Full flow engines

[Tony WestOZ]

Hello to all,

I am sure I asked these questions many years ago back in the days of the original forum but as it has been that long since I have had anything to do with Dodge (trucks mainly) I have forgotten and a lot of my notes have long gone or been misplaced.

1. In what year did Chrysler introduce the full flow oil system?

2. When was the 3 ring piston introduced ?

3. When did the rear crankshaft change from the one that bolted on externally to the rear main to the rubber lipped one that was incorporated in the rear main?

 

I don`t think they all happened at the same time but the way my memory is who knows.

 

Any help appreciated

Tony    

 

PS I forgot to mention this is for the 251 engine.  

Edited September 17, 2019 by Tony WestOZ

[dpollo]

full flow appeared on the 251 as used in the Chrysler in 1946

3 ring pistons  3 7/16 bore in 1957

seals changed in an evolutionary way in 54 -55  but interchanging is possible and commonplace

[Tony WestOZ]

Thanks for that dpollo.

I did not think the full flow filter appeared so early. Live and learn. 

[dpollo]

earlier FFs had a canister type filter with large pipes  maybe 3/8 to and from.

 

Full flow blocks had an interesting emergency and startup bypass circuit in addition to the regular pressure bypass. If and when this got plugged there would be a knock upon starting reminiscent of a rod bearing with too much clearance. This was caused as air was forced through the oiling system.   Alarming but not fatal.

[Andydodge]

Tony...is this engine from a 57 onwards Royal or an earlier 25" block

[Tony WestOZ]

20 hours ago, Andydodge said:

Tony...is this engine from a 57 onwards Royal or an earlier 25" block

 

 It`s a NOS engine that came out from an Army surplus sale (at least that is what I was told) some 30 years ago when I picked it up.

It had been run but not for very long which was lucky as the oil filter had been installed incorrectly and the oil slinger had been put in backwards causing it to rub on the cam chain.

 

As it was in its green

 

It does not have an engine number stamped on the pad area. 

I have never seen a full flow pad setup like this on any truck engine in Australia. I am

 not 100% about the car engines but I have never seen one in a car either.

 

 

 

On ‎9‎/‎25‎/‎2019 at 11:46 AM, dpollo said:

 

 

Full flow blocks had an interesting emergency and startup bypass circuit in addition to the regular pressure bypass.

 

Do you have any info on this setup.

Apart from the different plunger size the major difference I found was the long plug that screws up into the block oil port so force the oil into the filter then back into the block. 

The plunger, spring and long plug on the right are for the full flow engine.

 

Tony

[Andydodge]

I can't help re the difference between the two oil setups but am curious re the red paint on the back of the block..........was the whole engine originally red?..........back when the Chrysler Restorers Club first started in Sydney in the early 70's they were able to purchase the remaining stock of brand new 25" engines from Chrysler Australia  for the club to onsell to their members.........these engines from memory were painted red and had no engine numbers...there was something like 25 or 30 engines purchased and were installed in all sorts of cars ..........I'll check the books I have to see if I can find any info re the oil setup................andyd

[Tony WestOZ]

The engine was the green colour when I got it. The redish colour is like the old red oxide (or red lead) paint used as an under coat then painted green.

 

Tony

[dpollo]

the by pass and oiling setup in general is thoroughly explained in the manuals of the day but especially in a Tech bulletin called Engine Oiling. (c 1950)  I have this, but not handy-by

[Tony WestOZ]

The Australian car manuals I have do explain the oil bypass system. The Canadian and Australian truck manuals show virtually nothing. The Australian manuals go from 46 to 62 and there is no mention of a full flow system nor the extra parts involved with them.

I had not noticed it before but the car manuals do indicate that they change to a three ring piston in about 58 but the trucks are still listed with a four ring piston up to 62. Very strange.

Also the rear crankshaft seal never changed from the external six bolt system to rear main bearing mounted seal.  We were a bit backward here.

 

Tony  

[Don Coatney]

Plug must be installed for a full flow filter to work. Not all 25" engines have capabilities to convert to full flow. Must've the diamond port (3-4) as pictured.

 

[Tony WestOZ]

Hello Don how are you going?

I do understand how the full flow works. The pics in a previous post show the diamond area and the long thin plunger that goes into the block from the bottom blocking the port so that the oil is diverted to the filter.

 

 

 

On ‎9‎/‎25‎/‎2019 at 11:46 AM, dpollo said:

Full flow blocks had an interesting emergency and startup bypass circuit in addition to the regular pressure bypass

 

 What I was interested in is this comment by dpollo. I do not understand the "emergency and startup dypass circuit". Maybe I am just confusing myself. 

 

Tony

[Don Coatney]

[Tony WestOZ]

Thanks for that Don.

Seems I have been over thinking it, a simple filter by-pass valve.

 

Tony