All the 360's and 390's that work has have low oil pressure. So when we cranked our rebuilt motor for the first time and saw 95psi I almost fanted. the other day we went to drive it around for a while. When cranked it had 80psi, as it warmed it started dropping, which is normal, but after driving about 25 miles we stopped at a red light and had about 5psi, no noises. We drove it easy all week still having 5psi at idle and about 25psi when going 55 mph. today it started rattling. so we pulled the pan and checked a bearing and it still looked like a new bearing. We put it all back together and cranked it noises gone. Drove for about 2 hours with no noises and then as we go to park, it starts rattling again. The boss and me built the motor and we checked all the clearances, everything was fine. So my ? are, what can cause low oil pressure. And could it be the oil pan? we have a car oil pan on it. could it be pumping dry? sorry for the long post. Chad

 

What oil are you running? Does it burn any oil(are you losing any)? This rattling, is it a light tinking sound or a deep sound? Might check to see if your pickup tube isnt to close to the bottom of the oil pan. If it was me i would throw some straight 50w or even 60w in there to see if that ups the PSI. Im running Straight 50w and i get 80psi cold and 65psi and operating temp while idling. Get back to us.

 

it had 10w40 in it. i drained it and put 20w50 in because I didn't feel like going 25 miles to town just for oil and a filter with the way gas prices are. but anyway the pressure is the same. my boss was over and got me thinking. when we got the crank turned he asked if we wanted the clearances tight or loose, we said tight. when we checked they were all in spec. Could it be that the oil is too thick for the motor when it warms up? if so what would I need to put in? As for the noise it is just the lifters or something up on the top end. I'm not to worried about the top end, it is the bearings that I am worried about.

 

35psi at 2000 rpm is minimum oil pressure factory spec on FE engines. I would suspect you lost an oil galley end plug from the high pressure before and are dumping oil back into the pan rather than pumping it around the engine. I also suspect the high pressure was cause by a stuck pressure relief valve in the oil pump (probably still stuck). Press in galley end plugs are not designed to handle 95 psi or even 80. That's why I alway tap and screw in plug mine. The one I mainly suspect is the one in the dist shaft bore. I highly doubt the oil use is the issue.

 

how could i tell if it came out and what would i have to do to replace it? the machine shop put them in when they did the machine work?

 

there is plugs in the lifter valley they may have left them out. also a 15w40 will stand up to heat better that 10w40 or 20w50.

 

I looked up how to tell if the plug in the dist. hole is missing and to my disappointment it is still in there.so anybody else got any ideas. I hate it, but I think I may have to pull the engine back out.

 

How many qts does your pan hold? Are the rocker shaft install on correct sides. They can be installed upside down. Make sure plugs are in the end of rocker shafts. Make sure head drain back holes are clear. I know some people with 5qt pans run an extra qt because it is possible if you have no restrictors in the cyl head to pump all oil to the top of the engine with HV pump.

 

i believe there is also plugs in the lifter valley under the intake. my ft pan holds 13 to 14 quarts yours should be 5 to 6

 

the pan holds 6 quarts. it is off of a galaxie.

 

Then it holds 4 with a fifth in the filter. Only trucks got the 6 quart pans and then only the HD ones.

 

I would pull the pan and the maifold and put a oil leak tester on it. Nothing more than
a tank filled with oil that has air pressssure on it and a hose which is scewed into
the block oil fitting. I would hope it is a plug left out or loose, I have seen some
lifter bores which leak like the devil and cause problems.

 

Ok this is an odd thing to check. Some blocks on the oil filter adapter pad have an extra hole machined in them. If your using a different oil filter adapter (C8 style with enlarged passages) the gasket can blow out exposing the hole causing a loss of oil pressure. My 406 block has this mystery hole and I tapped and plugged it. I had this problem years ago on a 427. Drove me nuts till I figured what it was. Good chance this is not your problem but easy to check. When you take the adapter off it would be a small hole the size of the mounting screw holes to the right of the oil passages. Just a thought....G.

 

well i pulled the intake and there is a hole on the back passanger side of the lifter gallery. it is about an inch in diameter. so I guess I'll have to tell the boss we need another block. He'll probally get pretty mad and I imagine the machinist will hear all about it. My ? is how would this happen. Oh by the way the piece that broke out was found in the lifter gallery. I'm just glad it wasn't my personal engine. This is about the worse beatin I've seen an FE take. If you want to see pictures I'll post them sometime next week. Thanks for all the help with everything. Chad

 

sounds like they reused the old lifters in the wrong holes. or maybe the crack was already there i have never seen that happen before.