Zero Oil Pressure

[stumps]

There is more to bypassing the FDC than just bypassing it. You also have to turn the fuel (smoke) down, because after you bypass the FDC, it will tell the IP that you are running the thinnest fuel (gasoline), and will set the IP to get the maximum fuel possible... making a lot of smoke, and a lot more power than your engine can safely handle. The process has been adequately explained in a number of threads. ..even by me

-Chuck

 

[Bill W]

I put a mechanical guage my deuce also, 15-20psi at hot idle, 60psi+ at cruise. I haven't heard anyone having problem with one here on the forum but have you checked your engine oil pressure regulator valve?, its located on the block next to the starter. Theres a remote chance the bypass spring is stuck or broken. Just a out there thought

 

[renovate7]

This decal is on my new A2.

 

[Mongo]

There is more to bypassing the FDC than just bypassing it. You also have to turn the fuel (smoke) down, because after you bypass the FDC, it will tell the IP that you are running the thinnest fuel (gasoline), and will set the IP to get the maximum fuel possible... making a lot of smoke, and a lot more power than your engine can safely handle. The process has been adequately explained in a number of threads. ..even by me

-Chuck

Is there a rule of thumb regarding turning the fuel down that does NOT necessitate the use of a Pyro gauge? Keeping my engine in tact is much more important to me than winning the stop light drags....

 

[Mongo]

Stumps - Thanks for the heads up. Somehow I had missed the info on turning down the fuel at the FDC after the bypass.

davey8943 - I do have lube on the clutch plates. The previous owner "topped off" the tranny for me to ensure a smooth road trip and it puked out of the bellhousing as soon as it got warm. I am still weighing options to clean it up. Just the same, I feel like the clutch is at the end of its useful life due to pedal travel.

 

[Mongo]

I put a mechanical guage my deuce also, 15-20psi at hot idle, 60psi+ at cruise. I haven't heard anyone having problem with one here on the forum but have you checked your engine oil pressure regulator valve?, its located on the block next to the starter. Theres a remote chance the bypass spring is stuck or broken. Just a out there thought

I had one of those get stuck on a car two years ago. It blew the oil filter right off the block.

 

[stumps]

Is there a rule of thumb regarding turning the fuel down that does NOT necessitate the use of a Pyro gauge? Keeping my engine in tact is much more important to me than winning the stop light drags....

If you bypass the FDC on an LDT-465 engine that was previously set up correctly, you will need to decrease the fuel adjustment (smoke) by 12-16 nut flats (2 to 2-2/3T counter clockwise), and turn the droop screw 1-2T clockwise.

[It is very important to note that you do NOT turn the fuel screw, you turn the nut that engages the screw. The screw has a slot that prevents it from turning. If you succeed in turning the screw, you have broken it.]

These are just guidelines, and will get you in the vicinity of the correct adjustment. To get it right, you will have to experiment a bit. Keep a log of what you have done here. It will save you frustration as you are trying to get it just right.

-Chuck

 

[Mongo]

Adjusting the fuel setting on the FDC is no problem. I am still having a difficult time locating the "droop" screw though... I have been pouring over the TM (as much as I can at work) and they sure don't make it obvious where that screw is....

 

[stumps]

Adjusting the fuel setting on the FDC is no problem. I am still having a difficult time locating the "droop" screw though... I have been pouring over the TM (as much as I can at work) and they sure don't make it obvious where that screw is....

Assuming that you have a type E Injection pump, and most LDT465's do, look at the red arrows in the enclosed pictures.

-Chuck

 

[Mongo]

that sure looks like my pump. Of course they all look the same to me except the "A" and "G" pumps.....

I'll take a peek when I get home tonight...

 

[LowTech]

davey8943 - I do have lube on the clutch plates. The previous owner "topped off" the tranny for me to ensure a smooth road trip and it puked out of the bellhousing as soon as it got warm. I am still weighing options to clean it up. Just the same, I feel like the clutch is at the end of its useful life due to pedal travel.

We dealt w/ that on the 109. Brake cleaner works great. Through the access plate on the tranny, and/ or the drain plug on the bell housing

 

[Mongo]

So... I adjusted the fuel screw (nut) on the front of the FDC cover 14 flats CLOCKWISE as instructed. It appears that the spring on the lever assembly inside the cover is now FULLY compressed. Is this normal?

