oil pump failed

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My buddy ran over the infield berm and smashed the bottom of the oil pan on the 351-C in our dirt car. I didnt have a working oil pressure guage in the car that night...ran a 25 lap feature on a 1/4 mile track.

After we installed the new op gauge we saw a big zero on the gauge...found the oil pump laying in the pan... reused the bearings...light scuffing on the pistons. Ran the engine another season and a half with no issues.

You may have similar results.
 
Here's what happened to mine. Similar scenario, start up after some work on the 340, but caught it within seconds of failure. Happened to be looking at the oil pressure gauge went it let loose.
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RustyRatRod said:
That appears to have happened because the pump was not bottomed out all the way. That's actually a fairly common failure.
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True. The pump in this case was working fine since I got the car and ran it for a few years. Didn't touch it, had good pressure on the first start up, ran for a few minutes, then the pressure bounced around for a few seconds then went away. I definitely dodged a bullet .
 
Divenut said:
True. The pump in this case was working fine since I got the car and ran it for a few years. Didn't touch it, had good pressure on the first start up, ran for a few minutes, then the pressure bounced around for a few seconds then went away. I definitely dodged a bullet .
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No doubt. You were paying attention. That will save you purt near every time.
 
How about giving us a measurement from the bottom of the oil pump drive gear to the end of the shaft.
 
Krooser said:
My buddy ran over the infield berm and smashed the bottom of the oil pan on the 351-C in our dirt car. I didnt have a working oil pressure guage in the car that night...ran a 25 lap feature on a 1/4 mile track.

After we installed the new op gauge we saw a big zero on the gauge...found the oil pump laying in the pan... reused the bearings...light scuffing on the pistons. Ran the engine another season and a half with no issues.

You may have similar results.
Click to expand...
fingers crossed! Im grasping at any glimmer of hope ...

Divenut; I think this is what im looking at too. RRR; I failed to trust my old gauge.

pittsburghracer said:
How about giving us a measurement from the bottom of the oil pump drive gear to the end of the shaft.
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I think I get where you are going, but im having a hard time figuring out how to precisely measure that distance. Let me ask you this? Are the two radii (cam gear and shaft gear) supposed to meet exactly at their widest points? Mine was more difficult to remove this time. It was slightly below the apex of the cam gear radius. My priming tool extends down 11 11/16" from the top of the block down into the pump.
 
like_A_pike said:
fingers crossed! Im grasping at any glimmer of hope ...

Divenut; I think this is what im looking at too. RRR; I failed to trust my old gauge.


I think I get where you are going, but im having a hard time figuring out how to precisely measure that distance. Let me ask you this? Are the two radii (cam gear and shaft gear) supposed to meet exactly at their widest points? Mine was more difficult to remove this time. It was slightly below the apex of the cam gear radius. My priming tool extends down 11 11/16" from the top of the block down into the pump.
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Not worried about the priming tool. I’ve seen guys use stock oil pump drives with a high volume pump and shear the hex drive off so clean it didn’t appear damaged, till you measured it and compared it to a new one. If you give us a good measurement we can measure a good one and compare lengths.
 
pittsburghracer said:
Not worried about the priming tool. I’ve seen guys use stock oil pump drives with a high volume pump and shear the hex drive off so clean it didn’t appear damaged, till you measured it and compared it to a new one. If you give us a good measurement we can measure a good one and compare lengths.
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really? hmm my (what i think is original) intermediate shaft is 8 11/16", the tip is beveled not square but it looks like it was machined that way or at least not done recently.

4spdragtop said:
Was there a new bushing installed/reamed/burnished?
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it's wicked shiny inside and out ??? If the motor goes back to the machine shop, it'll be the on the list of questions I ask.
 
dartfreak75 said:
What do you mean by bottomed out? Wouldn't the bolts bottom it out when torqued?
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The pump shaft housing is a really tight fit. Sometimes they don't bottom out completely even when the bolts are tightened.
 
RustyRatRod said:
The pump shaft housing is a really tight fit. Sometimes they don't bottom out completely even when the bolts are tightened.
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Hmm that's got me wondering because I didnt feel like mine looked deep enough but the bolts bottomed so I just assumed it was right.

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dartfreak75 said:
Well I will check it I was just saying! Haha
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I’m just finishing up a 340 that had a high spot on the oil pump mounting pad. It wasn’t a big lip, but it was noticeable.

I didn’t catch it when I was installing the crank or I would have filed it off.

My thinking was it’s run like that for years, and I use a gasket under the pump so I was going to send it.

Then I got crossed up the compression ratio and had to remove all the pistons so I could mill a bit more of the dome off to get that right and I said screw it, pulled the cap and filed it down.

I feel much better and I glad I didn’t send it.

Anyway, my point is there was the possibility that had it let it go, even if the pump drive part of the housing had been in the main cap, it would have been ever so slightly cocked on the cap.

When you stick the pump drive in there you’ll have an alignment issue and it could cause problems.

I know it was running like that, because I know where that block came from. Knowing my luck, it would have bit me right in the *** and I’d be fixing it.

So I’m glad I missed on the CR and fixed it.
 
like_A_pike said:
long blocked and sleeved 340. Everything new but the valve train. Primed the new pump and got oil up top before buttoning it up and installing the motor. Started right up and sounded good. While working on getting up to temperature, I noticed the top end was kinda loud and then noticed zero oil pressure on the gauge. Shut it off and changed the gauge and started it again, still nothing but it would go to 10psi at 2000 rpm. Shut it down and checked that all the gallery plugs had been replaced and then put heavier oil in it. noticed some very fine metallic looking crud stuck to the oil pan plug. No chunks in the filter though. Still no pressure. Took the intermediate shaft out and tried to prime it again. When I noticed the bit wouldn't engage anything down there. So something is buggered up in there and the motor is coming back out.

My question to you all is; what can I do, shy of a tear down, to see if I've damaged anything else in the motor? The sum of run time was nearly ten minutes.

thanks
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You need to tear it down by a new set of bearings cam rod and Main. Clean the block really good after removing all the galley plugs.... use soap and water air hose to dry it off immediately and WD-40 to spray on to it. Then you can start putting it back together. If the cam is any good....buy all new lifters And re break them in... OR you can take yours all apart and make sure there's no debris inside them ..and inspect all the bottoms to see that they still have some crown. *Buy a new oil pump & hardened intermediate shaft*. You can maybe 'brake clean' to ckean off all the pistons and rings as an assembly and reinstall them in their cylinders. ...*Buy new gaskets of course*...so basically you got to start over not full-blown ,but close.
 
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Looks like the pump failed due to an alignment issue when installed.

Everything cleaned up well and no other damage was found!! Waiting on another pump and intermediate shaft. If I get as far as the hood back on and a new inspection sticker, I'll let you know...
 
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