wd and d17 iv pistons
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=199853
Printed Date: 04 Nov 2025 at 3:41am
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Topic: wd and d17 iv pistons
Posted By: HudCo
Subject: wd and d17 iv pistons
Date Posted: 15 Feb 2024 at 6:58pm
| i have scored a d17 series 4 engine for my wc puller project has any one measured the pin hieght on the wd piston and the d17 piston ? can the wd pistons be milled down to make 12:1 wondrering about useing reliance wd cylinder kit 470283616 if i read it correctly that part number is a flat top 4 1/8 piston |
Replies:
Posted By: HudCo
Date Posted: 16 Feb 2024 at 9:25am
| any one know what or whos brand , pistons i need for 4 1/8 bore d17 rods , crank to make 12:1 compression |
Posted By: IBWD MIke
Date Posted: 17 Feb 2024 at 8:07am
Hud, I've got a set of 4&1/8" WD flat-tops that might work for you. We've discussed this in the past but not sure what compression ratio people thought they would make with a 45 crank.
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HudCo wrote:Posted By: HudCo
Date Posted: 17 Feb 2024 at 9:55am
| any chance you can measure the center of the pin to the top |
Posted By: DrAllis
Date Posted: 17 Feb 2024 at 6:30pm
| 2.550" flat tops 4 1/8" makes 11.3 to 1 as I've outlined in the above "D-17 piston" post. So, more than that like 2.600" flat top 4 1/8" would be close or more than 12.0 to 1. |
Posted By: DrAllis
Date Posted: 17 Feb 2024 at 6:33pm
| BTT |
Posted By: HudCo
Date Posted: 17 Feb 2024 at 10:21pm
| over looked that post , but i did measure the part number 229717 4 inch pistons that i removed out of it , couldnt find that part number in the agco parts book listed for series iv . i got 2.835 pin hieght and .352 from the top of the deck to the top of piston not bowl at tdc , did not measure the volume of the bowl . reliance dosnt say what compression ratio their 4 1/8 wd flat top is so their sould be plenty of room for the valves to open and close it would be nice to have a dished or a bowl piston with that flat head hope i aint missing somthing |
Posted By: DrAllis
Date Posted: 18 Feb 2024 at 12:51am
| Knowledge Base info: "Compression calculators for 226 engines" near bottom of the page. My own personal notes have a 170 (8.0 to 1) power crater piston at a .263" to .265" deck clearance at TDC. The 175 (8.25 to 1 ) power crater piston has a deck clearance of .230" to .235". This is measured to the highest part of the piston at the piston pin centerline. A D-17 piston ( 7.25 to 1) should measure about .368" to .370" deck distance. So, WD 4 1/8" flat tops need to measure a deck distance of .263" to .265" or less to be more than 11.3 to 1. Probably more like .230" to .235" for 12 to 1. |
Posted By: IBWD MIke
Date Posted: 18 Feb 2024 at 6:02am
|
My flat-tops measure 2.375 c/l of pin to top. |
Posted By: DrAllis
Date Posted: 18 Feb 2024 at 11:41am
| BTT |
Posted By: steve fischer
Date Posted: 18 Feb 2024 at 11:41am
|
food for thought ,I don't like a flat top piston for a 226 they don't have the bark , I have gone back to cupped pistons for a burn chamber(power crater) Sealed power number 1728 is a 201 cupped 4 1/8 piston, fit right in ,hard to find, m&w ap46 also fits may have to cut top off ,I think I have some used left
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Posted By: DrAllis
Date Posted: 18 Feb 2024 at 11:49am
| SP-46's I used to remove .170" off the tops and had 240+ psi cranking compression, Always called it 11 to 1 or a little better. I like the bowls too. |