Problems with your Procomp HEI 7000 series? One fix...

[mguner]

I recently was asked to make a vehicle run properly. It had some carb issues but also a serious ignition problem as well. Check your ROTOR PHASING! It seems to be vacuum advance models with this particular problem. Apparently at least some of these are assembled with the wrong parts. The recesses that are supposed to allow you access to the hall effect mounting screws will not line up even with the advance pod loose. You can however use a small screwdriver and usually get the screws out so you can remove the vacuum pod. This distributor was only a few degrees from being midway between 1 and 8 at TDC! There are no real internal adjustments on these cast models but there is a solution. Since the vacuum advance rotates the Hall effect unit you may correct the rotor phasing by shortening the arm and re-welding. If you have spotweld pliers they hold both pieces for this process perfectly. I took out about 1/4" on this small block and it made a huge improvement in phasing and performance. Since the mechanical advance would only further aggravate the phasing issue the spark scatter under load was horrible. The cover screws on these are supposed to secure both the cover and the module to the housing so the module can use the housing for a heat sink. You will see many pictures of these units with the cover cocked up and not flush with the housing. That is also a big problem. These units use a version of the 4 pin GM module and the module needs to be touching the housing with a proper amount of conductive grease. The corners of the housing need to be ground to the proper contour and the screw holes in the cover usually need to be elongated towards the inside for proper fitment. Putting these back together can be a trick since the recesses don't allow proper alignment with the vacuum pod connected. There are also two snap rings that secure the reluctor wheel which must be removed during disassembly. Since I am not using the vacuum advance on this particular car I did not check to see how much was left after shortening the arm. It may not be a perfect answer but it darn sure worked.

 

[Abodybomber]

I recently was asked to make a vehicle run properly. It had some carb issues but also a serious ignition problem as well. Check your ROTOR PHASING! It seems to be vacuum advance models with this particular problem. Apparently at least some of these are assembled with the wrong parts. The recesses that are supposed to allow you access to the hall effect mounting screws will not line up even with the advance pod loose. You can however use a small screwdriver and usually get the screws out so you can remove the vacuum pod. This distributor was only a few degrees from being midway between 1 and 8 at TDC! There are no real internal adjustments on these cast models but there is a solution. Since the vacuum advance rotates the Hall effect unit you may correct the rotor phasing by shortening the arm and re-welding. If you have spotweld pliers they hold both pieces for this process perfectly. I took out about 1/4" on this small block and it made a huge improvement in phasing and performance. Since the mechanical advance would only further aggravate the phasing issue the spark scatter under load was horrible. The cover screws on these are supposed to secure both the cover and the module to the housing so the module can use the housing for a heat sink. You will see many pictures of these units with the cover cocked up and not flush with the housing. That is also a big problem. These units use a version of the 4 pin GM module and the module needs to be touching the housing with a proper amount of conductive grease. The corners of the housing need to be ground to the proper contour and the screw holes in the cover usually need to be elongated towards the inside for proper fitment. Putting these back together can be a trick since the recesses don't allow proper alignment with the vacuum pod connected. There are also two snap rings that secure the reluctor wheel which must be removed during disassembly. Since I am not using the vacuum advance on this particular car I did not check to see how much was left after shortening the arm. It may not be a perfect answer but it darn sure worked.
View attachment 1715030924

Thanks for the info!

 

[Dartish]

Thanks for the tips. Looks like the same distributor I tried. Ran for 2 months, then went dead over night. I noticed the cover on mine was cocked too!! Still waiting for the replacement to show up to see if I can get another 2 months out of this one.lol

 

[mycuda]

I recently was asked to make a vehicle run properly. It had some carb issues but also a serious ignition problem as well. Check your ROTOR PHASING! It seems to be vacuum advance models with this particular problem. Apparently at least some of these are assembled with the wrong parts. The recesses that are supposed to allow you access to the hall effect mounting screws will not line up even with the advance pod loose. You can however use a small screwdriver and usually get the screws out so you can remove the vacuum pod. This distributor was only a few degrees from being midway between 1 and 8 at TDC! There are no real internal adjustments on these cast models but there is a solution. Since the vacuum advance rotates the Hall effect unit you may correct the rotor phasing by shortening the arm and re-welding. If you have spotweld pliers they hold both pieces for this process perfectly. I took out about 1/4" on this small block and it made a huge improvement in phasing and performance. Since the mechanical advance would only further aggravate the phasing issue the spark scatter under load was horrible. The cover screws on these are supposed to secure both the cover and the module to the housing so the module can use the housing for a heat sink. You will see many pictures of these units with the cover cocked up and not flush with the housing. That is also a big problem. These units use a version of the 4 pin GM module and the module needs to be touching the housing with a proper amount of conductive grease. The corners of the housing need to be ground to the proper contour and the screw holes in the cover usually need to be elongated towards the inside for proper fitment. Putting these back together can be a trick since the recesses don't allow proper alignment with the vacuum pod connected. There are also two snap rings that secure the reluctor wheel which must be removed during disassembly. Since I am not using the vacuum advance on this particular car I did not check to see how much was left after shortening the arm. It may not be a perfect answer but it darn sure worked.
View attachment 1715030924

Thanks for the info. This explains why the one I had (never again) acted like no advance, drove me nuts. So it got advanced right back in the box to ebay.
What a waste of time.

 

[abodyjoe]

sounds like a ya get what ya pay for thing here...