330 MD engine questions

Moose · Post by **Moose** » November 30, 2007, 1:33 pm

Okay okay, I know it's not a widely known engine. But, here is my dillema! Our FD has a 68 C550 with a 330md, and we have Vacuum issues. Specifically we are wondering why there is a main intake vacuum source going to the booster, and a secondary line coming off the top of the air cleaner (oil bath) and going to the same line. Anyone have any pictures of how this is supposed to be setup, or does anyone have a vacuum schematic handy? Can't seem to get my CD repair manual to work for me right now.

Also, we are in need of a dipstick (no, we already have a couple of the two legged ones) but we seriously need a good one for the 330.......

Thanks guys,

Moose

ICEMAN6166 · Post by **ICEMAN6166** » November 30, 2007, 3:05 pm

Moose, i am assuming you have the oil bath air cleaner.
from what i can recall there were 2 hoses on the top of the air cleaner, one went to the top of the oil fill cap, the other was in to the line at the manifold like you said. also there should be another line coming off somewhere that goes to the vac gauge and warning light.

the later 330MD models that have the paper element type cleaner have only the 1 hose from the oil fill tube.the gauge and light come of a tee in the booster line.
sorry no pics

fmartin_gila · Post by **fmartin_gila** » December 1, 2007, 8:57 am

Is the booster under the cab on the drivers side? I do remember some of the MD trucks that had a breather for the atmospheric side right in back of the seat, they(Ford) may have changed it to breath from the air cleaner to get rid of the 'fart' noise when the brakes were applied. Or could be special purpose because of special body.
Fred

Moose · Post by **Moose** » December 1, 2007, 10:32 am

One side does come off and go to the right hand valve cover, the main line on the intake comes off and goes to the booster (which on our truck is mounted just behind the rear axle.

Now what I can't figure out is why there would be a line going from the air cleaner (oil bath) down to the tee that splits for the vacuum guage/light combo, and the main line going to the back. I'll try to go take a couple of pictures of the setup today (hopefully) and see what can be figured out.

To me it would seem to defeat the purpose of having the main vacuum line if you have one going to the air cleaner as well. My thinking is that it would be working against itself (just my logic, but I could be wrong)

Moose

fmartin_gila · Post by **fmartin_gila** » December 2, 2007, 9:49 am

Seems to me that somebody has misplaced some hoses. You will have to chase down your PCV system as well. They may be mixed up. You should have a hose from the air Cleaner to the Valve Cover, another from the other Valve Cover to the Intake Manifold. This would complete the PCV system. Then you should have a line from the Intake Manifold with a check valve in it(may be mounted on firewall), this should tee off(after check valve) to the gauge and then go on back to the booster. You may also have a breather right at the booster for atmospheric air or it may have a hose to a remote breather or it could come all the way back to the Engine Air Cleaner.
Hope this is a little clearer than mud, trying to jog my memory, but I did quit this kind of work in 1990.

fred

Moose · Post by **Moose** » December 2, 2007, 10:53 pm

Fred here is the way ours is run.

Passenger's side valve cover splits to top of air cleaner and to carb spacer for PCV.

Main line goes straight from intake to tee fitting.

Other hose from air cleaner (driver's side) comes down to tee fitting.

Tee fitting runs to steel line that goes back to booster mounted behind the axle.

I just can't remember right now if there is one that goes to the driver's side valve cover or not. I will check it out and take some pictures tomorrow after our business meeting.

Basically the reason I am asking is because everytime you are running in third or fourth gear and you try to speed up, the vacuum falls flat on it's face (Read 0.) And it's just a little discomforting to know that the truck has power brakes but you have no vacuum!

Moose

fmartin_gila · Post by **fmartin_gila** » December 3, 2007, 9:11 am

Sounds like your system vacuum gauge is reading manifold vacuum rather than booster vacuum. Definitly something wrong .
First, check that you have a clean air source to the engine for the PCV system, this could be a hose from the air cleaner to one of the valve covers, or it could be just a filler type cap with mesh in it.
Then you need a hose from the other valve cover to the intake, this should have a valve in it at either end, some screwed into the intake manifold and some were stuck in a grommet in the valve cover.
Should be all you need for the PCV system.
Then check like my other post as to the hoses for the booster system. I can't think of any reason that the two systems should be mixed, but that's what it sounds like you have.
Fred

jeepbut · Post by **jeepbut** » December 3, 2007, 8:40 pm

Moose, if you "Drive it like a fire truck", you don't need brakes! Thanks, Lyman.

fmartin_gila · Post by **fmartin_gila** » December 4, 2007, 10:17 am

Cept when you actually get to the fire.
Fred

fmartin_gila · Post by **fmartin_gila** » December 4, 2007, 10:41 am

Are you sure the check valve is working? Should be mounted on the firewall.
If the checkvalve is not sealing, it would loose all the vacuum when you floor it.
Fred

Truckfarmer · Post by **Truckfarmer** » December 17, 2007, 10:31 pm

Moose, I cleaned off the snow that Skip left here and took photos of my 66 F600 with a 330 in it. Maybe you can see the connections you need. Email me and I will send you the photos.