adding an oil filter to L134?

fwee willy

New member
I have a 47 Willys with the 134 engine. The engine currently has no oil filter. I have an old parts manual that shows a canister filter bolted to the right side of the head with the lines going over the head. I'm assuming the lines connect to the oil rail on the lower left side of the engine. Since I don't have the canister I'm planning on mounting a spin-on filter on it but don't know for sure how to connect the lines to the engine. The oil rail has 3 or 4 plugs in it. Can I connect the lines to any of these ports? I would appreciate it if someone who has a 134 engine could let me know where the oil lines from the filter canister connect to the engine. Thanks Stan
 

A spin on filter will not do much since it is more like a screen than a filter. The spin on filters on modern engines go in line right after the pump and trap only the biggest particles. The old engines, like the L head usually had a bypass filter. The bypass filter takes a controlled amout of oil from the galley, filters it, and returns the oil to the pan. Modern bypass filters are available and can keep the oil very clean. Best of luck - John
 
A spin on filter will not do much since it is more like a screen than a filter. The spin on filters on modern engines go in line right after the pump and trap only the biggest particles. The old engines, like the L head usually had a bypass filter. The bypass filter takes a controlled amout of oil from the galley, filters it, and returns the oil to the pan. Modern bypass filters are available and can keep the oil very clean. Best of luck - John


Are the bypass filters all of the canister variety? If I get a bypass filter I connect the inlet hose to the oil galley and the outlet hose where? Thanks STan
 
Hi Stan,

Sorry, I've been away from the forum for a bit...

The modern bypass filters that I've seen are cartridge type and are available in several sizes. Some of these use paper towel or even toilet paper rolls for filters. I don't know if I like that or not but as long as there is some sort of screen on the output side in case the paper breaks off it should be OK. Other filters use a cartridge element that you need to buy from the manufacturer. Big over-the-road trucks sometimes use the paper towel units and they supposedly only change the oil when it fails the lab tests for contaminants. Some of the guys with the old Dodge Cummins pickups have run them and claim that they work very well. I would do a little searching on the net and see what's out there for small units. The paper towel units are WAY to big for a Jeep. I think the factory made cartridge type might be less worrysome. Oil does not dissolve paper BUT I would worry about bits maybe coming loose. Like I said though, if there is a screen it might be fine to use. The input to the filter comes from the oil galley (might as well use the stock plug on your engine) and the output from the filter goes to the oil pan, or into the block just above the pan. (again, you may have a plug there too since these engines did have filters on them in some applications) . I can look on my M38 for exactly where the plugs are if you would like. If you can't find a modern filter that you're happy with you could always get an old stock unit. Napa still sells the cartridges for those. Best of luck - John
 

Hi Stan,

Sorry, I've been away from the forum for a bit...

The modern bypass filters that I've seen are cartridge type and are available in several sizes. Some of these use paper towel or even toilet paper rolls for filters. I don't know if I like that or not but as long as there is some sort of screen on the output side in case the paper breaks off it should be OK. Other filters use a cartridge element that you need to buy from the manufacturer. Big over-the-road trucks sometimes use the paper towel units and they supposedly only change the oil when it fails the lab tests for contaminants. Some of the guys with the old Dodge Cummins pickups have run them and claim that they work very well. I would do a little searching on the net and see what's out there for small units. The paper towel units are WAY to big for a Jeep. I think the factory made cartridge type might be less worrysome. Oil does not dissolve paper BUT I would worry about bits maybe coming loose. Like I said though, if there is a screen it might be fine to use. The input to the filter comes from the oil galley (might as well use the stock plug on your engine) and the output from the filter goes to the oil pan, or into the block just above the pan. (again, you may have a plug there too since these engines did have filters on them in some applications) . I can look on my M38 for exactly where the plugs are if you would like. If you can't find a modern filter that you're happy with you could always get an old stock unit. Napa still sells the cartridges for those. Best of luck - John

Hi John
Thanks for getting back to me. Yes I would appreciate it if you could check where the lines actually connect to the engine. Also i checked with United Auto and they sell both, a flow-through and by-pass filter head, of the spin-on variety. He didn't know what the difference was between the two. I'm assuming the bypass filter must have some kind of restriction to maintain oil pressure if it just dumps back into the oil pan. I would like to get rid of the mess related to the canister if possible but don't want to compromise the engine. This may be a mute point as I don't know how long the engine ran with no filter at all. Thanks Stan
 
Hi Stan,

Yes, the bypass type must have a flow limiting orifice so that you don't lose too much pressure. I'm not sure where that restriction is located but I would check it out before installing the kit. The directions hopefuly will say something about the restriction - some units may even be adjustable. I'll try to look at the M38 tonight and see where the hoses go. -John
 
Hey Stan...

Sorry it took me a bit to get down to the M38 - I sure miss driving that little Jeep (it's in storage right now:( ) . I see that the oil return line from the filter connects to the top edge of the timing chain cover - slightly right of center. The oil supply line runs down in between the fuel pump and the front motor mount plate. It's pretty tight in there and I can't see where it attaches but there must be a fitting into the block (oil galley) right in front of the fuel pump. The civilian motor mounts are probably different (more in the center of the engine) so you might have more room in there. Look closely right in front of the fuel pump and see if you have a plug there. The military motor mount grabs the front of the engine block and the Jeep is made so that you can lower the grille (it's on hinges) , disconnect the driveshafts, etc, and quickly remove the whole engine, radiator and transmission assembly as a unit. They called this a "battle field insert" . I hope this helps in your quest for a filter. Good to see an other Flattie get out there !! Best of luck - John
 
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