Which oil pump?

[RECHRGD]

I am going to change the oil pump on the 440 (mild build).  I want an exact replacement for what's on there now.  It was replaced about eleven years ago.  On the receipt it just gives the number 601-1029.  For whatever reason, I had been under the impression that it was a Melling high volume pump, but I cannot find that number at the Melling site.  When googling the number it comes up as a oem replacement pump, but from a different manufacturer.  I also cannot find any information on whether they come with new a new gasket and o-ring.  I have heard that the high volume pump may be a bit larger in size and don't want any issues when changing out what I've got.  Thanks in advance for any help.........

[cdr]

the hv pump is thicker, & requires longer bolts than the stock pump.  stock bolts  3 are 2 5/8 & one is 4 in, if your bolts are longer then you have the hv pump.

[RECHRGD]

Thanks!  I guess I'll just pull one bolt out tomorrow and measure it........

[A383Wing]

unless all of your oil passages have been opened up to take the extra oil that the HV pump puts out, just put a stock pump back on

[RECHRGD]

 

[cdr]

the best i can tell is the stock pump is 1 3/4 thick  the hv pump is a little more than 2 in thick, surface to bolt head surface of the 3 bolts

[RECHRGD]

Thanks Charlie!

[cdr]

I also agree with a383wing on using the stock pump. I went with the hv pump because i have the edm oiling lifters & pushrod oiling .

[V8-Rocker]

http://www.manciniracing.com/bhehivopuwbo.html

Comes with gasket, O-ring and the correct bolts


Holger

[RECHRGD]

Update!  I installed the standard pump even though it had a HV unit before.  With the HV pump it varied between 40 and 70lbs. pressure depending on rpm and temperatures.  At startup with the new pump it went to 50lbs. (Verified with a mechanical gauge) and just stayed there regardless of rpm.  After a few cruises it still just stayed at 50lbs. with little variation.  Valve train noise, although not bad, is more than I am used to with the old pump.  Yesterday I drove to a car show about 60 miles away on I90.  Traffic travels between 75 and 90 on this route, but the pressure remained at 50lbs..  A few miles before reaching our destination, I had a short punch off with a friends 2016 Challenger and let off at about 110.  The next time I looked at the gauge it had dropped to 40 lbs..  When off the freeway, it creeped up a little, but not much.  On the drive home it was the same 40+/- scenario.  I've ordered a HV pump to get back to what I had, but am baffled about the sudden pressure drop yesterday.

[cdr]

the harder you run them the hotter the oil gets, so the oil thins out & the oil pressure could drop a little.   

[RECHRGD]

the harder you run them the hotter the oil gets, so the oil thins out & the oil pressure could drop a little.   

Agreed   but when leaving the show and driving all the way home at a slower pace, the pressure never returned to "normal".

[A383Wing]

the relief spring probably took a "set" after it got hot....I would keep an eye on the pressure over the next week or so....if it stays the same around 40, then you could always get a Hemi spring or just shim the original spring that's in there now.....

think of it as a "break in period" for the standard spring

[RECHRGD]

Hmmm, well I hope it's something like.  I don't know how hot the oil got, but with the newer radiator I've never seen the coolant passed 180.  I am going back to the HV pump to hopefully rid it of the irritating tick tick tick I   have had since putting on the standard pump.....

[John_Kunkel]

the relief spring probably took a "set" after it got hot....I would keep an eye on the pressure over the next week or so....if it stays the same around 40, then you could always get a Hemi spring or just shim the original spring that's in there now.....

think of it as a "break in period" for the standard spring

If the pressure never exceeded 50 psi it's unlikely the relief valve ever opened.

This is a simple case of not enough volume for the existing conditions i.e. oil weight, clearances. The pump can't create pressure if there's no resistance to flow.

[RECHRGD]

the relief spring probably took a "set" after it got hot....I would keep an eye on the pressure over the next week or so....if it stays the same around 40, then you could always get a Hemi spring or just shim the original spring that's in there now.....

think of it as a "break in period" for the standard spring

If the pressure never exceeded 50 psi it's unlikely the relief valve ever opened.

This is a simple case of not enough volume for the existing conditions i.e. oil weight, clearances. The pump can't create pressure if there's no resistance to flow.

Thanks John!  That HV pump must have been in there for a reason.......

[BSB67]

Why did you change the pump in the first place?

Does the new pump have a standard or high pressure spring?

What was the idle oil pressure with the new, and the old high volume pump?

[RECHRGD]

Why did you change the pump in the first place?

Does the new pump have a standard or high pressure spring?

What was the idle oil pressure with the new, and the old high volume pump?

My pressure dropped considerably and wouldn't come back up.  I put the car away for the winter and went back to deal with it in the spring.  On the first startup the pressure went right back to normal.  After posting here, the general consensus seemed to conclude that the pressure relieve spring must have stuck open and somehow reclosed over the winter or startup.  Never having dealt with these pumps before, I just decided to buy a new one.  I got the standard volume melling pump based upon comments from the members.  With the old HV pump I would usually idle at 40+ lbs.  at highway speeds were 60+.  The new standard pump would maintain 50 regardless of rpm, until yesterday's drop to 40.  That's my story and I'm sticking to it........

[ws23rt]

These pumps are rather simple devices.

