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Oil pressure gauge readings

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Guinn

Guinn

Jedi Warrior
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At startup, 30 degree weather, my gauge reads 60# at 3000 rpm. After it warms up it reads 50#. I get the same readings at 90 degrees.

Question: I don't think my engine is that worn, so do I have a low setting on my gauge? How do I adjust the pressure? How do I check pressure with an accessory gauge on the 78 B?

Guinn
 
You can "adapt" a 'hard gauge' to the fitting at the bulkhead where the "Warning light switch" winds into the O.P. gauge line. It *could be* that your pressure relief valve piston is dirty or mis-shapen due to wear, or the spring has fatigued.
 
The "trick" in the "old days" was to either "shim" the spring in the relief valve or get a stronger spring. Ya gotta check the face of the piston in there first tho. I've seen 'em 'cut' from debris flowing past them in the past, to the point where NO amount of spring pressure would change the reading.

....and the reinstallation of that valve/spring/cap is a BEAR with the engine IN the car, BTW.
 
I'll probably wait 'til spring and we get warm weather again. When it gets down to below 60 degrees I shift to (mostly) photography for awhile. Just call me Wimp.

G
 
We're cut from the same cloth. I admit to being a wimp as well when ~cold~ is involved. /ubbthreads/images/graemlins/wink.gif
 
Miss Agatha dosn't like cold either she says. Hides out in the garage under a blanket.
 
I'm really surprised by this. It's been many years since I've worked on a B... but are your oil pressures normally that high? On the A-series engines our target pressure on a rebuilt engine is to adjust the relief valve to get about 50 psi for a cold idle. If everything is tight, hopefully the hot pressure will be close to that. On a worn engine/pump it's not uncommon to see hot idle pressures at or below 20 psi.

Again, this may not apply to B-series engines, but on the A-series a common thing to do is replace the relief valve plunger with a ball bearing and modify the relief valve cap nut so the spring pressure can be adjusted. This allows you to set the oil pressure almost anywhere you want. However, it obviously can't compensate for a worn pump or bearings.

Sorry if none of this is applicable to B-series engines.
 
60 hot at 2 or 3K and 20 at idle is super stuff. Fresh engine.
 
Yea......I wouldn't sweat 20 at hot tickover. /ubbthreads/images/graemlins/iagree.gif

In fact, I would suspect my gage is screwed up if it showed 50 hot....
You running 90 weight gear lube? /ubbthreads/images/graemlins/grin.gif
 
Ha, guess I always put em together too tight.
 
[ QUOTE ]
As the engine reaches operating temperature, the oil thins out. 50 psi on a 90 degree day is nothing to sneeze at.
Jeff

[/ QUOTE ]
Guinn, Jeff's right. Don't "amp" over this. At 50 P.S.I. and "normal" temps you've no worries. Run th' WHEELS off'n it!
 
Thanks, All. Having had the B for just over a year I have a lot to learn. I guess I won't try to fix it as the consensus is "it ain't broke"! /ubbthreads/images/graemlins/cheers.gif

Guinn
 
By the way, I have been spending my spare time helping a neighbor who has macular degeneration restore his fourth car,a 1923 Willis Knight! This is his fourth restore job, all old 1920ish WK's. At least he has a heated workshop.

Guinn
 
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