End play and loss of oil pressure?

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pett3227b
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End play and loss of oil pressure?

Postby pett3227b » Mon Jan 31, 2022 1:40 pm

I have just removed the cam from my block and am wondering if an excessive amount of end play would lead to loss of oil pressure? That is my biggest problem with my 47' after the oil warms up in normal running the oil pressure drops to below the danger level. I am definitely replacing the main bearings and probably the crankshaft. I was wondering if too much endplay could also lead to the pressure loss?

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Re: End play and loss of oil pressure?

Postby pett3227b » Mon Jan 31, 2022 1:45 pm

I was also wondering If I put the cam back in to check the endplay with the old bearings do the main bearing bolts have to be tightened to 55 pounds of torque to get an accurate measurement?

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Re: End play and loss of oil pressure?

Postby pett3227b » Mon Jan 31, 2022 3:55 pm

so I used the feeler gauges to check the end play. I did this with the cam only hand tightened around the main bearings. The end play on one side of the center bearing was 13 thousandths and the other side of the same bearing is at 11 thousandths. My question is this enough to cause a loss in oil pressure at warm operating temperatures? I looked at the bearings and I am going to replace them but they looked pretty good. General dull grey color and no obvious bad wear. I am trying to cover all the bases here before I get the replacement parts and reassemble. Is there anything else that i should check for a loss in oil pressure? I did not find any problem with the oil pump or the sump and tube.Thank-you

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Re: End play and loss of oil pressure?

Postby Mht » Mon Jan 31, 2022 5:06 pm

I don’t think end play will have a huge effect on oil pressure. Check the bearing clearance on the crankshaft and connecting rods with plasti-gauge as I think this is most likely where loss of oil pressure would come from. If clearances are out of spec you could most likely have your current crankshaft turned and then replace with bearings matched to the crankshaft after the necessary machine work is done.

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Re: End play and loss of oil pressure?

Postby 69ranger » Mon Jan 31, 2022 5:15 pm

The pressure loss that you describe, is more than likely an excessive clearence problem, some where, so you are on the right track.

You make reference to the cam, but then I get the idea that you are working with the crank as well. I will try and help and I am sure others will jump in as well.. I can not say for sure how much cam shaft lateral movement is acceptable, with out consulting the manual.

Before ordering any parts, you really need to be sure of the crank shaft size, on both on the rods and mains, other wise you are throwing money away hoping to get lucky.

The journal sizes are listed in the shop manual, and it gives a spec range. This can not be measured accurately with even a quality vernier caliper.
This must be done with a quality micrometer like a Starrett, tool. If you dont have these tools, take it to a machine shop where it can be measured accurately.
Once the measurements are determined, and the correct size bearings can be ordered, and installed. Bearing clearances can be checked with your old bearings, as well. They will need to be free from oil on the crank and both sides of the bearing shell, as oil takes up room, and alters the readings.

.001 - .003 Green Plastigauge can then be cut and placed on the bearing, and the cap torqued to the proper specs.
This is available at most auto parts stores, or from a local engine builder. An experienced counter person, (an endangered species) will know what you need.
Remove the cap and use the scale on the paper part of the material to check the crush of the gauge. The wider it crushes the less oil clearance you have. The manual give these clearances as well, .002 is about right, but there is a range that is acceptable.

Good luck on your project.

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Re: End play and loss of oil pressure?

Postby Glen » Mon Jan 31, 2022 7:55 pm

Hi,
The crankshaft is at the bottom of the engine, the cam or camshaft is above the crankshaft, at the left area of the engine.

The Cub and LoBoy service manual shows how to use plastigauge to check the crankshaft bearing clearances.
Below is the service manual, it has lots of info. I would read section 1, the engine section, before working on the engine.
There is a contents beginning on page 1 of most sections.
The crankshaft info begins on page 1-47, and the plastigauge info for the bearings on page 1-50.

http://farmallcub.com/rudi_cub/www.clea ... index.html

The connecting rod bearing clearances should be checked too.
Connecting rod info begins on page 1-32, and plastigauge info for them on page 1-34.

You can buy plastigauge at auto parts stores.

When measuring the end play of the crankshaft, slide the crankshaft fully ahead, so the gap is on 1 side of the bearing. The crankshaft is pushed ahead when you push the clutch pedal down. :)
Last edited by Glen on Mon Jan 31, 2022 8:06 pm, edited 1 time in total.

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Re: End play and loss of oil pressure?

