which oil pump
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Joined: Jun 2010
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From: Pulaski Wisconsin
which oil pump
I would like to know which oil pump I should use, standard volume or high volume.
I have Comp Cams XR274R kit assembled and looking to put the oil pan on but I'm not sure which pump would be best.
I have Comp Cams XR274R kit assembled and looking to put the oil pan on but I'm not sure which pump would be best.
Team Owner
Joined: Jan 2006
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From: Crossville TN
Unless you built up your engine with larger oil feed orifices and bigger bearing clearances...or you are going to road-race your car, I would suggest leaving the stock volume pump in it. It is plenty adequate for a 'normal build/use' engine. And, it won't eat up as much power trying to move [extra] oil that the engine doesn't need. Some will say "more is better". But, that's not always the case.
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As mentioned...the stock pump is fine...but I'd add the *Z-28* spring for slightly increased pressure or just order the M55A version that already has it installed. Try to find someone with the newest stock. Do a search but Melling (who also makes 99% of the pumps sold under other names) had cheapened them up until recently and there were issues with the housings breaking. They've recently gone back to the old design that is much better.
JIM
JIM
Le Mans Master
Joined: Jun 2004
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From: Seattle WA
St. Jude Donor '14
Melling still makes OEM-type pumps, but also has the Melling Select Performance line for performance use. All of them come with two springs and a metal intermediate shaft, and several are available with bolt-on pickups if you prefer.
http://www.mellingselectperformance....lPumps.aspx#GM
Make sure you get the matching pickup, and if you're going to use a press-fit (vs. bolt-on) pickup make sure you correctly set the pickup height AND use the right tool to drive it on. I use these tools with a bit of Loctite sleeve compound, and I have never had a pickup loosen.
http://www.goodson.com/store/templat...44806120f0a330
http://www.goodson.com/store/templat...44806120f0a330
HV pumps are definitely not required, or even desireable.
http://www.mellingselectperformance....lPumps.aspx#GM
Make sure you get the matching pickup, and if you're going to use a press-fit (vs. bolt-on) pickup make sure you correctly set the pickup height AND use the right tool to drive it on. I use these tools with a bit of Loctite sleeve compound, and I have never had a pickup loosen.
http://www.goodson.com/store/templat...44806120f0a330
http://www.goodson.com/store/templat...44806120f0a330
HV pumps are definitely not required, or even desireable.
Last edited by billla; Sep 23, 2010 at 01:16 AM.
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I've always had good luck with the "Z28" pump up to my from my warmed over L48 to my sold but missed 550HP 406ci never a problem. Don't know what they are doing with the casting these days but you need to look into that too.
My new 427ci I went with a Mellings pump with a bit more flow
My new 427ci I went with a Mellings pump with a bit more flow
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Le Mans Master
Joined: Jun 2004
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From: Seattle WA
St. Jude Donor '14
FWIW, the well-loved GMPP "Z/28" pump (Melling M55) was replaced in the GMPP catalog by the LT1/LT4 pump (P/N 1255884) and they also sell a HV pump P/N 14044872. I'm 99% sure these are both Melling pumps (M55A and M55A HV) and not from the Melling Select line.
As noted, the casting quality of the OEM pumps decreased significantly a number of years ago and most of those types of pumps come with a little note about being "not for performance use".
Another great part bites the dust...but the Melling Selects are fairly inexpensive
As noted, the casting quality of the OEM pumps decreased significantly a number of years ago and most of those types of pumps come with a little note about being "not for performance use".
Another great part bites the dust...but the Melling Selects are fairly inexpensive
Last edited by billla; Sep 23, 2010 at 09:42 AM.
Drifting
Joined: Dec 2005
Posts: 1,360
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From: NORTHEAST
The Melling M-55A now is coming through with steel gears instead of powdered metal gears and it has the heavy duty body compared to the M-55 pump.
I don't think we have used a 25% more volume pump for years!! The biggest pump we have been using is the Mellings select 10% more volume pump.
We mostly use those pumps in engines with bigger lifters or pressure feed roller lifters and so far no problems.
I don't think we have used a 25% more volume pump for years!! The biggest pump we have been using is the Mellings select 10% more volume pump.
We mostly use those pumps in engines with bigger lifters or pressure feed roller lifters and so far no problems.
Le Mans Master
Joined: Jun 2004
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From: Seattle WA
St. Jude Donor '14
The last Melling M-55A pump I recieved for a stock rebuild had a note on yellow paper in it that stated "Not recommended for use on high performance or off road vehicles." This was less than a month ago. If you call Melling, they're clear that only their Select Performance line is "suitable".
May all be a scam with the same pumps in different boxes at different prices
- but there's reality from their perspective.
May all be a scam with the same pumps in different boxes at different prices
- but there's reality from their perspective.
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
The pump I am referring to and I won't even give a part number anymore because it's so confusing is just a normal stock Melling pump with the same spring used in Z28 pumps the spring is just a little stronger than stock, I am not even talking about high volume or high pressure here, at least that's what I always thought, never really looked closely at the specs because I never had a problem with them 
Race Director
Joined: Mar 2006
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From: Florida
The correspondence I had with Melling last year stated that only the Select series pumps (5 digit) have the old time heavy thick housing and did have the coated gears. All of the newer old number system has the thinner casting.
The select series all come with a Pink spring installed 70psi (same as Z28 pump has) and also a yellow spring 58psi.
The old standard z28 pump is a M55A (70psi)
Those other links seem to have opinions all over the map.
I've never had any problems with the select series pumps.
