The Supercar Registry - Crappy idle, misfire on one cylinder.

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- - Crappy idle, misfire on one cylinder. (https://www.yenko.net/forum/showthread.php?t=149893)

DarrenX33

07-19-2018 03:19 AM

Quote:

Originally Posted by L78steve (Post 1408427)

If the distributor was run on a Sun machine and it tested good you can rule the Dist. out as being the problem, points included.

That is how Jerry does them, which is why I went with him. And I share your sentiment.

DarrenX33

07-19-2018 03:21 AM

Quote:

Originally Posted by cook_dw (Post 1408385)

Was it running fine before the distributor rebuild? Swap distributors would be the first thing I'd do if the previous statement was true. If it cleared up then I would send it back. But FWIW its more than likely the points. Local autoparts store used to have points/condenser kit where the condenser was made onto the point plate and they were great. Never had an issue with them. Blue Streak was the name but I wanna say it was owned by Standard Motor Ignition or Products..

It was running equally terrible. That is why I had the distributor rebuilt. The shaft and bushings were basically destroyed. I also have a box of vintage AC Delco points.

DarrenX33

07-19-2018 03:22 AM

Quote:

Originally Posted by Lee Stewart (Post 1408437)

Would the engine experience the same symptoms if either the lifter got stuck or a valve spring broke?

Problem is I have no, or very little spark on two. Not sure how those would factor in...

DarrenX33

07-19-2018 03:23 AM

Quote:

Originally Posted by Postsedan (Post 1408384)

This is what I use on all my cars. As Phil said, today's points are junk.
Your very first tow ride home and you will throw away them points.

https://www.lectriclimited.com/break...nversion-85309

Dan

I have the Crane ignition on standby. Didn't want to put it in but maybe I will try it. I was hoping the work Jerry did was good considering it was tested.

DarrenX33

07-19-2018 03:24 AM

Quote:

Originally Posted by tunes (Post 1408430)

Change the coil. This sounds like a friend's car last year that suddenly wouldn't run. It had a weak spark and would try to start. The culprit was the coil.

I do have another here, but it doesn't seem to help.

69L78

07-19-2018 10:48 AM

Quote:

Originally Posted by Woj (Post 1408382)

It seems like the coil is the only thing you have left to change. Maybe swap out the coil for a known good coil? One thing I have found in the past is that most point sets, even the later GM are junk. I was told to give Echlin points a try, I did and really do like the quality of their points. I bought these at NAPA.

Good luck and let us know what you find.

I have never had a problem with points my whole life. I also buy from NAPA and use the heavy duty or high perf points with the heavier spring so you do not get the points bounce at higher pm. These are Blue Streak DR2270XP - points & DR70X - condenser. The Echlin distributor cap with the copper contacts is RR165.

bbbentley

07-19-2018 01:16 PM

Quote:

Originally Posted by Lee Stewart (Post 1408437)

Would the engine experience the same symptoms if either the lifter got stuck or a valve spring broke?

I would hope and think the OP has hooked up a vacuum gauge and ruled out mechanical problems before narrowing it down to electrical? But good point to mention, should this not be the case? And, as a side note, mechanical lifters don’t “stick”. I guess I am assuming it is a 69 Z he is working on even though it was not stated. And, assuming a mechanical cam, as well.

Tommy

07-20-2018 12:32 AM

I would do a compression test and pull the valve cover. A stuck valve or hole burned in a valve will cause an engine to act this way. Also, by pulling the valve cover it is possible to find a broken rocker arm or a push rod has bent or come out of the bore (usually due to the rocker arm...

Tommy

Tommy

07-20-2018 12:44 AM

Quote:

Originally Posted by DarrenX33 (Post 1408462)

Problem is I have no, or very little spark on two. Not sure how those would factor in...

I reread first post. No spark until 1500 rpm then it is still weak? If all parts including coil have been replaced I would just drop in another distributor and see what that does.

Tommy

427_Rat

07-20-2018 02:34 AM

If one lobe on the distributor cam (for #2 cyl.) was wore down, might prevent spark at low RPM and allow a weak spark at higher RPM when points "bounce"...possibly? Just trying to think what would tie it to only #2 cyl. spark. You might check clearance of points on each distributor cam lobe or at least #2 cyl. and a couple others to see if any variation is apparent?

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