You have had so many good suggestions all I will say is I hope you get it sorted soon. Oh also, the MGA would suddenly start running roughly or die altogether. It took a long time for me to find that the riveted primary connector on the Lucas coil had come slightly loose and was only conducting intermittently. I soldered it and that solved the problem, but my uncle Al, VP at Mallory sent me a Mallory dual point distributor and coil and we never had anymore problems with it.
My buddy got real good with these carburetors, told me they’re very finicky- - just a change of the air flowing over them changes the engines response - need adjustments inside of them.
i do know those patronix are touchy, i burned out 2 in vw b4 i even got it running , an they are usually no guarantee Sounds like a power issue, is the Alt charging? how bout a dist of one of your running engines, are any the same?
Like many have said below it has to be electrical some how. Things got better (and then worse) when the fan kicked off/ on; clearly it is not a carb problem. Sadly electricity and I have never been close friends (I literally have the scar to prove it) so I'm not much help beyond that. Keep fighting the good fight!
try disconnecting the alternator if it is working too hard it will slow your engine down. you could put a battery charger on to keep a bit of charge going in or put some jump leads from your car, this would be a quick way to rule one more thing out . Its always best to do it one at a time then you know exactly what as caused it
Good suggestions below, but I wonder if having the electric fan come on sooner would help? Remember these motors originally were cooled by manual fans that were turning all the time and not waiting until the engine got up to full temperature. You are giving your fuel system a shock when the fan comes on causing the fuel temp to rise sharply and quickly. Have you considered using a mechanical fan just for grins?
Hi George, I thought the same. I have also tried running it with the fan on all the time. Same issue....Mechanical fan is pretty puny in this car unless I decided to upgrade that as well...
Hmm, sounds like you are covering all the bases, but something is missing yet, the fuel system shouldn't be quite so sensitive and this is with the stock carbs. I assume that it wouldn't be a problem running down the road, just at idle? How about removing the thermostat all together? Sometimes that actually makes a car run hotter, strangely enough. If you raise the idle speed it seems to help, right? Is this an issue for these cars normally? Since it isn't really overheating it wouldn't point to a faulty water pump impeller. I'm watching and trying to think of all the scenarios I have run across in my years as a mech as well as a hobbyist. Thanks for taking us along for the investigation. Troubleshooting can be very tedious and sometimes frustrating, but when the solution is found and fixed it can also be very rewarding. Keep up the good work, Dave.
How high does the temperature get with the electrical fan disconnected? I have mine wired into a toggle switch instead of a thermostat so I can manually control it in traffic if needed. My idle also tends to go a bit wonky when I use mine, so it's always in short intervals. I rarely use mine except for this time of year and I'm in South Carolina. I switched to the TR6 fan blades a while back and I noticed a huge difference.
Hi Jason, Not sure how hot the car will get with it disconnected...didn't want to overheat it and blow a head gasket or something like that....I have mine wired on a toggle to manual override it ON but not off.....
Hi Tom, fan has a relay installed and is hooked up to a secondary fuse box on the firewall. Yep, new coil is on the way. I'll swap that out next and see what happens. Cheers, Tush
I wonder if the fan is drawing enough juice that the alternator is having trouble keeping up and the battery voltage is dropping some. Try starting it, let it run til it gets hot, now jumper a second charged battery, into the ignition system. If it suddenly improves it's electrical. If not it's fuel related. If it's starting to run lean due to the hot air you could try gently putting the choke on. That would richen the mix and show you if that's an issue.
Good suggestions, thanks. I'll do more testing after I swap the coil out for a new one...I ordered a heat shield for the carbs tonight as well so that should probably help a little.
Blazer has a good idea here, I was thinking along similar lines as I watched the video. But instead of jumpering a second battery into the ignition system, consider just putting the fan power source on a separate battery. You have a relay system for the fan (saw that in one of your responses below) so it should just take a little temporary wiring to power the fan from another battery. Maybe from the TR6, that way the TR6 could be running and charging the battery while the fan is running.
