Piston Kit compression ratio WD45
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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=125917
Printed Date: 20 Jun 2025 at 9:51am
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Topic: Piston Kit compression ratio WD45
Posted By: 79fordblake
Subject: Piston Kit compression ratio WD45
Date Posted: 14 Jul 2016 at 4:44pm
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I bought a new piston kit and block together awhile back and nothing tells the compression ratio. I'm trying to figure out if I'm going to use them or not. I'm looking to make about 55HP with this new engine when done. It says JCC 1007P inside piston. Also has 6.6.2 inside of it. I'll try to get a pic. |
Replies:
Posted By: 79fordblake
Date Posted: 14 Jul 2016 at 5:07pm
 
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Posted By: Skyhighballoon(MO)
Date Posted: 14 Jul 2016 at 5:14pm
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If you can give the volume in cc of the dish in the piston and the height measurement from the the center of the wrist pin to the top of the piston some guys here can calc the exact compression ration. Mike ------------- 1981 Gleaner F2 Corn Plus w 13' flex 1968 Gleaner EIII w 10' & 330 1969 180 gas 1965 D17 S-IV gas 1963 D17 S-III gas 1956 WD45 gas NF PS 1956 All-Crop 66 Big Bin 303 wire baler, 716H, 712H mowers |
Posted By: DrAllis
Date Posted: 14 Jul 2016 at 6:22pm
| What is the BORE ?? 4 inch or 4 1/8 inch?? |
Posted By: 79fordblake
Date Posted: 14 Jul 2016 at 6:32pm
| 4" going by tape measure. I came up with 60cc and center of wrist pin to top 2 3/8. |
Posted By: DougS
Date Posted: 14 Jul 2016 at 7:51pm
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Find a 10cc veterinary syringe and start filling the bowl. That's the easiest way to determine the volume of the bowl. |
Posted By: Allis dave
Date Posted: 15 Jul 2016 at 7:03am
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What's the distance from the top of the wrist pin hole to the top of this piston? Or What's the diameter of the wrist pin? If you send me these and if you're block hasn't been deck, I can figure for you. Check out this discussion if you haven't already %20" rel="nofollow - http://www.allischalmers.com/forum/forum_posts.asp?TID=121191&title=wd45-reliance-vs-mw-engine-kit-comparison |
Posted By: 79fordblake
Date Posted: 15 Jul 2016 at 9:21am
| I'll measure when I get home. I feel like these are gonna end up being low compression pistons. Which I won't be happy with since I already have almost 2,000 in this engine and still buying parts. No machine work has been done yet. |
Posted By: DrAllis
Date Posted: 15 Jul 2016 at 9:54am
| To accurate measure the cc's, you need a flat piece of plexi-glass with a small hole in the center. Grease the outer rim of the piston and set the glass on top of it, squeezing the grease. Fill with a syringe until full. |
Posted By: 79fordblake
Date Posted: 15 Jul 2016 at 4:19pm
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Top of wrist pin hole to top of piston 2 7/8 I can't find any informatoon on these pistons. I've sent two messages to Sandy Lake about piston options and no reply. |
Posted By: Allis dave
Date Posted: 15 Jul 2016 at 5:55pm
That doesn't make sense, here you said center of wrist pin to top of piston 2 3/8 Then you posted 2 7/8 from top of wrist pin hole to top of piston. Distance from top of wrist pin to top of piston should be less than center of wrist pin to top of piston.
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79fordblake wrote:Posted By: Allis dave
Date Posted: 15 Jul 2016 at 6:08pm
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Just measures my wrist pin. It's .990 diameter. If your center of wrist pin to to top of piston really is 2.375, a 4" bore, and 60cc bowl, and .04 compressed head gasket thickness, you'd have a compression ratio of about 6.12:1. Also if you're block hasn't been decked (meaning it is the same height as mine). I figured my reliance kit with a 40cc bowl and 1.863 from top of wrist pin hole to top of piston and a compression ratio of about 6:1. You have a bigger bowl (and it looks bigger in the picture too) and the piston is slightly farther away from the head to boot. Sorry, just wne tthrough the same thing when I bought my reliance kit with D17 pistons. I figure they were .25 less compression than advertised. Take a look here http://www.allischalmers.com/forum/forum_posts.asp?TID=121191&KW=M%26W+reliance&title=wd45-reliance-vs-mw-engine-kit-comparison" rel="nofollow - http://www.allischalmers.com/forum/forum_posts.asp?TID=121191&KW=M%26W+reliance&title=wd45-reliance-vs-mw-engine-kit-comparison
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Posted By: 79fordblake
Date Posted: 15 Jul 2016 at 7:36pm
| Not happy with 6.12 at all. This piston kit will not be used. I hope to never open this engine again so I'm not settling with low compression pistons. Ill check measurements again when I'm back home. |
Posted By: 79fordblake