If a pump is worn to the point that they can't move the oil as designed it is because the rotor to housing surfaces have taken a beating. Scoring of those surfaces should be apparent  (measured with a straight edge and feeler gauges) and that of course would come from debris/abrasives flowing through the pump.

Of all the pumps I've opened up I have yet to see that condition to be an issue.

The standard volume pump should be more than enough to feed a stock engine until something else takes the engines life.

References to "bypass spring pressures" as being related to an engine oiling issue (IMO) may partly come from a misunderstanding about what they are for.  Since these pumps are positive displacement pumps. (they will hydro lock unless a bypass is available). So some bypass is required.

A loose engine would require a larger volume pump.--This is not the same as pressure.--- The "loose" engine calls for volume to maintain pressure.

With all that jabber having been said.     A mechanical gauge-- tapped into the normal ports will only tell the oil pressure at that point.

If one has a proper mechanical gauge and the pressure drops to ten psi or below it is cause for concern.  

Some oil is needed. ----Lots of extra oil has no additional value and is just that.--extra--

[RECHRGD]

These pumps are rather simple devices.

If a pump is worn to the point that they can't move the oil as designed it is because the rotor to housing surfaces have taken a beating. Scoring of those surfaces should be apparent  (measured with a straight edge and feeler gauges) and that of course would come from debris/abrasives flowing through the pump.

Of all the pumps I've opened up I have yet to see that condition to be an issue.

The standard volume pump should be more than enough to feed a stock engine until something else takes the engines life.

References to "bypass spring pressures" as being related to an engine oiling issue (IMO) come from a misunderstanding about what they are for.  Since these pumps are positive displacement pumps. (they will hydro lock unless a bypass is available). So some bypass is required.

A loose engine would require a larger volume pump.--This is not the same as pressure.--- The "loose" engine calls for volume to maintain pressure.

With all that jabber having been said.      A mechanical gauge-- tapped into the normal ports will only tell the oil pressure at that point.

If one has a proper mechanical gauge and the pressure drops to ten psi or below it is cause for concern. 

Some oil is needed. ----Lots of extra oil has no additional value and is just that.--extra--

Thanks for your input.  At this point, as said before, I'm just going to put a new HV unit on and hope to get my old pressures back.  If that does not happen, then I'll pursue this further.  Right now I'm just getting a headache.....

[ws23rt]

These pumps are rather simple devices.

If a pump is worn to the point that they can't move the oil as designed it is because the rotor to housing surfaces have taken a beating. Scoring of those surfaces should be apparent  (measured with a straight edge and feeler gauges) and that of course would come from debris/abrasives flowing through the pump.

Of all the pumps I've opened up I have yet to see that condition to be an issue.

The standard volume pump should be more than enough to feed a stock engine until something else takes the engines life.

References to "bypass spring pressures" as being related to an engine oiling issue (IMO) come from a misunderstanding about what they are for.  Since these pumps are positive displacement pumps. (they will hydro lock unless a bypass is available). So some bypass is required.

A loose engine would require a larger volume pump.--This is not the same as pressure.--- The "loose" engine calls for volume to maintain pressure.

With all that jabber having been said.     A mechanical gauge-- tapped into the normal ports will only tell the oil pressure at that point.

If one has a proper mechanical gauge and the pressure drops to ten psi or below it is cause for concern.  

Some oil is needed. ----Lots of extra oil has no additional value and is just that.--extra--

Thanks for your input.  At this point, as said before, I'm just going to put a new HV unit on and hope to get my old pressures back.  If that does not happen, then I'll pursue this further.  Right now I'm just getting a headache.....

I get the headache part and I also have always added an HV unit to my cars over the years. It is easy- cheap and helps me to move on to other stuff.

[BSB67]

Why did you change the pump in the first place?

Does the new pump have a standard or high pressure spring?

What was the idle oil pressure with the new, and the old high volume pump?

My pressure dropped considerably and wouldn't come back up.  I put the car away for the winter and went back to deal with it in the spring.  On the first startup the pressure went right back to normal.  After posting here, the general consensus seemed to conclude that the pressure relieve spring must have stuck open and somehow reclosed over the winter or startup.  Never having dealt with these pumps before, I just decided to buy a new one.  I got the standard volume melling pump based upon comments from the members.  With the old HV pump I would usually idle at 40+ lbs.  at highway speeds were 60+.  The new standard pump would maintain 50 regardless of rpm, until yesterday's drop to 40.  That's my story and I'm sticking to it........

Your call, but there are a few more questions in there that you did not answer.

[RECHRGD]

Ummm, like what?

[ws23rt]

Ummm, like what?

Hmm--Me too??  I think you stated your conditions/situation with clarity.

In every ones interest this need not become unnecessarily complex.

It's a simple question about oil pressure drop as stated. -- A stuck open relief valve could account for a drop in pressure.

Is this something that rings true as a condition identified from others?  If so how was that determined?

As for the idle oil pressure with the new vs the old?---This goes to my original observation that these pumps will move oil if they turn!! If they don't do that it is a rare anomaly indeed.

[myk]

You're running the hardened intermediate shaft right?  BTW my oil pressure does the same: reads at 40-50 psi no matter what's going on, and that's with a separate oil pressure gauge doing the monitoring...