Another thing you can try is when the fan comes on and starts to run rough. Turn the head lamps on. And it will probably die right away. Then that would be the answer.
I`ve seen this issue before, if you are using a stock Lucas generator, it cant keep up with the draw from the electric fan causing the stumbling idle. You probably need to upgrade to a 50-75 amp and change over to an alternator. I`ll be upgrading my TR6 to a Delco 75 amp shortly as I`ve installed an electric fan as well. Tim
I have to agree with what have said and to check the battery voltage when the fans are on. Check for a bad earth to the engine block and for the coil. Also, check the voltage with the meter lead on the engine and not just straight across the battery. The fact the RPM drops when the fans are on and picks up straight away after the fans stop suggest that the fault is directly related to it. I don't believe it is a heat issue, especially with the bonnet open.
where is the fan wired in to . does it and ign share power or ground . Wonder about a voltage drop test on the ign primary , when fan kicks on . If it only happens when fan comes on then thinking either it is something with it or where it gets power or ground .
I think you need a bigger battery due to the voltage drop and the alternator is pulling the engine down to far to keep up with the electronic ignition and the fan! What do you think?
I'm going to do some voltage checks at various points to see what is happening. Battery should be fine and the alternator is a Delco 10 is that should be able to handle the draw with no issues. We shall see!
Thats crazy Tush, I don't know... maybe a 400 Pontiac motor swap??? Just saying ;) Then again what do I know, my car is in a qaudzillion pieces right now and will prolly never run again.
I wonder if the alternator is too powerful for the engine and as the fan has dragged so much power from the battery the alternator is powerful enough to put currant in quickly but the small engine isn't powerful enough on tick over. I'd try it with the alternator disconnected.
I don't think it's a carb thing Tush 'cos it gets fat when it gets hot...Unburnt fuel from a weak spark I'd say...Run a "Hot wire" to the coil and see what happens then..Sounds like the electric fan is pulling all the current...Does it do the same if you turn on the lights(High beam) and heater fan on high.?...Does it run a 12v coil thru a resister or a straight wired 9v coil.?..What is the charge rate.?..Things I'd be looking at..Cheers mate.
You are almost there, I just know it. I'm sure that you have a DMM; use it to measure the voltage when running, and the change in Va when the fan comes on. And it's a simple thing, but what is your battery charge when the engines off? Your alt. looks new, but you never know. I'm not sure it's exactly heat related. Using the scientific method will serve you well in finding this, though!
Battery is brand new although I haven't checked the voltage in a few weeks since I installed it. I did confirm it was charging with a VOM when I first installed it. Will find out more tonight after work. Cheers, Tush
Yes Jim, good eyes. Its on the list for the winter. Im going to use a volt meter from a later TR6 and am going to swap the glass out so it matches the other gauges.
i miss playing with them Tr3's wanted to find a blown one and put a Buick nail head in one had 2 old wild cats at one time a 1964 401 and the 1967 425 both would make them fly those vanguard engines r heavy being from a tractor can't remember the weight of them they wasn't far off from each other
You have had so many good suggestions all I will say is I hope you get it sorted soon. Oh also, the MGA would suddenly start running roughly or die altogether. It took a long time for me to find that the riveted primary connector on the Lucas coil had come slightly loose and was only conducting intermittently. I soldered it and that solved the problem, but my uncle Al, VP at Mallory sent me a Mallory dual point distributor and coil and we never had anymore problems with it.
Thanks Bruce. We shall get it sorted out together!
i would try bringing the idle up by about 1 to 200 rpm when at full operating temp seems like the fan turning on puts a real strain on it
it's power starved when the fan kicks in, does it do the same when you put the lights on? if so i would at the alternator for the problem!
My buddy got real good with these carburetors, told me they’re very finicky- - just a change of the air flowing over them changes the engines response - need adjustments inside of them.
i do know those patronix are touchy, i burned out 2 in vw b4 i even got it running , an they are usually no guarantee Sounds like a power issue, is the Alt charging? how bout a dist of one of your running engines, are any the same?
