Pre-startup oil pressure in my 383 • The Dodge Challenger Message Board

by **challyrtse** » 19 Apr 2006 10:37

I have a 1970 R/T SE, and just rebuilt a #'s matching 383 to put back into it. I followed the book "How to rebuild big block Mopar Engines," but when cranking the engine prior to starting it I noticed no oil pressure. I also pulled the oil pressure sending unit and then cranked it, but no oil came out of the hole either.
This is my first attempt at rebuilding an engine, so any help is appreciated. I have not noticed any oil around the car after cranking, so I do not believe that it is leaking out from someplace. I have checked the oil in the pan, and it is definately there. I did not, however, have a priming tool to turn the oil pump prior to assembling the engine fully; but I have cranked the engine with and without spark plugs.
It just seems odd that there is no noticable oil pressure. Thanks in advance for any help,
Challyrtse

by **dave-r** » 19 Apr 2006 11:31

You shouldn't be cranking it if you have fitted a new cam.

I am trying to remember if I have seen oil pressure with cranking or not. I don't recall getting oil pressure that way.

On a fresh built engine I would prime it with the tool.
If I were you I would try that next to see if you get pressure then.

You can also make your own tool. A simple steel bar with a hex hand ground on the end to the right size will do.

But make sure you protect the pump/distributor drive bushing.

Also remember that you don't need pressure when you fire the engine up. Just as long as you saw some pressure when you primed it. The oil will then be in all the right places.

If you still cannot get pressure even with a priming tool then you probably have done something wrong like forgetting to install one of the oil galley plugs.

by **fbernard** » 19 Apr 2006 11:40

The starter must not be used before there has been some oil circulation throughout the engine.

You must prime the oil pump (drill and tool, anti-clockwise).

Not doing this will significantly cut down on the life expectancy of bearings, rings, and could wipe the cam lobes.

A cordless drill won't do. Sometimes it takes a lot of time to get the pump to flow (I've read about people who took ah hour to get the pump primed!).
You can pack the oil pump with vaseline to help it prime. you can also fill the oil filter (messy with a big-block, but it helps)

It's better to have someone to help you. The crank needs to be turned (slowly, NOT with the starter) to let the oil flow everywhere (unless you have full groove bearings). Stop only when oil has been pouring from the rockers for a few minutes.

The lifters should be primed too (standing in a pan full of oil, manually prime with a pushrod, then install).

Once all that is done, install spark plugs, and start the engine.

Depending on how long you've been cranking before, you may have already damaged the bearings, camshaft (most likely victim).

First things first, you should put some break-in compound/grease on the cam lobes again NOW (A paranoid man like me would remove and inspect the camshaft).

If you installed dual valve springs, I hope you only installed the outer springs for the cam break-in. If you didn't, it may still be time to remove the inner before you start the engine.

by **dave-r** » 19 Apr 2006 12:22

Good advice. :thumbsup:

by **fbernard** » 19 Apr 2006 14:12

I forgot to say (although it's obvious) prime the pump with the valve covers off, to see if oil gets to the valvetrain. Also, since you already installed the engine in the car, puu a large piece of clean cardboard underneath the engine bay, and check on it from time to time while you prime to see if anything's leaking...

You may even want to do the first start of the engine with the valve covers off.

I realize packing the oil pump with vaseline isn't possible with the engine in the car, so just fill the oil filter (and protect the floor, you will pour half of it when you screw the filter on).

The pump's self priming capacity is pretty lousy, when it's all new and dry. That's why it takes so much efforts to get it to suck oil from the pan for the first time. It must be able to suck only air for a few seconds, and the viscosity of air is very low! any kind of lubrication in the pump will help (seal it against air leaks).
By any means, you will know when it starts pumping oil and not air, because the drill RPM wil fall drastically.

By the way, make sure you installed the rocker arms the proper way (with the oil holes pointing down), one guy in my club had them on the wrong way, and the pushrods went through the rockers this week).

by **challyrtse** » 19 Apr 2006 20:36

Thanks for the quick responses, everyone. I had no idea that these oil pumps took so much prep work! I'm going to take the intake manifold off and pull the distributor gear, then prime it with a drill (I got a priming tool in the mail yesterday...)
Again, thanks for all of the help. This is my first go at an engine rebuild, and I don't want to start over from scratch 15 minutes after light-off!

by **Jon** » 21 Apr 2006 2:49

A little advice from the good people that have been there and done that is worth it's weight in gold. :wink:

Jon

by **challyrtse** » 21 Apr 2006 3:07

I pulled everything off and got in with a drill. It took about 2 minutes before it started to draw oil, but I'm glad that I did it. I was starting to think that my oil pump was faulty, but it works fine. I can't wait to finish up the wiring and start this thing up!
Thanks again for the great help. This is the best message board I've yet to find for Challenger owners, hands down.