WD Compression Increase
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=197123
Printed Date: 25 Sep 2024 at 9:22am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: WD Compression Increase
Posted By: Les Kerf
Subject: WD Compression Increase
Date Posted: 10 Sep 2023 at 7:31pm
|
I am in the planning stages of preparing to overhaul my late Father-in-law’s WD tractor. After much vacillating between rebuilding as a WD45 or a straight WD, I have finally settled on keeping it as a WD (even though I have a WD45 parts tractor as well). I have yet to tear it down, that is planned for a winter project. I will be ordering some of the items that I know will be needed such as sleeve kit, clutch parts, etc. and will naturally need to wait until after teardown to order bearings and such. My main question is how to best increase the compression ration on a WD engine. This is NOT going to be a competition pulling tractor, just a general use chore tractor around the homestead. I have been a gearhead long enough in my 65 years to recognize that the anemic compression ratio of a stock WD would benefit from a bit more squeeze, but I don’t want to go to any extreme measures to get there; I am only looking to grab the low-hanging fruit if there is any to be had. What cylinder sleeve/piston kit will be best to accomplish my goal of a reliable engine with a modest boost in efficiency while running on low-life regular pump gasoline? Thanks for the help  |
Replies:
Posted By: MACK
Date Posted: 10 Sep 2023 at 7:55pm
| Not much you can do with out cost. JD boys bolt aluminum plates to top of pistons for a inexpensive increase in compression. MACK |
Posted By: DrAllis
Date Posted: 10 Sep 2023 at 8:17pm
| Most fuel efficient will be staying with a 4 inch bore (instead of 4 1/8") and having compression from 6.5 to 1 (WD45 with 125 psi cranking comp.) to 7.25 to 1 (D-17 with 145 psi) or 8.0 to 1 (170 with 170 psi). BBChevy pistons have the same .990" piston pin. Maybe something in their thousands of piston height sizes could work ?? |
Posted By: IBWD MIke
Date Posted: 11 Sep 2023 at 7:04am
|
I have a set of 4&1/8" flat-tops for a WD, not sure what compression ratio they would be. More than stock is my only guess. |
Posted By: SteveM C/IL
Date Posted: 11 Sep 2023 at 12:57pm
| It would be silly to not put a 45 crank in it. |
Posted By: Les Kerf
Date Posted: 11 Sep 2023 at 2:11pm
Which I have. In the 45. Which is complete and stuck just like the WD. And is also a candidate for rehab. And both engines need torn down to see what is actually salvageable. Hence the aforementioned vacillation. The trouble with these tractors is they all seem to be cursed with the 'Midas Touch'; Midas well replace this while you're in there, Midas well fix that too, Midas well change it over to 12 Volts, Midas well buy new tires...  Before you know it your $3000 budget has morphed into $6000 and Mama is wondering just who this mysterious Alice is whom you keep spending all of your time with and by the way, why is there no money left in the bank account?Besides, my almost-thirteen-year-old Grandson has been casting his greedy little eyes upon the WD-45 so I think I shall leave it for whenever he can afford to take that on. I cannot justify rebuilding both of them, and my Wife and I had set aside some money from her modest inheritance to rebuild her Dad's WD. We used it around here for near 50 years and I am intimately familiar with it, and I know that a stock WD is plenty good enough for our simple needs. Unless there is a compelling reason why I need to buy a crankshaft I will just leave it as a WD. |
SteveM C/IL wrote:Posted By: Les Kerf
Date Posted: 11 Sep 2023 at 2:29pm
Thank you Dr, I was hoping you would say something like "Just order a kit for a WD-XYZ tractor and bolt it in, but it appears that is not to be Since I am not interested in re-inventing the wheel I will just go with what is readily available for a 'stock' rebuild. I am guessing that the various vendors probably purchase these kits from the same manufacturer; does anyone have any recommendation as as to what source would be preferred? |
Posted By: WF owner
Date Posted: 11 Sep 2023 at 5:05pm
| There are M&W pistons, if you can find them. |
Posted By: steve(ill)
Date Posted: 11 Sep 2023 at 6:05pm
|
Dr.... if he is using the original WD crank and needs sleeves and pistons... why not move up to the 4.125 inch ?? ------------- Like them all, but love the "B"s. |
Posted By: DrAllis
Date Posted: 11 Sep 2023 at 6:10pm
| He can do what he wants. I thought economy was one of his criteria. 4 1/8" always use more fuel. |
Posted By: MACK
Date Posted: 11 Sep 2023 at 8:16pm
| WD45, D17, 170 pistons will lower compression with his WD crank. MACK |
Posted By: AaronSEIA
Date Posted: 12 Sep 2023 at 5:53am
Many of those overbore kits have the same or lower CR than the OEM pistons did. AaronSEIA
|
Posted By: steve(ill)
Date Posted: 12 Sep 2023 at 7:43am
|
OK... i realized the D17 pistons were different pin location... but i thought there were WD Specific pistons in the 4.125 inch size........ guess that would be a big concern. ------------- Like them all, but love the "B"s. |
Posted By: DrAllis
Date Posted: 12 Sep 2023 at 9:06am
| Back in the old days (35 yrs ago) the easy tractor pulling trick was use M & W 4 1/8" pistons from a WC/WD in a WD45 or D-17. They came up so high you had to machine off .170" right off the tops to keep them from hitting the cylinder head. They were bowl design and would make 240 psi cranking compression. |
Posted By: captaindana
Date Posted: 12 Sep 2023 at 11:50am
|
Wow Doc! And the rest of the engine could handle that?? ------------- Blue Skies and Tail Winds Dana |
Posted By: DrAllis
Date Posted: 12 Sep 2023 at 12:44pm
| For pulling, sure. Only ran for 90 seconds at a time going down the track. Had to use 110 octane gas. |
Posted By: Les Kerf
Date Posted: 14 Sep 2023 at 1:33pm
Thanks for the input folks, it puts me right back in the vacillating mode again...  I really think I need to tear that WD down before making any decisions. If the engine is not worth salvaging then I will need to tear down the WD-45 and see what I have there. Judging by how my summer-fall work is going, this may be more than I can take on this year. I do appreciate your thoughts and opinions |