Oil pressure drop and Engine temp high

I have a 1954 235 motor I just rebuilt and when my engine is cold it shows 30psi Oil pressure. But after my car is warm is drops oil pressure even when I am on the freeway doing 50-55. Also as my pressure drops the engine temp starts to climb and then I start to hear my lifters chattering. So when I let the engine cool the chatter goes away and then my oil pressure is back. Any Clues? I am running 15 40 Delo oil
Motor has about 30 miles on it.

 

Not what you want to hear but you either have a plug missing or a very loose bearing or bearings. You could find it fast if you have an oil primer. Pull the pan and plumb the primer in where your sender goes in the block. Put some pressure to it and get under the engine and watch....

 

Did you Plasti-gauge the bearings? What are your clearances for the rods and mains?

What oil pump are you using? How far does pressure drop when hot, at idle? Anything over 8-lbs. is OK, 25-lbs. + on the road is good.

Does the dip stick read correctly? Engine holds 5-qts., 6 with a filter.

I would suspect the oil pump. DO NOT use the pump gasket that comes in the gasket set - they are usually too thick. The correct gasket is .009" thick - CHECK IT! I've made one from a file folder that was .008" thick, gave me .002" clearance between the gears and cover. Use a light dab of sealer on it, assemble and tighten the screws down. Take it apart and wipe away the sealer that squeezed-out, then assemble for good. Use care in connecting the supply line between the pump and block. Secure the pinch bolt last - do not OVERTIGHT, JUST SNUG to catch the divot on the housing, then the locknut - tight.

Also, make sure you have good oiling upstairs to the rockers. You can cut the handle off an old screwdriver and chuck it in a drill for priming and testing. Just make sure the dizzy shaft engages the oil pump - It will still fire and run if you miss it!!!

I wish I had a little more info to go on...

Good Luck, Tim

 

I notice you said Delo oil, that has an API service code for turbo charged Diesel engines. You need to consider a SN code oil.

 

what temp did your engine get to?

 

Did you check the timing???

 

Thanks for all the input I am going to work on the motor tomorrow. The Cam was resurfaced along with the lifters. I had the Head rebuilt and hard seats installed.The Block and crank were in great shape so I had them cleaned and flushed. The more I think about it the more I think that I dont have enough oil in the motor. I only have 5qt in the motor now and think I can start with adding one more to compensate for the Oil filter.My other thought was that I am going to replace the thermostat since I dont think it is opening.I will be working on my car tomorrow and will post my findings. I really appreciate all the knowledge and help.

When I start the car it pegs the Oil pressure needle at 30 then gradually goes down.After being on the freeway for about 10 minutes I see the temp going past 180 and getting to 200.
I used Plasti gauge as follows from front to back Main
#1 .003,#2.003,#3.003,#4.004.

 

Thats quite a bit of bearing clearance with a low pressure pump isn't it? Lippy

 

Or it could be that his engine is overheating before he looses oil pressure. A hot engine will clatter and loose oil pressure.

I am not going to bother asking what your clearances because I know that the machinist is perfect and there was no need to check.

 

I will get the cam card and yes the motor is a powerglide 235 with hydraulic lifters.I am running a Frame Oil canister

 

Sorry no I didnt not replace the came bearings they were in perfect shape.

 

Yesterday I worked on the car I added one qt of Oil to total 6qts The lifters no longer clattered and the oil pressure stayed up. I removed the thermostat and let the car run with no radiator cap to see if there was flow. The antifreeze is circulating correctly. I am going to try and run the car on the freeway today to see if it has been fixed.

 

SO today I took it out on the freeway and about 5 minutes into it the pressure began to decrease and temp began to rise. I am going to have my radiator checked and I think I may replace the oil pump.

 

So i pulled the oil pan and the bearings are a gonner . they are worn down to the copper. I plan to drop the motor off at the machine shop and have them ground down the crank and have them machine it so I do not need to use shims. Should have done in the first place but whats done is done.

 

So the bearings were shot to shit before you got started, at least you found it before it grenaded. I would still have the radiator serviced, put a new water pump on it as well to ward off evil spirits.

I would also get rid of the Fram oil filter and go with a Delco or other name brand, Purolator, Wix, etc. Napa has a good line of filters too.

Bob

 

Good thing you found what you did. If my grandfather were still around and you told him about the temp rising and pressure dropping and clattering etc, he would have told you to check for a cracked block.

 

Did you have oil up to the rockers? As I remember dont these engines have one hollow head bolt that allows oil up to the rocker arms? I'm wondering if it didnt get mixed up with a regular bolt and you werent lubricating on top?

 

So not only were the main bearings worn but the Rod bearings were even worse. Send the crank and block back to the machine shop and hope they can make sense of this problem and get me back on the road. Will post an update once I get the motor back from the shop.But yes I was getting oil up top it is real nice and clean. I noticed that there was a large build up of stuff on the bottom of the pan and where the lifters are in the side cover. I am going to make sure when I get it all back to clean out the oil journals with some brake cleaner and air to make sure all the crud is gone.

 

Bearings that kill oil pressure are the mains and the cam bearings rods not so much.

 

Think of ANY bearing, rods, mains, cam brngs as a leak of oil pressure. If the clearances are too great for the amount of oil pressure you have, you have a problem. Oil pressure and film strength are related. You can run .004 on the rods and mains if you have 100 lb of oil pressure and straight 70 oil. Lippy

 

@Lippy is there suppose to be shims on the rods?

 

Aristech, since you are getting your engine rebuilt pay attention to the service class of oil you use. Keep in mind that 15w-40 Delo oil you were using has a API service class for diesel engines. The combustion gas in a diesel is chemically different therefore the additative package is differnt. If you oxidize your oil it will not lubricate your engine.

Also I noticed you inreased the oil level. Be careful not to overfill your sump. If your crank foams your oil the volume of the pump is reduced. Because bubbles are taking up space in the pump where oil should be.

One more once you rebuild your engine and complete the break-in change the oil soon.

and thanks for keeping us filled in, take it easy, Tim

 

Curb Feeler, I am not suggesting his problem was caused by using the incorrect service class I was only suggesting since he is rebuilding the bottom end he should consider using oil with an additive package for gasoline engines.

Tim

 

What oil should I use to break in the motor? How long dose it take to break in? What oil should I get to run after break in? I plan on dropping motor off at machine shop and having them line bore the block so I can eliminate the shims. Alos plan on letting them assemble the block Crank,cam and pistons. That way I know it is done right.

 

Also thanks for all the info on here