Oil pressure gauge

[51Deluxe]

Looking for a place to plug in a mechanical oil pressure gauge as I don't trust the factory one. Someone mentioned a place below the exhaust manifold. I can see it but it looks very hard to get to. I noticed a fitting on the lower side of the oil filter housing. Is there pressure at that fitting?

[51Deluxe]

Never mind- I pulled the plug, started the motor and a couple of ounces came out, so it is obviously under pressure. Must have been a former tap for a gauge. I installed the underdash unit and it reads 20 at idle and 35 at fast idle. The factory gauge reads 20 max  and at times goes down near zero, while driving. I'll take it for a drive tomorrow and see if that happens with this gauge.

[joefrazer]

If you're tapping into the oil filter line, it works as a bypass circuit so your reading may fluctuate at times. The best place to install the line for your gauge is in place of the sending unit which is mounted under the manifold just in front of the bell housing. I've attached a picture of what it looks like.

[51Deluxe]

I saw that unit and decided not to try to remove it due to being hard to access. So how would being a bypass unit affect the readings?  Seems like it takes a few seconds to register a reading when first started.

[porsche1914]

Does the same hold true for a 6 cyl. Henry J? I have my oil pressure gauge tapped off the line to my oil filter.

[51Deluxe]

Took my car for a long drive and monitored pressure on the new mechanical gauge. Fine when cold (20 at idle, 35 at speed) but once well warmed up, pressure drops to 20 at speed and zero-5 lbs at idle. Engine is supposedly completely rebuilt, not sure where to go from here. I did check the oil level immediately upon returning from the trip and there is plenty of oil in the sump (at one time I suspected oil was not draining back fast enough).

[joefrazer]

The oil pump body is a cast iron unit while the end plate covering the gears is a stamped steel item. Their expansion rates differ and over time,  the plate warps and allows oil to leak out which lowers pressure when hot.

You can also check the relief valve. It's the bolt sticking out of the block behind the exhaust pipe. Washers are used to aid in keeping oil pressure up. Occasionally it helps to add a washer ahead of the spring behind the bolt. 

Just a couple of ideas!

[rialto]

You probably won't get a good reading from the oil filter tap. Best to use the original gauge hole. Slow oil drainback wouldn't be a problem in this engine unless it's all mucked up with sludge. You could pull the side cover to check for dirt. Recently rebuilt should be clean. During a rebuild some times the oil pump only gets a kit put in it instead of a whole new pump.  The 226 almost always needs a new pump.

[mbflemingkf]

Not hard to get to the gauge outlet from under the car.  That's where the engine is designed to read from; go for it.

[51Deluxe]

Yep, I'm leaning the same direction- new pump. Not looking forward to pulling the pan though. Wish I had a lift. Growing up rural, my dad had a "pit" to pull the car over and work on the underside. I was a bit spoiled by that.

[51Deluxe]

So where is the best place to get an oil pump and rear main seal?  Walck's jeep parts has a pump for '54 and up 226 "Hurricane" engines- is this the same pump?

My engine if I recall correctly has been replaced with a '54. The  model # on the engine plate is 6L226K.

[joefrazer]

Yes, it is the same pump. KF used the same pump from 47-55 and Willys used it in the 226 engine thru the end of production.