Re: Distributor timing on older machines.

Posted by ScottyHOMEy on September 06, 2009 at 20:37:33 from (71.241.210.189):

In Reply to: Re: Distributor timing on older machines. posted by Bob on September 06, 2009 at 18:00:17:

You could try that.

I don't know how much you're willing to fiddle with it, but we're trying to get rid of the skip. If you've got a helper to turn the distributor while you shine the light up underneath, here's some numbers.

Full advance on a B/BN is with battery ignition is 40 degrees. I don't have a flywheel laying around, but I just went out and measured an old ring gear and did some arithmetic. The flywheel diameter is close to 10-15/16". Multiply by pi and divide by 9 (40 out of 360 degrees) and you get a little over 3-13/16", not a whole 3-7/8".

If you wanted to mark that off, it would be to the right of your TDC mark as you sit under the tractor looking to the rear. That would be your mark to line up with whichever type index you have. It's tight quarters, but can be measured and marked off if it's worth the effort to you. Just paint it a different color from your TDC mark.

Two things to keep in mind. Your timing train will be a little sloppy from wear, as James Rumpf points out, so none of this (beginning with my close but not precise measurements) is going to be completely accurate, but would serve as a rough guide. The slop is more of a problem with static timing.

Which gets to the second point, which is that timing at speed is with no load and the slop in the gears floating. Even attaching a PTO implement like a bush hog won't help much as they will float, too, once up to speed. The only way that comes to mind right off to tighten up the whole timing train under load is on a dyno. But if the bottom end of your motor is reasonably tight, you should get a reading close to the 40-degree mark when up to speed.

Bottom line, I'd set it up on the static mark and see how it runs. If that gets the miss out of it and the tractor works like you want it to, great. If not, then you might try marking off the 40 degrees and checking it with a light to see where you are -- just remember you're dealing with paint dots, and a couple of degrees aren't going to make or break your miss. If it's close to 40 on the light, then you've got other, easier issues to check out. Some could be really basic -- weak coil or condenser, dirty points, burned cap or rotor, bad wire or connection . . . Others could be tougher, like a worn distributor shaft (making it wobbly so that it throws the points out of time -- your mark will jump around a lot or skip a beat when running under the light)

Replies:

Add a Reply Name: E-Mail: Subject: Comments: Optional Link URL: Link Title: Optional Image URL: Optional Video Title: Optional Video URL: Advanced Posting Options Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.   Advanced Posting Tools   Upload Photo  Select Gallery Photo  Attach Serial # List  Return to Post

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]