rjohnson442

New oil pump (not a HV) not shimmed. running 10w-30. on start up shoots right up to 60psi. once the motor is warmed up (185-190) will get max pressure of 40psi at 65mph. average temp in Ohio has been around 90 degrees. at a stop light I'm getting 10psi. the dummy light hasnt come on yet but seeing it that low make me wonder.. Motor was a complete rebuild about 35000 ago and the oil pump has about 2000 miles on it. I'm really asking if I shoud swithch to 10-40 and see how it is. OR should I start doinng a leak down test ect. (ring blow by is what I'm worried about) motor leakes nothing but seems like its eating this 10w-30? I don't want to be throwing thicker oil at somthing that may be a real problem. I've heard people say those readings are ok but it's enought to make me want to watch the gauge like a hawk. Any help would be great and Thank you in advance.

jensenracing77

you will get many opinions on this and i am not an expert but it sounds ok to me. the dummy light is likely set to go off around 3 to 5 psi. i would be concerned at that point. is this engine stock? rebuilt? what RPM are you idling at?

oldcutlass

If you switch to a higher viscosity it will go a bit higher, but it sounds fine! At what intervals do you change your oil? Ring blowby will not effect oil pressure.

Oldsmaniac

Seems normal to me...

rjohnson442

it's a 455 rebuilt 35xxx miles ago. the pan leaked so I put a new melling pump in while it was open. (pressure was jumping up and down with the old one) the oil light comes on at 7psi I tested that when I replace the pump 2000 miles ago. I change the oil every 2000 and I'm due now. this will be the first oil change since the new pump. I'll go with the 10w-40 tonight and report back on my paranoia. Thanks!

rjohnson442

ok went to change the oil and there was some on the filter. and on the filler neck was pretty dirty with oil coming down it. I measured how much was in there and I only had 3.5 qt. I draind the filster as much as possible. i have a stock pan How could I lose that much oil in 2000 miles?
the 10-40 gave me 2 more psi (12psi @ 750rpm warm in park 10psi in drive) and 5 more at highway speeds. (45 psi @ 2900 rpm) got anything for me

oldcutlass

So was that 3.5 qts + what was in the filter = 4.5 qts? I would change my PCV and ensure that the breather is clean.

rjohnson442

It had only 3.5 after I drained the filter as much as I could. The breather on the fill neck was pretty gummed up. The pcv looks clean only a month old... I'm losing about a quart every thousand miles. I'm hoping the 10-40 will solve this???

oldcutlass

Do your valve covers have baffels in them? And where is the breather on the drivers side hose going to?

rjohnson442

the hose looks gunked up on the PCV side does it jut pull right out the back of the carb to replace? and the breather on the driver side go's into the exhaust. it did look a little crimped where it meets the exhaust. I'll get a new hose PCV and oil fill cap just to be safe while I'm at it and report back. Thanks!!!

jaunty75

This is really not an abnormal rate of oil consumption for engines of this era. If you were losing that much every 100 or 200 miles, then you'd have something to worry about.

oldcutlass

That breather should not, I believe, go to the exhaust, it should go either to the air cleaner housing of vent to the atmosphere.

Oldsmaniac

If it is consumption that would not be good. If its leaking it should be fixed. Racers plumb the breathers to the exhaust for crankcase scavenging. I would disconnect that for sure and make sure baffles are in the valve covers.

rjohnson442

The valve covers are also about a month old. they have the metal deflector on the inside. the baffle and fill cap are the only old parts used at this point. Did all the seals when I did the timing change. no leakes from cover or pan. OIl was fine, maybe this has become a Breathing issue. only traces of oil were from the fill neck
(bad breather?) and the filter with was a little loose. I got it to turn about a quarter inch tighter.

oldcutlass

With the motor running disconnect that hose, and plug the PCV port, check and see if you have blowby. Then hook everything back up and rev the engine and see if it blows oil and smoke from your oil fill breather.

I think you may be building pressure with your hose to the exhaust. Try disconnecting that and see what happens. The scavenging may not be set up right!

rjohnson442

I'd be looking for blow by on the driver side then correct? and should I plug the oil fill tube as well to seal the system or just the PCV side?

rjohnson442

Ok so I'm not worried about oil pressure anymore. With the motor at idle and the baffle attached to the exhaust tube not the cover it sucks better than my shop vac! I believe I found where all my oil is going! I cut the tube in half and you could see a solid line of oil coming down the tube. is there supposed to be a reducer of some sort on the exhause side where the tube goes into the exhaust? it looks to have a baffle of some sort before connects to the exhaust.

ah64pilot

I believe you missed the post about the oil breather being plumbed into the exhaust. That is only for a race engine that doesn't make vacuum. It is not supposed to be used on the street as it will suck oil out of the valve cover. You do not need that much scavenging on the street...that hose should go to a vacuum source on the intake manifold or at the back of the carburetor.

You then need to plug the port on the exhaust or header.

bdub217

Anything running vacuum will need to have the valve cover breather ran open to atmosphere or tubed to the air cleaner housing as mentioned. Keep us updated.

rjohnson442

I oh did! I was just telling my findings.... the exhaust is pulling way to much vac. I could clean the crap off the carpets with it! the spring on the PCV valve was on the weak side compared to the new one I installed. I have the driver side vented to the atmosphere and the hole in the exhaust plugged. Now as for oil loss I will have to wait and see. I orderd a new fill cap went to pick it up by the time I got there engine was smoking open the hood to find out it fell off and had about half a quart all over the hood manifold firewall everywhere! Air filter was soaked! Now that everything's rust proofed and cleaned. I'll tell you my findings with the fluid topped off and a new cap. Does anyone sell a fill tube with a screw in type? not the notch lock kind? Thanks Steve! You've been a big help with this never ending project!

oldcutlass

There is nothing wrong with the notch and 1/2 twist lock cap on the fill tube. You want the pcv connected to full vacuumat the front of your carb or to the manifold, and on the opposite valvecover you want to have an open breather or a line to your air cleaner.

rjohnson442

Thats how it's set up now. PCV to carb, and driver valve cover to atmosphere. I Was just wondering if there was a screw in tube. the streets in my neighborhood don't have the smoothest ride and the cap has fallen off more then once. I've bent the tangs so it's tight as can be. I'll see if the new cap is better, BUT if there is a screw style I'd like to get it.

ah64pilot

You probably need a new cap. They are supposed to be fairly secure on the fill tube...not loose and wobbly. I believe Fusick sells the repop caps for a decent price.