Farm Equipment - Overhaul kit for AC 170 gas?

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Overhaul kit for AC 170 gas?

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=190471
Printed Date: 18 Sep 2025 at 9:07pm
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Topic: Overhaul kit for AC 170 gas?

Posted By: Tracy Martin TN
Subject: Overhaul kit for AC 170 gas?
Date Posted: 04 Sep 2022 at 9:34pm

Who makes and or sells the best overhaul kit 8:1 compression for AC 170 gas? Thanks, Tracy

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No greater gift than healthy grandkids!

Replies:

Posted By: Alex09(WI)
Date Posted: 05 Sep 2022 at 1:10pm

Only place you can get a stock 4" bore is with original Allis parts.

That being said, my shop offers several different piston/sleeve kits for the 226 'big block' gas engines:

A. Aftermarket 4 1/8" bore 7.25:1 ratio

B. Aftermarket 4 1/8" bore 8.25:1 ratio

C. OEM D17 kit, 4" bore, 7.25:1 ratio

D. OEM 175 kit 4" bore, 8.25:1 ratio

You may have to get a 8.25:1 kit and have 1/16"? machined off the top lip of the piston to get to the 8:1 range.

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Posted By: Tracy Martin TN
Date Posted: 05 Sep 2022 at 7:01pm

Alex, Thanks, PM sent. Tracy

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No greater gift than healthy grandkids!

Posted By: Allis dave
Date Posted: 06 Sep 2022 at 8:05am

Check out this topic from a couple months ago.

I don't think there would be any issues using a 8.25:1 175 kit in a 170

https://www.allischalmers.com/forum/d17-g226-any-4-piston-kits-still-available_topic189311.html?KW=" rel="nofollow - https://www.allischalmers.com/forum/d17-g226-any-4-piston-kits-still-available_topic189311.html?KW=