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Post by brucew on Dec 29, 2017 20:43:13 GMT -5
Dave, With your dwell-tach set to RPM's, watch how much the engine slows down as you pull individual plug wires. A weak cylinder will cause the idle speed to slow down less than the others, because it's not carrying as much "weight" as the others. It seems to smooth out at higher RPM's for two reasons - One, the flywheel tends to carry momentum over a weak cylinder's power stroke, and a small leak at, say, a valve may leak out enough volume/pressure to affect the power output by a large percentage, but when there is more mix being poured in and it stays in the chamber less time, the small leak still lets out just that small amount, so the percentage is less. Make sense?  B-dubya |
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Post by dluber on Dec 29, 2017 23:13:34 GMT -5
Bruce, Yes that makes sense. So if I had to say, the 3rd cylinder may be the weak link. I will check in the morning with the analog RPM meter attached to see the difference in measurement.
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Post by dluber on Dec 30, 2017 8:05:33 GMT -5
Scoutpilot, sorry for the delay responding, yes I've been using your video on timing without a timing light. Thanks for all the great resources here on this site.
I would be interested in your opinion on the electronic ignition vs. standard distributor with points. When I purchased this project from the previous owner, the standard distributor was in the box of old parts, so depending on its condition, I might be able to switch back to the normal setup.
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Post by Scoutpilot on Dec 30, 2017 13:40:22 GMT -5
While there do exist problems in the parts available to us for a standard points and condenser distributor, I have found them to be ultimately more reliable and cheaper to maintain over the long haul. Knowing and purchasing the best quality is incumbent upon us. Our motors were never intended to accommodate many of the so-called improvements being offered these days. We must keep in mind that power plant engineering and design technology abandoned our old, low compression, low tolerances motors decades ago. I would much rather spend $10 on a spare condenser, which takes up very little room in the tool kit to having to keep and maintain an expensive, delicate piece of spare electronic wafer board with very finicky electrical requirements.
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Post by rickg on Dec 30, 2017 14:13:06 GMT -5
When I purchased this project from the previous owner, the standard distributor was in the box of old parts, Bonus!! the stock dizzys are simple to disassemble and refurb with parts available as near as your FLAPS. The electronic module however is a throw away and replace item. I've never dealt with one but have read threads where even some of the replacement modules are bad straight outta the box.. Oh and when the hi altitude radiation pulse (HARP) is detonated your elect module is dead, but your point set dizzy is still truckin along..
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Post by Deleted on Dec 30, 2017 14:19:58 GMT -5
When I purchased this project from the previous owner, the standard distributor was in the box of old parts, Bonus!! the stock dizzys are simple to disassemble and refurb with parts available as near as your FLAPS. The electronic module however is a throw away and replace item. I've never dealt with one but have read threads where even some of the replacement modules are bad straight outta the box.. Oh and when the hi altitude radiation pulse (HARP) is detonated your elect module is dead, but your point set dizzy is still truckin along..
What's a FLAPS ?...... Harp, will it not demagnitize a starter motor, or ignition coil!...... BTW, ill side with Scoutpilot on the conventional distributor, I can get the guts from most parts stores, none for the Chi-Com electronic unit!... |
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Post by rickg on Dec 30, 2017 14:24:43 GMT -5
Friendly Local Auto Parts Store..
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Post by Scoutpilot on Dec 30, 2017 14:25:56 GMT -5
Favorite Local Auto Parts Seller. NAPA is where I go. I’ve got the counter guys trained in the ways of vintage jeeps. When they don’t know they say, “Here’s the book. Have fun!”
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Post by Scoutpilot on Dec 30, 2017 14:26:44 GMT -5
I would go for an emoji and be beaten by rick…
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Post by Deleted on Dec 30, 2017 14:26:54 GMT -5
Friendly Local Auto Parts Store.. Ok, I was just checking  , the first word is different sometimes  |
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Post by dluber on Dec 30, 2017 15:19:22 GMT -5
Bruce,
I ran the test you suggested and it appears that cylinders 1,2, & 4 reduce the rpms by about 100 when individually pulled from the distributor. Number 3 seems to reduce by 50-60 rpms. Sorry for being a novice, but I just got my compression tester in today so I'm going to try that next. Any other suggestions.
Scoutpilot, Thanks for the advice on the analog distributor. I will need to do some research to see if the old one I have is good enough to swap in. This project sat outside for 2-3 year uncovered by the previous owner and some parts were water damaged. At the minimum, I know I will need a new cap and rotor.
Thanks,
Dave
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Post by Scoutpilot on Dec 30, 2017 16:16:34 GMT -5
Plan on changing out the points as well. Be sure to check for play in the distributor shaft at the bushing. Grasp the shaft between your thumb and forefinger and try to wiggle it in four or five different directions. If there is a noticeable wobble, the bushing will need to be replaced.
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Post by brucew on Dec 30, 2017 18:20:59 GMT -5
Dave, Does your new compression tester screw into the spark plug hole threads, or use a rubber cone or some other method of sealing? If it screws in, make sure it doesn't reach in far enough for the intake valve to contact it during cranking. A bent valve could result. B-dubya |
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Post by dluber on Dec 30, 2017 19:00:37 GMT -5
Bruce,
The new tester has a screw in type connector (OTC 5606 kit). I have not done the test yet as we had some other things we had to do around the house. I did manage to take a look at the standard distributors that I have. The first is off this project and it's a IAD 4008 9AS. The second is off a CJ3A and it's also a IAD 4008 11E. I'm not sure of the significance of the last 3 digits, but each of these has issues. One needs new bearings (11E) and the other (9AS) is missing some pieces - like the oil fill. The shaft seems in better shape on the 11E, but the 9AS has some surface rust, If these are totally interchangeable, I think I can make one good 4008 out of the two. I need to find a good guide on how to rebuild this unit. Thanks for the tip on the threads. I believe the kit has one with short threads and another that's much longer, but I will compare it to the existing spark plug length to make sure I don't go too far.
Dave
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Post by rickg on Dec 30, 2017 19:16:31 GMT -5
Dave, w/2 4008's you have a real good chance at building a runner. Once you get into one you'll see, mechanically, they're simple as can be. Pay attn to the springs and advance weights orientation for re-assy. Hopefully the leftovers from the other dizzy can be saved for spares. I'm into a mil spec 24V dizzy on my M38 now..
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B-dubya
, the first word is different sometimes 