HV oil pump with stock pan
02-09-2008, 12:39 AM
#22
Staging Lane
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Right now I am in the middle of swapping out my stock style pan and oil pump for a Canton 242T and the Melling Select 10552. I chose this one because its has more features (according to their website) and its only 10% more volume than stock. I think it will be a very good combination.
Nick
Nick
02-09-2008, 01:58 AM
#23
TECH Apprentice
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I too am one who lost a motor using a HV meling pump and stock pan. At the track at WOT off the line I noticed a 10 psi drop in pressure for a second or two. Then back to normal pressure. This was caused by sucking the pan dry leaving the bearings supseptable to no oil. Thus a spun bearing. HV pump and stock pan ? not advisable.
HVY SS
HVY SS
02-09-2008, 08:47 AM
#24
I believe the stock LT1 pump is already slightly higher volume than the old gen 1 stuff and as said the LT1 is pretty much a gen 1 so we pick from the same assortment of aftermarket pumps.
As also said Melling is the company that makes the stock oilpumps for the LT1, wouldn't suprize me if they make a LOT of the OEM pumps.
People think GM makes a whole lot of stuff, they DON'T, they take a whole lot of pieces from many suppliers and assemble them into cars.
My vote on the oilpump thing is looik over the stocker, if it is in good shape put a new high pressure spring in it, the "white" spring seems to work well.
An oilpump moves "X" amount of fluid per revolutuion and does not build any pressure, pressure is strictly a function of the bearings and all causing resistance to flow. The stock spring gets weak and as rpms and therefore flow rises the pressure rises as the oil is trying to escape through bearings, the pressure gets to say 40-45psi and the stock spring begins letting oil bypass straight back into the pan, still moving the same amount of oil per revolution it is just getting dumped into the pan rather than pushed through bearings. Put a high pressure spring in it and at high rpms when pressure is high you just get the oil being pumped anyway to flow to the bearings rather than bypass back to the pan.
A HV pump with stock bearing clearances will build enough pressure to bypass at a lower rpm.
HV pumps are more prone to cavitation too which is why there are aftermarket pumps like the Titan which is more like an LS gerotor style pump, they are far less likely to cavitate. Cavitation is basically formation of little vacuum pockets that cause liquids to boil and when the bubbles pop it can do damage to the gears. You can see this damage in waterpumps and boat propellers.
As also said Melling is the company that makes the stock oilpumps for the LT1, wouldn't suprize me if they make a LOT of the OEM pumps.
People think GM makes a whole lot of stuff, they DON'T, they take a whole lot of pieces from many suppliers and assemble them into cars.
My vote on the oilpump thing is looik over the stocker, if it is in good shape put a new high pressure spring in it, the "white" spring seems to work well.
An oilpump moves "X" amount of fluid per revolutuion and does not build any pressure, pressure is strictly a function of the bearings and all causing resistance to flow. The stock spring gets weak and as rpms and therefore flow rises the pressure rises as the oil is trying to escape through bearings, the pressure gets to say 40-45psi and the stock spring begins letting oil bypass straight back into the pan, still moving the same amount of oil per revolution it is just getting dumped into the pan rather than pushed through bearings. Put a high pressure spring in it and at high rpms when pressure is high you just get the oil being pumped anyway to flow to the bearings rather than bypass back to the pan.
A HV pump with stock bearing clearances will build enough pressure to bypass at a lower rpm.
HV pumps are more prone to cavitation too which is why there are aftermarket pumps like the Titan which is more like an LS gerotor style pump, they are far less likely to cavitate. Cavitation is basically formation of little vacuum pockets that cause liquids to boil and when the bubbles pop it can do damage to the gears. You can see this damage in waterpumps and boat propellers.
02-11-2008, 12:54 PM
#25
Teching In
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Right now I am in the middle of swapping out my stock style pan and oil pump for a Canton 242T and the Melling Select 10552. I chose this one because its has more features (according to their website) and its only 10% more volume than stock. I think it will be a very good combination.
Nick
Nick
02-12-2008, 12:49 AM
#26
With all this being said you guys have me confused... So which is best? Stock new pump with the white spring?? My car has 161K and my oil pres has dropped from 50 to 28 at highway speeds and am looking for a cheap quick fix until I can get $ for a rebuild. Do you get the spring from the dealership?
02-13-2008, 05:57 AM
#29
I have the Melling selcet std. volume w/ GM white spring and all is well.
You dont need a high volume pump for a street car unless bearing clearances are too big and above spec.
I have heard over and over again its foolish to use the high volume pump on the stock pan, plus it even sucks a few more HP. Wives tale my ***, why take the chance considering the time and money down the toilet if in fact its not.
Not even worth considering to me.
You dont need a high volume pump for a street car unless bearing clearances are too big and above spec.
I have heard over and over again its foolish to use the high volume pump on the stock pan, plus it even sucks a few more HP. Wives tale my ***, why take the chance considering the time and money down the toilet if in fact its not.
Not even worth considering to me.
02-13-2008, 08:06 PM
#33
They are 3/4" pickups in the heavy duty applications, the same as almost all of the 95 & newer LT1 engines... but they are not high volume pumps like the Melling or other performance pumps. The pump gear height is what determines the volume of the pump, not the pickup diameter.
04-20-2008, 01:09 PM
#38
FWIW I have had the M55HV with welded on pick up and steel drive on my 383 for years with the stock pan. No problems. On the motors that had problems with spun bearings......my bet is those were not running a windage tray on their 383's.
Just use 1/8" washers under windage tray to add clearance.
Just use 1/8" washers under windage tray to add clearance.
