720 timing
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Garden Tractors
Forum Description: A great place to discuss the Simplicity and Allis Chalmers Garden Models
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=188957
Printed Date: 23 Nov 2024 at 2:12pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 720 timing
Posted By: AC720Man
Subject: 720 timing
Date Posted: 18 Jun 2022 at 10:44am
Been a few years since I’ve had to do this and for some reason my memory is failing me. Not wanting to remove the engine to see the timing marks, facing the engine, there are 3 marks on the clutch housing. A line which I assume is TDC, T, and then a triangle pointing towards the the engine. Is the triangle 20 degrees at which I should time to? My timing light broke so I was going to do static timing with a continuity light. Yeah, I need to go electronic but I need to mow the yard today. Appreciate the help.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Replies:
Posted By: AcFordHawk
Date Posted: 24 Jun 2022 at 7:44pm
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I copied a couple pages from the 9020 manual I have on digits. Bottom right of the first page starts the ignition timing instructions and top of second page has timing mark figure. Hope it helps.
I had some trouble loading the file. If it doesn't open clicking on it - right click on it and open in a new tab.
uploads/610/CCKBptset.pdf" rel="nofollow - uploads/610/CCKBptset.pdf
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IB (restoring), MF GC1705, MF 2705E
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Posted By: AC720Man
Date Posted: 24 Jun 2022 at 8:55pm
Thank you Paul!!! Not sure why my service manual does not have that explanation in it. But that makes perfect sense to me! Thank you sir!
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: Steve in NJ
Date Posted: 24 Jun 2022 at 9:06pm
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Rob, Did Brad call you? I sent him an e-mail with your phone number the day you called me to give you a call. Though he would be able to help ya out. He builds quite a few of those 720's. And quite nicely I might add.......!! Steve@B&B
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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife
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Posted By: AC720Man
Date Posted: 25 Jun 2022 at 5:19pm
Haven’t heard from him Steve. Going to start on the issue Monday. Have a busy weekend but hope to get it running again Monday
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: AC720Man
Date Posted: 26 Jun 2022 at 3:49pm
Paul the instructions were easy to follow and I now know my timing is spot on, wasn’t off by much. Still will not start. New Onan/Cummins plug wires, points, condenser and new plugs. Points gapped at .020”. Original engine with less than 650 hrs. Have good spark so I guess I’m pulling the carb off again to clean and recheck the float level.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: AC720Man
Date Posted: 26 Jun 2022 at 7:03pm
Adjusted the valves before I get into the carburetor. Intake valves were spot on. The exhaust valves were 5-6 thousandths too tight. Will disassemble the carb tomorrow to see if I find anything wrong.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: injpumpEd
Date Posted: 11 Jul 2022 at 9:46am
Went to put my new points in yesterday, and ran into the same problem I've had before, I cannot adjust a wide enough gap. I even got a new pushrod, which is indeed slightly longer, but still the eccentric will not allow much more than a few thou gap, which is probably why it's so low on power. Never gives the coil enough time to saturate. Do I need to take off the eccentric screw? Or make a custom pushrod? Am I the only one with this issue?
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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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Posted By: AC720Man
Date Posted: 11 Jul 2022 at 11:19pm
I also had that issue and ordered a new plunger Ed. Put the new plunger in and was then able to get the .020”. I removed my muffler to make it easier to get to it when I first had the issue which allowed me to see what was going on. Is your esentric worn? Is the breaker box tightened down? Those bolts do work loose occasionally. Mine were not as tight as they should have been. Would a round file in that area provide more room for it to move in case of a manufacturing defect?
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: injpumpEd
Date Posted: 12 Jul 2022 at 7:56am
The new pushrod is longer than old one, but still can't get enough gap where I'm happy with it. The box bolts are still tight, I put allen bolts in there last time I messed with it. The eccentric may be worn, but pushrod still moves up and down, so not sure how a wood stick would wear a steel eccentric lol! Thinking I may need to make a new pushrod out of brass? or ?? Plastic rod would be good if I could find some. Thanks for any input!
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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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Posted By: AC720Man
Date Posted: 14 Jul 2022 at 2:44pm
Ed I thought when you was referring to the offset adjustment screw that you turn to adjust the points?
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: injpumpEd
Date Posted: 15 Jul 2022 at 2:00pm
I was thinking of removing it so I can adjust further than it will go. I could open up the slot in the points base too. I don't need much, but I'm sure getting the gap out to spec will make this thing run like the animal it used to be lmao!
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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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Posted By: AC720Man
Date Posted: 15 Jul 2022 at 10:18pm
That’s why I mentioned a round file to open the slot in the points when you said you didn’t need much. Just an idea. Your like me, I just need to pull the engine and install electronic ignition and be done with it. Hope you get it adjusted, they can be a pain in the ars.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: injpumpEd
Date Posted: 12 Aug 2022 at 8:42am
ok, finally had time to mess with the 720 again, and I noticed that both screw holes are slotted on the points. Once in there it's hard to see with the muffler in the way, so I hadn't gotten down low enough to look under it to see straight in. It always pays to get a good view on things lol! So I was able to tweak the one slot over far enough to put the eccentric into use. Felt like a dum@$$ lol! It sounds better with opened up point gap already, and I'll see how it runs when I mow this weekend with it. Just wanted to point out that both ends are already slotted, so someone else doesn't make the mistake I did.
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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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Posted By: AC720Man
Date Posted: 13 Aug 2022 at 9:57pm
Glad you got it figured out Ed and for letting everyone know what you found. Haven’t got back to my 720 yet. Farming has kept me busy as we have had an exceptional summer. Plentiful rain has kept the hay coming on and the yards require mowing sometimes twice a week.
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1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD
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Posted By: injpumpEd
Date Posted: 18 Aug 2022 at 8:28am
Just wanted to update this, I finally took time to mow with it and it runs so much better with the points opening up to the correct gap lol! Hard to saturate the coil if they never open up. Like Robbie said above, the muffler makes it tough to see in the box, but no way am I removing that muffler, it's been on there too long lol! I could peek under it though.
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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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