440 ignition timing retarding when reving

[lewtot184]

I used several of those silent chain set ups back in the day. if the plastic stays on the alum gear the chain will wear the plastic enough to cause chain slop. the heavy spring in the distributor was there to compensate for some higher rpm retard due to chain slop. i'd be surprised if the engine doesn't have one of these chains.

 

[Joske2]

OK, guy's, thanks for the helpful reply's, i will check tommorow if its the chain.

 

[moparedtn]

timing light checked, and the play is normal, nothing excessive. Besides, once its running the cam pushes the shaft against the bushing, and
that looks all good.
have checked 2 other engine blocks, the same play on the shaft.

I'm not referring to the oil pump drive shaft, but the shaft in the distributor itself.
The tendency is to have not only lateral play in distributors but vertical play as well and if the "intermediate" oil pump shaft that drives the distributor is moving upwards with the inertial force of goosing the throttle (if said bushing is worn or not down in the block fully seated), that transmits right up into the distributor.
I've seen distributor shafts move vertically so much that they actually ground the rotor into the cap.

 

[lewtot184]

it's my understanding that the helix gear on the intermediate shaft is positioned to create a down ward thrust, not vertical. evidence of this can be seen on the bronze bushings thrust surface.

 

[Dragon Slayer]

If you believe your motor is fine, You need to disassemble the distributor and check it out for wear, especially the cam stop that the rotor attaches too. What do the elongated slots look like, what is the mechanical adv number, is it free or stuck. Is the Electronic Plate loose. Is the reluctor on correctly? The simple test is to install another known good distributor. If it display same symptoms, the motor has issues. If it is fine the distributor has issues.