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 Posted: 07-15-2005 05:39 pm
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Dave Smith
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I have a 73 Jensen Healey (engine #1616) that has been having a problem maintaining ignition timing. For some unknown reason, the ignition timing will shift 90+ degrees. So far this has only happened at the distributor and not with the valves and pistons. I am wondering if the pulley might be worn and the belt slipping or is there some other possible cause? Have you seen this problem before? Could the problem be corrected by a new belt? Have the pulley keys been known to fail? I've tried to contact Dave Bean and Delta but no response to date. Any help or suggestions you have would be greatly appreciated. 

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 Posted: 07-15-2005 09:30 pm
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Greg Fletcher
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Yes, bad things can happen. Your case may be completely different, but here's what happened to me many moons ago- I noticed my engine was acting strange, meaning that it was losing power, occasional backfiring and then seemingly going back to normal again. I checked the distributor and all looked fine, but the timing was off and I knew deep down something was terribly wrong. Just looking at the car, I couldn't figure out what was going on and I figured I'd better start taking things apart and inspecting since driving would be ill advised at this point. I pulled the timing belt off and started with the auxillary housing. Low and behold- the stupid pulley bolt had worked its' way out (but not enough to notice by eye), causing the the shaft key to almost come apart (but not quite, creating a most unpleasant "variable timing" effect), messing up the end of the shaft and the pulley. Both had become ovaled and messed up big time. They were on their way to being converted to pure energy. I didn't even see this until I had the removed the pulley! I had to replace the shaft, pulley and keys and it then ran perfectly. Besides torqueing to the correct 25 lbs (which I did before anyways), I always add a drop of Loctite on the pulley bolt threads. That funky, tapered allen head bolt used on the shaft is notorious for coming loose.

I'd say worth your time to look over and check everything before driving it any more. I'm guessing it's something simple along these lines.

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 Posted: 07-16-2005 06:59 pm
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Dave Smith
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Thanks Greg. That is what Darren from Dave Bean suggested as a starting point too. So that is my plan for the afternoon. If I resolve, I'll post a notice to let you know.

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 Posted: 07-22-2005 12:36 am
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Dan (Florida)
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My timing used to slip like that , but it was the distributor was not  pushed in far enough.  There is a spring between the oil pump and the distribtor that causes the distributor to want to hop out of the drive if  the base clamp  is loosened and the distributor slides out in the slightest.  Check your distributor base for  a slight gap where it meets the  oil pump housing.  It doesn't take much.

Dan

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 Posted: 07-24-2005 08:23 pm
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Dave Smith
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Dan - Thanks. I am slowly working toward that same conclusion just because I have eliminated everything else. How often did this occur? This has happened to me just 3 times in the past 2 years; ever since I had the heads off to replace the head gasket. Did you replace the clamp or anything to eliminate the problem? Were you able to reset the timing by just turning the distributor? Seems like mine looses sync and I have to reset the timing at the pulley end first. I think the distributor was engaged when I did that but I am not postive.

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 Posted: 07-29-2005 11:33 am
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Dan (Florida)
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It's happened a few times but usually when I loosened the clamp to adjust the timing and not notice the distributor  hopping out  of the drive. I'm sure that the distributor shaft gear wears against  the distributor housing and makes the condition worse to where the distributor drive will hop out of the slot really easy.  No, the clamp is fine, just don't loosen the clamp part without knowing what the spring is going to do. To retime the distributor, you may be able to remove the cap and twist the rotor until it reseats into the drive. Just don't twist the distributor housing when reseating. If it doesn't start, it may be out 180 degrees.  It's easier to move the ignition wires on the cap 180 degrees than to pull the distributor back out and reseat it.  Once it starts easily and runs ok  step back and don't touch it!!!

Dan

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 Posted: 04-28-2008 06:26 pm
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subwoofer
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Reviving an old thread:

I think this just happened to me. Now, I don't get spark at all, it seems, the timing light has only given me a single flash or two.

Attempting to adjust the ignition timing for the first time, the distributor jumped loose, and I tried to put it back in. There is a gap of 0.5 to 1mm between the clamp plate and the base of the distributor, this seems to be as far as I can get it. It should be completely flush?

I am just in the beginning of understanding the concept of Lucas darkness, according to a colleague of mine, there is no other darkness quite as dark. I will win in the end, but I am getting the sense that I have lots to learn...

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 Posted: 04-29-2008 01:44 pm
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Jensen Healey
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Try turning the rotor 180 degrees. The slot the shaft engages is not centered so it only fits one way.

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 Posted: 04-29-2008 06:06 pm
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Greg Fletcher
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The distributor clamp must be flush to the base for it to be engaged properly. You can thank Lotus for this swell design.

Attention people of Earth! Please, do not over tighten the clamp on the distributor. This happens all the time and it ruins the distributor base. The housing is a fairly soft aluminum alloy and smashes very easily. Just get the clamp snug, no gorilla touch needed here.

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 Posted: 04-30-2008 10:19 pm
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John Finch
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If you do happen to overtighten as I did send your dizzy to the shop listed below. He rebuilt mine and installed a steel collar. Excellent job and fast turnaround.

Jeff Schlemmer, 1149 Quincy Street, Shakopee MN 55379

612-804-5543   http://www.advanceddistributors.com  jeff@advanceddistributors.com

 

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