misfire that won't quit

[starliner62]

Ron,
Just a thought. How new is your timing gear? I just took a 259 apart and the gear was going bad. It was actually running one tooth off but getting ready to jump some more.

[Ron Dame]

I may do that, I'll send you a message with my phone. I've been awake since 2:00, and all that tossing around came up with two more wild shots I can't wait to try this afternoon: maybe the overdrive switch is shorting, and maybe I was a doofus and left the shop rag in the intake, and it's sucked down a little way and now not obvious.

[Ron Dame]

Timing gear has maybe 20,000 miles on it. The vacuum gauge doesn't indicate late valve timing, it fact it looks perfect.

Again all the ugliness starts when manifold pressure drops to 5", and clears up as soon as it rises above that. If I hold the throttle when it hits 5", it never will recover, only when I let off just enough to hit 6". And it is instantaneous: open the throttle that far, the ugliness starts IMMEDIATELY. close it and it's instantly perfect. And it all started by switching carbs, and even the old carb that was working OK does it now.

[Ron Dame]

Well I disconnected the overdrive kickdown from the coil, pulled the carb again and probed for a potentially missing shop rag, and checked fuel pump output. Guess, what? It's still awful. Il have attached a video of the vacuum gauge, and you'll see and hear it pop (one good blue flame) as I open the throttle. Maybe seeing will help someone figure this out.

[pdrnec]

Last time I experienced something like this it turned out the fuel line was kinked at the fuel pump where you couldn't see it readily, carb couldn't get enough fuel. Idles great, fell on it's face when I drove it.

[Ron Dame]

The output of this fuel pump reminds me of when I was 20....I don't think that's the problem.

[kamzack]

Hey Ron,
I don't want to come across as a wise guy, that's not my intention. In my earlier post I mentioned ohv 6 head problems. Even after I'd gotten a head welded up and stelite seats put in, I still had problems down the road. I sold the car for peanuts out of frustration. The family I sold it to completely rebuilt the engine and gave it away as a raffle car for thier Stude meet. The guy that won it drove them nuts about fixing the car. I know there are folk out there that have had and are having good succes with the "ohv" 6, I ain't one of them. Someone mentions "ohv" 6 to me, I run. I am encouraging you to seriously consider Wolfie's offer. Authenticity may mean something to ya, but peace of mind, power and sound of a twin piped V8 will make it all better. You might say "what ohv6".
Respectfull and graciously,
Kim

[wolfie]

Ron, Could you have wiped a cam lobe (no zddp)? Some of you guys that have been there already Is this indicative of that problem? Ron has said compression is good and very even across the board (+/- 2 psi), would that be so with a bad lobe? Steve

[bige]

Ron, I had a Dodge do something like this and it was the spark plugs. They were fairly new and I did everything short of yanking the engine until my son decided to change the plugs just because it was the only thing we didn't do. Again, they weren't old, tired plugs but only in there while I was getting the car roadworthy. Happened a second time on a Corvette I was putting together and I went right to the plugs and solved the problem without going through all the gyrations I went through with the Dodge. Both times they were Champion plugs...don't use them for anything anymore.

ErnieR

[jackb]

I'm going with electrical...not fuel...

[crusadex]

I'd think timing/firing order first.
I had a C cab with the timing off and it blew 3 foot flames out the carb.

[Ron Dame]

I'm not offended. I had the head checked out (including for cracks a couple of years ago when I blew a head gasket, and it has few miles on it since. I'm not saying it could not happen, but it seems weird to happen coincidentally with swapping carbs.

As far as a 259 or 289 swap, I've always been interested in the less conventional routes. I've got a 185 OHV 6 I built sitting on the stand to go into the truck one day, but every time I plan to do the swap (along with tebuilding the trans and detailing under the hood) SOMETHING happens to end those plans. One day it'll happen.

Hey Ron,
I don't want to come across as a wise guy, that's not my intention. In my earlier post I mentioned ohv 6 head problems. Even after I'd gotten a head welded up and stelite seats put in, I still had problems down the road. I sold the car for peanuts out of frustration. The family I sold it to completely rebuilt the engine and gave it away as a raffle car for thier Stude meet. The guy that won it drove them nuts about fixing the car. I know there are folk out there that have had and are having good succes with the "ohv" 6, I ain't one of them. Someone mentions "ohv" 6 to me, I run. I am encouraging you to seriously consider Wolfie's offer. Authenticity may mean something to ya, but peace of mind, power and sound of a twin piped V8 will make it all better. You might say "what ohv6".
Respectfull and graciously,
Kim

[Ron Dame]

That was checked very early on, and again and again. Dizzy was recently rebuilt by Bill Cathcart

[Ron Dame]

That's the only thing I have not tried, and these are Champion plugs. I was surprised they were in there, I don't like them either. It must have been all the FLAPS had the day I bought them. I may not get a chance to try this weekend though, I've got a major repair on my DD to do.

Ron, I had a Dodge do something like this and it was the spark plugs. They were fairly new and I did everything short of yanking the engine until my son decided to change the plugs just because it was the only thing we didn't do. Again, they weren't old, tired plugs but only in there while I was getting the car roadworthy. Happened a second time on a Corvette I was putting together and I went right to the plugs and solved the problem without going through all the gyrations I went through with the Dodge. Both times they were Champion plugs...don't use them for anything anymore.

ErnieR

[Ron Dame]

I've often heard that 90% of carburetor problems are ignition, but aside from brand new plugs, there's nothing else left in the ignition area.

I'm going with electrical...not fuel...