Author	[Modern View]
Ole Johnny 07-26-2012 13:47:33 67.142.164.26 Report to Moderator	Has anyone changed the head from a chambered stock head to a flat head on an early styled JD model A HAND CRANK model?? Im wondering if it is going to be too hard to hand start with stock compression gas pistons in it.. [Reply]   [No Email]
FactoryFarmer 07-29-2012 09:32:43 184.20.126.107 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-26-2012 13:47:33   I can't believe nobody has said this yet but if your tractor has a chambered head the flat head will not fit. A's are not like G's when it comes to swapping parts around. [Reply]  [No Email]
Mike n Mo 07-26-2012 14:04:09 69.29.82.15 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-26-2012 13:47:33   Ole Johnny, if I did the math right, given the facts you laid out, you'll have approximately 10.6:1 compression. If you can even roll it over, you'll get tired of it pretty quick. If you're going to the expense of a Murphy's head, spend a little more and put a starter on it. [Reply]  [No Email]
Ole Johnny 07-26-2012 19:21:29 67.142.164.21 Report to Moderator	Re: JD Model A head swap in reply to Mike n Mo, 07-26-2012 14:04:09   with the compression release pitcocks it has on it, I have learned to let the compression bleed off as i slowly turn it over untill it closes the port and then all that is necessary is for the top dead center snap of the mag to fire it. Im concerned if it will fire hot enough to turn the second cycinder up thru its compressiion stroke untill it gets a full stroke. Also, Im concerned with using 94 octain pump gas in it. [Reply]  [No Email]
jd b puller 07-26-2012 14:03:57 65.190.143.65 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-26-2012 13:47:33   If you're an older gent with limited strength and stamina, it will wear you out, but I've built numerous hand start A's and B's with 10:1 compression. There's other flat heads out there besides Murphy's. This post was edited by jd b puller at 14:06:31 07/26/12 3 times. [Reply]  [No Email]
Ole Johnny 07-26-2012 19:16:09 67.142.164.21 Report to Moderator	Re: JD Model A head swap in reply to jd b puller, 07-26-2012 14:03:57   Wont a 10 to 1 compression situation mandate racing gas? Or would the 94 octain pump fuel work since the tractors dont run but about 140 degrese anyways? [Reply]  [No Email]
jd b puller 07-27-2012 09:21:04 65.190.143.65 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-26-2012 19:16:09   10:1 will require 105-110 fuel. It"a about $7 a gallon around here, you"d use a couple gallons for 3 hooks. As to the compression, it depends on what pistons you have in there. I just did one for a guy who had a set of 0.125"s and had to cut 1/2" off of them to set the compression. [Reply]  [No Email]
Ole Johnny 07-27-2012 17:26:01 67.142.164.21 Report to Moderator	Re: JD Model A head swap in reply to jd b puller, 07-27-2012 09:21:04   Ray I sent you an E-Mail [Reply]  [No Email]
pmer 07-27-2012 10:13:02 166.156.116.29 Report to Moderator	Re: JD Model A head swap in reply to jd b puller, 07-27-2012 09:21:04   This might be apples to oranges but in 1969 Cadillac had 10:1 compression 500 cubic inch engines in their convertibles. Could one get gas with that high octane back then? [Reply]  [No Email]
bard 07-26-2012 20:48:55 173.189.139.172 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-26-2012 19:16:09   Got a G with 10.7:1 and with regular pump gas a simple quick snap of the throttle will make it ping, any load even driving it up a grade will make it ping. Mine has to have good gas. Pulls great with 110 octane. Thats just my case others may be different. [Reply]  [No Email]
Ole Johnny 07-27-2012 09:04:06 67.142.164.26 Report to Moderator	Re: JD Model A head swap in reply to bard, 07-26-2012 20:48:55   But I'm not gona pay 10 bucks a gallon for fuel to put in a tractor. If 94 octain could be used by adding methanon or acitone then I might put the head on it. [Reply]  [No Email]
pmer 07-27-2012 10:06:30 166.156.116.29 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-27-2012 09:04:06   E85 fuel. Can you get E85 around where you are? Cheaper than gas, high octane. Just have to open the carb to flow more fuel. [Reply]  [No Email]
Ole Johnny 07-27-2012 11:11:40 67.142.164.22 Report to Moderator	Re: JD Model A head swap in reply to pmer, 07-27-2012 10:06:30   will opening the jet screws compensate for the alky or would I have to drill the orfices?? [Reply]  [No Email]
pmer 07-27-2012 12:42:15 166.156.116.29 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-27-2012 11:11:40   If your main is out 1 1/2 turns or so now you"d prolly have to open your jets. My 77 has a bigger carb on it and when it is running on gas the main is out a 1/2 turn. On E85 it"s out about a turn and a half. [Reply]  [No Email]
Ole Johnny 07-27-2012 13:05:38 67.142.164.23 Report to Moderator	Re: JD Model A head swap in reply to pmer, 07-27-2012 12:42:15   high speed adjustment is only about 3/4 out now [Reply]  [No Email]
pmer 07-27-2012 14:04:43 166.156.116.29 Report to Moderator	Re: JD Model A head swap in reply to Ole Johnny, 07-27-2012 13:05:38   Well, it wouldn't cost too much to try a gallon or two. I should've said the big carb on my 77 has original sized jets in it. And I advanced the timing some. The carb has more condensation on it and it feels cooler to the touch when on E85. The exhaust has a different smell so you might want to check your rules too. E85 seems to work good, I tried it in a 55 Massey and the dyno showed a 5-6 horse gain which got it to about 86 horse. No PTO in the Ollie though. I'm gonna bum when they decide E85 costs too much to produce and subsadize. [Reply]  [No Email]
bob7337 07-28-2012 09:48:20 64.12.116.199 Report to Moderator	Re: JD Model A head swap in reply to pmer, 07-27-2012 14:04:43   At 10.5 compression you DO NOT need racing fuel. Premium gas will work fine. Just remember the old muscle cars of late 60's and early 70's had 10.5 compresspon ratios running on the roads for thousands of miles. [Reply]  [No Email]
north puller 07-28-2012 21:40:14 68.171.231.82 Report to Moderator	Re: JD Model A head swap in reply to bob7337, 07-28-2012 09:48:20   Another rocket scientist. What did those muscle cars blow on a compression tester? What does a 10.5:1 A with an advanced pulling cam blow? 150 psi vs 250 psi makes a difference in the required fuel. Also, a V8 with descent chambers vs a 2 lunger makes a difference in the required fuel. [Reply]  [No Email]
pmer 07-29-2012 09:25:40 75.235.197.69 Report to Moderator	Re: JD Model A head swap in reply to north puller, 07-28-2012 21:40:14   Sorry but I have to ask, How does 10.5-1 compression relate to such wide amounts of cylinder pressure? 150 psi in a car to 250 psi in a tractor and both having 10.5-1? Maybe these basics are deep for forum talk? [Reply]  [No Email]
Big Jugs 07-29-2012 10:35:12 174.124.118.101 Report to Moderator	Re: JD Model A head swap in reply to pmer, 07-29-2012 09:25:40   Just to add to the discussion....I have a handcrank G, short block, .090 over alum. high comp. pistons, with a flathead, and hot mag. I start this quite easily....get the flywheel at compression stroke-tip it over center and it"s running. And I"m considered a "runt of a guy", 5"8, 170lbs. It does need racing fuel in it. Hope this helps anyone. [Reply]  [No Email]