It might be the wire from the coil to the points this wire flexes every time the vacuum advance moves over time the wire inside can break and lose contact when it moves.
could be the filter but the clogged fuel filters that I have run accross would start to act up during a longer high speed run. you know, when the fuel system can't keep the float bowl full. I would think with a full float bowl and then you give it gas and it bogs or stumbles right away the problem would be in the carb itself. Now lets say the float bowl is not full becouse the filter is clogged, I think that would show up after running at higher speed (fuel usage is higher) for a time. All that said I would still check or replace.
Also maybe take the timing cover off and check to make sure your timing marks are correct. And look over your timing gears real good. As of now I'm betting in a bunk battery. Please prove me wrong so I can move off the battery issue...
Okay. I took the distributor off and remove the guts (spring and plunger) of the vacuum brake. Took it out for a short test drive and the problem of breaking up on hard acceleration all but stopped. There's still a little stumble, but hardly noticeable considering how bad it had become. It was so bad that I was worried about taking it even as far as the gas station four houses down the block. Really thought it would quit entirely at that point. Now, it pulls strong through all gears with just a little hiccup in second only. Before it had progressed to stumbling in all gears. In anything I have read on the vacuum brake, it says to lube the plunger with a little oil upon assembly. The plunger came out of the brake dry as a bone upon disassembly. I am concerned about lubing it and reinstalling it that the problem may come back in the future. So now my question is what are the pros and cons of running it without the vacuum brake installed at all? Thanks in advance for your input. Have a blessed day all. Going to meet my son at the rifle range. Will check back later. Andy
My flathead will ping to beat the band if I don't have the vacuum brake cranked down. I think I have a bit more compression and a larger CI than my gas can handle. An Ol timer from around here said he used to run with his absolutely loose though. So, I can't give you a solution, but I sure did wonder if that was the root of your problem. You cannot leave it all the way out because the vac line would suck air from your crankcase. Or remove your vac line.
I think that if you use some synthetic oil on the vacuum brake piston, it will be less likely to gum up/stick.
The brake needs to stay hooked up ( or at least installed) with some tension on the spring. This way the engine will have some slight retard when cranking and maintain advance when reved up. If totally left out the spark timing will jump all over the place at idle and mid range. You can use a light coating of grease on the piston or just oil really well. I put high temp wheel bearing grease on the leather and oil on the piston itself..
Yeah...I plugged up the vacuum line. Okay Bubba. I will take the dizzy off and look at the fit of the piston in its bore. Piston seems a little less than smooth. I'm wondering if it was inoperable due to wear. Maybe the vacuum was sneaking past the sides of the piston without actually retracting it. This would also essentially be a vacuum leak which would also compound the problem. Will examine and keep you all updated. Also, took it out for a good long test drive yesterday and it idled just fine with no hint of the timing jumping all over the place and mid throttle was good too. BTW...the rifle range I went to with my boy yesterday was CLOSED. Closed today too. Something about some kind of debate or something happening next door to the range tonight. I guess they don't want anybody sighting in their rifles next door to where the clown show is going to take place. Haha Andy
Since vacuum is high at idle and part throttle, the vacuum brake should not be in contact with the breaker plate, so how can it stabilize with out being in contact with the plate?
...and which side of the debating parties (left?) closed the range? (left?) Bet I can guess...(you know what I was gonna say)
My flattie misbehaves (under power) without the electric FP on! My guess is you are running out of gas under load.
Been a while since I chimed in on this. Had a little health issue so I've been out of commission for a bit. Had my second heart attack in late October and I've been dealing with recovering from that and recovering from the side effects of poisonous drugs too. Let me tell you all it has not been a good time. Just recently got back into trying to figure out my flathead problem. Got a new dizzy from Bubba, no change. Talked to Charlie Price at Vintage Speed. Changed out the power valve in one carb for a smaller one and plugged the power valve closed in the other carb as per his suggestions. No change. I'm running out of things to try here. Just spoke to Charlie again. He still thinks it's a fuel problem and has suggested that the 94's are flooding the engine with too much fuel. He suggested running it on one carb to see if that changes anything. I'm going to try that tonight. Here's a question though...Gene Boul in the post above says his flatty was having similiar problems when he ran it without the electric fuel pump on and that his was starving for fuel. Can I run an electric fuel pump in the fuel line before the mechanical fuel pump? Andy
I've never done it but I've seen lots of guys post about running an electric pump at the tank and leaving the stock mechanical on the engine. Some say they just run the electric before starting, to prime the system, but it must also work when the engine is running as well. Just make sure your pressure regulator is set correctly after BOTH pumps. I set mine at 2 lbs for my Strombergs, and you should probably do the same for your 94's.
