unwanted timing changes
 

i have a prestolite distributor on a carb'ed 454. (the electronic from points kit with external coil.) last week the ignition module gave out. it's the horseshoe looking kind under the cap. 98$ for the module, ouch. today, i was setting the timing. brought #1 cylinder to tdc on compresssion stroke, heard the poof, saw the mark on balancer reding 0*. made #1 where the rotor was pointing, nothing special. but when i went to tighten the distibutor down after setting initial at 10* after warm up the motor bogged down. timing changed at least by 10* from where i had it set. engine started running bad, missing etc. the timing light was still hooked up to #1 wire and it started firing intermittently or not at all until i revved the motor way up. the distributor wasnt loose, it was snug, just not tight. i think i may try a different distributor. i couldn't get it right with the one in there. at least not after i tightened the hold down clamp. any other ideas?

Really stupid question for ya excal... did you happen to have a timing light with the advance knob? Did you happen to bump it to off the 0 mark?

That would be way too easy I know.... but I have done it and nearly **** myself before coming around.

BT :cool:

no bt, my light isn't that fancy;) . set it at 10* and tightened the hold down clamp and the motor bogged like the cam was walking. the timing went from ten to around twenty and started running like crap and wouldn't act right no matter where i put the timing. very erratic. :confused:

But when you loosened it back up could you make it run well on 10* again?

BT :cool:

yes. it would go back to 10*. but the weird part is, the heads and intake have never been milled. and thats the same distributor that i used last year. the only thing that is different in the motor is cam and lifters and valvesprings this year.

Assuming the bushing in the distributor are tight... why not try shimming the dist. base up incrementally until the shift in timing stops. Then add another .010-.020 for gear backlash. Not pretty... but may get you rollin again.


BT :cool:

i was thinking along the same lines BT. first i was thinking of using marking compound on the dist. teeth to see how deep it is in the cam gear. and if it is deep, shim it up. where do i get shims to fit? i may have to make some i guess.

Excal.. I would check mcmaster carr for bronze thrust washers. They should have them in various IDs and thicknesses. Nother thought would be multiple gaskets under the housing.

Good luck bro,

BT :cool:

good idea, thanks BT. i'm heading to the boat now for a couple days. i'll let ya know the outcome. :)
Fran

How did you make you excal?

BT :cool:

hi BT,
i was boat riding around cape may point saturday evening. it turned out that the distributor hold down clamp was bent. it was cocking the dist. and wacking out the timing.
i may have the little boat back together soon also. i had dropped off the bravo to a "drive specialist" ( a&^%Fhole)because i was busy messing with the big boat. he told me the entire upper was trashed, bearings, gears, case, everything. he wanted $1800 to sell me a rebuilt upper. i told him to stop the job and i went and picked it up. it needs a new upper gear set, and a few other minor things but it was attempted robbery basically.

Great news Excal.. I love simple solutions to what could otherwise be a major PIA. So the big boat is running good now I take it, and the little boat needs a couple gears. Sounds like you have salvaged at least 1/2 your season. We are gonna take a rip down to Annapolis this weekend with maybe a stopover at Jellyfish Joels. Let me know when you are going be out and about and maybe we can hook up for that ever elusive brew or two. I run around in a 30' Panther white, with blue stripes and 2 of hotboats US flags on the front. No name on the boat. Yell if you see it.

BT :cool: