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one54dodgetruck 
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Joined: 25 Jul 2011
Location: Chehalis, wa
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 Topic: 185 pistons
Posted: 26 Jan 2016 at 9:43pm |
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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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MACK
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Joined: 17 Nov 2009
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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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one54dodgetruck
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Joined: 25 Jul 2011
Location: Chehalis, wa
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Posted: 26 Jan 2016 at 10:10pm |
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Thanks Mack
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2 WDs
B
B112
D14
D15 shuttle
180
185
7040
Hd7w
D14
D15
185
7040 pd
|
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tbran
Orange Level
Joined: 14 Sep 2009
Location: Paris Tn
Points: 3504
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Posted: 26 Jan 2016 at 10:19pm |
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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.
Edited by tbran - 26 Jan 2016 at 10:30pm
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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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Big Orange
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Joined: 11 Sep 2009
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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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Big Orange
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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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one54dodgetruck
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Location: Chehalis, wa
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Posted: 27 Jan 2016 at 8:13pm |
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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.
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2 WDs
B
B112
D14
D15 shuttle
180
185
7040
Hd7w
D14
D15
185
7040 pd
|
|
Big Orange
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Joined: 11 Sep 2009
Points: 315
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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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Big Orange
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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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tbran
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Posted: 29 Jan 2016 at 6:07pm |
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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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one54dodgetruck
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Posted: 29 Jan 2016 at 8:24pm |
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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
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DrAllis
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Joined: 12 Sep 2009
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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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tbran
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Posted: 29 Jan 2016 at 10:45pm |
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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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tbran
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Posted: 29 Jan 2016 at 10:47pm |
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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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