Overhaul kit
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=149147
Printed Date: 22 Aug 2025 at 6:38am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Overhaul kit
Posted By: allispuller
Subject: Overhaul kit
Date Posted: 04 Apr 2018 at 12:28pm
| Any idea where a person can get the 8.25:1 compression ratio overhaul kit for a 170 gas seems all I can find are the 7.25:1 kit |
Replies:
Posted By: Allis dave
Date Posted: 04 Apr 2018 at 1:05pm
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Reliance has the dies but won't make a production run. I went through this a year ago. Too bad, but they say the 7.25 kits are selling good enough they don't need the more expensive 8.25 kits. There are still pistons in stock, but no matching 4" sleeves. There was a 4" low compression kit in the classified's 1-2 months ago, maybe by "Matt(Jordan). I don't know if it's sold. You might be able to buy it and piece it together with pistons.
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Posted By: LeonR2013
Date Posted: 04 Apr 2018 at 9:22pm
| Baloney! Not you AP. Since when does it cost that much more to build higher compression pistons? It's just a marketing scam. I'm sure it takes a bit of retooling, but in today's computer age how difficult is that? |
Posted By: LeonR2013
Date Posted: 04 Apr 2018 at 9:26pm
| Dave do the 8.25 use a different sleeve? If so why? |
Posted By: Allis dave
Date Posted: 05 Apr 2018 at 7:05am
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The original Allis kits had 4" bores. Somewhere along the line aftermarket companies started making 4.125, M&W probably started it. After that everyone wanted the overbore kits, figuring more cubes = more power.I think only some of the later Gleaner E's, 170's and 175's used 8.0 or 8.25 pistons. So unless someone was hopping up a tractor there wasn't much call for them. I don't think the high compression pistons were ever made in a 4.125 version. The cost of the 4" 8.25 high compression rebuilt kit was about $400 more than a standard 4.125" 7.25 kit. Powermax used to make the kits, but they got bought by Reliance and Reliance doesn't seem to care about the 8.25's kits. They were slow movers probably because most people want the "more powerful" overbore kits and because they are not the stock kit for a WD45 or D17. The slow moving and smaller run batch sizes probably added to the cost, which makes them even slower moving. How many 175 gases were made, 1000? This has been discussed on here at length, but the fact is they're NLA until someone convinces Reliance to make another run.
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Posted By: DrAllis
Date Posted: 05 Apr 2018 at 7:13am
| Know what you are looking for when checking with an AGCO dealership !! The D-17 was 7.25 to 1.......the 170 was 8.0 to 1.............the 175 was 8.25 to 1...... the sleeves for all of these are the same and are 4 inch bore. The rings are the same for all pistons. Only the piston pin location is different between them. |
Posted By: Gary Burnett
Date Posted: 05 Apr 2018 at 7:18am
In that case then some of the companies that custom make pistons should be able to make any compression piston that was wanted. |
DrAllis wrote:Posted By: Allis dave
Date Posted: 05 Apr 2018 at 7:40am
| Most pistons aren't built with enough meat to move the pin around like these. |
Posted By: steve fischer
Date Posted: 05 Apr 2018 at 8:00am
| you can used the wd (201) flat top overbore in the 170 and 175 (226) if you cc it out it will be at 8,5-8.6 , mailto:A@I" rel="nofollow - A@I lists the wd set for high compression on the 226 engine , I don't know how to convert the area of 4 in to 4.125 to cc needed to get same compression the 4.125 would have to be less to get the same. I do have a list of pistons I have cc if someone wants to do some figuring |
Posted By: CAL(KS)
Date Posted: 05 Apr 2018 at 8:06am
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with a little math someone could build a 4.125 bore 8.25 cr with a small power crater piston
after a little machining ------------- Me -C,U,UC,WC,WD45,190XT,TL-12,145T,HD6G,HD16,HD20 Dad- WD, D17D, D19D, RT100A, 7020, 7080,7580, 2-8550's, 2-S77, HD15 |
Posted By: allispuller
Date Posted: 06 Apr 2018 at 12:15pm
| So I’m gathering that there isn’t one really available? |
Posted By: DrAllis
Date Posted: 06 Apr 2018 at 12:24pm
| I see where a 170 kit (8.0 to 1 compression) is available p/n 70257459. The D-17 kit (70257452) and 175 kit (70257458) are no longer available, according to my source. I am not a dealer, so call an AGCO dealer and give them p/n 70257459 and see what they say. |
Posted By: tbran
Date Posted: 06 Apr 2018 at 5:58pm
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We did a parts check - unknown availability thru Agco- a dealer , Card Brothers in Chesaning Mi. 48616 is showing the only kit available 989 845 7370 50/50 chance they have it... I have 2 G 226 engines on the farm running the overbore WD pistons from a Tisco Kit.. We drilled out a - can't remember exactly , say .125 x 1" drilling just under the spark plug to slightly lower the compression. We built some motors for antique pulled decades ago on WD's and D17's using the WD piston kits with no issues - we are no rocket scientists but best we could figure we were at 8.75-9.0 to 1 CR - but this was not a big daddy don garlits speed shop measurement either :-) . ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: Brian Jasper co. Ia
Date Posted: 06 Apr 2018 at 7:31pm
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There's a company called Egge Machine that makes obsolete and obscure classic car pistons. They might be worth a try. When I built my 445 stroker FE I found out that there are several aftermarket piston companies, Diamond in my case, that will make a piston to any size, compression ratio and stroke. Of course that was for a Ford FE and all of the other popular automotive V8s. They might be another option. ------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |