Wanted 3B High Altitude Compensator

[RufusTheDufus]

Location

United States

I'm looking for the HAC for an inline 3B injector pump.

 

[Roberto]

Rufus

what is this thing your looking for? optional equipment?

R

 

[RufusTheDufus]

I don't think it was optional. I think it's a country-specific item. I believe that it was standard on Canadian spec 3B engines but not available in most of the rest of the world.

 

[BreckenridgeCruiser]

If they are anything like the HACs from their gas motors, they are not really worth anything if you ever travel much above 4000 feet. If you read the (gas) specs, it is full open by around 3800 feet so anything greater and you are getting no adjustment...

 

[roalco]

It didn't come standard on my CDN 84 BJ60 (it has a fixed cartridge), and I haven't seen any that had it, but I do have one from a spare B engine (same DHAC P/N as on B, 2B, 3B and some gassers). I opened it up to figure it out what exactly it did and it is an aneroid which expands as the ambient pressure drops, and extends the maximum fuel stop arm to reduce the max fuel availiable at altitude, therefore less black smoke. There is also a spring loaded damper to help reduce rapid resopnse and overfuelling smoke. There are two adjustments on it but nothing in the FM to say how to set it up, except that it needs to be done by a shop, on a test bench, to deliver so many cc's of fuel per thousand revs. So it reduces smoke by reducing fuel, and power.

 

[cruiser_guy]

Nope, not standard on Canadian 3B's. With a turbo it is not necessary anyways. I've run my truck at 13,650' with no issues, no clouds of black smoke, no excessive EGT's and no significant power loss but then I'm also turbo'd.

 

[lowenbrau]

It varied by year and model. 40s and 42s had them... early 60s too, I think. They can be used as a bit of a boost compensator if you add a turbo and plumb the boost to them.

I'm a glass half full kind of guy and would argue that they allow more fuel at lower altitude.

 

[cruiser_guy]

It must be the real early '60's 'cause mine is an '82.

 

[cheric]

So if you have one from a spare 3B ... is it for sale? I am interested. Thanks, Eric