The four mile Tiger.

My Tiger quits as soon as the engine gets hot (about 4 miles) and will not restart until it cools down. I thought either a vapor lock or no spark caused the problem. If the accelerator is pushed down gas will squirt in the carburetor and there is a spark at the plugs (or at least one I didn’t try all of them)
Things that I’ve tried:

• Put an insulating plate under the carb.
• Replaced the water pump.
• Installed an electric fan.
• Removed the thermostat.
• Rebuilt the carb.
• Installed a new battery.
• Insulated the fuel line and fuel pump with Aluminized Fiberglass Semi-Rigid Split Tubing w/High Temp Adhesive.
• Moved the coil to the fender, off of the engine block.
• Replace the Petronix electronic ignition with a new set of points, rotor, condenser and coil. (I found an article online about an MG that had the same type of problem using Petronix with a ballast resistor, it seems that there was spark but not enough to run the motor. When I stopped driving the car last fall I thought that this had solved the problem but it did not.)

The engine is not overheating when this occurs. I would appreciate any suggestions.

First

Thought is to hot wire car. I'm thinking that you have stock car with the loop that goes to tachometer. That seems a bad system and a suspect to me.
Since you removed Petronix I'd also do the old matchbook trick and open points to .016 I don't recall the exact factory gap is the dwell or timing. I just know my old points motorcycle start harder with nearly closed points a hot motor and a low battery.
I've had several of the Petronix and they always worked great.

Need way more info too, 4 miles doesn't get my car to 180 unless a lot of stop lights.

Oh are the plugs wet , how about fuel fresh or old and water laden and stale?

Electrical?

Probably bad ballast resistor.
When that happens I jump it to to get home. That results in running 12 volts and will burn points over time. The function of the resistor is always bypassed when cranking to start so proof would be ignition would work when cranking to start but when the key is turned to run.. ignition stops and engine quits.

Sounds like your ballast resister is has become heat sensitive.

Best

Rick Admin

Have you tried swapping the coil?

Fuel system?

Years ago I had a what turned out to be a non vented cap that created a vacuum in the tank, one of those things that just isn't supposed to happen. Have you checked your fuel pressure and or a possible blockage that starves the system under pressure, then when the fuel pump is off, the blockage floats away until being drawn into the fuel pick up and or fuel filter when the key is back on? I saw a recent post on Facebook by Duke who has had a problem with a plastic bag being put into his gas tank, all kinds of head scratching with that one, until you pull the tanks. A fuel stop at an unfamiliar or non traveled route can also raise havock with water being sucked up from the bottom of the stations tank, water in your system sinks to the bottom and eventually makes it's way to your engine and it stops, it's an intermittent thing. Just suggestions, I hope it's an easy fix for you.
Brian

Thanks, everyone, for your great suggestions! I am going to try your suggestions, starting with the ballast resistor (because I happen to have an extra one someone from CAT said always carry a spare), then the coil since that seems the next easiest thing to change and work my way down the list. I will let you know if I have any luck. Thanks again.

odd problem

I second mr55s Brian's suggestion and take a look at the fuel cap.

I had an alpine that would conk out occasionally because the cap vent was plugged.

I had a chance to work on my car today and I will try to reply to some of the recommendations that some of you have given me. I checked the fuel pump to measure the rate of flow it filled a 500 ml bottle in 18 sec. (100 liters per hour) the rate stated in the shop manual is 68 liters per hour. This is well over that amount. The fuel in the bottle was not clear but did not look dirty or seem to have anything in it. Next the tank was checked to see if it was vented. The driver side tank has an overflow, there was a rubber hose put on this when the tank was installed this was not squashed or clogged.

I checked the gap of the points as Warren suggested. The shop manual recommends .017” I found mine were less than that and reset them. I pulled all of the spark plugs. This is the first time that I did this. Some of the plugs had some carbon on them but most were the gray color that is normal. I’m going to clean them and reinstall them tomorrow. I put the coil back in that was used before the Petronix was installed. The Petronix had a higher output coil that came out with the Petroinx. It’s odd that two different coils would cause the same problem. Could both be bad? The Petronix coil was brand new when the system was installed.

I did not have time to run the car today.

I didn't see any mention about changing the ballast resistor. That's my guess

Cap

I just tried my gas cap it has clogged cap, but luckily my cork gasket isn't tight enough to stop a slosh out when really full or parked on slope with cap on low side, or I'd have a problem too. I have had vent problems on motorcycle caps but they're much tighter. When I suggested hot wire I was saying under hood bypassing ballast as well. Good thread and I'll be adding ballast to my emergency kit. When I had a Petronix I carried the points in the car tool kit just in case.

Ballast Resistor

Ballast Resistors should only be used with points. Any electronic ignition will have issues with Ballast resistors. Oil Filled coils should not be used laying down as they can overheat and fail with heat. Check the contacts if you are running the SU Fuel Pump. Just a few ideas.

I thought that I had a spare ballast resistor but I don't. No one stocks them locally, and the MSD ones that can be ordered are 8 ohms which is more than the stock Ford resistors, I think. I'm ordered the last one in stock from Sunbeam Specialties.

My coil is on it's side. When I moved it to the fender I mounted it to the brace with an existing bolt. The fuel pump seems to be working fine, but I'm going to check the output next time that the motor quits.

How many ohm's do you need? Standard Motor Parts makes a selection of resistors in different ratings. Summit racing carries those and others. You just need to know how many ohms you want.

I ordered a ballast resistor from Sunbeam Specialties. They had one left in stock.