Date Posted: 15 Jul 2016 at 10:41pm
| Top of pin to top of piston 1 7/8. Center of pin to top of piston 2 3/8. |
Posted By: Don(MO)
Date Posted: 16 Jul 2016 at 10:14am
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I think it's time to tell a story from back in the day. So here go's. Back when I was a kid working in the dealership, farmers came in the shop looking to get the old tractor overhauled and time and time again the same thing old came up, I need to get more HP out of her so install a biggest set of pistons you can and crank-her up all she will go; the older wench bender had the same thing to say to all of them, if you need more horse power go up front and buy a bigger tractor because it will take a lot more than a set of bigger pistons and RPM to get that kind of power out of your old tractor and if it did put out that much she'd be back in here looking or a bigger repair bill then you will be looking at now! And the same response came back the farmer across the road have this newer and bigger tractor and he is getting more work done than I can with this old tractor so make her do what his can. Well you can guess the outcome most of the time from the higher horse power the shop put in the older tractor, yes broken shaft or might be a rod or two looking out the side of the block and yes the old wench bender had to give them that funny look as the engine was leaking oil all over the shop floor. I just love to tell this story, and yes it's a true story. lmao ------------- 3 WD45's with power steering,G,D15 fork lift,D19, W-Speed Patrol, "A" Gleaner with a 330 corn head,"66" combine,roto-baler, and lots of Snap Coupler implements to make them work for their keep. |
Posted By: 79fordblake
Date Posted: 16 Jul 2016 at 10:40am
| When you have almost 2 grand in a little 4 cylinder and I expect I have about another 2 grand to go to be done a person would hope its gonna put out a little more HP than stock. Its so expensive to rebuild something right and I'm not even doing anything crazy. |
Posted By: SteveM C/IL
Date Posted: 16 Jul 2016 at 10:43am
| Back in 60's-70's when dad had his shop all the area tractors got M&W's when overhauled.Mostly WD-WD45's and M Farmalls in them days.He tried to keep a set in stock but many times had to make the drive up to Gibson City to keeps things on schedule. |
Posted By: Don(MO)
Date Posted: 16 Jul 2016 at 10:55am
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I'm not saying don't do it, all I'm saying is they didn't all stay togather back then and now they are 60+ years older now. I love to here an old WD/WD45 barking like a big dog too, just don't build to much and pull her to hard for to long because they are like a old horse and might lay down. lol Blake you can get 55+ out of the 45 but it might need a carb and cam change + the piston change to get her up there. Forgot to say it's time for me to go dyno that WD45 engine I just overhauled with the same pistons in it you have posted above,I will let you know the hp she is putting out that will give some idea they will improvement over stock one's. Wish me luck. lol ------------- 3 WD45's with power steering,G,D15 fork lift,D19, W-Speed Patrol, "A" Gleaner with a 330 corn head,"66" combine,roto-baler, and lots of Snap Coupler implements to make them work for their keep. |
Posted By: 79fordblake
Date Posted: 16 Jul 2016 at 11:45am
| Don I have a bad feeling if you have the same pistons that I have we may be dissapointed. That would be great to find out though. Just emailed my closest dealer about D17 7.25:1 pistons if they are still available. |
Posted By: Don(MO)
Date Posted: 16 Jul 2016 at 1:35pm
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Well she did better that I thought, now keep in mine I have a older M&W dyno and they are not spot-on but I made one hard pass for the top HP and she was putting out 48 HP at 548 PTO RPM's plus this tractor has a D17 governor spring I installed too,
------------- 3 WD45's with power steering,G,D15 fork lift,D19, W-Speed Patrol, "A" Gleaner with a 330 corn head,"66" combine,roto-baler, and lots of Snap Coupler implements to make them work for their keep. |
Posted By: 79fordblake
Date Posted: 16 Jul 2016 at 2:18pm
| Well looky there that ain't to bad Don. I may still try to find another set but atleast now I'm not so down in the dumps about the set I got. Also might add my WD45 currently has a stock WD engine in it. So I'll be stepping up quite a bit. |
Posted By: DrAllis
Date Posted: 16 Jul 2016 at 3:56pm
| A compression test would give a pretty good indication what the compr ratio really is...... |
Posted By: 79fordblake
Date Posted: 16 Jul 2016 at 4:36pm
| Now that you said that hey Don you wanna do a compression test on that engine? Lol |
Posted By: DrAllis
Date Posted: 17 Jul 2016 at 6:50pm
| 6.5 to 1 ratio on a WD-45 is 130 lbs compression.... 7.25 to 1 ratio on a D-17 is 145 lbs compression pressure. These are with throttle wide open and a battery charger on the battery with all 4 spark plugs removed. |
Posted By: Allis dave
