The Ford Barn

midgetracer · 07-16-2021, 06:19 PM

I have a 39 60hp flathead in a Model A roadster. Oil pressure drops to 10 psi when it warms up. When I installed it, I used an electric fuel pump. I did not put the fuel pump push rod in the engine. Could the low pressure be due to the absence of the push rod and the oil pressure leaking from the push rod guide?
If so what is the best way to plug the guide so I don't have the push rod just bouncing in the guide? Any help will be greatly appreciated. Normally I post on the A site, but this is a question for flathead experts.

Kube · 07-16-2021, 06:41 PM

10# at idle when it warms or at 50MPH?

midgetracer · 07-16-2021, 07:20 PM

10 psi at idle and at 50 mph when warm. Maybe as low as 7psi at idle.

KiWinUS · 07-16-2021, 07:22 PM

More info on engine please. Rebuilt. Old. Junker Real race midget engine or what.

midgetracer · 07-16-2021, 07:27 PM

Rebuilt stock engine with two 81 carbs and aluminum eddie meyer heads.

Kube · 07-16-2021, 07:32 PM

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Quote:

Originally Posted by midgetracer

10 psi at idle and at 50 mph when warm. Maybe as low as 7psi at idle.

So, if I am to understand correctly, you have about 10# at idle AND at 50MPH?

midgetracer · 07-16-2021, 07:41 PM

Yes, maybe a bit lower at idle. Hard to read gauge at less than 10psi.

drolston · 07-16-2021, 10:23 PM

The fuel pump push rod bushing does not have full oil pressure, but it probably should be closed off.

10 psi at idle is fine. Not at 50 mph. Something is fishy. Maybe check with a mechanical oil pressure gauge.

Is the oil pressure relief on a 60 the same as the 85? Could be

Kurt in NJ · 07-18-2021, 12:34 AM

30 lbs pressure at 3200 rpm is spec in service bulletins
the fuel pump push rod is open to crankcase next to cam bearing has no involvement with oil pressure.
There is a pressure relief valve under the intake manifold, i have seen the spring broken
What attention was paid to the oil pump and cam bearings during the "rebuild"?

midgetracer · 07-18-2021, 09:10 AM

new cam bearings and new oil pump gears. I will check pressure valve next.

Kurt in NJ · 07-18-2021, 11:46 AM

With the pan off you could do a "drip test", with a pressure pot --pre oiler put oil under pressure into the gauge port then watch the leakage out the bearings anything more than drips out of each bearing is too much---this is a way to determine the loss of pressure without taking everything apart ,it is outlined in the Ford engine rebuilding book as a way of eliminating oil pressure problems after delivery of rebuilt engines

KiWinUS · 07-18-2021, 12:48 PM

Oil gallery plug installed behind cam gear?

midgetracer · 07-18-2021, 05:10 PM

Kurt, Thank you. this is a good thing to try. Also thanks KiWinUS. I will check all of this when the temp goes down a bit. It has been close to 100F every day lately and my shop has no AC.

07-16-2021, 06:19 PM	#1
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Low oil pressure in 60hp flathead I have a 39 60hp flathead in a Model A roadster. Oil pressure drops to 10 psi when it warms up. When I installed it, I used an electric fuel pump. I did not put the fuel pump push rod in the engine. Could the low pressure be due to the absence of the push rod and the oil pressure leaking from the push rod guide? If so what is the best way to plug the guide so I don't have the push rod just bouncing in the guide? Any help will be greatly appreciated. Normally I post on the A site, but this is a question for flathead experts.

07-16-2021, 06:41 PM	#2
Kube Senior Member Join Date: May 2010 Location: Wisconsin, USA Posts: 8,990	Re: Low oil pressure in 60hp flathead 10# at idle when it warms or at 50MPH? __________________ "I can explain it for you. However, I can't understand it for you".

07-16-2021, 07:20 PM	#3
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Low oil pressure in 60hp flathead 10 psi at idle and at 50 mph when warm. Maybe as low as 7psi at idle.

07-16-2021, 07:22 PM	#4
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 2,954	Re: Low oil pressure in 60hp flathead More info on engine please. Rebuilt. Old. Junker Real race midget engine or what.

07-16-2021, 07:27 PM	#5
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Low oil pressure in 60hp flathead Rebuilt stock engine with two 81 carbs and aluminum eddie meyer heads.

07-16-2021, 07:41 PM	#7
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Low oil pressure in 60hp flathead Yes, maybe a bit lower at idle. Hard to read gauge at less than 10psi.

07-16-2021, 10:23 PM	#8
drolston Senior Member Join Date: Jun 2014 Location: Williamsburg, VA Posts: 1,627	Re: Low oil pressure in 60hp flathead The fuel pump push rod bushing does not have full oil pressure, but it probably should be closed off. 10 psi at idle is fine. Not at 50 mph. Something is fishy. Maybe check with a mechanical oil pressure gauge. Is the oil pressure relief on a 60 the same as the 85? Could be

07-18-2021, 12:34 AM	#9
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,156	Re: Low oil pressure in 60hp flathead 30 lbs pressure at 3200 rpm is spec in service bulletins the fuel pump push rod is open to crankcase next to cam bearing has no involvement with oil pressure. There is a pressure relief valve under the intake manifold, i have seen the spring broken What attention was paid to the oil pump and cam bearings during the "rebuild"?

07-18-2021, 09:10 AM	#10
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Low oil pressure in 60hp flathead new cam bearings and new oil pump gears. I will check pressure valve next.

07-18-2021, 11:46 AM	#11
Kurt in NJ Senior Member Join Date: May 2010 Location: on the Littlefield Posts: 6,156	Re: Low oil pressure in 60hp flathead With the pan off you could do a "drip test", with a pressure pot --pre oiler put oil under pressure into the gauge port then watch the leakage out the bearings anything more than drips out of each bearing is too much---this is a way to determine the loss of pressure without taking everything apart ,it is outlined in the Ford engine rebuilding book as a way of eliminating oil pressure problems after delivery of rebuilt engines

07-18-2021, 12:48 PM	#12
KiWinUS Senior Member Join Date: May 2010 Location: Charlotte NC KiWi-L100 available here Posts: 2,954	Re: Low oil pressure in 60hp flathead Oil gallery plug installed behind cam gear?

07-18-2021, 05:10 PM	#13
midgetracer Senior Member Join Date: May 2010 Location: Bismarck ND Posts: 1,189	Re: Low oil pressure in 60hp flathead Kurt, Thank you. this is a good thing to try. Also thanks KiWinUS. I will check all of this when the temp goes down a bit. It has been close to 100F every day lately and my shop has no AC.