WD Piston to Deck Height
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=199136
Printed Date: 24 Sep 2024 at 5:21am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: WD Piston to Deck Height
Posted By: LexAdmn
Subject: WD Piston to Deck Height
Date Posted: 09 Jan 2024 at 2:37pm
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Hello. Curiosity question please. What is the piston to deck height on the WD? I bought the tractor a couple of years ago and the engine was very tired. So I decided to freshen it up a bit with new sleeves and a few other things. Now that the pistons are in (I am re-using the old pistons), I was curious what the piston to deck height should be. I am getting .773" using calipers. Pics attached. Thanks! KC   |
Replies:
Posted By: Gary
Date Posted: 09 Jan 2024 at 4:17pm
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I read it as 0.073, or 73 thou. The first mark to the right of '0' is 0.001, or 1 thousandth of an jnch. The 10 is 0.010, or 10 thou The 70 is 0.070, or 70 thou. G |
Posted By: jvin248
Date Posted: 09 Jan 2024 at 4:36pm
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. You may only be a few parts away from making that a W45 engine... Pistons, sleeves, crank, manifold. .
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Posted By: DrAllis
Date Posted: 09 Jan 2024 at 4:55pm
| There's more than one piston for those engines. As long as they are all the same, you are good to go. It ran before, right ?????? |
Posted By: LexAdmn
Date Posted: 09 Jan 2024 at 4:56pm
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You are correct on the dial, but if you look at the sliding rule, you can see we passed 7 but not 8. So we start at 700, then add the increments on the dial. KC |
Posted By: LexAdmn
Date Posted: 09 Jan 2024 at 5:00pm
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Yes, it did run before. Perhaps I was comparing apples to ....well, something else. On another engine I did notice the piston sitting lower in the cylinder than mine. But I do know the pistons are different than mine but did not know about the pin height. Thanks. KC |
Posted By: steve(ill)
Date Posted: 09 Jan 2024 at 6:38pm
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You have a 4 inch stroke so the piston at the BOTTOM is about 4.770 inches from the deck.. At full TOP it is about .770 inches from the deck... You have some room in the head ( and it is domed) but let say that adds another .130 inch ( just a wild guess. So you are going from a 4.9 inch ( piston to dome head) at the bottom to .9 inches when at the top........... 4.9 divided by .9 = 5.5 ... that would be your compression ratio.. It might actually be a little lower if the volume in the DOME is more than our "GUESS"............ New rings and liners will surely help, but part of your "LOW POWER" is the compression ratio... If it was up at 7.5 or 8 you would have more power. 4.6 Divided by .6 = 7.5 compression ratio ... so if your "deck to head" distance was more like .500 you would have quite a bit more HP. ------------- Like them all, but love the "B"s. |
Posted By: DrAllis
Date Posted: 09 Jan 2024 at 6:43pm
| No room in the head. The head is flat and valves protrude. Head gasket .060" I think. |
Posted By: steve(ill)
Date Posted: 09 Jan 2024 at 6:51pm
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OOOPS my bad... So its 4.770 + .060 or 4.830 ... and at the top it would be .770 + .060 or .830 So the compression is "about" 4.830 / .830 = 5.8 compression ratio.. Not great, but if the .770 was more like half inch, you would be at 8.1 compression.
------------- Like them all, but love the "B"s. |
Posted By: LexAdmn
Date Posted: 09 Jan 2024 at 7:17pm
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Interesting numbers. Thank you for sharing. KC
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