greg mgm
1/2 ton status
The bottom right black plastic component is the ignition module. Mine has 4 tabs, but there are many other variations-
By the way, thermal grease goes under the module, but all I had was dialectic grease for the photo. Thermal grease helps to dissipate heat since these modules get HOT! If you buy a new module, I'm pretty sure it comes with a small tube of grease- (I'll re do this photo later)
Modules can be tested with an ignition tester. One type of tester checks for continuity and can be purchased for $50
http://www.amazon.com/s/ref=nb_ss_gw?url=search-alias%3Daps&field-keywords=actron+cp9087&x=11&y=19
The better way to test it is with the testers Autozone and Advance Auto (Thanks TerryD) have, and they'll test it for free.
Next to the module is the capacitor assembly. Remember the capacitor only suppresses radio RFI. The wires and connectors should be in good shape like this one-
At the center is the magnetic pickup assembly which rotates for timing advance. Mine was stuck and had old crusty grease gluing it in place. When I tried turning it I broke the circular magnet. Here it is disassembled-
The pickup assembly base is retained by this small (and I mean small) circlip-
Here's the pickup base removed and upside down. Mine was scored where it rides on the bushing-
The pickup coil can be tested also. Between the white and green wires the ohm reading should be (according to Chilton) between 500 and 1500 ohms. MSD says between 400 and 1300 ohms-
The vacuum advance unit can be tested with a vacuum pump. As long as it holds vacuum and moves freely it's good to go-
Here's a close up of the end of the vacuum advance, attached to the pickup base. It rotates an arm which pivots on the center shaft-
And this is the mess when it's all disassembled. As long as you don't lose the circlip while removing it (it can go flying if you don't hang on to it) or lose any of the small screws, it's really easy to put back together-
Just read this thread in reverse to re assemble your distributor.
Hopefully I've shed some light on what's inside the GM distributor. This thread wasn't meant to be a comprehensive repair guide, but just an idea what is involved in distributor removal and component testing. The good news is replacement parts are easily obtainable, from Napa (or whoever) and also online.
http://store.summitracing.com/egnsearch.asp?N=700+4294925143+115+4294839065&NeXID=5
Thanks for reading!!
EDIT- Here's "A Look Inside a Distributor Pt 1"
http://coloradok5.com/forums/showthread.php?t=240131
By the way, thermal grease goes under the module, but all I had was dialectic grease for the photo. Thermal grease helps to dissipate heat since these modules get HOT! If you buy a new module, I'm pretty sure it comes with a small tube of grease- (I'll re do this photo later)
Modules can be tested with an ignition tester. One type of tester checks for continuity and can be purchased for $50
http://www.amazon.com/s/ref=nb_ss_gw?url=search-alias%3Daps&field-keywords=actron+cp9087&x=11&y=19
The better way to test it is with the testers Autozone and Advance Auto (Thanks TerryD) have, and they'll test it for free.
Next to the module is the capacitor assembly. Remember the capacitor only suppresses radio RFI. The wires and connectors should be in good shape like this one-
At the center is the magnetic pickup assembly which rotates for timing advance. Mine was stuck and had old crusty grease gluing it in place. When I tried turning it I broke the circular magnet. Here it is disassembled-
The pickup assembly base is retained by this small (and I mean small) circlip-
Here's the pickup base removed and upside down. Mine was scored where it rides on the bushing-
The pickup coil can be tested also. Between the white and green wires the ohm reading should be (according to Chilton) between 500 and 1500 ohms. MSD says between 400 and 1300 ohms-
The vacuum advance unit can be tested with a vacuum pump. As long as it holds vacuum and moves freely it's good to go-
Here's a close up of the end of the vacuum advance, attached to the pickup base. It rotates an arm which pivots on the center shaft-
And this is the mess when it's all disassembled. As long as you don't lose the circlip while removing it (it can go flying if you don't hang on to it) or lose any of the small screws, it's really easy to put back together-
Just read this thread in reverse to re assemble your distributor.
Hopefully I've shed some light on what's inside the GM distributor. This thread wasn't meant to be a comprehensive repair guide, but just an idea what is involved in distributor removal and component testing. The good news is replacement parts are easily obtainable, from Napa (or whoever) and also online.
http://store.summitracing.com/egnsearch.asp?N=700+4294925143+115+4294839065&NeXID=5
Thanks for reading!!
EDIT- Here's "A Look Inside a Distributor Pt 1"
http://coloradok5.com/forums/showthread.php?t=240131
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