Zaknafein

A little latitude, and I apologize if this draws the subject slightly tangent but this blanket is worthy of addressing...

Contrary to popular belief amongst the non-engineering crowd and those who feel we're all just idiots who've never turned a wrench, most of us don't spend 4-6-8 years studying at universities with some end goal of sitting on our duffs in the ivory towers of academia postulating theories and writing books.

Engineering is applied science and mathematics in its purest form. My first two years out of college were spent analyzing failure modes in gas turbine engines. I learned more in those two years than I did in my undergraduate studies!

Now that we've torn the blanket of "professional theorists", let's continue.

"We" as in the entire internal combustion engine building community? IC engines are not exactly unique to 4th and 5th generation f-bodies.

Looking at this logically and based on what "you" feel is impractical:

It is not possible that a drive gear from a mass production camshaft could have been poorly machined, suffering surface finish and/or tolerancing errors?

Not possible that one could have suffered damage in shipping or handling and simply been overlooked upon assembly?

Not possible that there could be excessive run out in the drive gear or drive portion of the camshaft itself?

I could honestly go on for days postulating the Murphy-factor of camshaft manufacturing issues, based on 35 years of experience OUTSIDE the ivory towers inspecting and analyzing failure modes.

Now you say you haven't seen any of these things and I'd have to ask, how did you determine that none of them were the cause of failure?

By the way, I have almost 40 years experience building and assembling engines--as a hobbyist--under my belt and I've seen all of these issues at one time or another.

I'd take your statement one step farther in saying that people see things and don't understand, and that that understanding is probably well outside their ability to comprehend in the first place.

The more you learn, the more you realize you don't know.

I see a trend towards lots of blanket statements and anecdotal evidence here and that's not addressable as it makes no argument based on logic.

You may, but many others may not.

No one suggested that they are. If you re-read for comprehension, I agreed that a SV/SP pump is the right pump most of the time.

ACE1252

For the most part, HV pumps don't get recommended because many people don't change to a high capacity pan...they stick with the stock one. As such, the HV pump can empty the stock pan and that ends in a bad day. That and the SBC oiling system is very good with just the SV pump.....simply no need to waste HP and money on it. The latter reason being better than the former.

The only time I can remember LT1 folks having trouble with the oil pump drive gear was due to excessive load from an HV pump and/or a materials problem with one of the gears.

jeremyhurt

Buy Melling Oil Pump M155 at Advance Auto Parts

This looks to be a standard volume Melling pump... What do you think?

shoebox

You asked for a recommendation and got it above. That pump has an inferior casting to the 10554.

96capricemgr

Far as Melling pumps, Melling was the OEM supplier, the "inferior casting" shbox brought up is a change they made a few years ago and some folks had them snap which is why the "select" pump gets recommended now. I realize this does not help the original poster BUT for most folks I think the stock pump is just fine, if you have concerns about the oil pressure relief spring getting weak a new one is $2-5.

Zaknafein, you actually bring up another good point. Often those who have been in the game a long time fail to adapt to newer ways/advances, professional and amateur alike.

Mystery Bird

Please while you have the engine out of the car and you're already there with the pan off at least inspect the bearings. You will kick yourself hard if this engine spins one a month down the road. At the very least I would pull number 5 and 6 rod bearing for inspection.

jeremyhurt

For sure...

I have a friend who is going to come by and look through everything with me.

I have also taken some pictures that I will share at a later date. I don't have a lot of time to work on it, but after the weekend I should know more.

pgerst

GM makes a mellonized drive gear (19052845) which is supposed to be on the replacement drive unit. As the cams are billet, a non-mellonized steel gear or a bronze gear will not last long even with a SV pump. Possible the wrong gear was installed with the hot cam? +1 on the all steel drive shaft. There are also billet drive assembly available as the stock GM drive assembly is nylon. (Herron Performance)

On a topic related to the post string, I run the HV pump with a stock pan and stock drive unit with the correct gear and have had none of the issues above. Yet. As a result of all the bad press HV pumps get here, before I put the pump in, I had extensive back and forth discussions with one of the engineers at Melling, did the math with overly efficient pump curves (Melling would not share the real curves), and you would need to run at very high rpms (well above the stock rev limit) for a sustained time to drain the pan with a HV pump. I think the problem is more with the stock pan's ability to control the oil in the sump at high g load conditions (e.g., race track) than with the HV pump.

MachinistOne

Melling went back to the good casting about 8 months ago.

shoebox

That is news I have not heard. Is there a place where this is posted from Melling? Of course, the consumer would have to look out for old stock with the inferior casting or need some other way to identify the "newer" one without having to do a direct physical comparison.

shoebox

How long has it been since you checked the drive stub? You won't notice anything until it actually fails one day and you have no oil pressure.

96capricemgr

It is nice that Herron offers the billet piece but I believe it comes without a gear, which is also the most common failure.

pgerst

shoebox -- i have about 5000 miles on the HV pump and my plan was to run it for awhile and then inspect both the gear and drive and see how they looked. Trying to avoid $120 for the composite gear and/or $125 for the billet drive. Coincidentally am taking the intake off this weekend for a spongy lifter and will report back on condition.

96capricemgr

What do you think the billet drive will do? The HV pumps have a tendency to wear out the gear.

Why do you have a HV pump?

pgerst

I had read of the nylon drive failing as a separate, though less frequent, problem, presumably fatigue wear with age? Running the HV pump as I had the engine out and mod plan includes remote oil cooler instead of radiator oil cooling so installed ahead of schedule. Wife and two kids later -- turns out installed way ahead of schedule.