Moparts

Melling Big Block HV Pump Shaft Siezed - Anyone Else?

Posted By: Dads426

Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 02:49 AM

Had 7 passes on the new motor and on the drive back to the pits oil pressure falls to 30 lbs and the motor starts knocking. Pulled the pan & #2 main is down to copper, #3 rod is worn with no crush. All other bearings OK. Thought the bypass stuck so I pulled the pump and the drive in the pump won't turn. Put a spare drive shaft in it and it turns, but takes a lot of force. Pulled the pump apart and the shaft is not scored, but the fit in the pump is very tight. It spun freely when it was put together. Anyone else have this problem? I have a spare pump that turns freely, but reluctant to use it. Any thoughts? Why did only #2 main wipe? Crank was not hurt. Tempted to throw new bearings in it and a new pump and try it again

Attached picture 6612861-bearings001.jpg
Posted By: Dunnuck Racing

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 03:03 AM

In my opinion that engine must be torn down and gone through completely.Trash from the bearings could be anywhere waiting t tear something else up.
I would think the bearing wear would be from a piece of something lodged in the oiling hole blocking flow,hard to tell for sure without looking at everything.I would bet the crankshaft would at least need polished.
Keith
Posted By: Bob_Coomer

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 03:11 AM

Quote:

In my opinion that engine must be torn down and gone through completely.Trash from the bearings could be anywhere waiting t tear something else up.
I would think the bearing wear would be from a piece of something lodged in the oiling hole blocking flow,hard to tell for sure without looking at everything.I would bet the crankshaft would at least need polished.
Keith


I agree
Look close at those rod bearings, they are the last to see oil. And some time the cap side looks good and the upper rod shell is toast. More so opposite for the mains.
Have a old friend that has been building and racing Mopars for as many years that I have been around. I once mentioned Melling Oil pumps... he says JUNK... Not really given a reason, but he prefers TRW/Speed Pro and Sealed power pumps..
I like the original oil pumps off old engines.. People will trash them, I will dig them out and pull them apart... I have found some good ones too.
Posted By: Dads426

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 03:31 AM

I was able to pull both halves on #3 and they were very worn, but not down to copper. Number 2 rod which is fed from the same main was OK. I was able to polish the crank in the block with 600 grit and crocus cloth (picture is before polishing). Oil holes in the crank are clear; not sure about the block. I may end up pulling it; I do have a spare shortblock.

Attached picture 6612991-bearings002.jpg
Posted By: rowin4

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/02/11 04:46 AM

Quote:

I was able to pull both halves on #3 and they were very worn, but not down to copper. Number 2 rod which is fed from the same main was OK. I was able to polish the crank in the block with 600 grit and crocus cloth (picture is before polishing). Oil holes in the crank are clear; not sure about the block. I may end up pulling it; I do have a spare shortblock.



Your kidding , right? polishing the crank in the block? maybe thats why you have a problem with your engine now. How are you going to clean the grit out and other debree that the bearings pealed off? Do yourself a favor and pull the engine apart, clean and inspect it will be cheaper than just putting in another set of bearings and blowing it completely up.
Posted By: CompSyn

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 05:02 AM

Quote:

Quote:

In my opinion that engine must be torn down and gone through completely.Trash from the bearings could be anywhere waiting t tear something else up.
I would think the bearing wear would be from a piece of something lodged in the oiling hole blocking flow,hard to tell for sure without looking at everything.I would bet the crankshaft would at least need polished.
Keith


I agree
Look close at those rod bearings, they are the last to see oil. And some time the cap side looks good and the upper rod shell is toast. More so opposite for the mains.
Have a old friend that has been building and racing Mopars for as many years that I have been around. I once mentioned Melling Oil pumps... he says JUNK... Not really given a reason, but he prefers TRW/Speed Pro and Sealed power pumps..
I like the original oil pumps off old engines.. People will trash them, I will dig them out and pull them apart... I have found some good ones too.



This from 440Source:

Quote:

Melling M-63HV High volume oil pump assembly. Completely brand new, assembled and ready to install. Currently, the only manufacturer of aftermarket oil pumps for the big block Chrysler is Melling Engine Parts. Melling has been in business since 1947, for over 6 decades. They currently manufacture over 3 million oil pumps every year. For most all applications, we recommend the high volume unit, M63HV. Aside from the billet and aluminum racing pumps made by Milodon, Keith Black and others, Melling is THE only source for stock replacement type cast iron pumps. Don't forget gaskets and attaching bolts as well (listed separately.) - http://store.440source.com/Melling-M-63HV-High-Volume-Oil-Pump-New/productinfo/M63HV/



Does TRW/Speed Pro, Sealed Power make their own pumps and if not is Melling their supplier?

I was advised by a friend after I built my 440 and had it on the road to take the Melling oil pump apart and make sure there were no shavings inside it. Luckily I didn't have any problems as it was too late.
Posted By: Dunnuck Racing

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 05:21 AM

Not sure if Melling is the only one casting these or not,but the last few castings I have seen leave a lot to be desired.There is a lot of casting flash left around the inlet/outlet ports that needs massaged.I could see it breaking off and causing some real issues.
Keith
Posted By: Dads426

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/02/11 12:40 PM

Quote:

Your kidding , right? polishing the crank in the block? maybe thats why you have a problem with your engine now. How are you going to clean the grit out and other debree that the bearings pealed off? Do yourself a favor and pull the engine apart, clean and inspect it will be cheaper than just putting in another set of bearings and blowing it completely up.



