Loss of Power Too

[stretchit2]

I was just reading Chickentenders loss of power item, and I too just experienced a loss of power. I have a 1961 BT7 Tri-Carb and I was out for for a drive in somewhat warm sunny California this evening and all of a sudden she started to misfire at about 2800 rpms and would not accelerate worth a darn. Within seconds I lost all power and pulled over to the side. When I went to try and start her all I got was click click click, dead battery.

As luck would have it a good samaritan came along gave me a jump start and we left it attached to his car for a minute or two. I immediately headed to the barn, which was about a two mile drive and just before I got her home she started to mifire again, coasted into the garage and put her on a charger.

I bought this car last September and since then I have had a lot of work done to her and my mechanic has had a wonderful Christmas as a result. There seems to be a limit on the number of characters I can use, so I will post the work I have had done on the car in a second post.

 

[stretchit2]

I'm back, (please read previous post) here are some of the things that have been done to the car,

changed to negative ground (and all that goes with it),
changed to electronic ignition,
new battery,
new fuel pump (I literally burnt up the old one),
had the tri-carbs rebuilt,
had the radiator re-cored,
reconditioned the gas tank,
complete tune up and had the valves adjusted.
All the fluids and lubricants have been checked or changed or both.

The car has been running fantastic until she just had this power failure. I am a novice at this and I was wondering if you guys might have a suggestion as to what might have gone wrong.

Stretch

 

[John Kuzman]

Stretch -

Your problem sounds like the charging system quit. You were operating off of straight battery voltage until the battery ran down. The jump, plus the fact that you have a relatively new battery, gave you enough juice to get home. Are you still running a generator with external voltage regulator? One test you can do ONLY IF YOU STILL RUN A GENERATOR (Do not do this with an alternator!) is start the BT7 with a jump. Get in running, then lift the positive battery cable off the battery post. If the car dies instantly, the charging system (probably generator) is the culprit.

 

[stretchit2]

John,

I failed to list the fact that the car is now running an alternator, rather than the generator.

Stretch

 

[Randy Forbes]

With a volt meter, check your battery voltage with the engine not running; should be pretty close to 12V.

Start the car and check the voltage at the battery again; should be up pretty close to 14V (13.8/13.9V) if the alternator is charging.

There are diffent ways of wiring and different alternators to use when making this conversion, so the responsibility for this job falls back on the guy that did it for you.

You deserve a freebie for getting this sorted out, so be sure to get that point accross :wink:

 

[Johnny]

With all above, a simple test with a voltmeter should reveal something amiss with the charging system. It could be something as simple as a loose alternator belt, or difficult like whoever put the alternator back on didn't wire it properly. The black box on the passenger side part of the firewall should be disconnected as the alternator has it's own voltage regulator.

Good luck, stretch, and keep us informed as others may be having similar problems.

Thanks for posting.

 

[Healey 100]

Since your battery is dying as you are driving, I suspect your generator/regulator system is not charging the battery. The car loses power when the voltage falls to the level where ignition becomes flakey.

There is a charge indicator light on the speedometer that is not all that easy to see in daylight. It should be off when the engine is running, on when the key is on, engine off. If your generator is not working, the light will stay illuminated.

If you have a decent voltmeter, with the engine running and the charger removed from the battery, the voltage at the battery should be about 14V with the engine reved up. If it is 12V or less, your generator is not charging and it's just a matter of time before the battery runs out of charge.

Fixing a bad generator is not too tough, metropolitan areas still have generator rebuilding services that can probably fix and test your unit. Make sure all the connections are good between the generator and regulator too. Loose and corroded battery terminals can also be a problem too.

Good luck!

 

[RAC68]

Hi Stretchit2,

With an alternator, there are a number of reasons for a non-charging condition. Since, as I understand it, you were on an evening run, I would assume you had (at least) you lights on. In this situation, you are drawing from your alternator and putting a generating resistance on your engine through the fan belt.

Although your alternator could have other issues, I would start by checking your fan belt.

As a basis for this recommendation, let me share an experience. I hate to admit but I pursued an intermittent charging condition for about 2-years. During that time, I rewired the alternator twice and rebuilt 2 different newly purchased alternators. I even called upon the assistance of 2 master mechanics that could find nothing wrong. The only thing I didn’t touch was the fan belt as it seemed to be tight and turned the alternator when observed.

Finally, during a short early evening run, the condition started and I pulled over to see what I could see. By happenstance I brushed the fan and it moved easily. The condition was resolved. It seemed the belt would maintain friction when cold but would loose it when hot. Since the alternator would only produce substantial resistance when electrical draw was high (lights, heater, wipers, etc.), the combination of high draw and a warm engine combined to cause the belt to slip. The obvious (and cheapest) resolution was a new fan belt.

All the best from within the NJ blizzard,
Ray (64BJ8P1)

 

[stretchit2]

I think you guys are spot on. I charged the battery overnight and drove her to the mechanic's shop in the morning and she ran great.

Based on the collective opinion of the group we focused on the belt. I left it at the shop for a couple of days, poor me I have to go to Del Mar. Anyway, my guess is that it is the belt.

After some discussion the mechanic felt that the alternator might need a different bracket to increase the tension in the belt. He is going to do some other diagnostics and I will let you all know what the verdict is.

 

[57_BN4]

Probably one of the most common causes of this condition is plopping an alternator on that has a pulley with a different groove shape than the generator. Easy test is to start a cool engine that has sat for a few hours and rev it up about 3000rpm with the highbeam headlights and heater and anything else electrical switched on. After half a minute or so, turn it off and quickly (carefully) touch the alt pulley. It should be only warm, ok to touch firmly. If it is burning hot then the belt is slipping. You should also be able to turn the engine over a little by turning the alt pulley nut without it slipping much.

After owning a V8 Mk3 Zephyr and a Vitesse both with the wrong alt pulleys I have some experience of this mode of driving-interruption.

On the alt itself- if it is a Lucas ACR type, the earlier type of diodes are notoriously crappy. They also have a voltage protection device under the cover which actually fails more often than the parts it is there to protect. I worked at an auto sparky for a bit and it was my job rebuilding them. If an ACR alt doesn't whine loudly as soon as the red light goes out or whenever the headlights are on, it is not charging. An audio amperage gauge even.

Andy.

 

[GregW]

After some discussion the mechanic felt that the alternator might need a different bracket to increase the tension in the belt. He is going to do some other diagnostics and I will let you all know what the verdict is.

Was a kit used for the alternator installation? I went with the one sold by Hendrix, which I believe is the same kit Don Lenschow sells through the North Texas Healey club. Link to Hendrix site I've had no trouble with that kit. If you need a new bracket, there is a place not too far from you that can make the part with a water jet. Charisma Design is the place and it is near the 5 @ Sunland Blvd in Sun Valley. An Illustrator file is all you'd need for them to make it. If you need help with that let me know, I'm not too far from you.

 

[chickentender]

how much play should there be on the fan belt?

 

[Johnny]

The manual says 1 inch, but that's for a generator, don't know for a alternator. What's more important is fitting the belt to the pulleys, are you sure you have it set up right? I mean do the pulleys line up?

 

[tahoe healey]

Is the one inch from center either way or 1/2 each way making a total of one inch? And is that with a warm belt of cold? I've just set it a little tighter than easy slip on the pulley when warm.

 

[TimK]

The inch would be in one direction--up or down.