Increasing ground speed in a 1940 RC
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=135806
Printed Date: 08 Nov 2025 at 4:04am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Increasing ground speed in a 1940 RC
Posted By: Mustangkeith
Subject: Increasing ground speed in a 1940 RC
Date Posted: 05 Mar 2017 at 7:09am
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Hi everbody, I'm new to the forum and have a quick question in regards to a 1940 Rc that I purchased last fall . when I bought it the valves were seized solid after freeing it up and getting the carb tore apart and cleaning the 5 inches of tar looking stuff out of the gas tank I got it running good and took it on a local tractor run for antique tractors according to my gps I was only going 9 MPH and it wasn't long before I was way back at the pack of about 90 tractors lol My question is other then fiddling with the govenor (which some say using a cheat string , but I have premonitions of the rods scattering everywheres so I won't do that ) is there any other way of playing with the gears to get it to at least 13 or 15 mph . I thought of buying a set of rims and modifying them to work doing some reasearch on the ring and pinion turned up not a whole lot of info on the size or bolt patterns that would be compatable. I'm not too worried about pulling as this will mostly be a road travel tractor . Right now i have the metal all stripped as the previous owner painted it with yellow paint and it looked like a minion . ------------- Nothing beats the smell of gunpowder in the blind. |
Replies:
Posted By: Mustangkeith
Date Posted: 05 Mar 2017 at 7:09am
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Thanks in advance :) ------------- Nothing beats the smell of gunpowder in the blind. |
Posted By: MACK
Date Posted: 05 Mar 2017 at 7:27am
| There are pullers with WCs that would trade ring and pinion with you. The WC R&P are faster. MACK |
Posted By: JoeM(GA)
Date Posted: 05 Mar 2017 at 7:30am
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I'm sure others who know more will chime in, but I believe a WC chunk will drop in and give you more ground speed. If I remember conversations here, people were putting RC setups in their WC to gain pulling power, so it would seem that the swap would get you speed. ------------- Allis Express North Georgia 41 WC,48 UC Cane,7-G's, Ford 345C TLB |
Posted By: mike a
Date Posted: 05 Mar 2017 at 7:34am
| swap the whole wc rear-end,tires and all.you will gain a whole gear faster. |
Posted By: 45 turboa-
Date Posted: 05 Mar 2017 at 7:42am
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Welcome to the forum ! First put a D15 gov spring on it we did that to our "B" years ago Next "WC" ring and pinion and then 14.9-28s rear tires you will get some speed ! ------------- turbocharged |
Posted By: Mustangkeith
Date Posted: 05 Mar 2017 at 8:12am
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Thank you gentlemen :) lots of good ideas. There was what i believe to be a wc scrapped quite a long time ago in my area and they hauled it to the woods afterwards I may take a walk in and see if the gears are intact . The RC is really rare in my area and its nice having people ask what the heck it is on the tractor runs lol as for rims i have a set of 14.9 x 28s off a massey 165 i had . I may modify them to fit that way im not hacking my original goodies up on the old girl . ------------- Nothing beats the smell of gunpowder in the blind. |
Posted By: Gerald J.
Date Posted: 05 Mar 2017 at 11:19am
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First you need a op manual and a service manual. I have bits of the RC service manual it was in the same manual with WC and WF. I have it on this computer in about 10 parts, the last two cover RC. The shop manual says high idle on the engine is 1750 to 1850 RPM and the speed in the top gear is 7.5 mph. So it wasn't made for roading. The specifications for RC don't show rear axle ratio but showed 4.7 and 6.6 (pulling option) for the WC. 14.9 tires squeezed on to your narrow rims will stand taller than on their design rims. Gerald J. |
Posted By: DrAllis
Date Posted: 05 Mar 2017 at 12:39pm
| RC is the slower 6.6 R&P. A WC pumpkin is faster. Also use D-15 governor spring. |
Posted By: Mustangkeith
Date Posted: 05 Mar 2017 at 1:18pm
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Would anyone happen to know the tooth count on the WC ring and pinion i was looking in both my manuals and couldn't see it anywheres just wanting to make sure that when I get the scrapped tractor opened up that its what I'm looking for . or should the ring gear have the ratio stamped on it ? ------------- Nothing beats the smell of gunpowder in the blind. |
Posted By: B26240
Date Posted: 05 Mar 2017 at 1:36pm
| Welcome Mustang; I have two WC ring and pinion sets one is out of the tractor. You can have one FREE if you want to drive here and pick it up, (northern MN) For more good detail info on RC's I suggest you go to Tom Foss site he has many detailed pictures of the inside of one of these tractors. Mark |
Posted By: dawntreader74
Date Posted: 05 Mar 2017 at 1:37pm
| put some taller tires on it' will help the speed a lot' 14.9 or 16.9 get it up to 12 mh' or so. |
Posted By: TramwayGuy
Date Posted: 05 Mar 2017 at 3:43pm
| Unless the WC is a high crop, it should have the 4.7 gears in it. |
Posted By: Eldon (WA)
Date Posted: 05 Mar 2017 at 4:18pm
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I always thought it would be neat to make a trailer using a truck axle and run the pto back to it. Kick the tractor out of gear and engage the pto for road gear. Maybe even have a two speed rearend and hook up the brakes. ------------- ALLIS EXPRESS! This year: |
Posted By: Mustangkeith
Date Posted: 05 Mar 2017 at 5:39pm
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I was thinking that too eldon. I heard the old fella that owns this scrapped tractor mention the sherman transmissions for them too but not sure if they are compatable hes also not sure of the rear gears are still in it or not but told me to check also has some other vintage goodies junked too that I can't wait to see ------------- Nothing beats the smell of gunpowder in the blind. |
Posted By: Gary Burnett
Date Posted: 05 Mar 2017 at 6:10pm
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Sherman should bolt right in just like in a WC or find a set of Farmall 36" spoke wheels some of them will bolt right on the RC. |
Posted By: Gerald J.