You can get them for around 60 bucks retail with a good drive rod. Relief is screwed in and some have a 3/4 inlet, all a plus.
Here is a link to Mellings select pump guide
http://www.mellingselectperformance....umps-guide.pdf
The select series all come with a Pink spring installed 70psi (same as Z28 pump has) and also a yellow spring 58psi.
The old standard z28 pump is a M55A (70psi)
Those other links seem to have opinions all over the map.
I've never had any problems with the select series pumps.
You can get them for around 60 bucks retail with a good drive rod. Relief is screwed in and some have a 3/4 inlet, all a plus.
Here is a link to Mellings select pump guide
http://www.mellingselectperformance....umps-guide.pdf
Le Mans Master
Joined: Jun 2004
Posts: 6,231
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From: Seattle WA
St. Jude Donor '14
I prefer to follow the guidance of the manufacturer - Melling is very clear on their guideance, so I use their products as they intend. The price differential is negligible ($50, and the Melling Select includes 2 springs and a steel intermediate shaft as well as other features) so I can't see why anyone wouldn't just use the right product per the manufacturer.
Why risk something like a $5K build on an $85 part?
Why risk something like a $5K build on an $85 part?
Last edited by billla; Sep 23, 2010 at 09:43 AM.
Le Mans Master
Joined: Dec 2003
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From: Fremont CA
Melling has supposedly upgraded the M55 body but, the Mselect series of pumps has steel billet gears again, I'm not sure if the std M55 does. I would go with a M10553 std volume HP pump with the steel billet gears for my build.
Race Director
Joined: Apr 2000
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
This has caught my interest enough I looked up the pump I bought for my my 427ci small block and it is the Melling Select 10552 and the specs are as follows:
- 10%+ more volume than OE
"This line of Melling oil pumps has a larger inlet hole and hardened steel gears, which are about 25% longer, supplying additional oil flow for wider bearing clearances. The driveshaft and idler shaft have been extended into the cover to provide extra support and eliminate any shaft deflection. The pressure relief spring plug is threaded for easy replacement, and some pumps have a heavy-duty driveshaft with a steel sleeve and extra spring where noted."
I am happy with this pump as the oil pressure is where want it
- 10%+ more volume than OE
"This line of Melling oil pumps has a larger inlet hole and hardened steel gears, which are about 25% longer, supplying additional oil flow for wider bearing clearances. The driveshaft and idler shaft have been extended into the cover to provide extra support and eliminate any shaft deflection. The pressure relief spring plug is threaded for easy replacement, and some pumps have a heavy-duty driveshaft with a steel sleeve and extra spring where noted."
I am happy with this pump as the oil pressure is where want it
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
This has caught my interest enough I looked up the pump I bought for my my 427ci small block and it is the Melling Select 10552 and the specs are as follows:
- 10%+ more volume than OE
"This line of Melling oil pumps has a larger inlet hole and hardened steel gears, which are about 25% longer, supplying additional oil flow for wider bearing clearances. The driveshaft and idler shaft have been extended into the cover to provide extra support and eliminate any shaft deflection. The pressure relief spring plug is threaded for easy replacement, and some pumps have a heavy-duty driveshaft with a steel sleeve and extra spring where noted."
I am happy with this pump as the oil pressure is where want it
- 10%+ more volume than OE
"This line of Melling oil pumps has a larger inlet hole and hardened steel gears, which are about 25% longer, supplying additional oil flow for wider bearing clearances. The driveshaft and idler shaft have been extended into the cover to provide extra support and eliminate any shaft deflection. The pressure relief spring plug is threaded for easy replacement, and some pumps have a heavy-duty driveshaft with a steel sleeve and extra spring where noted."
I am happy with this pump as the oil pressure is where want it
Now that Mellings has corrected the problems with the M55A pumps we probably will be using those from now on seeing that they are only cost us 26.00 and the steel driveshaft is only 6 bucks and I think we are paying 56.00 for the 10553 pumps.
I wonder how many engines blew up because of failed light weight pumps and PM gears???
Last edited by BLOCKMAN; Sep 23, 2010 at 03:52 PM.
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
Before you bolt you pump you may want to look this over!!
We have found on every GM rear main cap the oil port in the pump does not match the rear main cap and we have seen some with up to 60% restriction
The cap on the left has been matched to the oil pump
The cap in the middle has been marked with a black marker showing the area that has to be ground out ( I should have used a colored marker)
The cap on the right shows the the peice of oil pump we use to lay out the area to be ground out.
We have been doing this for years and even on the Dart blocks we have to do a little work to them as well. So far we have never had any issues with customers complaining about low oil pressure.
We have found on every GM rear main cap the oil port in the pump does not match the rear main cap and we have seen some with up to 60% restriction
The cap on the left has been matched to the oil pump
The cap in the middle has been marked with a black marker showing the area that has to be ground out ( I should have used a colored marker)
The cap on the right shows the the peice of oil pump we use to lay out the area to be ground out.
We have been doing this for years and even on the Dart blocks we have to do a little work to them as well. So far we have never had any issues with customers complaining about low oil pressure.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
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From: Seattle WA
St. Jude Donor '14
60+ years of GEN I's have been out there without having any machining required on the rear main cap and no issues.
Always a good thing to check, and a little smoothing is worth considering on engines making 1.4HP/CID or more, or just as part of the general block clean-up prior to machining. It's clearly not a precision fit.
Always a good thing to check, and a little smoothing is worth considering on engines making 1.4HP/CID or more, or just as part of the general block clean-up prior to machining. It's clearly not a precision fit.
Last edited by billla; Sep 23, 2010 at 04:50 PM.