CAV Alternator
- Thread starter Veek
- Start date
Veek,
Merry Christmas and Happy New Year to you.
I think a number of CAVs have a 1-wire (GM style) 100 amp alternator. I do not have access to the part number this weekend but will on Monday if you want it. In the mean time, I previously tracked down a poor connection and found this alternator diagnostic worksheet helpful. My only comment is that if you are adding components that require additional power also an additional power wire direct from the battery (with slave relay) to carry the load. No not rely on the stock wiring harness as it is theorically close to its limit.
Alternator Diagnosis Worksheet
Bob
Merry Christmas and Happy New Year to you.
I think a number of CAVs have a 1-wire (GM style) 100 amp alternator. I do not have access to the part number this weekend but will on Monday if you want it. In the mean time, I previously tracked down a poor connection and found this alternator diagnostic worksheet helpful. My only comment is that if you are adding components that require additional power also an additional power wire direct from the battery (with slave relay) to carry the load. No not rely on the stock wiring harness as it is theorically close to its limit.
Alternator Diagnosis Worksheet
Bob
Hi Veek,
We've run the bigger Ford alternator, in the interest of providing more voltage at low RPM. So it can be done, although you should check your pulley diameters too. Make sure the alternator pulley is as small as possible.
I think most guys are running March pulley sets as they are top quality and come with easy to adjust brackets, my concern is the crank pulley diameter as it's quite a bit smaller than the stock Ford. While intended to save horsepower by reducing the speed of the water pump, alternator, air pump, A/C pump, power steering pump in the case of CAV GTs the current demand at idle, with the A/C, headlights, cooling fans, interior fans, high pressure fuel pumps, ignition box etc. is more than an underdriven alternator can provide.
So your counting on the battery to carry the load while idling, that's tough too because once your voltage drops below 10.5 volts the gauges start acting up, ignition boxes can get misfire. We're probably asking for 60 amps at idle with all loads on, no alternator can provide that below a minimum RPM, hence my concern about pulley diameters.
Try bumping up the idle at full electrical load and watch the volt gauge, you'll probably see 12v by 1000rpm and all the gremlins will disappear too. Here's a pic of our big alternator install. Hope this helps.
Cheers
We've run the bigger Ford alternator, in the interest of providing more voltage at low RPM. So it can be done, although you should check your pulley diameters too. Make sure the alternator pulley is as small as possible.
I think most guys are running March pulley sets as they are top quality and come with easy to adjust brackets, my concern is the crank pulley diameter as it's quite a bit smaller than the stock Ford. While intended to save horsepower by reducing the speed of the water pump, alternator, air pump, A/C pump, power steering pump in the case of CAV GTs the current demand at idle, with the A/C, headlights, cooling fans, interior fans, high pressure fuel pumps, ignition box etc. is more than an underdriven alternator can provide.
So your counting on the battery to carry the load while idling, that's tough too because once your voltage drops below 10.5 volts the gauges start acting up, ignition boxes can get misfire. We're probably asking for 60 amps at idle with all loads on, no alternator can provide that below a minimum RPM, hence my concern about pulley diameters.
Try bumping up the idle at full electrical load and watch the volt gauge, you'll probably see 12v by 1000rpm and all the gremlins will disappear too. Here's a pic of our big alternator install. Hope this helps.
Cheers
Attachments
Hey Bob, great alternator work list, I downloaded a copy, thanks.
Veek, another thing to check is the grounds. Some of the early CAVs did not have a ground cable bewteen the engine and the chassis.
I make sure there's a ground cable on the block connecting via a bolt through the chassis to another cable direct to the battery negative. Inadequate grounds drive up current demands. Just something I should have mentioned earlier.
Cheers
Veek, another thing to check is the grounds. Some of the early CAVs did not have a ground cable bewteen the engine and the chassis.
I make sure there's a ground cable on the block connecting via a bolt through the chassis to another cable direct to the battery negative. Inadequate grounds drive up current demands. Just something I should have mentioned earlier.
Cheers
Pat
Supporter
My original post is a couple of years old. I ended up going with a 1G to 3G-alternator conversion with a 105A alternator. It’s been in the car quite some time now and works great. This is what I have: Ford 3G small case high output alternator
Since then, I’ve not had any of the starter problems that necessitated annual rebuilds, the tach readings are stable at low RPM and everything works great.
Since then, I’ve not had any of the starter problems that necessitated annual rebuilds, the tach readings are stable at low RPM and everything works great.
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