Postby tst » Mon Jan 31, 2022 8:01 pm

also check the pressure relief valve to make sure it is free, crank end play is .004-.008 , so you probably have worn bearings, check main bearings with plastic gauge for .002-.003 clearance

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Re: End play and loss of oil pressure?

Postby ricky racer » Tue Feb 01, 2022 9:11 am

I agree totally with those above. I don't understand why you are messing with the cam if your issue is low oil pressure. Low oil pressure is usually the result of worn main and rod bearings. I suggest you take a look at the link below, I believe on page 6 you will find where Stanton uses plasti-gage to determine the clearances on his Cub's crankshaft and bearings. Plasti-gage (you'll need the green colored stuff) is cheap and available at any auto parts store (even if the clerk has no idea what it is). If the clerk doesn't know what it is, have him look it up!

viewtopic.php?f=1&t=111534&start=75
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Re: End play and loss of oil pressure?

Postby pett3227b » Tue Feb 01, 2022 2:07 pm

My plan is definitely replace the main bearings. I have gotten a consistent response from the forum that they are the problem. I am also going to replace the cam shaft.I will check on the relief valve as well. Thank-you for mentioning the valve. I never knew that there was one. Does anyone know where to get an engine gasket kit with front and rear main seals that fit a 47' cub?

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Re: End play and loss of oil pressure?

Postby SamsFarm » Tue Feb 01, 2022 2:13 pm

Whats wrong with your cam?

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Re: End play and loss of oil pressure?

Postby Eugene » Tue Feb 01, 2022 2:37 pm

pett3227b wrote:My plan is definitely replace the main bearings. I have gotten a consistent response from the forum that they are the problem. I am also going to replace the cam shaft.I will check on the relief valve as well. Thank-you for mentioning the valve. I never knew that there was one. Does anyone know where to get an engine gasket kit with front and rear main seals that fit a 47' cub?
No need to replace the cam shaft. It doesn't wear out.

Engine gasket kit - - local auto parts store. Rear main seal, send your retainer to TST and have him machine the retainer and install a new seal. Link below.
viewtopic.php?f=223&t=112430

You keep saying cam shaft when I think you are referring the crank shaft. For the crank shaft you need to measure all of the journals. If out of round or worn beyond specs you can have it "ground" which will require new oversized rod and main bearings.

Do you have the service manual for the tractor? It's available, free download, upper left of this page, Quick links.
I have an excuse. CRS.

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Re: End play and loss of oil pressure?

Postby pett3227b » Thu Feb 03, 2022 1:41 pm

yes the Crank shaft. Not the cam shaft. I am not used to working on these things very often. Just enough to get er right again.

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Re: End play and loss of oil pressure?

Postby 69ranger » Thu Feb 03, 2022 2:30 pm

Crank shaft could be suspect, but as mentioned it needs to be measured accurately to make sure.
Some insight on the crank condition can be learned by looking at the old bearings. How worn are they? Copper showing? More so on one side than the other? Are they scratched up, scored, or other wise damaged?

Measure, and look carefully at the bearing surfaces, and you will gain insight as to the condition of the crank.
If it has lots of hours on it, or has been ran low on oil, or not had proper service, then it may be in need of turning and the appropriate sized bearing installed and the oil clearances checked.

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Re: End play and loss of oil pressure?

Postby Clemsonfor » Fri Feb 04, 2022 1:45 pm

Eugene wrote:
pett3227b wrote:My plan is definitely replace the main bearings. I have gotten a consistent response from the forum that they are the problem. I am also going to replace the cam shaft.I will check on the relief valve as well. Thank-you for mentioning the valve. I never knew that there was one. Does anyone know where to get an engine gasket kit with front and rear main seals that fit a 47' cub?
No need to replace the cam shaft. It doesn't wear out.

Engine gasket kit - - local auto parts store. Rear main seal, send your retainer to TST and have him machine the retainer and install a new seal. Link below.
viewtopic.php?f=223&t=112430

You keep saying cam shaft when I think you are referring the crank shaft. For the crank shaft you need to measure all of the journals. If out of round or worn beyond specs you can have it "ground" which will require new oversized rod and main bearings.

Do you have the service manual for the tractor? It's available, free download, upper left of this page, Quick links.

Good catch, I and I think others couldn't understand all this talk about the cam shaft and why it was being talked about and referred too especially since people said it's the crank and the bearing clearances where the problem probably lies.

I know I kept being confused myself.


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