CA Horsepower
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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=50444
Printed Date: 22 Jun 2025 at 6:24am
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Topic: CA Horsepower
Posted By: Gary(MO)
Subject: CA Horsepower
Date Posted: 12 May 2012 at 8:51am
| I know that the C's and CA's have a 125 engine but, where does the extra horsepower of a CA come from. My book shows a C with about 23 horse and CA with about 26. I know the rpm;s are higher on the CA but, does the CA engines have more compression? thanks Gary |
Replies:
Posted By: Orange Blood
Date Posted: 12 May 2012 at 8:56am
|
Don't know every detail of it, but like the similar engine the 226, More RPMs, and, extra Fuel were the two key reasons the 226 climbed in HP over the years. HP is not the actual measure of work. You can take the same engine and spin it faster and the HP will go up, because HP is the measure of potential work, torque is actual work, it does go up with RPMs, but not as much, given all other things constant. ------------- Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7 |
Posted By: RichinWis
Date Posted: 12 May 2012 at 9:02am
| If you are talking about Drawbar horsepower, the C has different gearing versus the CA, I know some of my CA's had the PA suffix on the engine number denoting High compression. The CA made a nice peppy little tractor. |
Posted By: Max(ia)
Date Posted: 12 May 2012 at 9:50am
| According to TractorData, the C turns at 1500, CA at 1650. C Compression 4:25x1, Ca 6:25X1 plus the CA has the 4 speed |
Posted By: Gary(MO)
Date Posted: 12 May 2012 at 1:10pm
| Max ia Where did the CA's get the extra compression? Different pistons or was it in the HEAD? I always thought C's and CA's were identical engines but, with the different comp. ratios something was different. Thanks Gary |
Posted By: CTuckerNWIL
Date Posted: 12 May 2012 at 1:22pm
Different pistons ------------- 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 |
Gary(MO) wrote:Posted By: wfmurray
Date Posted: 12 May 2012 at 6:23pm
|
Don,t know if i can help but when i restored my B the carbuator was bad , got one off a C A . Had to longate holes in manifold to get C A on . Tracor cranks and run good but speed flucates when not pulling . When it pulls it level out . Think it is a little richer than the B carb was. IT don,t have adj. |
Posted By: CTuckerNWIL
Date Posted: 12 May 2012 at 7:31pm
Sounds like you are missing the anti surge spring on the throttle control rod. ------------- 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: 12 May 2012 at 7:56pm
| I have the anti sugge spring .Qustion why was flange holes 1/4 in wider on CA carb than B . I think the venture may be different . |
Posted By: ACEd2010
Date Posted: 12 May 2012 at 8:14pm
|
Raw Horsepower is Torque x RPM x constant. Typically Torque curves have a peak before they reach highest design RPM - somewhere I think I have typical AC torque curves and I think they peak early - so More RPM may or may not equal more HP by itself. But if you add compression and tweak timing or camshafts, the torque curves and peaks can be changed - or if you improve combustion like the 226 Power Crater design did. And of course displacement makes more torque so the CE engines made more power than the BE. As to drawbar HP, that does include factors like tire size, transmission gearing, and rear end ratios - hence the need to also look at Belt HP which is more straightforward. But I think the simple answer is CR was increased to take advantage of higher octane gas as it became available and torque increased. RPM increase x increased torque = increased HP. Only variation significant to CR were Pistons and Head Gaskets - yes Head Gaskets. On early engines - mostly the 116 CI BE, but also used for the earliest 125 CI variant in the R tractor - they used 2 head gaskets to lower CR for Low Octane (Distillate) fuel. And the differences in the pistons - as pointed out by another poster would be height from piston pin to top of piston and possibly piston top geometry. Pistons for early CE Low Octane were 4.7:1 Cast Iron - these would be CE engines with K suffix Pistons for early CE Low Octane High Altitude were 5.2:1 with both CI and AL variants Pistons Pistons for early CE gasoline engines in B & C tractors up to early 1950 were 5.7:1 Cast Iron - presumably these would be the G suffix engines Pistons for CE gasoline engines in mid 1950 up to s/n CE153961/CR47264 were 5.7:1 Aluminum - presumably the GA suffix engines in early CA and some B tractors Pistons for late CE gas engines beginning mid-1950 at CE153962/CR47265 were 6.2:1 Aluminum - presumably the PA suffix engines in late CA and B tractors |
Posted By: ACEd2010
Date Posted: 12 May 2012 at 8:23pm
| As to carbs, yes venturi size increased with displacement BE to CE and with RPM. A number of different carbs were used on B, C, CA. Early CE used 9/16 venturi, mid years used 5/8. Last used 3/4. And yes more gas generally makes more Torque & HP as long as engine can use it. |
Posted By: Bill Long
Date Posted: 13 May 2012 at 6:24am
|
ACEd2010, That is an outstanding explanation of the genealogy of the B-C-CA engine pistons. Working with B-C engines I did not know the technical terms or the proper wordage but it always seemed that you could get more power in a B-C-CA engine by putting in a new engine kit. Pistons and sleeves seemed to add horsepower. In fact when we did an overhaul to an older unit we always told them to expect more horsepower but cold not explain it as completely. Thanks again for clarifying the reason. Good Luck! Bill Long |
Posted By: Scott(SC)
Date Posted: 13 May 2012 at 9:18am
| ACEd2010, are you saying that alluminum replacement pistons have more compression? The reason I ask is I bought a B for parts that had been rebuilt, the owner died, and It froze and cracked. I am taking the new parts out and putting them in a good block. How could I tell what compression I can expect? |
Posted By: ACEd2010
Date Posted: 13 May 2012 at 12:38pm
|
There were both Aluminum and Cast Iron pistons in 5.2:1 and 5.7:1 range depending on year. The 6.2:1 were only in Aluminum. As to telling the 5.2:1 or 5.7:1 Al vs the 6.2:1 Al I think you would have to have a Part Number or have the 2 side by side and measure height from pin to top. You could infer the higher 6.2:1 compression if Alum pistons are coming from a PA suffix engine, but since others may have been rebuilt over time - who knows? |
Posted By: ACEd2010
Date Posted: 13 May 2012 at 12:42pm
| You might also do some research on what Rebuild Kits are available - I would guess in interest of having only one kit to inventory, the 6.2:1 kit may be the default as all Gas engines would be fine with that and realistically, no one was using distillate after 1960 or so. |
Posted By: DennisA (IL)
Date Posted: 13 May 2012 at 2:49pm
|
Stock "CA" has more HP (26.7hp) than a stock "C". ------------- Thanks & God Bless Dennis |
Posted By: CTuckerNWIL
Date Posted: 15 May 2012 at 10:47am
I have a 38 B with a 39 engine, a 51 CA with original engine and an old C manifold and all measure 2.5 inches between bolt centers for the carb to bolt up to. Don't know where your "new" carb came from but if it was off a CA, it should bolt right on with no alteration of the manifold. ------------- 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: 15 May 2012 at 10:58am
| CTucker I got my carb off of a parts CA ,. IT was still on the tractor . Seems AC made a lot of varations along the way. |
Posted By: mdtractormechanic
Date Posted: 15 May 2012 at 11:04am
The compression ratio was 4.75:1 on the Model C with distillate fuel and 5.75:1 with gas at 1,500 RPM's. ------------- Joe's 1939 Model WC, 1940 Model RC, 1944 & 1950 Model C's, B-125 PU |