8RT engine differences

[skidmarks]

I got this motor a few years ago and got it out to put in a truck.

I noticed that it has 3 oil ports and made in Canada on the heads. It does have a number stamped in the intake rail but didnt write it down.

Anything different about this engine compared to any of the other 49 to 53 ford and merc motors?

Compared to a 53 car motor that was sitting next to it, the end of the crank flange was drilled on the car motor and not on this truck motor. Is that for automatic transmissions?

[JSeery]

The third oil port was for an oil filter. This engine should have had a PCV system originally as well.

[skidmarks]

So the extra port is were the filter returns to instead of the side of the pan or block like older motors?

[51 MERC-CT]

Originally Posted by skidmarks

Anything different about this engine compared to any of the other 49 to 53 ford and merc motors?

Compared to a 53 car motor that was sitting next to it, the end of the crank flange was drilled on the car motor and not on this truck motor. Is that for automatic transmissions?

The 8RT's were used in the trucks from '48-'53.
Yes, the bored out crank was to accommodate the automatics starting in '51.

[JSeery]

Originally Posted by skidmarks

So the extra port is were the filter returns to instead of the side of the pan or block like older motors?

It is similar to what is currently referred to as a 95% filter system as opposed to a by-pass filter system. The by-pass setup routes a small part of the oil through the filter and them returns it to the oil pan. The setup shown in the diagram routes all of the oil (except the part feeding the rear main) through the filter and then to the engine oil passages.

[Phil Gillespie]

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Originally Posted by JSeery

It is similar to what is currently referred to as a 95% filter system as opposed to a by-pass filter system. The by-pass setup routes a small part of the oil through the filter and them returns it to the oil pan. The setup shown in the diagram routes all of the oil (except the part feeding the rear main) through the filter and then to the engine oil passages.

Have a 59A Canadian engine which has the 3 ports as shown.
It is set up for the by-pass oil system. So to fit a mechanical oil pressure gauge need to tee of the oil sender unit or discharge to oil filter.
Phil NZ

[skidmarks]

I got the filter like shown in the picture but not the bypass valve.

Story I got with the motor was it came from a irrigation business that sold stationary power units for pumps.

Anything different about the 8rt made in Canada heads then a 7rt or a made in USA head?

I also got a 59AB factory relieved motor from the same place with a 2 piece oil pan, crab distributor and a 40/41 crank pulley

[rotorwrench]

Canadian military engines prior to WWII were set up to fit in the Bren gun carriers. They have external oil cooling & filtration systems. Ford USA manufactured an updated version of the carrier during the war except that it was equipped with the larger 239 CID engine but had the same cooling and filtration system. After the war, all the civilian blocks had the boss for the oil out tap but it was never finished. It's just a bump there. The Canadian engines continued to use their own oil filtration system after the war but mostly for trucks & other heavy duty industrial applications.


A person can go back to the standard Ford bypass oil filtration system as long as the port from the pump is crossed over to the port for engine oil internal feed. There were special fittings for the input port that blocked the opening between the oil pump output side and the engine oil feed side but I don't know if they were used in all applications. A person has to remove the plug from the side of the feed block and put a tool through to the oil output port to make sure its open if going back to the standard bypass system. If it has the full pressure bypass system the port between the outlet & inlet has to be blocked or it will bypass the filter.


Many of the Canadian systems were set up just like their USA counterparts but industrial & heavy duty applications should be checked. You want to make sure you get oil pressure to the engine or it won't last very long. This has happened to folks before that were unaware of some of these different applications.

[skidmarks]

The motor is used but no Idea how many miles . Both people that would have known are deceased.

It looks like it had a bypass filter set up on it by the lines and the third port is plugged.

[JSeery]

Originally Posted by skidmarks

It looks like it had a bypass filter set up on it by the lines and the third port is plugged.

That would be my guess as well.

[Ol' Ron]

Good information on the oil filter system. Also the 8RT heads have a larger combustion chamber and a low compression. Replace with 8BA or EAB/ I used this oil filter system on all my builds. With the cost of putting these engines together, it might make them last alitter longer.

[JSeery]

Originally Posted by Ol' Ron

Good information on the oil filter system. With the cost of putting these engines together, it might make them last alitter longer.

Unless you connect the hoses backwards!