185 pistons
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=118134
Printed Date: 28 Jun 2025 at 5:06am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 185 pistons
Posted By: one54dodgetruck
Subject: 185 pistons
Date Posted: 26 Jan 2016 at 9:43pm
Is there a difference between the non turbo 185 pistons and a 190xt turbo pistons?
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2 WDs
B
B112
D14
D15 shuttle
180
185
7040
Hd7w
D14
D15
185
7040 pd
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Replies:
Posted By: MACK
Date Posted: 26 Jan 2016 at 10:08pm
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Yes, non turbo is a little higher on comp. MACK
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Posted By: one54dodgetruck
Date Posted: 26 Jan 2016 at 10:10pm
Thanks Mack
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2 WDs
B
B112
D14
D15 shuttle
180
185
7040
Hd7w
D14
D15
185
7040 pd
|
Posted By: tbran
Date Posted: 26 Jan 2016 at 10:19pm
originally, no. With the advent of the 200 around 1973-4 there were pistons gaulding in the sleeve. The fix was to machine a few thousandths off the top of the piston ABOVE the top ring. Now there are naturally aspirated pistons and turbo pistons in Agco kits.
Late old friend Joe Dewanne who wrote a lot of the service bulletins swore that cranking ability went down with the smaller diameter pistons which slightly lowered the CR.
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When told "it's not the money,it's the principle", remember, it's always the money..
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Posted By: Big Orange
Date Posted: 26 Jan 2016 at 11:56pm
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Joe is right, about the start-ability,but it's not the CR. as the amount of material removed from the piston above the top ring, is less than .005 CCs. Rather it's the air path to the top ring endgap that has been opened up, that's causing the lower cranking compression & the extra blowby.
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Posted By: Big Orange
Date Posted: 27 Jan 2016 at 12:04am
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Plus in later years the top ring endgap was increased greatly, adding to the low cranking compression, & start ability.
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Posted By: one54dodgetruck
Date Posted: 27 Jan 2016 at 8:13pm
So the big question for me is do i get the 200 overhaul kit or the 185? I would like to add a turbo in the future.
-------------
2 WDs
B
B112
D14
D15 shuttle
180
185
7040
Hd7w
D14
D15
185
7040 pd
|
Posted By: Big Orange
Date Posted: 28 Jan 2016 at 1:03am
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If you can find a kit for a 180, that will be better, as the sleeve bore was increased about .002 OEM spec. after the piston scoreing problems. Even better install a set of Hasting piston rings, not the ones in the kit As the top ring endgaps on the Oem spec, is about .025+. the early engine spec. is about .015.
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Posted By: Big Orange
Date Posted: 28 Jan 2016 at 1:48am
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By the way, the piston scoring problem was caused by the camshaft spec. change to increase the torque rise. Not a good move in my opinion. The new cams made the engines to run hot & killed the performance & the fuel economy, at hi rpms.
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Posted By: tbran
Date Posted: 29 Jan 2016 at 6:07pm
what and when did the cams change and on what engines. Also when figuring compression ratio there is the combustion chamber volume measurement that figures into the equation. Since the combustion chamber is in the piston, a larger bowl cut out would lower the compression ratio as in pistons for the early 4.33I engines. The outside of the piston being cut .003 will yield the same negative CC's as a larger bowl thus lowering the effective CR.
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When told "it's not the money,it's the principle", remember, it's always the money..
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Posted By: one54dodgetruck
Date Posted: 29 Jan 2016 at 8:24pm
So would it help to send off the new pistons and get coated in case i decide to add a turbo in the future?
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2 WDs
B
B112
D14
D15 shuttle
180
185
7040
Hd7w
D14
D15
185
7040 pd
|
Posted By: DrAllis
Date Posted: 29 Jan 2016 at 9:07pm
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As I remember, the diameter above the top ring was .030" smaller in diameter, or there was .015" of material removed all the way around. So, if you can imagine a ribbon .015" thick and 3/4" tall and 12 inches long, that would be a fair amount of cc's displacement and that's how they went from 16 to 1 down to 15 to 1 leaving the bowls the same. I have actually measured 15 to 1 and 16 to 1 pistons and know this to be true. Lay a straight edge 90 degrees to the pin and you can easily see the difference above the top ring area.
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Posted By: tbran
Date Posted: 29 Jan 2016 at 10:45pm
typo. meant .030
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When told "it's not the money,it's the principle", remember, it's always the money..
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Posted By: tbran
Date Posted: 29 Jan 2016 at 10:47pm
Some of the oe bowls on the 4.33 were different, larger as well. They have been discontinued.
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When told "it's not the money,it's the principle", remember, it's always the money..
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