"Dizzy dizzy?"

[Anonymous]

After pulling my hair (whats left of it) out for past two weeks, think I may have found cause of my spark knock/detonation problem. From what I've read so far on this very helpful site (Thanks to all so far) the total timing on my '68 200 should be in the 28-36* range. So... about an hour ago, I went back out in the shop and disconnected the vac advance hose from my supposedly "quality remanufactured" distributor. With vac disconnected and dial-in light hooked up, I found dizzy to have 23* centrifugal advance built in. Letting car idle, hooked vacuum pump to advance fitting on dizzy and determined dizzy to have 11* vac advance built in. Someone, ANYONE please, please, tell me that I am checking this correctly and that this distributor is MESSED UP!! It seems logical because if I set initial at anywhere from 8-12*, engine idles and performs well with exception of very noticeable ping at varying throttle/load conditions. If I set initial down to 0*, engine will not ping, but hesitates and hasn't got enough power to get the little '68 coupe out of its own way. I am thinking that these advance curves are way off and really messing me up due to fact that I am ending up with 42-46* total under varying conditions if I set initial timing where itr runs decent, except for pinging.
Actually seems to run best with all vac disconnected and letting centrifugal advance do all the work (23*) but obviously has bad hesitation problems due to no vac advance "off the line"

What do you think, tell auto parts store "Get me a new one!!!!!" and maybe even have curve checked prior to install due to poor quality of most rebuilts today. Thanks to anyone in advance that can maybe help me figure this out once and for all!!

 

[cfmustang]

For now, you could just run it without the vac advance. I did for quite a while last Summer while I was working out other issues.

Also, as someone else mentioned in another post, I would really consider verifing that the TDC mark on your damper is true.

In my case, the damper had slipped 10 degrees so trying to set timing with a light and that mark was just not working.


It is a very common problem with the balancers on our engines...

 

[Anonymous]

Chris,

You are correct as I already have run car with vac disconnected and does run pretty well with exception of small stumble/hesitation off line. Thats kinda whats making me think that with the vac hooked up, I am getting
+/- 11* advance from vac and the the +/-23* mechanical is kicking in, causing my ping. I think the 11* the vac advnce is giving me would work and cure the hesitation problem, but that the 23* centrifugal is jacking the total timing up too high. The balancer is brand new, by the way, and did confirm valve timing to be correct. Thanks for your response.

 

[JackFish]

Perhaps during the dizzy reman the cam plate was flipped 180* to an incorrect position.

 

[Anonymous]

Good news: Grabbed different reman dizzy from parts store this AM. Transferred Pertronix gear from old dizzy. Installed into engine, played with timing, got her running great @ about 6* initial, 30* total timing with vac hose coming off carb ported source. Definitely made my day but learned a lot, especially that all the talk about poorly remanufactured parts is 100% TRUE!!! Thanks to all for suggestions, help, etc.


Phil

 

[Greg]

Hmm... My DuraSpark II ignition has ~17-18o advance from vacuum alone (i.e. the difference between the timing with and without vacuum is about 18 degrees) Is this too great a change for the vacuum alone? If so how would I fix the problem?

Thanks,
Greg

 

[Anonymous]

Greg,

What you could try, if you have not already, is to run the vac advance off a continuous intake vaccuum supply. That way, your advance is already working at idle, and when you punch it, intake vac drops, but your mechanical takes over to compensate. By doing it that way, I found you can also jack your initial timing up to 12-14* for really nice idle and good off line performance. You'll maintain that 12-14* range under throttle because you'll be losing vac advance as mechanical is coming in. Then, once you're up to cruise RPM, the intake vacuum will rise back to a good 18-20in. hg. and the vac advance will come back in, hopefully putting you in that 28-32* range where these things seem to like to run. Its kind of a pain trying to figure carb vs. intake vac, total timing, etc, etc, but worth the trouble once you get her tweeked. OR, you could take the DS dizzy to a shop and have them recalibrate it for 15 vac and 15 mechanical and just run the thing in a off carb vac and play with your initial till its right.

Good Luck

Phil

 

[cfmustang]

Glad to hear you got it sorted out.

Weird. Usually it is the vacuum advance that is the problem, not the mechanical. The weights or stops must have been messed up. I know that you can switch the weights (with a lot of work), but you were probably just better off going back to the store.

Let them sort it out.

 

[Anonymous]

Yeah, exactly. Figured by the time I recurved my old one, better off trying my luck with different one from parts store. Good luck with yours.

Phil