My 1000-Mile Melling Oil Pump

There is "More" to building a motor than knowing how to put all the pieces back in place.
The Wizzard

 

Keeping extra pieces out of the pan is a good start!

 

I talked to fomocopower last nite.The small chunks are the bottom of the dipstick.They were in the screen and didnt make it to the pump.but smaller chunks may have made it past the screen and locked the pump.

 

doesn't take much to lock up the pump. i learned about that eons ago with a 6 cylinder falcon pump. same spiral shaft. went through two shafts before i found a tiny bit of crap in the pump. not the pump's fault.

 

The small chunks are the bottom of the dipstick.They were in the screen and didnt make it to the pump.but smaller chunks may have made it past the screen and locked the pump.[/QUOTE]

I hate it when that happens. Odds are the pump isn't destroyed. A little de-burr and polish the bottom plate and it will most likely be fine. Did he get the motor shut down as soon as the pressure died?
The Wizzard

 

Didnt say if it did any more damage.But he did check the gauge and a few other things before determinihg it was the pump.Hopefully he didnt hurt the bearings but seems like Murphy is always lookin over Jims shoulder.

 

I had a high mileage 289 (stock pump) twist off just like that. I just happened to look down and see the gauge go to zero..... no damage, new pump and a lot more miles.

 

HIH did pieces of the dipstick get loose in the oil pan?
Did that Fucking Scotsman in the commercial run amuck in his engine?
Dave

 

my first car was a 1979 5.0 mustang. And I went through this problem prolly 5 times in 6 months. we finally figured out that the valve stem seals, and the hard plastic covering that they used to use on the timing gears was breaking down, and getting into the pump. It looked exactly like that when it would twist and break.

 

I was parking it in front of my house Sunday,and just happened to look down at the gauges as the Oil Pressure just dropped to zero just before I was going to shut it off. I checked the gauge,and checked the line before I figured out it was something more serious.

The lil pieces of metal are the end of the dipstick that somehow snapped off on the crankshaft over a week ago. They were both stuck in the oil pick-up screen and did not make there way into the pump. The pump just looks like it ran itself dry. The blades on the rotor are all scored as well. There was a small black spot inside the pump that I can not figure out what it is,definately not metal as it scrapes away very easily.


Oh,and BTW.....all I keep hearing from people is that Melling HV pumps do this all of the time.

 

No they don't do it all the time.

I've never has a Melling pump do that.

 

First time I heard that!

 

I have heard of this, but never a chevy pump, just the fords.

 

Look real close at the gear surface - inside & out.

Bet you find a mark were ( somthing ) locked the pump up.


With any new pump - Any brand - you should always completly diss-asemble - clean & inspect it.

I have found ( extra parts & machining chips ) in many of them.

 

I killed the 302 in my coupe with a similar failure. Just a little bit of gasket got into the pump, and it was all she wrote....

 

All you folks that have experienced the same or similar situations...............You had the same type of evidence, on the pump drive shat, i.e. nice, perfect symmetrical twist, from one engagement area to the other?????

Also, forgive me iffn' I'm mistaken, but I thought the shaft was made with that twist in it???????

 

Atleast you got yourself a sweet turn signal switch outta the deal...

And no... they don't come twisted.

 

Yes. It's mystical the first time you see or hear of it though!

Here's the super simplified explanation.....when metal twists it work hardens and becomes harder to twist. That's why the spirals are so nice and even, because it literally starts at one end and goes to the other as each ring takes twist, gets harder, and passes the force on to the next twist. The rod is manufactured with a lot of toughness (the actual term) knowing it's critical application. So it doesn't snap at first, it's tough enough to take the twist without snapping. At least until the twist work hardens it. Make any sense??

I suspect as it's twisting the motor acts weird because a lot of people are reporting watching the gauge when it happens.

 

They do not come twisted like that. And yes, everyone of mine was twisted EXACTLY perfect like that one.

 

Hehe, nope, they don't come twisted - or two-piece.

I've never heard of an oil pump self-destructing. It's always been from some external contamination or the engine running out of oil.

 

It looks almost as if a piece of gasket material made it`s way into the pump somehow.

 

Well dammit all!!!!!!!!!!!!!!!!!!!!!

Thats wild!!!!!!!!!

 

At least im not the only one surprised by such a perfect twist! ???
What surprise me the most is not the twists themself but the fact that the shaft
is sooo damn straight instead of wavey (if this is a word), but then Shiftys explaination
makes sense to both....i just hope i will never learn this in 1st person.

 

I had do it in a motor i built for an old truck back in the 80's, luckily i had just started the motor and was paying attention, so I didn't hurt anything but the pump. I was told afterwards to makes sure i prime the pump, which i had done..just one of those quirkie type things.

 

WOW~ I thought I was the only one.. I have a collection of these apparantly ..
About 1 month ago. A new build 302 .040 over. ... about 15 miles on the motor... turned about 2500 rpm shifted into second and ..... NO OIL PRESSURE.. tore engine down and found the first posting (picture) ... Im talking I can post mine and you cant tell the same except my bench is red. As per Melling... My fault. Apparantly debris in the pump.. piece of silicone, metal (from shaft breaking) and a piece of valve seal the size of my little finger nail.. (BULLS&ITT) Well I bought new.

Now yesterday fired the new engine after getting the run around from Melling. Idles great.. reved great set carb, timing etc... tonight ran it up to 2700 rpm shifted to second.. and oil pressure drops again to ZERO...
I spun the shaft with primer shaft and its broke again.. I bet im going to have the same image again..
WTF>>>?????????
How long should the shaft be? I read that it could be too long... someone help!
This is getting frustrating..!!! I want my truck back

 

By the way.. my pump shaft broke in the identical spot.. same twist.. I will pull my motor tomorrow night and see the end result of this round.. so far.. engine is eating oil pumps.. mmm mmm good

 

Wow, I had that happen about 15 years ago in a daily that I had. I was about 2 miles from home heard a pop then no oil pressure. Since I didn't think the car was worth much at the time I drove it home anyway. Same twist on the shaft, I found some gasket material in the pump as well. My stock pump was cracked though as well, I had another sitting in a bucket in the garage that I put in, just to see what damage I did to the engine. Turns out I drove that 302 another 2 years before I got rid of the car.

 

I have pulled apart brand new long blocks for warranty.
This is very common.
I have found a single wire from a wire brush/wheel do the same thing to a new pump.
Also a dingleberry of silicone from where someone sealed the intake manifold.
Things can never be too clean when working on a motor.
The smaller something is just makes it that much easier to get in the pump and lock it up tight.

 

Yep its official... identical results of a locked up pump.
Maybe I can keep making these and selling them for christmas ornaments... by the time I throw in parts and labor they will be about 140.00 each.. LOL

I just put the original oil pump back in the motor *1979 and drove it home..
What a load of crap.. LOL Happy thanksgiving everyone

 

2-1/2 years later and I just got done installing an all new motor...and guess what...went for a maiden voyage and 10-min later motor started clacking so I shut it off...got it home,pulled the pan and the pump looks identical to the one in this thread.

I bought the short block from a machine shop and they used...you guessed it...a Melling HV oil pump.

Oil pick-up screen is clean,nothing stuck in the rotors....

Last one I replaced with a standard volume pump and it ran fine for 2+ years.