hey there. im I desperate need of advice! im trying to finish my 73 grabber by this weekend and have spent the last 2 weeks on this project. it has been starting great but had a bad hesitation when I stomp the pedal and it would start missing. I checked the vac advance and found it was leaking. I got a new one and installed last night. it had 2 vac ports, one side advances and the other retards. it started the same and ran the same maybe worse. I opened the dist and started checking deeper to see if the plate was sticking. im not sure if I did it or it was already out of order but the plate did not seem to mount to anything other than the pin with the spring on it. I found a plastic button looking item and found where I thought it went in the slotted area of the plate. I put it back together and would not even start. it would only sputter. im afraid I lost a little slider button like thing under the next plate. I tried to take it off but it felt like it was attached by a spring or something. today I will replace cap rotor plugs and wires. what else am I missing? my car is points. please help if you can! thanks!
a picture would help a lot.. but it sounds like an advance limiter bushing located around the mechanical advance stop pin. Without the bushing in place.. the mechanical advance goes through greater range of sweep. Unfortunately it starts out more retarded and also gives more total advance without the bushing in place. Have you rebuilt that disty and reset the dwell correctly in the process? There's also usually excessive gear to housing clearance issues to be dealt with as well and causes timing variations as the gear slides up and down the cam gear under accelleration/decelleration. You didn't say which motor you're running here(which would also be helpful info).. but if you can swap in a duraspark and aftermarket coil to eliminate the crappily inconsistent points setup?.. it'll pay for itself in just a few months of driving time with the improved mileage. Plus.. you can truly set it and forget it compared to having to monkey around with points every year or so. And the dual advance ports can be of differing designs. Doubtful that these models used the vacuum advance only type mechanism(way to check is to looky see if you have weights and springs).. so it's likely a port that originally led to a thermostatically controlled switch which would turn on the vacuum source at higher engine temps to apply additional advance to help cool the motor down. Personally.. I always tear those units off and toss them into the trash in favor of a single ported adjustable pot which can be more finely tuned for the exact engine/drivetrain combo. Just depends on how much you want to fiddle with it.. but there is HUGE IMPROVEMENT POTENTIAL to be had by upgrading that setup.
Agreed.. I think he may be talking about the little nylon buttons that the breaker plate rides on... There needs to be some clarification about the plate, it's mounted to the pivot pin and is moved by the arm on the vac advance, otherwise it should just be setting on the nylon buttons already mentioned... If the pin or bushing in the breaker plate is worn, you'll never be able to accurately set dwell or timing...
sorry I thought I had put it in there, factory 302. update... I only have spark on 3 cyl. 1-no 2-no 3-yes 4-no 5-no 6-yes 7-yes 8-no. crazy comet, it is the button it slides on. I don't have a way to send pics right now. it is running the same after new plugs gapped at 35, re-set points to.017, new wires and cap. double checked no spark. I cant believe it even starts...I found a Chilton manual that cover 1973 ford trucks with 302 so im working out of it. I didn't rebuild the dist. it idled and started great before I jacked with it, but had bad hesitation on revving engine and higher rpm miss. now it all went bad! thanks for responding. I would love to replace dist but I am way over budget! if it has to be then I will, I just don't have the $. im payin bills on a credit card and have to finish this to sell it. (sorry just crying the blues) I am a bit desperate. my family is relying on it. hope you all can understand....
it did have a single vac port on it and parts store gave me dual port. it is on the pivot pin and seems to pivoting correctly...
If there is no spark at the plug wire(s) there has to be some oddity going on with either the dist cap or maybe the points cam is gone flat on those lobes... That last one would no doubt be a stretch as I've never see such... Are you sure the points are correct?? Too wide could maybe holding them open on the base of the cam lobes... Would be a good idea to look at the pivot I mentioned in my last post... BTW there should be a braided grounding wire that gives the breaker plate a solid ground, if it's broken or missing there will be erratic spark issues...
You would be better off by buying a fresh reman distributor. They're not that expensive, about $55 for the last one I bought. And get rid of the points, replace it with a Pertronix or any other electronic module that drops in place of the points.
I replaced the braded ground inside...it looked pretty frayed. I made my own... I also put the old vac advance back on. its way better! it still has the hesitation on hard revving. i also rechecked points gap, it may have been a bit wide. my book says .017. i may still replace dist. now for the vac advance question... i saw a post last night about setting it with an allen wrench. could my new one need setting? i don't own or have access to a dwell meter or timing light so t may be impossible. i really appreciate all the help so far!
Don't be afraid to reduce point gap a bit, will give a bit more dwell and increase spark voltage... For years Ford specked .015 on V8 which is what I use on all single point dist... New points can set at .012-.014, but remember to reset timing as closing gap retards timing...
That .017" setting is only a starting point. To accurately set the gap, you MUST use a dwell meter. If you're not using a dwell meter to set the points, you're shooting in the dark. You can eliminate all this by switching it out for a pertronix unit. Set it once and forget it. Points constantly wear, changing the dwell setting over time. You must periodically reset the dwell with points to maintain an optimum ignition.
ok its all together. im using old vac advance right now til I can find a single port or new dist. it still cuts out and misses when I romp it. drove it for the first time today and even running poorly it was still a rush! still a few things left on my to do list but I think I can fix it. thanks for all the help!
Some old pros might be able to get by without using a timing light but if you don't have a LOT of experience you NEED a timing light to do this kind of work. My two cents.
Especially if you're gonna swap dist or install the Pertronix unit... Also it likely runs poorly with the new vac canister because the arm is a slightly different length, which is throwing off the timing...
