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bard 08-05-2012 14:45:23 75.88.136.236 Report to Moderator	I bored an unstyled A .125 and put M /W style pistons in it with late A rods. Any idea what the compression ratio would be? It appears the new pistons go up one inch farther than the stock ones. The new pistons JUST clear the spark plugs. ALSO what would this setup be with a heisler head? Got one sitting here and debating whether or not to put it on. I would assume that extra inch with the newer pistons is going to be quite a bit more compression and adding the heisler head on top of it should get the compression up alot? Any close ideas would be greatly appreciated. Thanks. [Reply]   [No Email]
Bigmotors 08-06-2012 17:56:16 132.161.0.47 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   If it's a early Heisler Head the (bra) tips are about 15/16 into the chamber. The Heisler will bolt on with the 6.500 crank you might have to take a little off the tips for 6.750. If you have a good mag or dist. you can hand start it. With .125 over late crank and flat head your looking at a 47-52 hp tractor. 5.500 + .125 over X 6.500 = You went from 309 to 323 cu. 5.500 + .125 over X 6.750 = You went from 321 to 336 cu. Pump Gas is not going to get it. [Reply]  [No Email]
jd b puller 08-06-2012 16:57:50 65.190.135.248 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   You said the piston just cleared the spark plug. Spark plug sits pretty low in the cylinder on US/A. Assuming you have a FLAT TOP PISTON, here's some compression numbers for you. Number on the left is how far the top of a FLAT piston is to the deck and on the right is the compression ratio. I did it in 0.100" increments. Notice how it JUST DOESN'T matter until you start getting close? So when people say they put MW pistons and "shaved the head to the max", it just doesn't matter that much until the compression starts getting in the 8-9:1 range. inches -----------> ratio 1.5 --------------> 5.14 1.4 --------------> 5.42 1.3 --------------> 5.74 1.2 --------------> 6.11 1.1 --------------> 6.55 1.0 --------------> 7.07 0.9 --------------> 7.7 0.8 --------------> 8.47 0.7 --------------> 9.44 0.6--------------> 10.7 0.5--------------> 12.4 0.4--------------> 14.82 [Reply]  [No Email]
BushogPapa 08-06-2012 09:57:38 173.88.51.117 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   The Heiser Head will put you into the Ultra High Octane or E-85 range for Fuel requirements... The limit for actually "Using" it for field-work with 87 octane gas will be around 7:1 Ron.. [Reply]  [No Email]
Puln70 08-06-2012 03:30:21 68.73.215.224 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   Why don"t you measure the stroke & let us know? [Reply]  [No Email]
Big Jugs 08-05-2012 18:39:20 24.214.190.130 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   if you didn"t change over to the 6 3/4" crank, the rods won"t work(if I"m correct) The pistons will work, will have to shave some down for spark to get up in chamber, and it won"t be too high for pulling, whbich is all it WILL be good for. No, you won"t be able to hand start it...all depends on what you want to do with it. [Reply]  [No Email]
bard 08-05-2012 18:56:20 75.88.136.236 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to Big Jugs, 08-05-2012 18:39:20   I didn't change the crank but honestly don't know if it was done at some point before or not, I have no way of knowing. Why won't the rods work? I measured everything and was sure they fit the crank before I put them in. Maybe I'm missing something. [Reply]  [No Email]
BushogPapa 08-05-2012 17:16:03 173.88.51.117 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   A '35 "A" will have only a 6 1/2" Stroke.. Ron.. [Reply]  [No Email]
Larry Baker 08-05-2012 17:06:18 204.116.154.80 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   She'll be tough to hand stat for sure [Reply]  [No Email]
Ole Johnny 08-05-2012 15:54:07 67.142.164.24 Report to Moderator	Re: JD '35 A with late A pistons/ compression? in reply to bard, 08-05-2012 14:45:23   I essentially asked the same question just about a week ago and got replys that the compression should go up to between 10 and 10 1/2 to one. [Reply]  [No Email]