Sears Penske dwell meter

[towbar]

So being that I have a couple vehicles that still use point style ignition timing, I decided to buy me a dwell meter so I could accurately adjust the point dwell timing. I made my purchase off ebay, the purchase arrived within a a few days and I was really pleased how good of a condition this vintage piece was!! I was very excited so I jotted down to the garage to try it out on my c10 and Nova....well unfortunately it doesn't work. Taking it apart I found an old durscell made by Mallory, 4.3v battery, which looks like a fat AA battery....well of course this 4.3v battery is no longer available. I can find a 3.7v and a 4.5 v replacement. so now I come to my friends and experts on which battery would work well with this meter...will a 4.5v fry it, will a 3.7v work just fine??

I know there are some battery geeks out here that are shaking their heads in disbelief of my question....but your help would be appreciated

thanks, Lenny

[1970 CST Short Wide]

Originally Posted by towbar

So being that I have a couple vehicles that still use point style ignition timing, I decided to buy me a dwell meter so I could accurately adjust the point dwell timing. I made my purchase off ebay, the purchase arrived within a a few days and I was really pleased how good of a condition this vintage piece was!! I was very excited so I jotted down to the garage to try it out on my c10 and Nova....well unfortunately it doesn't work. Taking it apart I found an old durscell made by Mallory, 4.3v battery, which looks like a fat AA battery....well of course this 4.3v battery is no longer available. I can find a 3.7v and a 4.5 v replacement. so now I come to my friends and experts on which battery would work well with this meter...will a 4.5v fry it, will a 3.7v work just fine??

I know there are some battery geeks out here that are shaking their heads in disbelief of my question....but your help would be appreciated

thanks, Lenny

I have this one you can have for shipping cost. PM me if you want it

[HO455]

I would say either battery would work. I would bet there isn't any sensitive circuitry inside the meter that is going to care if the voltage is a quarter volt high and those meters probably worked fine until the voltage dropped past 50% of rated voltage. Personally I would go with which one fit the best. And if there's no difference there then cheaper one.

[Keith Seymore]

I did a similar swap for the sending unit of my Sun Tach.

Took some crap for it (on this forum, I think) but it seems to be working fine (it's been thirty years, I think).

K

Originally Posted by Keith Seymore

You might appreciate this little tidbit:

My car still uses the old battery powered sending unit, mounted underhood -





When I got the car running again back in the mid 90's, naturally the batteries were dead and the tach didn't work. I thought "...where am I going to get those old batteries like that?"





Well, I noticed that they were physically about the same size as a modern "AA" size battery, although the modern battery is 1.5V and these vintage batteries were 1.35V.



I asked one of the electrical engineers at work about it and he said "...I'd just put a couple AAs in a flashlight and run 'em down until they're 1.35V".

That's what I did and it's been working fine ever since.

K

[towbar]

70 CST Short Wide: thank you so much for that offer, I'm hoping the battery will get this unit back up and going again?? Should have a battery in a week or so, if that doesn't help mine, them I may take you up on the offer...once again, thank you for that offer, that's one of the reason I love this site!

HO455: fitment is something I need to work out...finding the right size battery, I think I can spring the terminals to accept a slightly longer one, but the diameter is tight with capacitors and resistors on each side.

Keith: those batteries look similar to mine, a fat looking AA, Mercury type....happy to hear that you had success, I'm going to try it!

Thanks again for the responses guys...I appreciate it very much!