Engine Performance problem
1969 Dodge Dart 6 cyl Two Wheel Drive Automatic
I have a 1969 Dodge dart with a 225 Slant six and a 1920 holley carb. I cleaned and rebuilt the carb, put a new ignition coil on, new spark plugs, new points (proper dwell angle set), new condenser for the distrb, and new ballast resistor. Did not put in new distrb (doesn’t seem to be worn).
I found out that the timing mark on the pulley was off, so I had to find TDC and make a new mark with white out. After putting the distrb back in, the car started up right away versus when the timing mark was off.
The problem is that:
A. It runs strong for about 10-15 min then starts to slowly drop in rpm till it stalls out.
B. I can’t get the timing mark to line up with 5 degrees BTDC (according to the Haynes manual). The distrb ends up being fully retarded yet it won’t go past 0 degrees TDC. Some times it jumps over but rarely.
C. There is some smoke but only at certain points when adjusting the timing and the smoke is not thick white smoke, not black, and not blue. It’s just an accumulation of smoke.
D. Initially, the carb seems like it’s at proper idle then of course, as mentioned above, it drops in rpm. Can never get it set right. The carb mixture screw is set some where around 1 ¾ to 2 turns out from fully in (can’t do any better). In addition, the choke is working fine. The carb is not a cleaner air package/emissions type of carb. The carb itself is also not flooding.
E. Also, in the past, after rebuilding the carb and adjusting the settings (because the rpm was too high at idle) it would rev all the way through the RPM range in Park but as soon as you put in drive and put on the gas it would stall out. This was before pulling out the distrb and putting in new spark plugs, points, and condenser. I have not been able to take it out yet because I was still working on why it keeps stalling at idle, so I do not know if it stalls out when in drive.
I would appreciate if somebody could help me out on this problem.
Sounds like timing chain to me. Stretched/sloppy timing chain means cam timing isn't right/changes & consequently, ignition timing too.
September, 10, 2009 AT 10:44 PM
Actually, I put on new spark plugs, points, condenser, plug wires, distributor cap, and rotor, which solved the problem for the most part. Even the smoke seemed to go away. Although, I still think I probably should check/replace the timing chain.
September, 11, 2009 AT 12:08 AM
Given that the engine's 40 years old & assuming the timing chain & related parts have not been replaced along the way, the symptoms you describe are directly related to the chain.
The 225 " Slant Six" is one of the most dependable engines ever made, I've modified/run 'em harder than they were ever designed for without breakage, but it's a given fact that anything mechanical starts to wear the moment you use it.
Timing chains stretch so much that they should be replaced periodically, unless there's an automatic chain tensioner which covers a wide range - which your engine doesn't have. And the pull on the chain affects cam bearings, etc.
The distributor can't possibly work right if the timing chain/cam, et al assembly isn't working right & here's some info you can use: Timing chain is PN 3514866, crank sprocket is PN 2128912, cam sprocket is PN 2806945. These pieces are NOT for a roller chain design. Special pieces to convert the slant six to roller chain - cam sprocket P4007715, crank sprocket P3690280, roller timing chain P3690279.
If it was me, I'd go roller chain so I wouldn't have to deal with the problem again for a long time.