Date Posted: 17 Jul 2016 at 7:51pm
| I've been recently discusisng the same things. It cost a lot to rebuild these or any motor to stock. It costs even more if you want to up HP. |
Posted By: Robacpuller
Date Posted: 17 Jul 2016 at 7:58pm
| Dr how much is 187 lbs. |
Posted By: DrAllis
Date Posted: 17 Jul 2016 at 8:24pm
| A model D-19 gas is 170 psi and is called 8.0 to 1 compression ratio. The same D-19 in an LPG version was 210 psi and called 9.35 to 1. I expect any of my Puller engines to be 260 psi or more. |
Posted By: JC-WI
Date Posted: 17 Jul 2016 at 8:50pm
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Seeing this thread is about pistons, compression and WD45, I am hyjacking it for a moment or two. What compression was the WD45 LPgas or D17 LP? 8:25? I have a set of pistons, sleeves and rings from Napa some 35 years ago and don't remember what compression they were for a WD. They are dished, 4 1/8" NAPA-DANA # 226-1263 with a 711 sideways vertical in front of the numbers. The rings are Perfect Circle S 41019 and inside the pistons the only thing I can find is 1046 cast in them. I am wondering if anyone has info on this set anymore, I tried to google them but struck out. Also wonderin if these could be shaved down to work in a WD45/D17 application. and while I am at it, I also have a set of pistons and sleeves for our 170 that were bought from an AC dealership just before they closed their doors and held an auction so I don't know if they are the right ones or 'can use' because they were the last ones on the shelf... That number, AC- 0257459 F19A . thanks ------------- He who says there is no evil has already deceived himself The truth is the truth, sugar coated or not. Trawler II says, "Remember that." |
Posted By: Allis dave
Date Posted: 18 Jul 2016 at 7:11am
| I'm getting 6.3:1 from a deck height of .518 and a 60cc bowl. If you're measuring with a tape measure instead of a caliper it's hard to be exact. Just 1/16 more distance from pin to piston top jumps you up to 6.7 compression. I'm guessing these are a stock WD45 4" piston kit at 6.5:1 |
Posted By: Allis dave
Date Posted: 18 Jul 2016 at 7:13am
| 70257459 is the AGCO part number for a 8:1 motor kit for a 170 |
Posted By: Don(MO)
Date Posted: 18 Jul 2016 at 8:48am
I'll start on the 170 engine kit first, the new part # for your kit is 70257459. On your NAPA kit I don't know, sorry ------------- 3 WD45's with power steering,G,D15 fork lift,D19, W-Speed Patrol, "A" Gleaner with a 330 corn head,"66" combine,roto-baler, and lots of Snap Coupler implements to make them work for their keep. |
Posted By: The Hooker
Date Posted: 18 Jul 2016 at 6:24pm
This link is dead and i have looked for it to no avail. Can anyone find and relink it? |
Posted By: YT
Date Posted: 18 Jul 2016 at 8:15pm
| put a set of WD flat tops in it. |
Posted By: JC-WI
Date Posted: 19 Jul 2016 at 1:39am
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Maybe try this link again... http://www.allischalmers.com/forum/forum_posts.asp?TID=121191&title=wd45-reliance-vs-mw-engine-kit-comparison" rel="nofollow - http://www.allischalmers.com/forum/forum_posts.asp?TID=121191&title=wd45-reliance-vs-mw-engine-kit-comparison ------------- He who says there is no evil has already deceived himself The truth is the truth, sugar coated or not. Trawler II says, "Remember that." |
Posted By: 79fordblake
Date Posted: 19 Jul 2016 at 5:36pm
| My nearest dealer told me to use the kit I have to get the sleeves and orings from it and he could sell me 175 pistons for $50 a piece and $128 for a ring set. From the way I understood it no complete kit available anymore. |
Posted By: Allis dave
Date Posted: 20 Jul 2016 at 6:55am
| If you want the high compression pistons, that's a good deal and you better do it. Actually, even if you don't want those pistons, you better buy them, and sell the whole thing as a kit. You could recoup some of that rebuild money. |
Posted By: 79fordblake
Date Posted: 29 Jul 2016 at 8:08pm
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Got this in the mail today. [  
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Posted By: TramwayGuy
Date Posted: 29 Jul 2016 at 10:10pm
| Dr Allis; I am curious. Since atmospheric pressure at sea level is 14.7 PSI how does a 6.5 compression ratio translate to 130 PSI? Mathematically 14.7 X 6.5 = 95.6 PSI (assuming perfect sealing of rings and valves |
Posted By: DrAllis
Date Posted: 29 Jul 2016 at 11:06pm
| You'll have to contact Allis-Chalmers on that. 130 psi is what the official A-C Service Manual says cranking compression should be. It's their spec, not mine, and it is accurate, just like a D-17 is 145 psi. |
Posted By: Allis dave
Date Posted: 30 Jul 2016 at 11:48am
| Looks like you made a good find for an original D17 motor kit |
Posted By: DougS
Date Posted: 30 Jul 2016 at 1:13pm
I don't think it's that simple. As you compress air to any degree it will heat up. This in turn will cause an additional rise in compression. Perhaps someone here with a better understanding of physics can provide a formula. |