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Topic Review (Newest First)
02-09-2013 08:03 PM
DoubleVision Your warnings were well heeded Bob. We was installing the screen on the oil pump, just starting to press it in when the pump broke between the mount housing and the pump itself and it broke rather easy. I inspected it and was really surprised to see it was made out of really cheap pot metal that was thin casted.
My nephew was somewhat upset as he's had other things go wrong and I told him "Be happy it broke here and not at the mud park where it would have took the engine with it"
When I got the M55 that I used on my 4.3 V6 back in '07 it was the old style pump and it was obvious it was made of better material. Isn't that something, used to we could get the M55 that lasted forever for $20 bucks. Now to get a good pump you gotta pay $75. I've been using Melling's stuff since I was a kid, hard to handle they went so cheap.
02-07-2013 02:52 PM
BOBCRMAN@aol.com I only worry if the pump binds a bit. I have had Dynagear pumps with the driven gear, axle pin, located out of proper position. Had to send some back.
02-07-2013 12:48 PM
DoubleVision Even so the vehicle it's going is a 4x4 when we did the fabrication for the motor mounts it was with the cab off the frame. We used standard chevy motor mounts and tack welded them to the frame in the Ranger.
We used custom cut angled steel plates about 1/4 inch thick that mount to the side of the block and angled them off to the stock ears which ride on the mounts.
The tranny mount is the stock ranger mount that was drilled in a new position for the TH400 tranny. So even with the mounts being rubber will it survive? Something else I thought I should mention is when I went and picked up the new M55 I took it out of the box and spun it with my finger. It moves super smooth with little resistance which is making me question rather or not the pump is any good as all the melling pumps I bought in the past always had resistance of the meshing gears that you could feel. So I wasn't sure if maybe they had did a improvement to the pump or if there's something possibly wrong with this pump.
02-07-2013 12:10 PM
BOBCRMAN@aol.com
Quote:
Originally Posted by gearheadslife View Post
anyone have photo's of a failed m55 pump, is the cause the pump housing or just the p/m gears failure
or ?

as far as the high volume pump. I only used one on my 355 because the spec's are on the loose side for running dual shots of silly gas..
If I can remember. I have a couple of broken ones on "The wall of shame" I'll take a couple pics of them. They break between the mount boss and pump gear housing.

The only gear I have had break was because it sucked up a wire from a rotary Taiwan wire brush, that was used by the customer, to clean intake manifold area. That little 1/4" long piece of wire really cause some catastrophic results!!
02-07-2013 10:37 AM
MouseFink That is correct.

GM is just like Wal-Mart. Those corporations will determine what they will pay for a something and some company will be more than happy to figure out how to provide it at that price.

Melling introduced the Select line of oil pumps for their high performance customers.
02-07-2013 06:51 AM
gearheadslife
Quote:
Originally Posted by MouseFink View Post
Before I purchased a SB Chevy Melling Select oil pump, I E-mailed Melling and discussed this with George Richmond, their PR man. He said the thin castings were breaking just below where they attach to the main cap, mainly in engines that had solid motor mounts and some 4WD off road vehicles.

He went on to say that GM requested that the oil pump be made of thinner castings to save a few pennies. That sounds ridiculous but i believe him because that is the way the bean counters at GM does things.
a few pennies x millions of sbc.. not hard to, not think g.m. would require that...
it was more likely g.m. had another surplier that walked in and said they could surply them for x amont less.. and g.m. told mellings if they wanted to keep the contract. they'd need to meet the oursourced surplier..
thats more of a believable been counter story..
02-07-2013 05:07 AM
MouseFink Before I purchased a SB Chevy Melling Select oil pump, I E-mailed Melling and discussed this with George Richmond, their PR man. He said the thin castings were breaking just below where they attach to the main cap, mainly in engines that had solid motor mounts and some 4WD off road vehicles.

He went on to say that GM requested that the oil pump be made of thinner castings to save a few pennies. That sounds ridiculous but i believe him because that is the way the bean counters at GM does things.
02-07-2013 12:19 AM
gearheadslife anyone have photo's of a failed m55 pump, is the cause the pump housing or just the p/m gears failure
or ?

