The Ford Barn

Ol' Ron · 11-12-2014, 10:10 AM

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 · 11-12-2014, 12:02 PM

Quote:

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 · 11-12-2014, 12:24 PM

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 · 11-12-2014, 12:58 PM

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 · 11-12-2014, 01:25 PM

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 · 11-12-2014, 01:51 PM

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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 · 11-12-2014, 02:08 PM

Quote:

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 · 11-12-2014, 02:43 PM

Quote:

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.

11-12-2014, 10:10 AM	#21
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: Fuel Pump Push Rod Bushing 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!

11-12-2014, 12:24 PM	#23
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Fuel Pump Push Rod Bushing 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.

11-12-2014, 12:58 PM	#24
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,860	Re: Fuel Pump Push Rod Bushing 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.

11-12-2014, 01:25 PM	#25
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: Fuel Pump Push Rod Bushing 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.

11-12-2014, 01:51 PM	#26
flatjack9 Senior Member Join Date: May 2010 Location: Oshkosh, Wi Posts: 4,526	Re: Fuel Pump Push Rod Bushing Sponsored Links (Register now to hide all advertisements) 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.