Fuel Pump Push Rod Bushing

[larry/Texas]

I need to replace the push rod bushing in an operating engine. How do you pull the existing one out and replace it in a late 21 stud engine? Any help and/or advice would be greatly appreciated.

Thanks

[Ken/Alabama]

I gotta ask.What's the reason for replacing?

[larry/Texas]

The rod is very loose in the bore and I understand this is a cause for reduced oil pressure.

[Andy]

They are always loose in the bore. There is no oil pressure on that cam bearing journal where the push rod runs. It just gets spray/ mist from oil getting out of the top of the oil pump. You can't loose oil pressure as there is none there. The bushing can not be removed without pulling the cam. They are driven down into the bearing cavity. It will be fine.

[Bruce Lancaster]

Absolutely correct! On other aspects of looseness, as long as it stays in between the cam and the cup on the pump it will be fine. New bushing can wait until engine needs an overhaul.
Also, on oil pressure, before you even worry remove one of the plugs or sender unit at back of engine and temporarily install a mechanical tube pressure gauge...there are too many imponderables in ancient electric gauges until they are verified with a mechanical gauge.
And remember...flatheads can survive with the barest flicker of movement down at the bottom of the pressure scale.

To emphasize...you can DISCARD the pushrod and not lose oil pressure. I have heard of cases of it causing some blue smoke thus (no umbrella put on hole) because of allowing more of the general oil fog into valve chamber, but it cannot drop pressure.

[Ken/Alabama]

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Originally Posted by larry/Texas

The rod is very loose in the bore and I understand this is a cause for reduced oil pressure.

Not true. I don't even have a pushrod in mine cause I have a electric pump. Been that way for 20 yrs and many miles.

[JSeery]

The oil goes around the outside of the bushing.

[Ralph Moore]

But on the 8ba this is an issue right?

[flatjack9]

No.

[Binx]

Originally Posted by flatjack9

No.

Yes

https://fordbarn.com/forum/showthread.php?t=99948

Lonnie

[JSeery]

Put a plug in mine but it is a 59a.

[larry/Texas]

Thanks for the information and discussion. I will not wporry about it until I need to do an overhaul. Thanks again

[El Rat]

To answer your question: Tap the bushing and pull it out. If you're worried about the debris use a vacumn while tapping.

[Andy]

Originally Posted by El Rat

To answer your question: Tap the bushing and pull it out. If you're worried about the debris use a vacumn while tapping.

Very bad advice!!!
The bushing is extreamly thin walled. Any tap will just cut it off when tapped. It takes a special thin ridged punch to get them out by driving them down.

[JSeery]

Also, something has to be there, so if you remove the bushing you have to install a plug. The bushing sets in the center of the oil galley.

[19Fordy]

After installing an electric fuel pump, I removed my 8BA fuel pump rod and the oil pressure did not drop. I did not remove the bushing nor plug it. Overcame mist problem by extinding a rod with a little cover that covers the bushing when oil filler cap is screwed down. Been like that for 20 + years. No problems.

[JSeery]

Originally Posted by 19Fordy

After installing an electric fuel pump, I removed my 8BA fuel pump rod and the oil pressure did not drop. I did not remove the bushing nor plug it. Overcame mist problem by extinding a rod with a little cover that covers the bushing when oil filler cap is screwed down. Been like that for 20 + years. No problems.

Yep, the oil flows around the bushing, not the rod. It is only if you remove the bushing that you will have major oil pressure issues. The oil coming out of the fuel pump rod hole on a 59a block is just oil splash. On the later blocks there is a small bleed hole that oils the fuel pump rod. If you do not plug it you will loose some oil pressure down stream from it. This may not show up as lower oil pressure on the gauge because it is up stream, but it will reduce the volume of oil down stream from the bushing. And it is true that flatheads can get by on fairly low oil pressure.

[flatjack9]

I don't believe this for a minute. Any change in restriction to oil flow will be seen at the gauge. Open up bearing clearance downstream and you will see a loss in pressure at the gauge. And removing the pushrod will make no measurable difference.

[JSeery]

Originally Posted by flatjack9

I don't believe this for a minute. Any change in restriction to oil flow will be seen at the gauge. Open up bearing clearance downstream and you will see a loss in pressure at the gauge. And removing the pushrod will make no measurable difference.

