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Duskylady

Water pump & oil pump

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Greetings and salutations! Currently I’m doing an engine swap on a 1941 Plymouth sedan, no updates, still a 218. Using the original service manual has answered most of my questions. I am stuck on a few things. One, what kind of gasket sealer should I use on the new water pump? Two, how do I know if an oil pump is good with the engine on a stand? Many thanks for any help!

B6BEF0FF-52CD-4BC7-BFF7-C2493DE13DAE.jpeg

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I believe you can take the distributor out and spin the pump with a spare shaft and a drill motor. I have done so on a Ford, but not on a Plymouth

 

I used to use Permatex Aero on my engines, but nowadays I tend to use Permatex silicone.

Make a thin even coat, so you don't get excess sealer in the coolant, plugging up holes you want open.

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14 minutes ago, Ulu said:

I believe you can take the distributor out and spin the pump with a spare shaft and a drill motor. I have done so on a Ford, but not on a Plymouth

 

I used to use Permatex Aero on my engines, but nowadays I tend to use Permatex silicone.

Make a thin even coat, so you don't get excess sealer in the coolant, plugging up holes you want open.

Unfortunately the pump on the Mopar is the driver as it has the gear rather than the distributor.  So, you can't spin it with a spare shaft as the gear is engaged with the cam.

 

But, it is easy to remove and disassemble for inspection.

 

Yes on the silicone.  It is a boon for these old engines.  Cheap vinyl gloves to apply and spread work better for me than trying to use the 'even bead' approach. Also great in the oil pan corners that so often are sources of leaks.

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The key on the distributor turns the pump. Make a shaft to fit that key. On my ford it was a hex shaft, so easy.

Plymouth has a straight key drive, so a collar might be needed to keep it engaged.

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Thank you for the advice!  I will check the oil pump when the engine is assembled closer to completion. I have Permatex for the water pump. Just wanted to be certain it would be okay to use. 

Edited by Duskylady

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40 minutes ago, Ulu said:

The key on the distributor turns the pump. Make a shaft to fit that key. On my ford it was a hex shaft, so easy.

Plymouth has a straight key drive, so a collar might be needed to keep it engaged.

You cannot rotate the flathead oil pump in any manner after taking out the distributor.

The distributor does not drive the oil pump.

The cam gear turns the oil pump drive gear.

The only way to rotate and say prime a flathead engine using the oil pump is to use another pump with the pump drive gear teeth ground off.

To inspect your old oil pump follow what the factory shop manual instructs.

 

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1 hour ago, Ulu said:

The key on the distributor turns the pump. Make a shaft to fit that key. On my ford it was a hex shaft, so easy.

Plymouth has a straight key drive, so a collar might be needed to keep it engaged.

On the Ford, yes.  On Mopar flatheads, no.  The oil pump drives the distributor, See post 3.

 

Another example of good engineering.  I've had the pleasure of repairing the carnage that happens when that too small hex drive on early versions rounded or sheared on a cold winter start.  Not mine, thankfully, customers.  Distributor was happily making the engine run. Oil pump, not so much.  Some folks noticed before the engine quit, others didn't.  Can't happen with a flathead Mopar!

Edited by kencombs

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Well it's been too long since I tore one apart guys. I just looked at my distributor and you are absolutely right.

 

And you are right about the Ford because I saw a few of them in Minnesota that had sheared oil pump shafts in cold weather.

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By the way back in the seventies I primed an oil pump on a tractor by filling the engine with a drum of motor oil and letting it sit overnight.

 

Nobody had primed the oil pump before it was installed, and they wanted me to pull the pan off. It too could not be primed from above.

 

 

I drained it down after oil had seeped into all of the passages.  Then I had half a barrel of slightly used oil that we just put into other engines. That engine had instant oil pressure when we started it

 

It saved me a lot of Labor and Gasket scraping.

 

 

 

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Oil pumps in the flat heads are very reliable other than the oil pump cover rubber O -ring getting hard and leaking.

Edited by Dodgeb4ya

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You guys are awesome and full of knowledge!  I blew the camshaft out of the oil pan on my other motor in December on my way to my sisters to bake cookies. Not sure what the cause was yet,  motor is still in the car.  Attempting to get the replacement up to snuff and  doing everything I can to prevent that mayhem again. Keep the knowledge flowing!

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You must have been haulin Azz to get to those cookies🤣

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I've seen cams seize but I've never seen one break. The engine normally just stops.

You should post a gruesome photo of the carnage! I'll bet it's a bloody mess.

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1 hour ago, Ulu said:

I've seen cams seize but I've never seen one break. The engine normally just stops.

You should post a gruesome photo of the carnage! I'll bet it's a bloody mess.

Probably broken with a hit from a rod.  Broken bolt/piston/seized and broken etc.  Not to uncommon with some engines, rare with 6 cyl mopars.

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I've seen some use a pressurized container of oil connected to the oil gauge port to prime the engine.  Something like a garden sprayer with a fitting on the end of the hose instead of the sprayer wand would do.  Similar to this

  oilprimer.jpg

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6 hours ago, Sniper said:

I've seen some use a pressurized container of oil connected to the oil gauge port to prime the engine.  Something like a garden sprayer with a fitting on the end of the hose instead of the sprayer wand would do.  Similar to this

  oilprimer.jpg

i've done similar with my Sure Shot sprayer and an adapter.  Same one I use to spray cleaning fluids and solvents.

LInk: https://www.amazon.com/sure-shot-sprayer/s?k=sure+shot+sprayer

Edited by kencombs

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If you have not done so be sure to prime the pump. To do so remove from the engine and submerge in oil and rotate the pump shaft so all air is expelled and install in the block.

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