VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 38 running issues

When I got 37/38 it had been sitting at least 10 years if not a little more. So I have been going though the mechanical systems and repairing and restoring. I was able to get the engine running some time ago but have not driven it until recently. A couple of weeks ago I was able to drive it up and down my street and it was driving well. I was able to get up to about 30mph. Yesterday I drove it around the "block", a loop around the streets near my house about 4-5 miles. The first part of the trip the car drove great and got up to about 50mph. The last part is a long incline but not very steep. As I was going up the incline the car started bucking and not taking throttle. If I pushed in the clutch I could rev it but in gear it would buck and back fire. After a little bit it died. I was eventually able to restart it and get home. I started checking things and found the exhaust/heat flap stuck in the heat carb mode so I locked it in the not hear carb mode. Today I ran the same loop and had the same problems, not as bad and did not stall out but definitely problems. I am not sure what is going on. I checked the timing and it was advanced and when I tried to set it at 5 BTDC I could not get it that low. When I would adjust it to 5 BTDC it would run badly and stall. I followed the directions in the shop manual. At probably 7-8 BTDC it runs great. Any ideas?

Thanks,
Matt

What have you done with the fuel system? Literally everything must be cleaned. Often one item gets skipped and gunk gets pumped to the carb and everything gets contaminated again. Make sure the gas is fresh.

As for timing, you can run a lot more than than the shop manual recommends as the fuel is way better now than when the manual was written. Many guys adjust the timing by ear - keep advancing it until it idles the fastest and then retard it a little bit.

Are the points and condenser new?

I had the tank cleaned and all the other fuel lines are new. There is a filter before the pump (which is also new) and a glass bowl style filter before the carb. The points, condenser, cap, rotor, spark plugs and wires are all new. What does not make sense to me is when I run it up and down my street (it has an incline) it runs great. The coolant temps seem good and I am not seeing a rise when I was having the issues.

This may be a stupid question. Is the gas tank properly vented?

Even though the ignition parts are new that doesn't guarantee they are in top notch condition. I often have to clean new points to get them to work well.

The other thing that comes to mind is an over heated coil. I have had that happen several times when running a lower speeds in high gear on an upgrade. When cooled by pouring a little cool water on it comes back to life.

Finally heat increases resistance so check the grounds on the condenser and coil.

I once had a 48 that wouldn't top 50 mph. 30 mph in second it stalled badly. Did everything including overhauling the carby to no avail. Suddenly it was cured but we couldn't figure out why. Then we realised that we hadn't put the air cleaner back on. That was it. The felt silencer had shrunk and would collapse and block off the air.
The 38 I have recently went silly. Would wander along but would buck and carry on under acceleration. Road service couldn't find a problem so it got sent home (250 miles) on a tilt tray. I found that a wire to the amp meter was loose!
Coils usually start the day OK but can fail when they get hot. I put a brand new one on and it failed. I found a coil off a 1954 Holden that was lying around and put that on . Perfect.
Back firing I usually find indicates a fuel shortage but you never know. All something to consider.

Ok here is what I have done. I have another W1 carb that I cleaned thoroughly and installed it on the car. I ran the 4 mile loop and it worked great. Seemed like the problem was fixed but it was not. Today I drove it to my friend's house about 15 miles one way. The way out it ran great no issues. When I got there I took his son on a trip around the block. Again it ran great. On the way home I had the same issues I had with the old carb. Drove about a mile and stopped at a stop sign and it stalled. Took some effort but I got it refired. It died several times on the way home, I barely got back. It feels like it is running too rich. When it starts to sputter and bog down I can sometimes put in the clutch and rev it a couple of times to clear it. When it does die to restart it I have to hold the throttle wide open and crank it for a fair amount. When It does refire I get a could of white/gray smoke. I set the float level to what the shop manual says, 3/8".

I had problems with the first coil I used. It had the heat issue, where when it got hot it would fail. I had a spare and have been using it and it seems to be working. With the bogging and sputtering it does not feel like an ignition issue but I will check the points.

I would not be surprised if the fuel line from the tank to the pump has some blockage.

Even though the tank was cleaned there will still be pieces of loose crud in it. Unless they took the tank apart and cleaned each half before re-welding it.

I have a filter on my tank outlet. I amazes me how much fine rust accumulates in it even though I have had the tank cleaned twice.