression like 6.5 to 1. Some may be the same compression as factory and 4 1/8" bore. Don't know which kit you have. I do know that 4 inch bore at 7.25 to 1 compression ratio (or higher) will use less gas than 4 1/8" bore at 6.5 to 1 compression ratio. A-C never made any engine bearings. FM is Federal Mogul. Those are A-C part numbers that A-C used.

Posted By: WF owner
Date Posted: 31 Aug 2024 at 6:56pm

Make sure you change the cam bearings.