I agree flatjack, the claim was that with the fuel pump rod removed there was no drop in oil pressure. I was just trying to think how that could be. On a 59a there wouldn't be any pressure loss, but on a later model there would be. So, I will stop speculating and stick to the facts! These has to be some pressure loss on a late model engine with an open hole in the oil galley. Not sure how much it would show up on the gauge, but that hole is in the same range as the oil bypass restrictor.

[flatjack9]

Remember that the pushrod is not a tight fit in that bushing, so would hardly restrict any flow from that hole. So there would not be any difference with or without the rod. However it would definetly cause a more oil to spray around in the valve chamber.

[Ol' Ron]

With all the threads posted on the Flathead oiling system on the Barn for the past 10 years, how could this be an issue. Where would the pressure come from?? Think!

[JSeery]

Originally Posted by Ol' Ron

With all the threads posted on the Flathead oiling system on the Barn for the past 10 years, how could this be an issue. Where would the pressure come from?? Think!

Ok Ron, got me on that one, not sure what you are referring to. Could you explain? Are you saying that if the fuel pump rod bushing was removed where would the oil pressure loss come from? Or are you referring to not losing that much pressure through the hole on the late model bushing if it is left in place and the fuel pump rod removed?

[JSeery]

Nice diagram posted by 51 MERC-CT: The 8Ba push rods did not have the splash skirt, in fact the earlier 59ab pushrods were a smaller dia.

[Ol' Ron]

The small hole in the 8BA bushing might drop the pressure a pond or two, but it will make a mess of your fire wall. I weld these shut on my engines so you could run a stock fuel pump or not. The rod gets enough lubrication from the oil pump leakage. And that's another story.

[JSeery]

Quote from Bubba: I just fired a new flathead on my test stand, engine had good oil pressure but gauge actually had a jerk to it and oil pressure was a bit lower than usual. I didnt like the jerk in the gauge but ran the engine for a minute as well. The breather opening was covered with a piece of masking tape as i hadnt installed the breather yet. After some run time and coming to temp the tape blew off at about 2000 rpm and oil blowed out the hole.
A friend had stoped by and seen this and said the fuel pump hole MUST be pluged to stop this. We pluged the hole with a plug made up on my lathe. The jerk in the gauge went away and the gauge shows 5-10 psi more than it did.
On my engine the open bushing did change the oil pressure.??

Quote from Bruce Lancaster: More on the early block: Oil flow is around that bushing via a cast passage, sealed on its inner curve by the bushing. Note that with an intact bushing, it remains sealed with or without a pushrod...
Ol'Ron, one of the most experienced flatheaders on the planet, removes the bushing and ports that passage with a ball ended burr to ensure free flow. On pumpless engines, he removes the bushing permanently, taps the top of its hole to seal it, and plugs the bottom with the cam bearing below. This completely opens the area to oil flow.


Me:
That .060 hole is the same size as the restrictor in the by-pass oil filter system, so the pressure drop would be about the same as adding the by-pass setup.

[flatjack9]

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I agree that the hole is going to cause a drop in pressure. My contention is that it will also be about the same drop with the rod in also. Totally agree that something has to be done to eliminate the mess.

[Ross F-1]

Originally Posted by flatjack9

I agree that the hole is going to cause a drop in pressure. My contention is that it will also be about the same drop with the rod in also. Totally agree that something has to be done to eliminate the mess.

Exactly, not like the pushrod is tight in the bore.

I had a homemade plug in mine and drove it for 4 years with fine oil pressure. Pulled the manifold to do some work and found the plug laying in the lifter valley. I put it back in, started it, and it promptly blew right out again. So I'd been driving without it plugged for 4 years. I made a new plug out of a long bolt that bore against the underside of the block-off plate, can't blow out. And my oil pressure is essentially the same as it's always been; pushrod, no plug, or with the new plug.

[JSeery]

Originally Posted by Ross F-1

Exactly, not like the pushrod is tight in the bore.

I had a homemade plug in mine and drove it for 4 years with fine oil pressure. Pulled the manifold to do some work and found the plug laying in the lifter valley. I put it back in, started it, and it promptly blew right out again. So I'd been driving without it plugged for 4 years. I made a new plug out of a long bolt that bore against the underside of the block-off plate, can't blow out. And my oil pressure is essentially the same as it's always been; pushrod, no plug, or with the new plug.

Guess this answers two questions: 1. there is pressure loss or it wouldn't be blowing the plug out and 2. it doesn't seem to make enough difference to most people to worry about. I plugged mine and used a safety wire.