- Apr 18, 2018
- Reaction score
- Long Island, NY
Ok so after being almost gone earlier the symptoms came completely back pretty suddenly. So I’m thinking a new timing set and a new carb.
Checked and the timing has Not moved so the carb is the main culpritOk so after being almost gone earlier the symptoms came completely back pretty suddenly. So I’m thinking a new timing set and a new carb.
Thank you! That’s a lot of great info. When I set my timing it was to the prescribed 12.5, and earlier today when I checked it was about -3 so that’s about one spark plugs worth.Once, a state polic e car came into the local Chry dealership while I was there one afternoon, back in the middle '70s. The complaint was that it wasn't running right. The old-line Chry service manager went out, loosened the distributor hold-down bolt, and twisted the distributor one spark plug wire's worth in the advance direction. It ran better. The diagnosis was "jumped time". If it does jump time, it will be much harder to start as the distributor is now very retarded from the normal situation.
The base timing should be more like 12.5 degrees BTDC, but that shouldn't make a huge amount of difference, but a little. I used to run my '66 Newport 383 2bbl at 15 degrees as a normal situation, but then we also put premium fuel in it, as that was what it liked, even at the normal 12.5 timing spec.
Is the gas cap one like needs to be on it? Not just to hold the fuel in, per se?
There used to be methods to check for timing chain "slack" by marking the balancer and moving the crank with a breaker bar. I've only read of that, not seen it in use. If the timing chain has never been changed, that you know of, then it might be a good insurance issue to replace it. My pref is either a Cloyes Plus Roller chain set of the similar Mopar Perf roller chain set. But if the car will start and run with what's in there, I doubt that's the cause of the issues you are having.
I replaced the WWC3 on my '66 Newport with a '70-spec Holley 2210 2bbl. Ran better as it has a better venturi design and just a more finessed design. It is ALSO susceptible to the air horn warpage, but Chry/Holley did a "bridge kit" to push the air horn back down straight so the air horn gasket would seal. The '72-spec 400 2bbl carb might have a touch leaner calibration, but not a lot. The '73 versions were set-up for EGR and were dubbed 2245 as a result. Use the THICK OEM base gasket, not the thin one which might come with the carb.
Hopefully, the carb kit you got had the thick gasket, too! The replacement Holley I got had one, too. But after a while, I noticed the idle would bet a bit unsteady. I'd get my wrench out and retorque the base plate nuts, about a 1/16th turn. Then the idle got smooth again. After the third time that happened, I got an OEM thick base gasket (with the metal bushings in the holes) and problem solved.
In a prior thread, somebody mentioned that Autoline rebuilders knew about and compensated/fixed the air horn issue on the Holley 2210s. I take their word for that.
Other than the air horn warpage issues and the long-term "accumulation" issues in the venturi tubes, or possibly wear issues in the accel pump well and throttle shaft, just not much to go wrong with those carbs. I presume the choke pull-off is still working?
Just some thoughts,
Thank you! That’s a lot of great info. When I set my timing it was to the prescribed 12.5, and earlier today when I checked it was about -3 so that’s about one spark plugs worth.
I actually have a spare Holley but unfortunately the bolt holes don’t quite line up. It’s an 80s spec for a 318.
You might want to check your timing chain while you are at it. An unexplained change in the timing can be an indicator of a loose and failing chain.
You need to be changing that chain before you do real damage. Line up the timing mark at TDC, Have a helper rotate the crank back and forth with a breaker bar and socket on the big bolt for the harmonic balancer. You should have a maximum of about 12 degrees free play before the distributor starts to move. At 15 degrees the chain is out of spec at 20-25 degrees, the chain is at the point of failure. The factory plastic faced gears can go any time from about 70k onward.
He mentioned the vacuum gauge fluttering "quite a bit" early on. I suspect a loose timing chain.
I think you may have hit on the issue, I always tighten my air cleaner wing nut, kinda a lot. I’ll check for that first, and then if it does appear to be sealing I’ll srop doing that, and move to taking out the venturis and using the twist drill.
I’m not looking for a pissing contest, I’m sure you can relate to the frustrations when you think you fixed something and then the problem is still there. I was really just looking for suggestions as to what I could do to correct the lean mixture. I was personally leaning towards rich but I’m not ruling anything out
Well, some years ago, I can try to look in it with a flashlight. But the fuel flow at the carb is great, there’s no sign of any obstruction or resistanceSounds more like crap in the fuel tank. A timing chain will not "come and go". It will be crappy, and stay that way. When was the ;last time the fuel tank was examined or cleaned out?
Some more troubleshooting and I’m back to thinking it’s too rich. I’m able to pump the accelerator level by hand without disturbing the throttle and giving it a shot of gas like that makes it almost stall