I have run electric fuel pumps upstream of the mechanical more than once with no problem. The check valves in the mechanical will just allow the elec. to pump right on thru. Just be careful that the diaphrram in the mech. doesn't rupture from the actions of the crap thay sell today and call it gas. If that happens it's not only possible, but probable that the elec. will pump gas thru the rupture and into the crankcase. And as said above make sure your pressure regulator is on the downstream side of both pumps. Followed your link in first post on this thread back to your original thread and in the first post there you state you have an Edmunds dual carb manifold. That, IIRC is a 180* manifold, which basically means that one carb feeds 4 cylinders and the other feeds the other 4 cylinders. There are only a couple of small balance passages between these 2 systems, and blockinf off one card will result in an extreme imbalance with 4 cylinders getting plenty of air/fuel mixture and the other 4 trying to breathe thru those small balance passages It will run, but not too well
You should be running power valves on both carbs. I've run power valves on both 94 carbs for 18 years. 94's NEED powervalves to operate effectively. Do a search here. Lots of info on this subject.
You had a great running car before.... you jets don't suddenly change size and make it run poorly. my thought is that since you took away fuel and it made no difference, you have a LACK of fuel. several people have suggested rebuilding your fuel pump and checking the pump rod length. I pulled mine apart years ago and found it was bent! it's extremely easy to pop out the fuel pump, check the diaphragm and replace the check valves. and it only costs a couple bucks. the other thing you can do is pick up a cheap electric pump and plumb that in instead to test... if it were me, i'd just rebuild the stock pump.
^^^Thanks for the suggestions. Been there, done that. PLENTY of fuel. No issues there. Pump is good. Had it apart and inspected. Everything good. Push rod good. Tried the electric thing. no change. running out of things to try. Still thinking it's spark and not fuel. Still recovering from heart attack in October slo not a lot of actual work on Hot Rod, just inside my head at this point, plus it's still fucking COLD up here so screw going out to the garage noir feeling my best in the freaking cold and all. Spring is coming soon I hope. Andy
Spent a little time on the flatty this week. Took a plug out and grounded it to the block attached to plug wire to check quality of the spark. Looked pretty weak so I took the plug out of the wire and stuck a screwdriver into the wire to see how far I could make the spark jump off the screwdriver shaft to the head. Crappy looking whitish spark that couldn't even jump more than 1/8". Decided to get a coil that produces more juice. Got the MSD Blaster 2 coil on Saturday and threw it in. Engine started right up and ran great. I guess it was spark all along. The Standard Motor Products coil was just not hot enough for the engine. As to why it DID run great and then slowly began to run worse and worse and then not at all? Well, I'm going to just say that perhaps the plugs became partially fouled due to not hot enough spark, OR because the flatty is a bit overcarbureted (two 94's on a basically stock rebuild with hi compression heads). My GUESS is that as the plugs got a little black, the weaker coil couldn't produce hot enough spark to fire the engine. Haven't taken it out yet because the car is partially apart for winter modifications but it will go back together soon and I will update after some road testing. Thanks everyone on the forum for shooting me ideas on how to overcome this issue. The thing that messes with MY head on this is that the old Standard coil worked perfectly in my '54 Chevy pickup when I tried to sway it out with the one in the truck. Hotter spark is better no doubt. Happy to know that I will be cruising again soon. Andy
[/QUOTE] The thing that messes with MY head on this is that the old Standard coil worked perfectly in my '54 Chevy pickup when I tried to sway it out with the one in the truck. Hotter spark is better no doubt. Andy[/QUOTE] Glad to hear you figured it out Andy. But not to throw a wrench in the works. Its important that you realize A good stock distributor should work fine on your setup. Your MSD coil is just compensating for the resistance either in the Ignition wiring or the distributor. PJ
didn't look back through but is there a resistor in your ignition system?? is it possible that you have the wrong combination of coil and resistor?? if you have a coil that requires a resistor without one in the system then it will work fine for a while until it eventually burns up the coil and or the points. conversly if you have a coil that does not require a resistor with a resistor in the circuit you may not be getting enough voltage to the coil.
Problem finally solved. Bad set of Champion plugs. They were fouling due to it running rich. I cleaned them in my plug blaster several times but it did not solve the problem. Replaced with a set of NGK's and problem went away completely. the Champions just plain sucked and gave up. Have spoken to Dick (dickster27 on the HAMB) and he hooked me up with what to do to modify the carbs so it doesn't run so rich anymore. Back in business. Andy
Thanks for the feedback. Long time friend old Dick. He will never steer you wrong. What is he having you do?? Sent from my iPhone using H.A.M.B.
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