B and CA same block?
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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=149809
Printed Date: 29 Aug 2025 at 1:17pm
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Topic: B and CA same block?
Posted By: littlemarv
Subject: B and CA same block?
Date Posted: 24 Apr 2018 at 12:47pm
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Are the blocks for a B and a CA the same? Just different size pistons and liners? Heads, crank, rods the same? Thanks in advance. ------------- The mechanic always wins. B91131, WC23065, WD89101, CA29479, B1, Early B10, HB212, 416H |
Replies:
Posted By: HoughMade
Date Posted: 24 Apr 2018 at 1:13pm
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The B (from 1947), C and CA have the same bore and stroke, so I imagine the block is the same as well. The C and CA have higher governed engine speeds than the B.
------------- 1951 B |
Posted By: Gerald J.
Date Posted: 24 Apr 2018 at 1:26pm
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Without a parts book I can't be sure. In the shop manual http://geraldj.networkiowa.com/Trees/Allis-Chalmers-G-B-C-CA-Service.pdf" rel="nofollow - http://geraldj.networkiowa.com/Trees/Allis-Chalmers-G-B-C-CA-Service.pdf The engine for the B is listed as model BE with a different bore than the engine for the C listed as model CE, but probably the same stroke. BE bore 3-1/4" CE bore 3-3/8". Compression ratio for BE 4.92:1 CE 5.25:1. The specs for the CA engine match the CE engine version in all listed details. In the CA tractor section on crankshaft seals the engine serial numbers begin with CE and its noted that the seal was changed a couple times in the production run and the timing cover was changed once along with the seal. It might be that http://grandpas-tractor-site.s3.amazonaws.com/manuals/ac" rel="nofollow - http://grandpas-tractor-site.s3.amazonaws.com/manuals/ac has parts books for the three tractors so the parts could be compared. Gerald J. |
Posted By: HoughMade
Date Posted: 24 Apr 2018 at 1:54pm
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The B had the "BE" engine (116 ci) from 1938 until the change to the "CE" in 1947. After that, it had the "CE" engine the same (basic) engine as the C and CA. There were definitely different governor springs in the C and CA to allow for higher RPM (the CA even higher than the C). The "CE" engine had a "low octane" version with the 4.75:1 compression ratio, but standard compression for the B, C and CA was 5.75:1 for all. The "BE" engine had lower compression than the "CE", but was never used when the C and CA were manufactured. In other words, it looks like the block, sleeves and pistons for a B after 1947 with the "CE" engine, the C and the CA are all the same. ------------- 1951 B |
Posted By: littlemarv
Date Posted: 24 Apr 2018 at 2:43pm
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If you compare the latest B engine to the CA engine, tractor data says the CA was higher compression?? ------------- The mechanic always wins. B91131, WC23065, WD89101, CA29479, B1, Early B10, HB212, 416H |
Posted By: HoughMade
Date Posted: 24 Apr 2018 at 2:53pm
I see that, but I am going off the manual. Granted, perhaps the manual I am looking at was published at a time before a bump up in the CA compression.  ------------- 1951 B |
Posted By: DrAllis
Date Posted: 24 Apr 2018 at 3:52pm
| A very old "B" will not have the mounting bosses for a generator bracket cast into the block. So, you could always use a newer CA block on an old B, but not an old B block into a C or CA. |
Posted By: littlemarv
Date Posted: 24 Apr 2018 at 4:26pm
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By mounting bosses, do you mean the two threaded holes on the left front of the block? ------------- The mechanic always wins. B91131, WC23065, WD89101, CA29479, B1, Early B10, HB212, 416H |
Posted By: CTuckerNWIL
Date Posted: 24 Apr 2018 at 7:19pm
Yes, I have seen a lot of BE blocks that were drilled and taped so a generator could be mounted. They just didn't have the boss and the block is thinner there without it. CE sleeves and piston can go in a BE block or visa versa if you wanted. ------------- 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 |
littlemarv wrote:Posted By: CrestonM
Date Posted: 24 Apr 2018 at 7:22pm
| Is that when the bore was increased, with the CE engines? |
Posted By: CTuckerNWIL
Date Posted: 24 Apr 2018 at 8:50pm
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Yea, they just put in a bigger piston with a larger bore in the sleeve. ------------- 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: wfmurray
Date Posted: 24 Apr 2018 at 8:58pm
| Put c a carb on my 49 B and had to file holes to get it to go on .Old carb fit but venture was gone .Engine surges some when not under load.I think there is some difference in a B and a C A . May be in intake or head.Venture seems to be to big but i can live with it. |
Posted By: Bill Deppe/AC Salvag
Date Posted: 24 Apr 2018 at 11:03pm
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One slight detail is the CA crank has a divet in each of the rod journal. The crank also has a different casting number |
Posted By: TedBuiskerN.IL.
Date Posted: 25 Apr 2018 at 7:30am
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The 125 engine actually was first introduced as the R engine in the RC.Then became the CE engine when the model C was introduced in 1940. I have RC #686, with engine #R692. Also I think the rod bearings on the CA are lubricated through the crankshaft, which is why there is a number change for the crankshaft on the CA. The connecting rod number should also be different for the CA, and should not have the little hole along the beam of the rod that was used to oil the rod bearings on the Bs and Cs. But I don't know about this for sure. ------------- Most problems can be solved with the proper application of high explosives. |
Posted By: Dick L
Date Posted: 25 Apr 2018 at 9:15am
| I do not remember the piston measurements but the pistons on the CA came even with the top of the block and the older pistons were down a tad which would chance the compression. they were down even further for the dual fuel tractors all in the 3 3/8" diameter pistons. The only difference in the block was a cast in non machined area that looked as though it was for a possible fuel pump. As far as the head the only difference I found was in the ports below the valves which was in the internal casting cores. This would have nothing to do with horse power. |
Posted By: wfmurray
Date Posted: 25 Apr 2018 at 10:48am
| My B cranks good .When pullng real hard and low on gas it will cut off but crank right back up.I think venture is big and pulling hard vacuum drops and will not pull fuel in . |
Posted By: Dick L
Date Posted: 25 Apr 2018 at 11:12am
I found an oversized venture will help with higher RPS's but will cause less lugging power when getting larger than needed. It is kind of a balancing thing with what has been done to up the HP. |