oil pressure gauge • 2 • The Dodge Challenger Message Board

by **Jon** » 12 Jul 2008 3:01

I have used new Mellings in the past four or five motors. No problems I know of. Spun one bearing and broke a rod but can't trace it back to the pump. Probably too long on the throttle. :roll:

I think I have an old one that is still good to check the spring tension. Is tomorrow soon enough?

I forgot to ask, on the rockers is the shaft set with the grove on the end towards the center of the motor? Just checking

by **MLMFLCN** » 12 Jul 2008 11:13

Thanks Jon. Tomorrow would be great. I am not starting on the car again til later in the afternoon.

My rockers are Harland Sharps, and I remember putting some posts out here re: them, and talking to their tech support. They told me this style was reversible, and from looking at them on either side, they were.

Thanks again everyone.

- rich

by **Jon** » 12 Jul 2008 16:36

Sorry, looked everywhere for the pump and could only find a pickup tube.

by **Eddie** » 12 Jul 2008 16:47

MLMFLCN wrote:pulled the pump out tonight...real easy. Looked like the spring may have locked up and been fully extended, as the valve was not sliding very easily. May have caught a small burr from the original start up. Does that spring really compress when the motor is running to allow the oil to flow? Seems like a pretty stiff spring. I imagine that when the spring is compressed, it allows oil to pass through the pump. My sense is that the spring was not able to, and therefore, severly limited the flow of the pump.

How easy should that valve slide in the bore? I oiled it up, and it still was not really easy to move. I remember when I was installing the lifters in their bore, with 20-50 weight on them, they spun really nice. Probably not the same thing, but it looked liked the machining was kind of the same.

I think this was the problem. Off to summit racing in the morning, installing a new high volume melling tomorrow. Hope that's the ticket.

The spring is set to a certain pressure. I would send that pump back to Melling. I'm sure they will send you a new one :wink2:

Good Luck with the install Rich and keep us informed :thumbsup:

by **MLMFLCN** » 12 Jul 2008 20:58

Oh well, cleaned up some burrs in the pump, now the valve slides easily, still no pressure. Dropped the pan but cannot get the pick up tube out. The screen was perfectly clean. Ran some compressed air through the pickup tube, and although it is not a clear shot, still feels like the air movement is fine. Pickup tube is maybe a 1/4 inch from the bottom of the pan, this is correct, right?

I'm really going to buy a pump this time, since I can't think what else it could be. :s008:

Car kicked my butt today, so I may take a few days off.

I'll keep you posted.

by **MLMFLCN** » 12 Jul 2008 21:03

BTW, thanks for looking Jon. Find anything else good?

by **Jon** » 13 Jul 2008 3:49

MLMFLCN wrote:BTW, thanks for looking Jon. Find anything else good?

Lots of good trim and engine parts along with a few long forgotten items that almost brough tears to my eye. There was a couple of perfectly good timing chains, replaced cause that's what you do on a new build, some old lifters and pushrods from a bad solid cam set, 7 connecting rods (#8 is still MIA) and a windage tray with a hole in it. :roll:

Ah the memories.

Seriously though hope you get that oiling problem figured out.

by **MLMFLCN** » 17 Jul 2008 19:10

Finally getting back to the car. Eddie you mentioned the number 4 cam bearing, and the impact it would have not allowing oil up to the rockers and valve train. Would a spun cam bearing also stop the oil from reaching the hole where the oil sending unit is, or is that area fed with oil differently?

Had another mechanic tell me the same thing and a way to test for it, but I am certain I did not rotate the engine by hand when I spun the oil pump with a drill when I first fired her up. It registered oil almost immeditely that time on the electric guage. It was with the engine at TDC for #1, so not sure if that is where the #4 cam bearing is aligned or not.

I just want to make sure I don't change the oil pump, when it is a spun cam bearing instead. Thanks again all.

- rich

by **Eddie** » 17 Jul 2008 19:39

Rich, the big block's oil delivery to the top end is fed through the #4 cam journal. This journal in the cam bearing and the journal of the cam and the passageway in the block "line up" when the cam rotates to that point. Hence the term "timed oil supply" meaning the oil flow is not full time. Thats why I recommended rotating the engine to see if the oil gushes up to the rockers or rocker shafts.. Without turning the engine over how do you know if the cam bearings have been positioned properly and if the lube will reach vital areas. (You can use a this steel welding or wire type rod and force it gently into the #4 cam journal after first removing the rocker shafts of course to check the passage way into the cam bearing/)I am explaining it this way to ensure we are on the same 'wavelength' :wink:

Now that thats out of the way, the rear plug gets it's oil directly from a passageway that comes from the camshaft lifter oil galley at the rear of the block. It's Y shaped and feeds directly to that rear orfice at the back of the block.

by **Eddie** » 17 Jul 2008 19:55

They say a pic is worth a thousand words. here is what I am talking about Rich. The pipe cleaner is shown in the #4 Cam journal and the passageway shoots up into the valley area into the cylinder head then the rockershaft. Look close and you can see it protruding into the cam tunnel. The other pic is the rear of the block showing the cam lifter oil galley and the passageway that goes to the oil pressure sender orfice. Hope this helps clear some things up or helps you discover something. BTW, there is a plug in the oil filter/oil pump

by **Eddie** » 17 Jul 2008 19:57

Rear oil passage from cam lifter galley(Right above this is the pressure sensor).

