Tach problem or distributor problem?
Thread Starter
Heel & Toe
Joined: Feb 2010
Posts: 21
Likes: 1
Tach problem or distributor problem?
When engine revs above 2500 rpm the needle does not drop down as the engine revs drop. The needle slowly goes down to about 2000 rpm and then drops back to idle. I replaced the cable and housing but it didn't help.
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,062
Likes: 4,197
From: US-PNW
Disconnect the cable from the distributor and chuck the core into a reversible drill. You should be able to test the cable and the free movement of the gauge with the drill. If that checks out, you can remove the brass bushing from the distributor body and pull the tach drive gear out. Be careful not to lose any shimming washers. These gears often get mangled which means more than likely the main shaft of the distributor has a chewed gear too. The only fix after that is to pull the distributor and rebuild it with a new shaft - or live with the wonky tach behavior.
Melting Slicks
Joined: Jun 2017
Posts: 2,262
Likes: 1,766
From: Central Michigan
2023 C1 of the Year Finalist - Modified
How could the distributor possibly continue to "rev" after the engine rpm drops down? Think about this. Even if the gears were "blown" in the distributor how would they continue to "rev" faster than the distributor shaft as the engine slows down?
