Inside Valve compartment on Plymouth "28 and later engine ,Oil?

[ArticiferTom]

On my L4 Plymouth behind each set of valve lifters  is a dam of motor oil . What is it purpose ? And how done oil move through it ? Maybe cooling or something with running in to lifter guides , but what filled it .

  I am in process of flushing whole oils system clean . Looks like all channels are below the lifter guides and splash gets above ?

[keithb7]

Little oil pools. Oil collects here and drains out through strategically drilled holes that align with the tappets.  This is how the tappets are lubricated. 
 

If you are switching up to a modern detergent based engine oil, yes indeed clean these pool out. Remove all built up sludge from earlier SAE oil use. 
 

Additionally drop the oil pan. Clean it out thoroughly.  The main oil suction screen too. Open the oil filter canister (if the engine is equipped with an oil filter) and be sure get all the sludge out of there as well. 

Edited July 12, 2022 by keithb7 (see edit history)

[keithb7]

The oil remains in the pools as the drain holes are situated up high near the top of the pools.  
 

Pools seen here.  How oil gets up there, I have yet to witness. Maybe oil mist settles here and collects?  I am certain oil is not pumped into these pools. I’ve been in my engine, head up in there checking valve clearances while the engine is running. I’m not seeing any oil splashing up into these pools.
 

 Just one more secret hidden with the Caramilk Bar and the KFC spices recipe I guess. 

 

Edited July 12, 2022 by keithb7 (see edit history)

[ArticiferTom]

Great , thank for explanation . I wish my job was that easy . But my whole system is contaminated with babbitt from bad rod . I already removed crank and working to figure out cam ,my first ever engine tear down . Also need to pull crank upper shells . Any insight welcome ..

[Pete O]

12 hours ago, keithb7 said:

The oil remains in the pools as the drain holes are situated up high near the top of the pools.  
 

Pools seen here.  How oil gets up there, I have yet to witness. Maybe oil mist settles here and collects?  I am certain oil is not pumped into these pools. I’ve been in my engine, head up in there checking valve clearances while the engine is running. I’m not seeing any oil splashing up into these pools.
 

 Just one more secret hidden with the Caramilk Bar and the KFC spices recipe I guess. 

 

 

I'm no expert on Plymouths, but was the 4 cylinder engine oiling fully pressurized?  I tend to think it wasn't as very few engines from the '20s were.   Anyway, I know first hand that in the 4 cylinder Ford Model A, that the oil pump pumped oil up into the valve chamber and no where else.  There was a dam toward the front of the valve chamber where excess oil overflowed and oiled the timing gear.   The valve chamber was kept at the oil level that dam controlled, and gravity fed oil to the the main and camshaft bearings through drilled passages.  The valve tappets were oiled by spray from the  pump discharge- there weren't drilled holes like the Plymouth seems to have for the tappets.  I suspect the Plymouth worked in similar way and that the oil pump filled the valve chamber.

[ArticiferTom]

Thanks ,Pete , That's what I was trying to figure . So can blow out all orifices and  channels . Will look in dams after cleaning to day . Have rags in absorbing know . Mine are little different then pic above in that on four cylinder it has dam behind valve tappets . But is hole on front side . Will get pic of what I find . backing off adjustment to remove cam now . Seems will not need to compress springs . Also mine is pressurized system .

[ArticiferTom]

Here pic of cleaning up valve area . On right is valve backed off seems to cleared . Do not see any feed orifice so must get from below squirts and splash . You can see dam ares in pic I found also . It holds the level to lube tappets as you said , Keith . Thanks again .

[DFeeney]

Plymouth 4 cylinder  engines from 1928-32 had a pressure oil system like modern cars.  Please note the 1928 used the Maxwell engine .  Plymouth redesigned the engine for 1929-32 , they were better and more robust and about the only parts in common with the 28 engine were the valves and valve guides.

[ArticiferTom]

Another problem going to have is rod bolts and nut where more modern one time disrupted thread . And have been un able to locate replacement of either original tee head with cotter pin hole or 2- 7/32 x 3/8 fine thread .  Only few vendors list my size most by engines with none matching my 4 ,  there are probably 6's  that cross I can not id . Best number can find is CRB481 and CRN454 . Any reference would grateful . Even old used cotterpin type . 

[DFeeney]

As a member of the Plymouth club, I have been in many garages over the years  with used piston /rod assembly's laying around.  If you need rod bolts I would think you could post  in the Plymouth section and find them. I have a 1928 Plymouth parts engine but think the 29/32 bolts might be different.