Engine Oil Pressure Relief Plunger

[keithb7]

According to the parts drawing there should be a plunger to remove. Is there a trick to removing it? 
 

I don’t seem to have anything removable inside my 1953 block. Poked around in there a little bit with an oring pick. Nothing is moving. Tips appreciated. Thx. 
 

 

[dpollo]

It is there.  look into the two small holes  just inside the pan rail.  If the crankshaft is still in place, a shot of air into the oil gallery should push the plunger out.

 

If it were not there, you would have had no oil pressure.  If it were stuck the oil pressure would have been 100 lbs or more just after startup.  Make sure you get it out. If it remains in place and is stuck, you have real problems.

[keithb7]

Thanks dpollo I’ll try compressed air tomorrow. Crank is out. Block is stripped. Just a few remaining pieces to pull before it goes to the machine shop. 

[MarcDeSoto]

this reminds me of the time I rebuilt my first engine, a 1950 Chrysler Spitfire 6.  I had the block boiled out and when I finished the rebuild and started up the engine for the first time, I checked the oil pressure gauge to see if I had pressure.  The dial indicator had pegged and broken off!  The oil pressure relief valve had rusted tight. I didn't know anything about the oil pressure relief valve at that point.  I sold the car to a Navy man who was going to drive it cross country.  It blew up mid way across!  

Edited December 4, 2020 by MarcDeSoto

[Dan Heston]

My 15 year old and I just finished rebuilding our 230 flathead and got it back in the Coronet.  Got it started and...no oil pressure.  We realized that we didn't have the oil pressure valve in place.  We bagged and tagged each piece as it came off the block before it was sent to the machine shop.  We believe the valve must have still been stuck in place by the old oil sludge, and we didn't think anything of it at the time.  Needless to say, we are now without a valve plunger and there are no reproductions or eBay items around.  ANy help from anyone would be really good.  Hoping someone has one laying around or an old block that can be cannibalized.  

 

Dan and Andy

[Knaveofdarts]

Dan Heston, Vintage Power Wagons has your part:

 

Vintage_Power_Wagons_Parts_Catalog-Group_01_Engine.pdf - Google Drive

 

scroll down to the middle of page 5.

 

Vintage Power Wagons - VPW News - New Products & More

[sidevalvepete]

On 12/5/2020 at 9:55 AM, MarcDeSoto said:

 I sold the car to a Navy man who was going to drive it cross country.  It blew up mid way across!  

If this guy joins you on the forum one day he might set the hounds on you..... ..

[Sniper]

Hmm, you see my pic to the left?  That's me sitting on my destroyer somewhere out in the Persian Gulf.  So now I know who that was that sold me that junker, lol.

[ChrisMinelli]

When I was in the service we were expecting three new enlisted to join the unit.  I got a call from a Sgt. halfway across the country the day before who was working in a recruitment office.  One of my new guys was sitting in his waiting room with his orders on his lap not knowing what to do, because he had MapQuest’d the drive that morning (dating myself there) and realized there was no way he was going to make the morning muster without driving all night at 200 mph.  Needless to say once he showed up he was not the brightest star in the sky.  

[Sniper]

TO date myself, I am reminded of this quote

 

Elwood: It's 106 miles to Chicago, we got a full tank of gas, half a pack of cigarettes, it's dark, and we're wearing sunglasses.
Jake: Hit it.

[Dartgame]

I bought a stripped down standard bore 218 block that had been hot tanked and then shelved. Unfortunately the pressure relief valve was not removed and rusted into the block. I tried like He** to get that thing out and gave up. It now sits in the garage. 

[Sniper]

Ever try the molasses trick for rust removal?  I hear good things, but no direct experience.

 

https://christinedemerchant.com/molasses-rust-removal.html

[Plymouthy Adams]

as phosphoric acid does not eat good metal and reacts only with oxide (rust) I would recommend this application and monitor the process and not just leave it to dry out also...

[normanpitkin]

My 48 new yorker suddenly had full oil pressure and i removed the plunger to clean it ,no dice ,but when i soaked it in vinegar for a week and then buffed it with my dremel ,it was good as new!

[Dartgame]

I'll Give the plunger another try some day. Too darn cold here to fool with it. Block is sitting in the unheated part of the garage...

[Dodgeb4ya]

2 hours ago, normanpitkin said:

My 48 new yorker suddenly had full oil pressure and i removed the plunger to clean it ,no dice ,but when i soaked it in vinegar for a week and then buffed it with my dremel ,it was good as new!

At least Chrysler relief valves are easy to service being a cartridge style valve...and easily adjustable too.

Edited December 30, 2020 by Dodgeb4ya

[Plymouthy Adams]

yes and you pay more so in reality you should get more....is this the straight 8 engine?

[Dodgeb4ya]

It is the straight eight.

This removable cartridge OP relief valve design started in the very early Chrysler production cars...and is also found in the big Moly Block DT engines too.

Up thru 1948 on the cars a cast iron dome is used to cover the adjustable relief valve.

On the trucks and 1949-50 Chryslers a big hex nut covers the valve...shown is the Moly block regulator...

Edited December 31, 2020 by Dodgeb4ya

[dpollo]

I successfully dealt with a stuck plunger by installing an oil pump with the relief valve in the cover (53-4 Chrysler)

 

the downside is that the bypass oil filter does not work.  Temporary repair, still running so far as I know 30 years later.

[Knaveofdarts]

hmm. so my '50 which i just got running, which apparently makes 70 psi at idle, probably has a stuck relief valve. Good to know. I'll pull it, check it, clean it before I run it too much more. I know at least some of the oil is getting to the bypass filter, because it has a small leak from the oil filter canister top nut washer.

[dpollo]

Oil is supplied under pressure to the filter.  with a stuck bypass, it cannot return to the pan.

[Knaveofdarts]

Gotcha. So, no filtering action and the only oil returning to the pan is what sheds from the various bearing clearances. It's probably putting additional stress on the pump too.

[50BusiCoupe]

8 hours ago, dpollo said:

Oil is supplied under pressure to the filter.  with a stuck bypass, it cannot return to the pan.

So newbie question my ‘50 dodge has never had an oil filter. Is there still a bypass valve in the block?

Edited December 31, 2020 by 50BusiCoupe
Spelling

[Jerry Roberts]

Yes . 

[rallyace]

On 12/30/2020 at 1:41 PM, Plymouthy Adams said:

as phosphoric acid does not eat good metal and reacts only with oxide (rust) I would recommend this application and monitor the process and not just leave it to dry out also...

Phosphoric acid is what makes Coca Cola such a good rust remover.