fuel pump rod

IVT1

IVT1

Senior Member
I want to not run a mech.pump at all & go all elec. do I need to remmove the fuel pump rod, or is blocking off the opening enough ?
 
The bushing that the push rod operates in does have a small orifice that gets pressure from the valve chamber supply tube. How much pressure would be lost there is an unknown factor but I would gestimate it to be a small effect. If a person was worried about it they could machine a 2 inch bolt shank down to fit in there (0.442" is the Diameter of the 8BA types). The idea would be just to block the hole but not where you couldn't pull the plug out and reinsert the rod if you wanted to.

Some folks just pull the rod and let it leak. Many say that it doesn't effect the oil pressure noticeably.

Kerby
 
Rotor Wrencg is right on the 8BA block, If the engine is a 59AB or older it does not have the small hole in the bushings so you don't have to plug it. Walt
 
Walt:
Not trying to be smart.
( I tried that once, But I could not find a hat to fit )
When you said Rotowrench was correct, did you mean that with out the fuel pump push rod there would be very oil pressure loss OR that the plug should be made and installed in place of the push rod.

THANKS
BILL W
 
Bill. that litle piss hole in the 8BA bushing is so small you won't notice any drop in oil pressure if it's not plugged. BUT, it squirts a little stream of oil against the side of the bushing half way down the hole and it likes to put a mist of oil in the valve spring area that won't hurt anything but it could make the engine suck a little more oil past the the valve guides. SO, that's why I plug the 8BA push rod hole. Walt
 
In the early 8BA blocks produced in 1948, that were used in the trucks, and probably in some of the early 1949 8BA engines, there was NO fuel pump pushrod bushing. The block was machined to accept the fuel pump pushrod with the same tolerance as the hole in the bushing used in later production. The oriface that allows oil to get to the pushrod is much larger than the "piss" hole that's in the later bushing and allows a much greater flow thus a much larger amount of oil splashing around in the valve chamber with the pushrod removed. I'm not sure of the amount of pressure at that location; JWL has that info for sure, but in my '48 8BA, I used a shortened 8BA pushrod with a washer welded to the top that suspends it in the hole without it touching the cam.This takes care of the splash problem as well as any pressure loss that may occur. All this assumes operation with a full time electric fuel pump. Setting it up this way allows you to go back to a regular mechanical fuel pump operation as originally supplied by Ford if you want to JMO. Ken
 
Agree totally with KGS. I don't like the idea of the pushrod hopping freely up and down hammering the pushrod lobe on the cam. My preference is to machine a bolt to fit the rod hole, but short of reaching the cam. If you ever want to go back to the stock pump, just lift the bolt out, being assured the lobe is in good shape.
 
KGS said:
In the early 8BA blocks produced in 1948, that were used in the trucks, and probably in some of the early 1949 8BA engines, there was NO fuel pump pushrod bushing. The block was machined to accept the fuel pump pushrod with the same tolerance as the hole in the bushing used in later production. The oriface that allows oil to get to the pushrod is much larger than the "piss" hole that's in the later bushing and allows a much greater flow thus a much larger amount of oil splashing around in the valve chamber with the pushrod removed. I'm not sure of the amount of pressure at that location; JWL has that info for sure, but in my '48 8BA, I used a shortened 8BA pushrod with a washer welded to the top that suspends it in the hole without it touching the cam.This takes care of the splash problem as well as any pressure loss that may occur. All this assumes operation with a full time electric fuel pump. Setting it up this way allows you to go back to a regular mechanical fuel pump operation as originally supplied by Ford if you want to JMO. Ken
Click to expand...
Hi KGF, I've done a couple of those 48 truck 8BA engines without the pushrod bushing. Those blocks have a pipe plug in the back of the block so the factory could bore that little hole through the push rod hole into the main line. I didn't relize that piss hole was bigger but your probably right. But I usually make up some kind of a plug when leaving out the rod in the 8BA engine. Walt
 
You must log in or register to reply here.
Back
Top