The Ford Barn

old ugly · 03-25-2022, 08:09 PM

Quote:

Originally Posted by nkaminar

Pull the engine and take it apart to make sure all the holes are clear and the bearings have the right clearance. The Model A engine is one of the simplest engines to work on. Why screw around? It is so easy to do a proper job. If it was running well then it means that a major overhaul is probably not needed, just a cleaning and adjustments. Maybe grind the valves while you are at it.

this may be what he ends up doing.
but
if it were I, i'd run it again and further diagnose the engine noise ,(which i think he said he was going to do).
sometimes searching for the source of a rattle or noise once the engine is apart is like looking for a needle in a H S.
id say if it still makes a noise after he gets it running again, the next step is to pull the pan or head depending on how the diagnosis goes.
lots of work to tear down the engine if it is a simple shim job.

bavArian · 03-26-2022, 05:39 AM

Thanks for all your input.
I've located the oil hole, and with a small endoscope-camera I can at least partially see it.

It seems to be a bit higher than the current oil level, so I'll check today to make sure the oil drains properly and it's not clogged.

As old ugly wrote the plan is to fill it up again and check with the regular oil if the knock is still present. Then I'll diagnose further. I won't pull the engine before I know where the problem is, especially because it's running good without any odd noise under load and didn't knock with the old oil from the previous owner.

Who knows, maybe the 15W40 was too thin for the (I assume) relatively low oil temperatures of the A? If that's the case the regular 40 should reduce the knock noticeably.
Never the less I'll of course make sure to check where it's coming from.

nkaminar · 03-26-2022, 06:58 AM

bavArian, Thanks for the update. Good luck with your car. I think I must have a problem as I love tearing an engine apart, always have every since I was 12. It is one of the first things I do with a car new to me. I always find something to fix and/or adjust.

There are a whole number of things that can cause a knock. The latest on my car was caused by the plunger for the cam gear not having a stiff enough spring. The knock was only at idle. The cam was moving forward and backward. I solved it by adding a spacer under the spring.

bavArian · 04-29-2022, 09:51 AM

Update:

A few weeks ago I jacked up the right side of the car to get the oil level higher in the valve gallery. Then I was able to verify that all oil drains are in fact free. The rear oil drain is a bit higher than the opening for the valve cover, no wonder I couldn't get the oil to drain through the rear drain hole. :P

Also switched over to regular 40W oil. That eliminated the knock under normal conditions. I still hear a slight knock for a few seconds when I start up the hot engine but it disappears as soon as there's proper oil supply.

I assume that either a main or a rod bearing is on the loose side. Will have to check that sometime this summer but it isn't a problem that needs to be fixed immediately.

Thanks for your help!

rotorwrench · 04-29-2022, 10:52 AM

The rear most cam bearing bore and journal is the one that required the service bulletin to drill a feed bore from the valve chamber down to that rear journal. It has to be done while the engine is disassembled.

A lot of these early engines had excessive wear on that rear bore area due to lack of lubrication over time. The fix is to have it centered up & resized with a boring tool for a repair bushing to go in there. Ford didn't use cam bearings so it is a more common problem than it should be. When the cam is under valve spring tension it will be quiet but as soon as the valves back there close then it makes a knock sound. It tends to quiet up as the rpm builds while driving so it's generally only noticeable at lower engine rpms.

bavArian · 04-29-2022, 11:59 AM

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That could very well be the problem. Is there a test to determine if that's the problem? I guess that it can only be properly tested if the head and valves are removed?

rotorwrench · 04-29-2022, 02:24 PM

It certainly has to have the tension removed. The pan has to be off to get to the shaft.

I had a similar problem with a helicopter transmission pinion bearing journal. The transmission was originally designed to take a max load of 1,750 lbs. After many model design changes it ended up in a max load of 2,500 lbs. About half way to overhaul on the new heavier design, it developed a knock sound with each full turn of the tail rotor drive shaft. It was a very noticeable pop each time. After tear down we found the drive pinion Timken bearing inner race was loose on the shaft. It was about .005" beyond limits. The manufacturer had it hard chrome plated back up then precision surface ground back to specs. The repair was expensive and it changed my attitude about the design. It changed the owners attitude as well. The machines were traded off several years later never to go back.