Seems to me Clockwise turns the fuel "UP" and after an FDC bypass I would think it needs to be turned down....

 

[stumps]

So... I adjusted the fuel screw (nut) on the front of the FDC cover 14 flats CLOCKWISE as instructed. It appears that the spring on the lever assembly inside the cover is now FULLY compressed. Is this normal?

Seems to me Clockwise turns the fuel "UP" and after an FDC bypass I would think it needs to be turned down....

Your reasoning is sound.

The manual lists it as Clockwise as viewed from the governor side of the IP. When I wrote up the instructions way back when, I wrote to turn down the fuel. Later, I thought it would be best to give a CCW, or CW direction, but I couldn't remember which it was, so I cribbed off of the manual, and forgot that the TM specified that turning the fuel down is CW when viewed from the governor side, which is CCW when viewed from the screw shaft side. Sorry!

The part of the shaft that sticks out should become shorter.... which makes pushing the pedal hit the stop sooner than it would in the gasoline setting.

For more info, see page 3-106 of TM9-2910-226-34

-Chuck

 

[Billy Bobbed]

Man you need a pyrometer to set it right.When you bypassed the FDC you changed the fuel setting,its hard to get it right without a pyro.Your adjusting in the dark now.

 

[stumps]

Man you need a pyrometer to set it right.When you bypassed the FDC you changed the fuel setting,its hard to get it right without a pyro.Your adjusting in the dark now.

Not really, the army sent out a bulletin that described how to do just this very adjustment on trucks where it was necessary to bypass the FDC but there wasn't time to send the engine to a depot to have the IP completely readjusted.

All he needs to do is go back the 14 nut flats, and continue on 14 more, and he is in the close enough for government work area.

A pyro would be nice to perfect the adjustment, though.

-Chuck

 

[Mongo]

Thank you very much for the clarification. I just wanted to make sure before I reversed it on my own.

What tool do I need for the droop screw? I haven't looked too close at it yet and also haven't seen any mention of what keeps it from turning on its own.

On the up side, I spent my spare time putting a remote resevoir on the master cylinder. Seemed like a good way to spend my time while waiting for the details.....

 

[Mongo]

Nevermind. I find the Fuel easier to adjust if I just pull the whole FDC off the pump anyway so I should have a perfect view of the droop screw while I have the cover off again...

 

[stumps]

Nevermind. I find the Fuel easier to adjust if I just pull the whole FDC off the pump anyway so I should have a perfect view of the droop screw while I have the cover off again...

It was a medical day today, so I was unavailable until just now.

Just as a note for your bonnet, the test for a servicable FDC (when it is still plumbed) is to remove it from the IP, but hang it from its hoses, and then turn on the accessory switch. That will fire up the pump in the tank, and put the FDC under normal operating pressure. Then, while holding the FDC in its normal upright position, watch for drips of fuel forming around its piston shaft. A drip every minute or two wouldn't be a problem, a drip every second, would. Unfortunately, the FDC isn't rebuildable in the traditional sense, you would have to replace the shaft, or rebush the hole in the FDC's casting that it passes through, to eliminate excessive leaking.

The screw for the droop/drop adjustment screw is just a setscrew with a lock nut and washer to hold the adjustment. It could be either a hex key, or a slot... I'm thinking hex key, but I can't remember for sure.

-Chuck

 

[greg2560]

my bad it is 30 psi hot cold

 

[Mongo]

Sooo... I backed off the adjustment nut 14 flats to its original position. I then moved it 12 more to the new fuel position (bypassed FDC). I then set the droop screw to 1 1/2 turns in.... and my deuce wouldn't start. So I moved the droop screw another 1/2 turn (2 full turns in) and the deuce wouldn't start. So I got mad.... and turned the smoke screw back in (more fuel) about 5 flats. The deuce started and seems to run OK. There is no black smoke... just a little grey smoke when I floor it. Now I just need to take it out for a spin....

BTW- The droop screw is a 1/8th hex head screw. I didn't see a lock nut or any locking device when I had the FDC off. It wasn't easy to move so I am not too worried about it backing off.