Pulling Forum - Advance Curve

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Advance Curve

Printed From: Unofficial Allis
Category: Other Topics
Forum Name: Pulling Forum
Forum Description: Forum dedicated to Tractor and Garden Pulling
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=93293
Printed Date: 24 Nov 2024 at 6:19pm
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Topic: Advance Curve

Posted By: DaSquatch
Subject: Advance Curve
Date Posted: 04 Aug 2014 at 5:38am

Just put a Z code Gleaner engine in our WC puller. Engine is absolutely stock, but tight (180 psi compression) with the exception of an electronic ignition adapted from a Ford pickup. Our class limits us to 700 pto rpm.

Prior owner had used a long sheetmetal screw to hold the points down and wrecked the springs on the mechanical advance mechanism. Hadn't discovered that at the first pull. Tractor ran smoothly, but power was flat. Haven't been able to put our hands on a set of new stock springs, so we've tried a few combinations of automotive springs, and hardware store springs. We've discovered that this is a legitimate tuning parameter, as some results have been noticeably better than others, but we don't think that we've hit the perfect recipe yet.

So, my question is, can anyone recomend a profile? Initial timing, total advance, and what rpm total is achieved at?

Replies:

Posted By: DrAllis
Date Posted: 04 Aug 2014 at 6:44am

TOTAL ADVANCE OF 25 DEGREES BTDC AT WIDE OPEN THROTTLE. At idle it should be TDC. Full distributor advance is achieved by 1600 RPM as a rule on that engine, but always set timing at wide open throttle regardless.

Posted By: DaSquatch
Date Posted: 04 Aug 2014 at 11:26am

Thank you, Dr Allis.

Posted By: Steve in NJ
Date Posted: 04 Aug 2014 at 11:45am

If you shoot me the number of the Distributor, I may have the springs in stock. I do a lot of Distributor work for stock engines and pullers.
Steve@B&B
bb-customcircuits.com

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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

Posted By: DaSquatch
Date Posted: 04 Aug 2014 at 1:49pm

The distributor is a Delco Remy model 03238. It would be awesome if you had them. Local dealers just gave me a blank stare.

We're relearning the tractor with the new engine. We made a mistake by getting in a rush and not marking tdc on the flywheel when we installed it (re-used the wc flywheel, which had no visible marks left). With the 201 and magneto, we had always timed it to maximum manifold vacuum, with good results. When we do that with this engine, it fires too early and won't start (though it seems to run really well at that setting). Leads us to believe that we may not be getting the full range of motion out of the advance mechanism. Haven't had time to find and mark TDC, so really just guessing what's happening. That's why my inquirery for the numbers, so we have a target to shoot for as we get our act together.

Posted By: DrAllis
Date Posted: 04 Aug 2014 at 3:45pm

Trying to "time" one of those 8 to 1 compression engines without a timing light AND a proper F-25 degree mark on the flywheel is just plain stupid. Your WC flywheel should have a TDC mark and maybe a "FIRE" mark which is 30 degrees BDTC not 25 degrees BTDC. THERE IS A REASON AC BACKED THE TIMING DOWN TO 25 DEGREES !!!!!!!!!!!!

Posted By: DaSquatch
Date Posted: 04 Aug 2014 at 7:33pm

Maybe I am stupid, but I promise, there's no mark on the flywheel. We never could find it before we took the engine out, and when we did, we cleaned the hell of it looking. Nothing.

And, I know how to do it right, but we didn't even get the combine pulled out of the woods until two weeks before the first pull (winter just flat refused to give up this year). That, two kids, 70 hour a week job, fire dept meetings, softball, etc......sometimes you take shortcuts. And we still beat 9 tractors and took first place last weekend!