03-26-2022, 05:39 AM	#22
bavArian Senior Member Join Date: Sep 2019 Location: Germany Posts: 215	Re: Proper oil level in the valve galley Thanks for all your input. I've located the oil hole, and with a small endoscope-camera I can at least partially see it. It seems to be a bit higher than the current oil level, so I'll check today to make sure the oil drains properly and it's not clogged. As old ugly wrote the plan is to fill it up again and check with the regular oil if the knock is still present. Then I'll diagnose further. I won't pull the engine before I know where the problem is, especially because it's running good without any odd noise under load and didn't knock with the old oil from the previous owner. Who knows, maybe the 15W40 was too thin for the (I assume) relatively low oil temperatures of the A? If that's the case the regular 40 should reduce the knock noticeably. Never the less I'll of course make sure to check where it's coming from.

03-26-2022, 06:58 AM	#23
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,903	Re: Proper oil level in the valve galley bavArian, Thanks for the update. Good luck with your car. I think I must have a problem as I love tearing an engine apart, always have every since I was 12. It is one of the first things I do with a car new to me. I always find something to fix and/or adjust. There are a whole number of things that can cause a knock. The latest on my car was caused by the plunger for the cam gear not having a stiff enough spring. The knock was only at idle. The cam was moving forward and backward. I solved it by adding a spacer under the spring. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

04-29-2022, 09:51 AM	#24
bavArian Senior Member Join Date: Sep 2019 Location: Germany Posts: 215	Re: Proper oil level in the valve galley Update: A few weeks ago I jacked up the right side of the car to get the oil level higher in the valve gallery. Then I was able to verify that all oil drains are in fact free. The rear oil drain is a bit higher than the opening for the valve cover, no wonder I couldn't get the oil to drain through the rear drain hole. :P Also switched over to regular 40W oil. That eliminated the knock under normal conditions. I still hear a slight knock for a few seconds when I start up the hot engine but it disappears as soon as there's proper oil supply. I assume that either a main or a rod bearing is on the loose side. Will have to check that sometime this summer but it isn't a problem that needs to be fixed immediately. Thanks for your help!

04-29-2022, 10:52 AM	#25
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: Proper oil level in the valve galley The rear most cam bearing bore and journal is the one that required the service bulletin to drill a feed bore from the valve chamber down to that rear journal. It has to be done while the engine is disassembled. A lot of these early engines had excessive wear on that rear bore area due to lack of lubrication over time. The fix is to have it centered up & resized with a boring tool for a repair bushing to go in there. Ford didn't use cam bearings so it is a more common problem than it should be. When the cam is under valve spring tension it will be quiet but as soon as the valves back there close then it makes a knock sound. It tends to quiet up as the rpm builds while driving so it's generally only noticeable at lower engine rpms.

04-29-2022, 11:59 AM	#26
bavArian Senior Member Join Date: Sep 2019 Location: Germany Posts: 215	Re: Proper oil level in the valve galley Sponsored Links (Register now to hide all advertisements) That could very well be the problem. Is there a test to determine if that's the problem? I guess that it can only be properly tested if the head and valves are removed?

04-29-2022, 02:24 PM	#27
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: Proper oil level in the valve galley It certainly has to have the tension removed. The pan has to be off to get to the shaft. I had a similar problem with a helicopter transmission pinion bearing journal. The transmission was originally designed to take a max load of 1,750 lbs. After many model design changes it ended up in a max load of 2,500 lbs. About half way to overhaul on the new heavier design, it developed a knock sound with each full turn of the tail rotor drive shaft. It was a very noticeable pop each time. After tear down we found the drive pinion Timken bearing inner race was loose on the shaft. It was about .005" beyond limits. The manufacturer had it hard chrome plated back up then precision surface ground back to specs. The repair was expensive and it changed my attitude about the design. It changed the owners attitude as well. The machines were traded off several years later never to go back.