Engine break in issue

[KMBeers]

I have finally started my engine after a full rebuild and the initial start went OK but I had some issues and I am looking for some help. The break in process is to start the engine, run at just above idle for 10-15 minutes, then shut off and allow to cool. Do this for 2 hours of running and then extend it to 30 minute intervals for another hour. I had a fuel leak on the fitting at the cast iron strainer at startup from an over tightened fitting (rookie mistake) which was fixed by replacing the furrell and fitting. Fuel flow was checked at the carb inlet and all seemed ok. The engine would not restart. I pulled one of the plugs and after cranking for a few 10 seconds intervals I expected the plug to be wet and it was bone dry. My assumption at this point was a carburetor issue, perhaps debris from the fuel line furrell.

I let it sit overnight and pulled the carburetor off and took a look inside. A little debris but nothing extraordinary so I cleaned everything, including all of the jets and reinstalled. Still would not start so I looked in the fuel tank and the fuel level was about 1/2 down the strainer in the tank. To be sure I added about 2 gallons to the tank and the engine started. I was trying to run at high idle for 15 minutes, except the engine shut off at about 14 minutes and would not restart. Plugs again looked dry after cranking.

The distributor was rebuilt on the engine and with the engine getting warm I am wondering if the condenser might be flakey and stops working when it gets hot. Both times the engine quit was at about the 14 minute mark. Not sure about the dry plugs so I am reaching out to the Barners to see what they think. I was also thinking of testing the height of the fuel in the bowl. Perhaps the needle and seat are hanging up allowing the car to “run away from the fuel”. Perhaps both are issues? Thanks for the help…..

[kurt v]

Gas tank cap vented

[Kurt in NJ]

When it shuts itself off first check the spark— move the plug connectors a little ways away from cap connection post and see if you have spark.
what color/deposits are on the plug when you looked just after it shut down?
take the drain plug out on carburetor and check flow,use a gallon sized bucket,let it flow and see if it changes to trickle.
Is it possible that the engine is too tight,does it crank very slowly when it shut down?

[Jim Brierley]

I was a truck mechanic for 20 years, we used American Hammered rings on our rebuilds, their recommendation was:

Get engine fully tuned and ready to drive.
Warm the engine to normal operating temp.
Drive, after getting in high gear, floor the throttle from 25 mph up to 40, ease the throttle (not fully release it) down to 25, repeat 10 times.
The rings are now fully seated.

First of course, it must be completely ready to drive.

[KMBeers]

Kurt, I will check for spark after I try a run tomorrow morning, the plugs are blackish grey, they look “normal” after stopping, they are a little darker in color after trying to start again and using the choke a bit. I will get some pictures and post them tomorrow. I checked fuel flow from the fuel line disconnect from the carb, I also opened the petcock on the bottom of the strainer and the fuel from there was clean. I have never done a fuel flow check from the bottom of the carb. Are you thinking that is the way to check needle and seat for interrupting fuel flow? Thanks for the suggestions.

[KMBeers]

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Kurt v, good question about the fuel cap, yes the cap is a vented one.

[Kurt in NJ]

If you have full flow from the drain it proves that the main jet has enough fuel to it,that the entire fuel system is clear,if it flows for longer time than it ran you can probably cross off fuel flow problem.

[Synchro909]

I can't contradict anything that has been said above but I notice that no one has mentioned retorquing the head after getting the engine up to temperature, not that that would change anything, just prevent problems down the track.
I'd check the vital things that make an engine run. Fuel, compression, spark and spark at the right time. If you have those, it should go.

[Big hammer]

When you added 2 more gallons of gas into the tank and it started is a hint to your issue. Do you have a inlet screen in the gas shut off ? It maybe partially clogged and the extra weight of the gas caused more flow ?

[KMBeers]

Big Hammer, good suggestion. The screen on the bottom of the tank was replaced along with the line and shut off valve last summer and looks clean in the tank. As Kurt in NJ suggested I am going to try the flow test from the bottom of the carb bowl tomorrow and see what that tells me. I will also look to test the ignition system to make sure I have spark from the coil. I will update everyone once I run a few tests.

[nkaminar]

I am going to go with the gas cap not vented. Synchro has a good suggestion to check the torque on the head nuts.

[KMBeers]

Well I seem to have things running properly. This morning I checked the fuel flow out of the carb drain. No change in flow in 15 minutes so I checked off that issue. When I installed the distributor that was rebuilt, it looked like I had it threaded the jacketed ignition wire from the firewall terminal box up too tight, the collar was almost tight on the distributor body. It was about 1/8 of a turn before it was tight. I loosened it up 3/4 of a turn more and the engine started right up. I have run 4 of my 15 minute cycles and everything seems to be good. My guess is the spring on the ignition wire must have vibrated after running for a bit and got against the distributor body. Thanks for the help everyone!