No oil pressure rebuilt 455

[Tim72]

Hi all,

I will try to be as brief as possible but...

I had my motor rebuilt by a guy who supposedly new oldsmobiles. I supplied The Edelbrock aluminum heads,Roller rockers,pan etc while he supplied the labor. Once the motor was back in the car the motor was started with little oil pressure. He probably ran the motor for 2 to 3 minutes trying to figure out the problem. Checking with other olds motor folks we found the plug that supplies the oil to the distributor was missing after tanking and left out of the motor when rebuilt. The trans was dropped and the plug was instaled from behind the motor. So far so good, we now had oil pressure about 60 lbs. Took the car about ten miles and watched oil pressure dropped to about 5 lbs and pulled over on I-96. We checked the oil and found we had lost a quart.The temperature climbed to about 240 degrees. After towing home I found the rear main was leaking at a rate of 1 quart per 10 miles. I also found metal chips in the bottom of the inspection cover. Could possibly have come from the new starter or?..... This motor also had resricters put in hopefully in the correct spot. It also has a 7 quart oil pan and high presure oil pump. I drained the oil pan and found no alarming amount of metal shavings on the pan plug magnet. The car is back to the engine rebuilder who will stand behind his work. Since I have learned the hard way many times and consider this another can somebody explain what possibly went wrong after we found the missing plug? Do other motors have a similar plug that is hidden away behind the Distributor for oiling purposes? I was told that this plug is usally left in when tanked which would be hard to believe. The plug is suppose to have a .048 thousands hole in it for lube to the distributor. Any idea's on what went wrong would be apreciated.

[Guest Joe_Varley]

Olds engines should NEVER have oil restrictors in them. This is an old wives tale. I am not an engine guru but have done my share of work having owned over 75 Oldsmobiles over the years. I have seen a couple of Olds engines damaged by oil restrictors. Hopefully you will get some good info from the group. Tough to diagnose an engine problem via keyboard.

Joe Varley

OCA # 1448

[Tim72]

Joe,

Thanks for your reply. I certainly have been woried about thoise restrictors. It seems I should be able to get enough oil pressure from a high volumn Pump and a 7 Quart oil pan.

The motor made it 108,000 miles (1970 335hp) before I decided to rebuild it on a 5 quart oil pan.

Tim

[rocketraider]

OK- one post says you have a high pressure pump, and the other says HIGH VOLUME pump. Which do you have, since there's a lot of difference in the behavior of the two. A high pressure pump will definitely keep pressure up where you need it, while a high volume pump will suck the pan dry at high RPM. High pressure pump= no restrictors needed. HIGH VOLUME pump= you need something to keep the oil on the crank instead of in the rocker arm area.

[RocketDude]

I have built many hi performance Olds engines, and the restricters are definitely the way to go. I got the restrictors from Joe Mondello. There is no one anywhere who knows more about Oldsmobile engines than Joe, so to say not to use them is just plain wrong...!

If you know what you're doing and install them correctly, they are a god send... Use 'em..!

http://www.mondellotwister.com/

[Guest imported_pete324rock]

I lost a 455 once with the missing plug in the back deal and it fired up and wasn't very long before I had spun a rod bearing-what a drag! I feel for ya!

[RocketDude]

To clarify my previous answer a little more, if you just install restrictors in your engine and don't alter the main bearing shells, then Joe is correct, you could starve your mains and cause a problem.

To do the job correctly, the main bearing shell has to be altered or you could restrict the flow of oil. Once the restrictors are installed, the oil hole in the bearing shell and the hole in the restrictor no longer line up..!

I elongate the oil hole in the bearing shell with a drill and a grinding tool. Those shells are extremely hard and not easy to cut. Once the hole is modified to align the holes, I use a de burring tool, and after the bearing is cleaned up and pretty again, I lightly sand the bearing surface of all the bearings with 400 wet and dry sand paper in solvent, which in effect, breaks the bearing in. You will feel the bearing surface get much smoother to your touch.

Then clean them good, check all tolerances with plasti-gauge, use lots of good assembly lube and your ready to go...

Where I said lightly sand the bearing, please underling "lightly"..!

I like to tuff ride, straighten, and balance the crank shaft also, a process that makes the crank bearing journals extremely hard to further resist galling. I am not real sure what that process involves, but when you get the crank back, all of the bearing surfaces are black, instead of the shiny you are all familiar with.

I also break in the rings on the engine stand. I use a mixture of Bon Ami and 10 weight oil. with the short block together, I use a paint brush to paint the cyl walls with the mixture,and put a large ratchet on the crank nut and start cranking the engine over. I turn the engine at least a 100 to 150 times, until you see the cyl walls start to change color. You will have to re-apply the oil mixture as you go along. This procedure is not at all necessary for a standard rebuild, I just mention it in case anyone is interested. I have built a lot of 455's that run on Natural gas and propane, and if you don't break the rings in as described, the rings will NEVER seat, and you will burn oil like crazy. Using gaseous fuel there is no cyl wash down like gasoline, so rings won't seat.

Sorry to get so far off the subject, sometimes I get carried away..!!

[rocketraider]

I like it! I had never thought about breakin on a gaseous fueled engine.

[Tim72]

Thanks to all for the help. I believe we got it correct the second time.

Tim

[Guest JRZYBOB442]

Rocket Dude is correct about the oil restrictors.

Also: Rear Block Oil Lifter Galleries - The left rear oil lifter gallery plug (3/8” pipe plug closest to the distributor gear) should have a 0.040” hole drilled in it. This plug is located behind the 29/32" freeze plug on the left rear side of the camshaft in the bell housing area.

Replace the cup plug with a stock OEM tapped plug as shown on the right side in the diagram on the left, and drill the 0.040" hole in it. You may also purchase a PP-40 pre-drilled plug from Mondello.

My Perfomance Manual goes over the entire rebuild process from stem to stern, especially if using oil restrictors. If you do get the pressure you want using restrictors, you should also relieve the rods by machining or too much oil will stay on the bearing.

Bob G

[joe_padavano]

The cam bearings are oiled AFTER the mains and the oil doesn't go anywhere else after that. Oil restrictors in the cam bearings are almost worthless unless the cam bearings are badly worn. More to the point, a virtually free way to get the same effect is to drill smaller oil holes in the cam bearings and install the bearings with these new smaller holes lined up with the feed holes in the block. No need to buy and install Modello's expensive restrictors and no need to worry about the holes in the main bearings.

The real problem with the Olds oiling system is that the lifters and top end are fed from the main galleries, BEFORE the main bearings. The only effective mod is to put restrictors in each of the sixteen lifter oil feed holed that come off the main galleries. THIS will help push more oil to the mains.