WD45 Reliance vs M&W Engine kit comparison

All my old M&W info had the SP-48 kits at 7.4 or 7.5 to 1 compression ratio, not 7.3. Your new kit might be 7.25 to 1 and that's all.

http://brianahart.net/mwallisspecs.jpg

they have 8.25:1 available also. they're for the 175 and lp applications.i got a set last year for a future build someday.   http://www.powermaxparts.com/DEMO/AC-226-E.html

Well at least it documented here.
When I checked last December, the 8.25:1 4" bore kit was on backorder from reliance.

Today AGCO said they have the 8.25 motor kit available and would sell it for $900

Edited by Allis dave - 06 Jul 2016 at 9:57am

Called AGCO back to order a motor kit. The 8.25:1 kit is "available", but on back order.

That was my original plan. That piston came from a 2nd set I bought a few years ago. I very good mechanic friend of mine told me he didn't ever want to catch me wasting a good fresh rebuild on a set of used pistons. Now I just wish I wouldn't left the bottom end alone, no more than I use the tractor.

Also remember a couple people on here, like Doc I think, say they think the M&W sleeves were just a tad different than a standard 4.125 sleeve. I don't know from experience. Maybe someone will chime in. I don't have the head or oil pan on yet, so I could change pistons.

Correction - Update

I'm sorry to say that I may have misled some people. I more accurately measured the piston dish volume last night using a flat plate with a hole in it and sealing with vasaline. I was originally quite a bit off. I edited my original post for reference.

I originally posted the D17 kit with a 40cc dish , it really was a 32cc dish.
The M&W kit actually has a 73cc dish instead of my original measurement of 80cc.

The D17 piston has a 32cc dish.
The 32cc dish, .530 deck height, .04 compressed head gasket, and 4.3 head gasket bore make a compression ratio of almost exactly 7.25:1. So This would be a good D17 replacement piston.

The M&W has a 73cc dish.
The 73cc dish, .280 calculated deck height, .04 compressed head gasket, and 4.3 head gasket bore make a compression ratio of about 7.85:1.

I have a Reliance 175 8.25:1 Kit here also.
distance from top of piston pin hole to piston top is 2.161
The 65cc dish, .239 calculated deck height, .04 compressed head gasket, and 4.3 head gasket bore make a compression ratio of about 8.49:1

At these higher compressions even a couple cc difference or a few thousands of deck height change the ratio considerably so this may bot be exact. When measuring piston heights, some of different pistons in the sets had different pin to top heights by up to .010. Just that would change the ration by .1:1

The M&W and 175 kits seems a little high to me, but my point here is to say that I do believe the D17 Reliance piston is advertised correctly and the M&W kit has a fair amount more compression over an original D17 piston and a 175 piston has quite a bit more compression than an M&W piston.



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Edited by Allis dave - 19 Jul 2016 at 10:36am

Now I am asking a question.

I have heard of people using (201) flat top pistons with the 4.5" crank, which we all realize would increase compression significantly (I have heard of 12:1 compression ratios). I have also been told that the highest compression "Power Crater" pistons will dyno more horsepower than the (higher compression) flat top pistons. Is this true?

I know Chrysler had great success making horsepower with the hemi (head) engines of the late 60's and early 70's. Was AC doing the same thing using the top of the piston, instead of the hemispherical head?

ARE YOU SURPRISED !!!!!!!!!







Edited by Fred in Pa - 19 Jul 2016 at 12:45pm

Fred in Pa wrote: ARE YOU SURPRISED !!!!!!!!!

Well Fred all I can say is no I'm not surprised and I have not learned much that I didn't know before.

Now Dave don't get all bent out of shape.This is asked on here one or more times per six months and it's been addressed time and time again. This might help someone out.
I left out the low octane INFO. This is taken from Allis Chalmers service manuals.
One more little bit of info to keep in mind 4 diff head gaskets where used in the later ser#WC/WF and WD/WD45 tractors alone,so all this info is going to be off some with the newer head gaskets we use in them today.
WC/WF gas early ser# factory piston 5.0 to 1
WC/WF gas later ser# factory piston 5.5 to 1
WD gas early ser# factory piston 5.5 to 1
WD gas later ser# factory piston 5.7 to 1
WD45 gas factory piston 6.45 to 1 below 4000 feet
WD45 gas factory piston 7.20 to 1 above 4000 feet
WD45 LPG factory piston 7.20 to 1 all heights
D17 1,2,3,4 gas factory piston 7.25 to 1 below 4000 feet
D17 1,2,3,4 gas factory piston 8,25 to 1 above 4000 feet
D17 1,2,3,4 LPG factory piston 8.25 to 1 all heights
170 gas factory piston 8.00 to 1 below 5000 feet
170 gas factory piston 8.25 to 1 above 5000 feet
175 gas factory piston 8.25 to 1 all heights
I hope this will help out someday.
Sorry I didn't post the INFO on E Gleaners, I can't find my service manual. 

Edited by Don(MO) - 19 Jul 2016 at 5:19pm

I just got off the phone with my closest dealer. He said dont worry about running a 175 kit that it would be fine. Said his WD45 and D17 has been running one for years. I forgot to ask him if timing should be turned down?

Edited by 79fordblake - 19 Jul 2016 at 5:45pm

What the best way top get the timing set to 25 degrees since there's no mark there?

so is this 175 kit 4" or 4 1/8"? is that agco or reliance ?

The kit pictured is a 4" Reliance kit. AGCO still "offers" the 175 motor kit, but it's on backorder. Probably meaning they're not making anymore until they get enough orders for a run.