I was able to polish the crank with a long piece of 600 grit and crocus cloth, rotating the crank 90 degrees 4-times and pulled #2 & #3 rods to flush out the oil passages. I did that just to see if it would clean up. The motor was pristine when it went together. I am concerned that only #2 main went bad, so we will pull it and check the passages and cam bearings.
Posted By: sasquatch

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 12:41 PM

Melling oil pumps are fine. I have used and sold literally hundreds of them. As with all parts they should be dissassembled and checked for burrs and shavings. Clean it and reassemble. There is practially one on every HP mopar in America.
Todd
Posted By: John_Kunkel

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Else? - 05/02/11 06:20 PM


I had a brand new Melling HV pump seize while priming the engine with a drill. While I had taken great care to pre-lube the rotors and pack the cavities with Vaseline I hadn't thought to lube the inner rotor shaft.

I had never pre-lubed a rotor shaft on many previous builds and never had a problem (I thought) but a dry rotor shaft might cause some minor galling that doesn't appear as a problem until later.
Posted By: maximum entropy

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/02/11 06:50 PM

Quote:

Quote:

Your kidding , right? polishing the crank in the block? maybe thats why you have a problem with your engine now. How are you going to clean the grit out and other debree that the bearings pealed off? Do yourself a favor and pull the engine apart, clean and inspect it will be cheaper than just putting in another set of bearings and blowing it completely up.



I was able to polish the crank with a long piece of 600 grit and crocus cloth, rotating the crank 90 degrees 4-times and pulled #2 & #3 rods to flush out the oil passages. I did that just to see if it would clean up. The motor was pristine when it went together. I am concerned that only #2 main went bad, so we will pull it and check the passages and cam bearings.


that engine needs to be COMPLETELY torn down, inspected, cleaned, and repaired/ replaced as necessary. my guess is the oil pump failure was secondary to another problem. that engine needs to be inspected with the finest tooth comb.
Posted By: SomeCarGuy

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/02/11 07:24 PM

I had a Melling pump die on me after less than 1000 miles in 2009.

I had taken it apart before use, everything checked out OK.

Replaced with a Sealed Power. Hope that Melling didn't make it.
Posted By: DoubleD

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 01:32 AM

If you seize a pump - usually it breaks the hex end off the shaft - My guess is your clearances were not right or you were sucking the pan dry - either way - that thing needs to come apart or it will come apart by itself if you cobble it back together again. Big block oil pumps are pretty stout by design and rarely fail by themselves - usually they fail when junk gets run through them.
Posted By: 440Jim

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 01:41 AM

Quote:

If you seize a pump - usually it breaks the hex end off the shaft - My guess is your clearances were not right or you were sucking the pan dry - either way - that thing needs to come apart or it will come apart by itself if you cobble it back together again. Big block oil pumps are pretty stout by design and rarely fail by themselves - usually they fail when junk gets run through them.



But I can't rule out a pump problem. But the pump may have failed from the bearing debris.
Posted By: AndyF

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 01:48 AM

That is what I was thinking. The pump will seize very quickly if any bearing trash gets in it. I've lost several engines over the years that way. A rod bearing starts to let go and then the pump seizes and then it goes down hill from there.
Posted By: dOoC

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 01:50 AM

YOU SHOULD have been running some of that 10$ a quart SYN stuff .....you know that stuff that some claim you could drain the oil and run it for miles WITH OUT any oil ..... ...some of those claims they make ....

BUMMER about your prob though ...seriously. I also agree .. the motor should come out to be safe.

GOOD luck ...It could only need new bearings and maybe a crank polish.
Posted By: Dads426

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 02:04 AM

Thanks for the replies. I decided to pull the motor and put in the spare 493. I will go over the entire motor with a fine tooth comb. It is too nice a shortblock to just throw bearings in and risk losing it. I did get a reply from melling and they want the pump back. The shaft is not scored; it is just really tight in the pump housing; like the clearance closed up or the shaft is bent. I have other rotors, so I may see if it is a bad rotor or pump housing (just to see what is wrong). The intermediate shaft was not twisted nor was the bronze gear worn (as hard as the pump was to turn I expected to find a problem there).

With all the oil flying around in there, that is the last place I expected to run dry. But, I agree with Andy (BTW, love your book). I think the bearing started to go or something got into the pump and caused the problems. Good thing it didn't happen at 134 mph (Oil pressure dropped on the return road).
Posted By: flynbyu

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 02:20 AM

A few years ago I had 2 that seized up on me at about 1/2 track but didnt hurt the motor.It woulda been 3 but on the 3rd pump when I put it together it would not turn,thats when I stopped.The gear and the rotor didnt have enough clearance and when it got hot it would seize up.Mellings didnt wanna fess up to their screw up,now I dont run any of their products.. good luck
Posted By: Ari440

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 02:32 AM

did you torque the oilpump on or just tigthen it ?

if you over tigthen it it will bind up
Posted By: Sport440

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 03:44 AM

From your description the pump never actually siezed. Right!

If so the damages were caused by some other oil delivery issue. Starvation etc. The oil pump is now bound up tight most likely because of the resulting bearing grit.
Posted By: Dads426

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 12:32 PM

Oil pump was torqued properly. I must have installed at least 2 dozen over the last 35 years.

Pump never completely seized. It is very hard to turn by hand (with an intermediate shaft/gear, even with the outer rotor removed). Oil pressure drop may have been due to the main bearing failing and excessive clearance. So, it may have been binding up on it own due to poor manufacturing, due to residue from a bearing failure or who knows what else
Posted By: supercomp

Re: Melling Big Block HV Pump Shaft Siezed - Anyone Els - 05/03/11 01:49 PM

Try taking the center shaft out and put it in a drill press to see if it't bent.
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