Oil pump failures

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clutchdust

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Seriously, how does it really happen? I mean unless the retainer on the pump drive breaks or a shotty rebuild and the pickup is loose or mispositioned, maybe debris from something else getting sucked up into it. I'm really struggling to see how a pump can fail, at least before other parts. Hell, it's the first and last part to get oil.
I've heard of oil pump failures but I just can't imagine a scenario where such a simple device locks up before anything else.
 
1000 monkeys typing on 1000 type writers for 1000 years will come up with the complete works of shakespear :)

Anything can happen, just some are more prevalent than others.

That said, it's the shaft that is usually the culprit in an oil pump failure. However, oil system failures, at least in my world, come down to improperly machined pump, broken shaft, dropping the pickup into the pan, or Mr. Hamfist not torquing the bolt that holds it on (he "just" twisted it tight) and stripping the threads. But no, I've not seen a properly made pump fail. That said, in the Buick world, it's a pretty common issue because the gears ride in an aluminum housing.
 
pump housing breaking (for ex. Melling had thin castings). PM gears getting metal shavings in between the teeth, screen coming loose, spring breaking, shafts breaking
 
Only thing I know of is my engine builders cautioned me decades ago to spot weld the suck/pickup tube to the pump body.....

been done since, and never a problem....I suppose the p/u tube could vibrate itself loose over time......I never fought with my short block assemblers....

:smash::surrender:
 
The standard Melling has a weak casting - from what I read back in 2007 they changed the design and made it weaker on the standard pump only. The HV pump is way stronger....


2006.jpg
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Dynageardm55a.jpg
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here's the HV pump I bought:

100_1955Small.jpg
.
see how much thicker the material is.....

100_1956Small.jpg

.

here's another ugly photo I found... looks like a standard pump and maybe that bolt was a little too tight ?????

4new-m55-lessthanseason.jpg

.
 
mrvette said:
Only thing I know of is my engine builders cautioned me decades ago to spot weld the suck/pickup tube to the pump body.....

been done since, and never a problem....I suppose the p/u tube could vibrate itself loose over time......I never fought with my short block assemblers....

:smash::surrender:
Click to expand...

I was taught to remove the pressure spring before tack welding pickup tube.

I had an extremely low oil pressure issue with a SBC with a new oil pump back when I was in high school after tacking the pickup on with the spring installed. I'm not sure if that was the cause or not but I haven't tacked a pickup tube on with the pressure spring installed since.

Sent from my SCH-I500 using Tapatalk 2
 
MYBAD79 said:
The standard Melling has a weak casting - from what I read back in 2007 they changed the design and made it weaker on the standard pump only. The HV pump is way stronger....


2006.jpg
.
Dynageardm55a.jpg
.
.
here's the HV pump I bought:

100_1955Small.jpg
.
see how much thicker the material is.....

100_1956Small.jpg

.

here's another ugly photo I found... looks like a standard pump and maybe that bolt was a little too tight ?????

4new-m55-lessthanseason.jpg

.
Click to expand...

Due to the bad rep this got, they changed back to the original design in the mean time. Just last week I've seen a post on this.

As a matter of a fact, only the select pumps did have the heavier body with billet gears.
 
Well this thread has taken an interesting twist.
I have yet to tack weld the pick up to the pump. I do generally use an epoxy or something to bond it and always check the bond before assembly.
I did not know about the Melling casting. I put a Melling in the Vette engine, but I think it was the HV model.
 
Somewhere out there in internet land is a photo of a oil pump that ingested a small piece of wire. It jammed the impeller and caused the shaft going to the cam shaft ( and distributor) to shear. The oil pickup certainly had a screen filter, but luck had it that the wire went through the filter openings sideways. The little piece of wire was made of hard steel. The failure forces caused it to indent and mold itself into the cast iron pump body.
 
Somewhere out there in internet land is a photo of a oil pump that ingested a small piece of wire. It jammed the impeller and caused the shaft going to the cam shaft ( and distributor) to shear. The oil pickup certainly had a screen filter, but luck had it that the wire went through the filter openings sideways. The little piece of wire was made of hard steel. The failure forces caused it to indent and mold itself into the cast iron pump body and also into the impeller body.
 
clutchdust said:
Well this thread has taken an interesting twist.
I have yet to tack weld the pick up to the pump. I do generally use an epoxy or something to bond it and always check the bond before assembly.
I did not know about the Melling casting. I put a Melling in the Vette engine, but I think it was the HV model.
Click to expand...

The select pumps (which are double the price btw) have a screw to attach the screen. Not all epoxies are good for high temp, so be carefull.
 
I will admit that one of the (few) advantages I see to the SBF is the pick ups are bolted to the pump.
I understand the debris causing a failure, I just am having a hard time seeing an iron body pump just failing without some kind of external element.
 
clutchdust said:
I will admit that one of the (few) advantages I see to the SBF is the pick ups are bolted to the pump.
I understand the debris causing a failure, I just am having a hard time seeing an iron body pump just failing without some kind of external element.
Click to expand...

Solid motor mounts. Jacking the engine up under the pan, pushing the pan up against the pickup, HV pump which have the body close to the bottom.
 
98% of my builds use bolt on pick ups and I do use nye rod to weld the press on pick ups, I only weld about a 3/4 inch bead and so far never had to remove the spring and no problems.

That being said if your brazing the pick up tube on brazing will generate alot of heat then the spring should be removed.

Did you use a shaft with a steel sleeve?
 
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