by **MLMFLCN** » 17 Jul 2008 23:36

Hey Eddie, those pix are great. Was it luck the first time I primed the pump when I first started and broke in the engine that the journals lined up? Maybe they are in line with the #1 cylinder at TDC. :hmmm:

If this is the problem, how difficult is it to re line up the cam bearings and is it just #4? Does the rear most cam journal then feed the rear of the engine? From my shop manual, it looks like the left and right main oil galleries feed everything in the engine, but the valvetrain.

Finally, since my machinest installed the cam bearings, does this really fall on him? That was the only piece I did not do. :fight:

I am not one to blame, but as you know, this is a real investment.

Thanks again so much, I am learning :thumbsup:

by **Eddie** » 18 Jul 2008 1:07

When you first primed the engine with the dizzy removed and not turning the engine slowly over by hand you probably did no harm to engine whatsoever. The fact that you use Crane alloy rockers,(I remembered), and they are low friction combined with the fact that as soon as the engine fired the lube will intermittently shoot up into the cylinder heads and the rocker shafts will have pressure is fine and perfectly acceptable practice. I just explained all this to illustrate that the oil can be seen and therefore the camshaft bearing alignment is verified. When you get you're new oil pump simply prime as usual and at the same time spin the engine over by hand slowly until oil is seen coming out of the rockers/shafts on both heads ect..then you can be sure the cam bearings are OK The rear galley is for the hydraulic lifters.

by **MLMFLCN** » 18 Jul 2008 11:38

Great Eddie, I will do all this tomorrow. Thanks again.

How's the motor build coming? Firing it up this year? That thread is like a masters level physics and chemistry class :mrgreen:

by **Eddie** » 18 Jul 2008 12:52

MLMFLCN wrote:Great Eddie, I will do all this tomorrow. Thanks again.

How's the motor build coming? Firing it up this year? That thread is like a masters level physics and chemistry class

Well Rich, I am almost completed with the shortblock. This Fall I am taking the engine to school where we can develop the induction. I found a free vehicle to install the engine once completed but it's an ugly piece of junk!(1990 Dodge Ram 2 wheel drive ) but hey it's free and in one piece. I have a 1990 4 wheel drive truck, but I'm gonna leave it alone. It's rust free and much too nice to cut up. It's also very very reliable. But all in all I'm excited about getting my 'new' ignition system in. It's from a 1998 Ford Crown Victoria V-8 4.6 Liter engine. This engine uses a distributorless ignition system, thats "easy' to retro fit to other V-8's with a simple trigger wheel it can provide spark to the plugs at 65k volts. It should be here shortly and I'll post some pics. Thanks for asking. :wink2:

It's like a dysfunctional engine class with Master Dave as our dysfucntional Instructor!!LOL We should be so Lucky!! :lol:

by **dave-r** » 18 Jul 2008 13:14

Hey! Who are you calling disf...dysfunk...Oh forget it.

:lol:

by **Eddie** » 18 Jul 2008 13:41

by **MLMFLCN** » 18 Jul 2008 18:02

You guys are too much.

by **MLMFLCN** » 20 Jul 2008 20:24

New pump, new gauge, same problem. Oil literally bubbles out of the sending unit hole by just touching the drill.

What is going on here? I am ready to throw in the Mopar towel. :frown:

by **Eddie** » 21 Jul 2008 0:52

MLMFLCN wrote:New pump, new gauge, same problem. Oil literally bubbles out of the sending unit hole by just touching the drill.

What is going on here? I am ready to throw in the Mopar towel.

OK Rich, you put the new pump on, attached the pickup tube, oil pan, then placed the prime tool in the pump hex, why is the sending unit 'open? do you mean that there are just 'bubbles of oil spewing out of the sending unit hole? It should be strong spurts of lube not bubbles of oil or oily bubbles. When you spin the prime tool did it start out easy then 'catch' and become a little more difficult? This is a sure sign that the oil is flowing through the system. Did you remove a valve cover and have some one spin the tool and rotate the engine slowly to see if oil is making it to the top end? What did the mechanical gauge register? Your sure the pickup tube is okay no cracks or leaks there? When you removed it did you check it thoroughly especially at either end where the tube is attached to the pickup feed and the block attachment point. Did you put every plug in the block that needed plugged? (2 at the rear of the block that are the hydraulic lifter galleys 2 at the front that seperate the oil filter and oil pump pickup tube. The other thing that can cause lost oil pressure is a lifter that has become 'unseated or flat spotted by the camshaft

Did you rotate the engine with the valve covers off and observe the springs and how far they are depressed by the rocker arms? When you check the top end lube see or observe that all the rockers push down on the springs about the same amount. A rocker that doesnt move "down"is suspect. Keep us up to date and sorry to hear of your probs Rich.