Hi Kenny, ya I swapped the Pertronix for a Dizzy with points installed....no difference. Going to check charging and voltage this evening.
Like many have said below it has to be electrical some how. Things got better (and then worse) when the fan kicked off/ on; clearly it is not a carb problem. Sadly electricity and I have never been close friends (I literally have the scar to prove it) so I'm not much help beyond that. Keep fighting the good fight!
try disconnecting the alternator if it is working too hard it will slow your engine down. you could put a battery charger on to keep a bit of charge going in or put some jump leads from your car, this would be a quick way to rule one more thing out .
Its always best to do it one at a time then you know exactly what as caused it
Good suggestions below, but I wonder if having the electric fan come on sooner would help? Remember these motors originally were cooled by manual fans that were turning all the time and not waiting until the engine got up to full temperature. You are giving your fuel system a shock when the fan comes on causing the fuel temp to rise sharply and quickly. Have you considered using a mechanical fan just for grins?
Hi George, I thought the same. I have also tried running it with the fan on all the time. Same issue....Mechanical fan is pretty puny in this car unless I decided to upgrade that as well...
Hmm, sounds like you are covering all the bases, but something is missing yet, the fuel system shouldn't be quite so sensitive and this is with the stock carbs. I assume that it wouldn't be a problem running down the road, just at idle? How about removing the thermostat all together? Sometimes that actually makes a car run hotter, strangely enough. If you raise the idle speed it seems to help, right? Is this an issue for these cars normally? Since it isn't really overheating it wouldn't point to a faulty water pump impeller. I'm watching and trying to think of all the scenarios I have run across in my years as a mech as well as a hobbyist. Thanks for taking us along for the investigation. Troubleshooting can be very tedious and sometimes frustrating, but when the solution is found and fixed it can also be very rewarding. Keep up the good work, Dave.
How high does the temperature get with the electrical fan disconnected? I have mine wired into a toggle switch instead of a thermostat so I can manually control it in traffic if needed. My idle also tends to go a bit wonky when I use mine, so it's always in short intervals. I rarely use mine except for this time of year and I'm in South Carolina. I switched to the TR6 fan blades a while back and I noticed a huge difference.
Hi Jason, Not sure how hot the car will get with it disconnected...didn't want to overheat it and blow a head gasket or something like that....I have mine wired on a toggle to manual override it ON but not off.....
Voltage drop at the coil? bad coil or could the fan wired up to the ign without a relay?
Hi Tom, fan has a relay installed and is hooked up to a secondary fuse box on the firewall. Yep, new coil is on the way. I'll swap that out next and see what happens. Cheers, Tush
I wonder if the fan is drawing enough juice that the alternator is having trouble keeping up and the battery voltage is dropping some. Try starting it, let it run til it gets hot, now jumper a second charged battery, into the ignition system. If it suddenly improves it's electrical. If not it's fuel related. If it's starting to run lean due to the hot air you could try gently putting the choke on. That would richen the mix and show you if that's an issue.
Good suggestions, thanks. I'll do more testing after I swap the coil out for a new one...I ordered a heat shield for the carbs tonight as well so that should probably help a little.
Blazer has a good idea here, I was thinking along similar lines as I watched the video. But instead of jumpering a second battery into the ignition system, consider just putting the fan power source on a separate battery. You have a relay system for the fan (saw that in one of your responses below) so it should just take a little temporary wiring to power the fan from another battery. Maybe from the TR6, that way the TR6 could be running and charging the battery while the fan is running.
Thanks, Will be doing more tests this evening. Stay Tuned! Thanks for the comments.
