327 low oil pressure

[61TWUK]

In my 61' Apache I'm running a 327 and even at high RPM's the motor barely has 30 oil pressure... are any of you running 327's and having the same issue and if so what are you doing to correct it? I've put a High volume oil pump and still no luck. If it helps the motor is FRESHLY rebuilt and has a 270 cam, double hump heads its bored 40 over...

Chet

[MacAttack]

If it's freshly rebuilt - then the bearing clearances are too large.

Try to find some 60w Valvoline Racing Oil and see it that brings it up.

[Northern lights]

Was the crank turned?. Being bore .040 over, there's a good chance the crank was done also. Perhaps the crank was turned and the outfit doing it turned the journals a few thou to much??. Check with whoever did the rebuild and ask if they plastigauged the bearings and if so, what were the clearances. If not, ask WHY NOT. New bearings should never be installed without checking the clearances. I found THAT out the hard way.

[61TWUK]

rock out thanks I'll check on those things...

[MacAttack]

http://www.jegs.com/i/Valvoline+Raci...VV241/10002/-1

This is the stuff I ran in my '400' for 3 years and it bumped the PSI up a bit.

Mac.

[onebad65c10]

Originally Posted by 61TWUK

In my 61' Apache I'm running a 327 and even at high RPM's the motor barely has 30 oil pressure... are any of you running 327's and having the same issue and if so what are you doing to correct it? I've put a High volume oil pump and still no luck. If it helps the motor is FRESHLY rebuilt and has a 270 cam, double hump heads its bored 40 over...

Chet

Not being funny but ditch the high volume oil pump. We installed one in my dads 79 3/4 ton and running up the beltway everyday for school and then the hour for drive for work on the weekend. Everything was fine and then one day coming from school it decided to let go. The n=motor only had a few thousand miles on it from a total rebuild. The machine shop said that the oil pump was sucking the sump dry in the oil pan and just putting the oil in the top end.

Another thing I talked to my machine shop about my stroker when building it. If you have a larger cam shaft that doesn't produce the right vacum you may have problems with the oil pressure readings. The engine may have the presure but it does not read on the gauge properly.

Just my $.02 Hope you get the problem fixed.
Later
Phil

[19GMC63]

are you positive the gauge/sender are good?

[mike73]

I agree...... run a different gauge/sender you very well could have a bad gauge!

[Eagar1]

I came across someone that had the same problem and posted what they found below, it may be of some help.

Quote:
Originally Posted by CWPASADENA
You said you had low oil pressure and dirty oil. No pluges in the front of the block will definately cause low oil pressure but should not have caused dirty oil. Thru the years, I have run across several SBCs that had dirty oil after a complete rebuild (fortunately, not by me) and found the plug in the vertical oil galley at the rear of the engine was left out and I bet the first rebuilder also left out this plug.

There are two horzontal oil passages from the rear vertical oil galley that go to the oil filter. These horzontal passages are about an inch above one another. The lower one feeds all the oil from the pump to the filter and the upper one returnes the filtered oil to the vertical oil galley which feeds the rest of the engine. There is supposed to be a plug in the vertical galley between the two horzontal oil filter passages. This plug prevents the unfiltered oil from the pump from bypassing the filter and continuing up the vertical galley. If this plug is left out, none of the oil from the pump is filtered and dirty oil is allowed to circulate thru the engine.

A lot of people do not remove this plug because they do not know it is there, but a lot of rebuilders will remove this plug so this vertical galley can be cleaned. Good re-builders will make sure this plug is in place when the engine is assembled.

It is easy to check to see if this plug is in place on an engine that has been assembled. You can made a tool out of a piece of welding rod. (1) Measure the "Hight" of the block, from the machined pan surface to the machined intake manifold surface. (2) Cut a piece of welding rod that is one inch longer then this deminsion. Bend one end (the last inch) over 90 deg. to the long portion of the rod. Now, remove the oil pressure line and the fitting at the rear of the block, back by the distributor. Drop the rod down the hole (which is the main vertical oil galley). If the rod will not go all the way down, and the end of the rod is an inch or so above the manifold surface, there IS a plug in place. If the rod goes all down to the bent over end, there is NO PLUG. Note, the bent over end of the rod will prevent the rod from falling down in the engine if there is NO plug in place. The plug can only be installed from below. You have to removing the pan and rear main cap. Check with your machinest if you find you have this problem.

When this plug is left out, most of the time the bearings will fail before the engine is run very much.

Just some suggestions, but it sounds like you have a good man on the job and I am sure your "New" engine will work out just fine.

Chris, CWPASADENA

Thanks Chris,

The dirty oil for the most part came from the poor job done on the engine boring. The cylinders with the heads on were out by .003. With the the heads off they were .001. The rebuilder did not use a torque block for the job. The leak down was 40% or more. I did drop pan and the rear bearing plug was in. Also the plug you mentioned. I drove the car for 400 miles before I got help from forum members. What saved the engine was the high volume oil pump that was installed.

I have attached a picture of the front of the engine with the timing cover off. Those are my lifters on the lower two holes. John Z was amazed that I did not do more damage considering that all three front plugs were missing. My engine has almost 300,000 miles on it. The last rebuilder had to bore it out to .040. In doing so he did not use the torque block, causing the distortion when the heads were put back on.

Carl Hinkson read of my problem and came to the rescue.

Jack

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