I recently installed an oil filter and now have low oil pressure using 10W30 oil. Is there a likely cause of low pressure, other than main bearing wear? Suggestions appreciated.

Try using SAE-30 oil-this is recommended for temperature 65 and above. This will give you higher oil pressure. Hope it helps.

Back in the early 50's I never had a problem with SAE 30 in my Crosley. But with a slightly larger 4 cylinder in my '61 Sprite the recommended SAE 30 just wouldn't hold up in the Texas heat. I found Castrol 20-50 Racing Oil will hold up and the pressure stays up no matter how far, how fast, how long I drive the car. I've used it the past 25 years with no engine problems.

This could help. On the right side just under the generator is a large plug. remove this plug,clean the spring and ball check. before reassembling stretch the spring. this should increase oil pressure.

I had a 54 Dodge pickup with a flathead 6. It used a canister oil filter (Big Mess!). If I remember it was possible to install the oil filter on backwards....Thank goodness for spin ons...

When I first start the 47 CC the oil pressure gauge reads at about its midpoint. After the engine warms up the reading falls to just above ZERO. I know the book says that the idle pressure is only 7 lbs but is this large a drop normal. I have replaced the pressure regulating spring but when I overhauled the engine I did nothing to the main bearings because they looked good. Any comments will be appreciated.

Although 7lbs at idle is what I deem scary, it is probably more than enough..More important is where does it go to when rpm goes up, beyond 35 psi?

I think the best bet is to do a oil pressure check with a real gauge to find out what your true oil pressure is. Don't rely on the dash gauge until you know for sure what your dealing with. Also, it can't hurt to check your bearing clearances- Platigauge works well- even if they look good there can be excessive clearance.

You are either loosing pressure from too loose bearings, or the oil pump housing and gears are worn out. I would plastigage the bearings, and check your clearance. Anything over .0025 on a Crosley will cause low oil pressure. Check the clearance between the oil pump gears, and case, and also the clearance between gears and the cover.

Thin oil at temperature. Try the 20W-50W racing oil.

When the oil gets hot, it loses its viscosity. In other words when the oil gets thin, it cannot take-up the extra clearance between the moving parts, thus low oil pressure. Jim is right try using 20W50 oil. 20w50 is a 20 weight oil that has the same pouring viscosity as a 50w when hot. If that does not help much, then it is time to get inside that engine, and see.

Crosley Car Owners Bulletin #25, dated August-September,1956, has an article on oil pump repair that I used on my 50 h/s. it gave my car 50, that's fifty lbs of pressure for the first year. the second year the pressure dropped to 40 lbs . this is at an idle, and goes up to about 60# at driving speeds. would be a good thing if this repair was republished.

The oil pump rebuild article was been reprinted in the Quarterly at least twice. I have scanned the article and insert below.

Well I switched the oil to 20W50 and the oil pressure is 55 to 60 when the engine is cold but drops to about 10 at 30 mph and about 7 at idle when the engine is warm. Is there any way to check the oil pump without removing the engine? I did replace the pressure spring during the overhaul and the gears looked OK. I assume I have to remove the engine to check out the main bearing but would appreciate verification of that. Is there anything else that can cause low oil pressure? thanks for any help. Skip

I have seen a lot of reasons why low oil pressure. I have seen worn cam bearings, loose tower shaft bushings, cracks in the oil galleries. I took a portable air tank and put 2 gallons of oil in it, pressurized it, hooked it to an engine with the pan and valve cover removed to find were my oil pressure loss was. That particular engine had an internal crack in the oil gallery.(Warning this method is very messy!!)

Barry I think that is the only sure way to find out what's going on I had to do the same with a 55 Ford 6 cyl panel truck I had and found out it had a small piece broke out of the block next to a cam bearing oil hole. The oil light did go out but the Ford lights were set for 3 lbs. So when motor was kind of stiff when running I decided to do that very same test to find out what was wrong.

If your oil pressure problem is from loose main bearings, you will probably egg shape the main lobes if you keep running it. If the mains and rods are tight, then 10 lbs won't hurt the crank, but, is 10 lbs enough pressure to push oil up to the cam? I don't think so. So either way you are going to hurt something.