Another thing you can try is when the fan comes on and starts to run rough. Turn the head lamps on. And it will probably die right away. Then that would be the answer.
also check your fuel pressure at full operating temp may be a bad fuel pump
I`ve seen this issue before, if you are using a stock Lucas generator, it cant keep up with the draw from the electric fan causing the stumbling idle. You probably need to upgrade to a 50-75 amp and change over to an alternator. I`ll be upgrading my TR6 to a Delco 75 amp shortly as I`ve installed an electric fan as well. Tim
Hi Tim, I do have a Delco 10si alternator conversion installed. Cheers, Tush
I have to agree with what have said and to check the battery voltage when the fans are on. Check for a bad earth to the engine block and for the coil. Also, check the voltage with the meter lead on the engine and not just straight across the battery.
The fact the RPM drops when the fans are on and picks up straight away after the fans stop suggest that the fault is directly related to it. I don't believe it is a heat issue, especially with the bonnet open.
where is the fan wired in to . does it and ign share power or ground . Wonder about a voltage drop test on the ign primary , when fan kicks on . If it only happens when fan comes on then thinking either it is something with it or where it gets power or ground .
Fan has a relay an is then wired into an auxiliary fuse box for power. I'll check for ground and voltage drops as well.
maybe with a spark tester , you may be able to see if spark is weaker when it is happening . Is there anything electrical on the carbs ,
+wtbm123 yeah, wish I had some colour tune glass plugs....no, nothing electrical on the carbs.
Coil temp? Relocated mine to inner wing on TR6 - that helped.
Could be. Thanks for the comments
Electrical for sure....I like the second battery idea, you are losing voltage.
Thanks for weighing in .
So what was the solution? and what was the problem?
I think you need a bigger battery due to the voltage drop and the alternator is pulling the engine down to far to keep up with the electronic ignition and the fan! What do you think?
I'm going to do some voltage checks at various points to see what is happening. Battery should be fine and the alternator is a Delco 10 is that should be able to handle the draw with no issues. We shall see!
Thats crazy Tush, I don't know... maybe a 400 Pontiac motor swap??? Just saying ;) Then again what do I know, my car is in a qaudzillion pieces right now and will prolly never run again.
I wonder if the alternator is too powerful for the engine and as the fan has dragged so much power from the battery the alternator is powerful enough to put currant in quickly but the small engine isn't powerful enough on tick over. I'd try it with the alternator disconnected.
Hi Luke. Going to try and do some voltage testing this evening and will report back.
I don't think it's a carb thing Tush 'cos it gets fat when it gets hot...Unburnt fuel from a weak spark I'd say...Run a "Hot wire" to the coil and see what happens then..Sounds like the electric fan is pulling all the current...Does it do the same if you turn on the lights(High beam) and heater fan on high.?...Does it run a 12v coil thru a resister or a straight wired 9v coil.?..What is the charge rate.?..Things I'd be looking at..Cheers mate.
Hiya Zig, no resistor on the coil..straight wire. Im going to be doing some voltage tests this evening. Stay tuned!
have you checked all of your grounds?
Grounds should be good but will be checking everything again. Thanks
If it is a generator you should clean the commutator and add new brushes.
That seems electrical. Could be the fan motor.
You are almost there, I just know it. I'm sure that you have a DMM; use it to measure the voltage when running, and the change in Va when the fan comes on. And it's a simple thing, but what is your battery charge when the engines off? Your alt. looks new, but you never know. I'm not sure it's exactly heat related. Using the scientific method will serve you well in finding this, though!
Battery is brand new although I haven't checked the voltage in a few weeks since I installed it. I did confirm it was charging with a VOM when I first installed it. Will find out more tonight after work. Cheers, Tush
I see u still running a DC meter U need one for alt not a gen it's not reading right
Yes Jim, good eyes. Its on the list for the winter. Im going to use a volt meter from a later TR6 and am going to swap the glass out so it matches the other gauges.
i miss playing with them Tr3's wanted to find a blown one and put a Buick nail head in one had 2 old wild cats at one time a 1964 401 and the 1967 425 both would make them fly those vanguard engines r heavy being from a tractor can't remember the weight of them they wasn't far off from each other
Crapola!
You said it Stevie!