y block oil pressure
- Thread starter cvicky
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Dobie Gillis
Well-known member
Yup, mine runs 25 to 30 warmed up. Y's are not high pressure engines. What weight oil are you using?
You need a 180 deg. thermostat. Y blocks have a sludge build up problem, especially if mostly driven at slow speeds in city traffic. The 'road draft tube' system is not very efficient at low speeds so a 180 deg. thermostat helps the engine maintain operating temperature for less sludge formation. Your oil pressure is fine.
I agree about needing 180 degree thermostat. And gosh, put another quart of oil in.
To answer your specific question, those oil pressure readings don't seem bad, though they're maybe not optimum. Within the range of acceptable, but that's kind of a loosely defined range. As I understand it, oil pressure is secondary to how well - and thoroughly - the engine is being lubricated. Some higher readings can be caused by blockage in oil passages, which is far worse than low readings. Also, some early Y blocks had lubrication problems with the rocker arm shafts. Taking off the valve covers and seeing how well that part of the engine is doing is probably a good idea.
My '54 Ford with the non-rebuilt 239 has what I consider decent oil pressure for a 65 year old engine, and it reads (as I recall) just under 50 at start up idle, about 18-25 at hot idle depending on amb. temp., and I think about 35-38 at hot highway speed (2500 to 3000 rpm.)
To answer your specific question, those oil pressure readings don't seem bad, though they're maybe not optimum. Within the range of acceptable, but that's kind of a loosely defined range. As I understand it, oil pressure is secondary to how well - and thoroughly - the engine is being lubricated. Some higher readings can be caused by blockage in oil passages, which is far worse than low readings. Also, some early Y blocks had lubrication problems with the rocker arm shafts. Taking off the valve covers and seeing how well that part of the engine is doing is probably a good idea.
My '54 Ford with the non-rebuilt 239 has what I consider decent oil pressure for a 65 year old engine, and it reads (as I recall) just under 50 at start up idle, about 18-25 at hot idle depending on amb. temp., and I think about 35-38 at hot highway speed (2500 to 3000 rpm.)
dmsfrr
Well-known member
A lack of oil to the rocker arms due to sludge buildup may not be helped by the oil passage at each head gasket.
The oil comes up from the center cam bearing in a 5/16" hole. (photo 1) At the head gasket the passage turns 90* into a shallow groove. (photo 2) Then another 90* turn up into a 1/4" hole thru the head to the rocker stand. (photo 3)
The groove in the underside of the head may be slightly shallow (1/8" ?) which could be a problem by itself (esp if the head has been re-surfaced) and if a composite head gasket swells into it, it is now even smaller.
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This is my impression, too, for idle pressures. As I recall, my near brand new S-10 Chevy had idle readings under 10 lb.s (I think) and I was worried and called the warranty center, and they said it was fine as long as the warning light didn't come on. I put 150k miles plus on the truck. When I had my '50 Plymouth flathead six several years ago, the manual said ANY indication on the gauge that there was even a trace of pressure at idle - even a couple of pounds - was acceptable. I don't think that's the Ford standard, but the oil requirements at idle weren't great.
streetdreams
Well-known member
pressurizing your rocker arm assemblies will add 5-15 psi depending on what condition your oiling system/bearings are in.
"will ADD 5-15 psi..."?? Could this be a misprint? Piping oil from the main galley to the rocker shafts will actually cause a drop in pressure.
Im in the process of a rebuild 56 fairlane, 2 door, 312 Y block. Im new to this hobby.
barely put new gauges, just installed oil pressure gauge right in between fuel pump and oil breather..............So gauge has black for ground, red to acc on ignition and wire to sending unit.... is this correct..........or fuse box has to be involved? please advise and thanks.
barely put new gauges, just installed oil pressure gauge right in between fuel pump and oil breather..............So gauge has black for ground, red to acc on ignition and wire to sending unit.... is this correct..........or fuse box has to be involved? please advise and thanks.
Dobie Gillis
Well-known member
Welcome to the forum! No fuse block unless somebody rewired the car with a modern harness. Ford didn't use fuse blocks back then. If this is an aftermarket gauge just wire it up per the instructions that came with it.
streetdreams
Well-known member
"will ADD 5-15 psi..."?? Could this be a misprint? Piping oil from the main galley to the rocker shafts will actually cause a drop in pressure. "
No misprint. I always pressurize rocker assemblies on a Y Block. The spillover system from the factory is: 1) an oil leak directly to the oiling system, and, 2) does a lousy job of oiling the rocker arms, as evidenced by scored up shafts on just about every y block torn down for rebuild, because there is very little if any oil pressure in the rocker shaft.
You can argue modern oils vs '60s oil if you want, but I routinely get 30-35 psi oil pressure hot on any Y blocks I rebuild.
No misprint. I always pressurize rocker assemblies on a Y Block. The spillover system from the factory is: 1) an oil leak directly to the oiling system, and, 2) does a lousy job of oiling the rocker arms, as evidenced by scored up shafts on just about every y block torn down for rebuild, because there is very little if any oil pressure in the rocker shaft.
You can argue modern oils vs '60s oil if you want, but I routinely get 30-35 psi oil pressure hot on any Y blocks I rebuild.
40cpe
Well-known member
I'm not speaking for anyone, but I think there is a misunderstanding of terms. Pressurizing the rockers is done by closing off the overflow from the rocker arms. Oiling the rockers from the main galley involves external tubing and was usually done to correct insufficient flow to the rocker arms from the cam bearings/head passages.
Okay, that would make sense.
34pickup
Well-known member
Last Y block I had idled at about 5lbs. But it never showed any problems. Y blocks are tough as tractor engines.
