SPF oil pressure gauge

[ou812545]

I need to bleed my oil pressure gauge line at the gauge on my SPF.

Any suggestions on how to best access the oil pressure gauge?

Thanks,
Dan

[thudmaster]

When I did mine I just pulled the gauges out fromt the left to the right. You will have enough room to do the deed. Good luck.

[RedBarchetta]

Just pull the speedometer and you'll have enough room to get at it. I have Mongo hands and it wasn't too bad once I got that out of the way. I think I only filled the swear jar 1/4 full on this job.

-Dean #747

[ou812545]

Dean,
That's a good idea. I will pull the speedometer first.

Thanks,
Dan

[Got the Bug]

Dan,

What do you mean by "bleading the oil pressure line at the gauge"?

[Got the Bug]

Dan - FYI.

I recently swapped the stock line out with a braided line. Here's the thread with the info and install advice from Blas and Velox.

Best way to access back of oil pressure gauge

Per Blas' post:

"Technically, the air pressure in that small oil line is what registers on the gauge. The oil does not necessarily ever make it to the instrument. (thought sometimes you can see some in the original plastic tube) If oil actually made its way to the gauge, that tells you you have an air leak at the gauge fitting."

[ou812545]

We recently installed my rebuilt 418 and the pressure stays at 43lbs at all times. We expect the high output oil pump to produce closer to 65lbs. My engine build suspect it's one of 2 things.
1. There is an air bubble in the oil pressure line.
2. The spring valve on the oil pump is set incorrectly.

In order to eliminate option 1, I need to crank the motor and bleed the oil pressure line at the gauge. Loosed the oil line with a rag ot remove the air.

That's what we are planning unless there is a better way.

Dan

[RedBarchetta]

Dan, be careful how much you crank up the spring pressure on that adjustable oil pump. I'm running a similar Mellings unit and I ended up turning it back down to stock because I was seeing too much pressure (after I decided to turn it up some). I run straight Kendall 50 SAE and my pressures are stable. Mid 50's upon start-up and reaches low/mid 60's until the oil gets warm. Then maintains 39-40 at a 800 idle when fully warmed up. You only need 10psi per every 1,000 rpm to get effective lubrication...anything above that and you're just pumping more oil than you need and working the oil pump that much harder. I see at least 60 psi at my redline of 6,000rpm (rev limited...I don't twist this particular motor as hard as I have others...this one doesn't need it).

-Dean

[Got the Bug]

Originally Posted by ou812545

We recently installed my rebuilt 418 and the pressure stays at 43lbs at all times. We expect the high output oil pump to produce closer to 65lbs. My engine build suspect it's one of 2 things.
1. There is an air bubble in the oil pressure line.
2. The spring valve on the oil pump is set incorrectly.

In order to eliminate option 1, I need to crank the motor and bleed the oil pressure line at the gauge. Loosed the oil line with a rag ot remove the air.

That's what we are planning unless there is a better way.

Dan

It's possible that the gauge is bad. One option (before getting into the dash...which is a pain in the rear) might be to try and rig something up to check the pressure at the engine to validate the accuracy of the gauge.

[ou812545]

Doug,
Great info. on your posts regarding the replacement of the oil pressure line and I like your idea of checking the pressure at the block.

Dean,
Good information as well. Did you pull the engine each time to make the adjustments to the pump or is there a way to test this with the engine on the stand?
I have a consistent 43lbs no matter what the rpm is.

Thanks,
Dan

[Blas]

You should not need to bleed the oil line. The air will transfer the oil pressure signal to the gauge. If you were to disconnect the fitting at the back of the gauge while the engine is running, oil would pump out of the line...Thats why I said that if the line is full of oil, you have a leak in the fitting at the back of the gauge. I would think that you do not want oil to ever reach the gauge in a proper installation.

[ou812545]

Blas, That makes sense. I will set something up to test the pressure at the block.

Thanks,
Dan

[Blas]

Remember, that oil can be quite hot. And it squirts out real nice...

[ou812545]

I hear you. The plan was to crank the motor without starting it and just crank the nut with a rag around it. After reading your replies, it sounds like air in the line will not affect the pressure gauge. In fact, it sounds like it is good to have air in the line. Not having the oil come all the way to the gauge.

We will set up a pressure gauge at the block. This sounds much easier and less messy.

Thanks again.

[madmaxx]

"I run straight Kendall 50 SAE and my pressures are stable",

Is your engine a gear pump?? That is insane to run that high of oil viscosity, your roller lifters are probably starved for oil. You want to run the lightest weight oil which provides lubrication, even Roush recommends 10w30. New engines from GM and Ford run 5w20. Go ahead and install a 160F thermostat that will ensure your engine be worn out in about 3500 miles.

[RedBarchetta]

Originally Posted by ou812545

Doug,
Dean,
Good information as well. Did you pull the engine each time to make the adjustments to the pump or is there a way to test this with the engine on the stand?
I have a consistent 43lbs no matter what the rpm is.

Thanks,
Dan

Dan, the only way to check and recheck this (unless you are a pro and have installed a gazillion of them and know, by sight, where to set the spring) is to drop the pan (in the car). I just eye-balled it off the old pump and am comfortable with where the pressures are.

Originally Posted by madmaxx

Is your engine a gear pump?? That is insane to run that high of oil viscosity, your roller lifters are probably starved for oil. You want to run the lightest weight oil which provides lubrication, even Roush recommends 10w30. New engines from GM and Ford run 5w20. Go ahead and install a 160F thermostat that will ensure your engine be worn out in about 3500 miles.

Max, the engine was run on 20w-50 synthetic its entire life, but then I had my oil pressure go and I swapped out the bearings (they were showing signs of premature wear). My clearances were all .002-.0025 (on the higher side). Moved to a 10w30 just like you specified and the pressures were not consistent both at idle and throughout the rpm range. Went to the Kendall on a recommendation and it's worked fine thus far. And I'm running a 180 T-stat and the engine stays at 190-195 in traffic. I've never heard of roller lifters being starved by a heavier oil...educate me.

-Dean

[madmaxx]

Heavier oil resist the tendecy to flow. Pour a glass of rubbing alchol and compare to a glass of 50wt motor oil. The advantage of the lighter oil is it gets into tighter places, (between roller bearings) much much easier than thicker oils. It also flows easier to remove heat and get it back to the oil sump. As far as your clearance you were well with the maximuim of .004-.005". I imagine the signs of premature wear were due to a dirty engine assembly or varnish. You are definelty on the right track with the 180 f thermostat. the problem with the 160F is the pistons get hot, but the cylinders stay cool and you wear your cylinders out. There is a nice chart on the performance unlimited website that clear demonstrates. I though you were running straigth 50w, 20W50 is digestible but still to heavy for most applications, 20w50 is closer to 30w straigt oil. Needless to say you want to minimize the viscosity range since the viscosity modifiers take up volume in the oil but provide no lubricating properties.

[PANAVIA]

my 50 cents worth.

1. no-need-to-bleed. the gauge may be 'stuffed' .

2. 10psi per 1000 rpm , i like to see bare min 40psi with it warm and the oil cooler flowing.

3. Dean - SAE 50W >? wow!

[jrjmac1]

Here is an excellent article on oil viscosity, it should answer all your questions and concerns. www.micapeak.com/info/oiled.html

John

[thudmaster]

Dean, run what you like...........it seems to work for you.