Date Posted: 05 Mar 2017 at 6:43pm
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Pinion gears tend to be in the range of 8 to 14. The only pinion that gives an proper number of ring gear teeth is a 10 tooth pinion and a 47 tooth ring gear. Gerald J. |
Posted By: cpg
Date Posted: 05 Mar 2017 at 6:53pm
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If you can find one there were some aftermarket companies like sherman that made overdrive boxes made for the WC that go where the axle disconnect usually is between the transmission and axle. Maybe they would fit the RC as well? I had a WC that had one of the Sherman boxes so they are out there |
Posted By: B26240
Date Posted: 06 Mar 2017 at 6:27am
| In order for the Sherman to fit you need a pinion with the short shaft as in WC's with the traction disconnect. I put a Sherman into a WF and had to change the ring and pinion set to get the short shaft pinion. Also the Sherman with overdrive is 25% over so if his RC goes 9mph now it would go 11.25 with Sherman OD. Also remember if looking for a Sherman unit that some were also UNDERDRIVE. Simplest would be to change ring and pinion set if you want to keep the looks original. |
Posted By: Gary Burnett
Date Posted: 06 Mar 2017 at 7:50am
The Sherman I had in a WC the gears were identical but two different sizes so high was higher than the WC was originally and the low was slower than the original. |
B26240 wrote:Posted By: Mustangkeith
Date Posted: 06 Mar 2017 at 7:59am
Thanks guys . I ordered a better govenor spring last night and just came back from looking at the scrapped wc . The gears are still in it and still attached to the tractor from what the owner recalled he parked it due to the motor constantly locking up and knocking I would imagine the bearings in the old thing look like swiss cheese if they are even intact still he told me to haul the rear out any time so when my snow leaves I will be making a trip back lol. He had an old LA deere sitting there and a few older tractors that were in pieces don't think he was too mechanicly inclined as he said the LA was parked from a clunk in the transmission . Its neat going into the woods never know what you will find , now to get the rear home without the wife seeing it and thinking I bought another tractor  ------------- Nothing beats the smell of gunpowder in the blind. |
Posted By: Dusty MI
Date Posted: 06 Mar 2017 at 2:42pm
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Some of the guys that have increased the ground speed, with the sherman gear box, sometimes have a little problem making some of the hills. Dusty ------------- 917 H, '48 G, '65 D-10 series III "Allis Express" |
Posted By: TomMN
Date Posted: 07 Mar 2017 at 9:27pm
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I wrote a couple articles on the RC for our newsletter a few years back if you are wanting to read them. I mention the gear ratio differences between the RC and WC and tried to mention the many other differences I found. The first story was about my Grandpa's first tractor: http://www.allis01.com/fossto/39RC/AC_RC_Story.pdf" rel="nofollow - http://www.allis01.com/fossto/39RC/AC_RC_Story.pdf The second was how it was stuck in the middle: http://www.allis01.com/fossto/39RC/AC_RC_StuckInTheMiddle.pdf" rel="nofollow - http://www.allis01.com/fossto/39RC/AC_RC_StuckInTheMiddle.pdf The RC is pretty slow when configured like it came from the factory, not sure how to best make it go faster and still call it an RC.
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Posted By: CTuckerNWIL
Date Posted: 08 Mar 2017 at 10:19am
I thought of doing that for wood cutting in the hills of the timber. If you got the trailer set up to run the same as 1st or second gear,you could run 4 wheel drive and get into places you prolly shouldn't be  ------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Mustangkeith
Date Posted: 12 Mar 2017 at 4:36pm
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Well I aquired a set of 38" rims off a john deere B from a friend . i tryed bolting them on and they will work i just have to shave a little bit out of the center hole for the bearing cup on the axle this should make it a little quicker along with the d15 govenor spring that just showed up . I took it for a little drive with the new spring on today it was minus 25 celsius which was roughly minus 13 fahrenheit so i didn't get to drive it long but it was long enough to notice a difference.. Can't wait to see what the 38s will do to it according to my gps today the new govenor spring took it to 10.8 mph so it made quite a difference. I'll be glad when spring gets here so I can actually putter with it some more these atlantic canada winters can really put a dampner on working on things in the outdoors lol ------------- Nothing beats the smell of gunpowder in the blind. |
Posted By: DougS
Date Posted: 12 Mar 2017 at 5:00pm
| Without knowing the exact height of the 38 tires, I predict it will go 13 to 14 MPH. Not bad, but many stock tractors will go that fast. |
Posted By: Mustangkeith
Date Posted: 12 Mar 2017 at 5:48pm
The 38s are 11.2x38 tires they have air in them butare split prettybad wouldn't trust them to get me too far a couple of paycheques and a mild distracton for the wife and i should have new rubber for them .  ------------- Nothing beats the smell of gunpowder in the blind. |