as far as the high volume pump. I only used one on my 355 because the spec's are on the loose side for running dual shots of silly gas..
02-06-2013 08:32 PM
DoubleVision Thanks for the info. I think this one I'm putting together now is the 11th small block I've built and I've always used the standard volume M55.
When the bearing clearances are correct there's no need for anything else, not on a mild rodded street engine anyways. However this build is a mild performance build to go in my nephews 89 Ford Ranger 4x4. This truck will see some street plus will be hanging out at the local mud park.
The only time I would use a high volume pump would be as a band aid for excessive bearing clearances in a engine I was trying to keep alive for a little while longer. I don't care much for HV pumps as they require up to 20 horses to drive.
It's pretty basic 350. Ported 305 heads, .224 duration cam, headers, KB 12cc D dish pistons, Weiand Action plus intake, Quadrajet carb, windage tray, comp double roller timing set and comp push rods. TH400 tranny, 2800 stall, NP241 transfer case, 3.73 gears and sitting on 36 inch tall Gateway Buckshot Mudders. In a light Ford Ranger it should be lots of fun.
02-06-2013 07:43 PM
MouseFink I have known some so-called "engine pros" that could not find their butt with both hands. LOL
02-06-2013 06:52 PM
cobalt327 Amazing what three years of internet ejukashun will getcha!

What I see is just argument for arguments sake. On another thread it was said that the way to pick a Roots blower was to use flow charts and such, not the manufacturers recommendations, etc. Then goes on to provide a flow chart for a positive displacement blower IIRC as "proof".

But here, apparently it's perfectly acceptable to go on "what if's", "just in case", and "maybe's" when choosing an oil pump.

I would- again- suggest that the OP's problem be addressed. Sure- make corrections to info as needed- but make sure the OP's problem is dealt with, not just flapping jaw to start something.
02-06-2013 06:43 PM
OLNOLAN
I can't help it either, I get tired of biting my tongue

Quote:
Originally Posted by cobalt327 View Post
Sorry but I can't help it.

I just LOVE to hear no-nothing-from-hands-on-experience, never-built-a-real-engine, wanna-be's lecture REAL engine pros. Makes me laugh, but not in a good way.
Dis is da injunearin jenyus sayvant that can't even make a one cylinder engine run. Click dat link ;

http://www.hotrodders.com/forum/smal...on-174318.html
02-06-2013 12:03 PM
MouseFink
Quote:
Originally Posted by AutoGear View Post
Only thing I'll add is if you get a pump and wonder if it has the billet or Powdered Metal (PM) gears; put a mark on it with a felt-tip pen. If the mark fades away, its Powdered Metal. Nothing wrong with PM in the correct application, however if you put any trash through the pump, it can break the gears, where a billet gear will probably chip a tooth and pass it through.

I haven't seen a PM one in awhile but, it sure is nice of companies being forced to upsell you if you question their old stock having the PM gears or not. I understand that there are rising costs of manufacture; but I also know that investing in the powdered metal dies is NOT cheap at all and takes tens of thousands of pieces to amortize the cost in a reasonable timeframe
The more expensive Melling Select oil pumps have 8620 carburized billet steel spur gears. Carburizing of steel is a form of case hardening similar to austempering of cast iron. Steel billet camshafts are carburized.

Select austempering is the case hardening process used on cast iron hydraulic roller camshafts. Select austempering retains the malleable cast iron core.
02-06-2013 09:59 AM
cobalt327
Quote:
Originally Posted by AutoGear View Post
Only thing I'll add is if you get a pump and wonder if it has the billet or Powdered Metal (PM) gears; put a mark on it with a felt-tip pen. If the mark fades away, its Powdered Metal. Nothing wrong with PM in the correct application, however if you put any trash through the pump, it can break the gears, where a billet gear will probably chip a tooth and pass it through.

I haven't seen a PM one in awhile but, it sure is nice of companies being forced to upsell you if you question their old stock having the PM gears or not. I understand that there are rising costs of manufacture; but I also know that investing in the powdered metal dies is NOT cheap at all and takes tens of thousands of pieces to amortize the cost in a reasonable timeframe
That's good to know, thanks.

Also FWIW, I had occasion to tear down a '97 Vortec engine w/a thrown rod. It wasn't pretty- the rod was in about 8 pieces (no exaggeration)- and it looked to have shattered (reminded me of a failed hypereutetic piston) instead of bending/breaking like a normal forged steel rod tends to do.

I still have the pieces if anyone's interested in seeing them all, here's one of the bigger ones:



I don't know the exact mode of failure, the crank's rod journal was badly worn, so it might have been driven in desperation long after it started knocking. That could have overheated it, although there's no discernible bluing of the metal. The rod bolts were still nutted and were holding onto pieces of the cap and rod (in two separate pieces) and hadn't broken although they may have stretched.

Until seeing this I believed the PM rods were at least as good if not better than the forged steel rods before them. The finish is much better on the PM rods, that much is known. But this does raise a little doubt, although one case does not mean that much either way.
02-06-2013 08:59 AM
sbchevfreak No one mentioned the shear on the oil, as it is forced through the bypass. Causes a lot of heat generation, and kills the additive package in the oils. It is the same effect that kills power steering pumps when people repeatedly hold the wheel on the lcoks.
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