The 340 is out....again.....

-
UPDATE:

Received a call from the shop yesterday and the real issue has been identified as a missing freeze plug. Apparently this had been removed by the first engine shop I had hired to do the rebuild and was never replaced. It's not one which comes in a rebuild kit of plugs, and shouldn't have been removed in the first place from what I'm told. The plug is visible in the closeup photo, dead center and aluminum colored.

340 block.png


340 Closeup.png
 
It depends on how dirty the block is, and what method is used to clean it determines if I remove that plug.

If the block was cleaned by baking and shot peening I take that plug out every time. It will hold shot and kill the engine. You just have to remember to put it back it.
 
340_dart_power said:
UPDATE:

Received a call from the shop yesterday and the real issue has been identified as a missing freeze plug. Apparently this had been removed by the first engine shop I had hired to do the rebuild and was never replaced. It's not one which comes in a rebuild kit of plugs, and shouldn't have been removed in the first place from what I'm told. The plug is visible in the closeup photo, dead center and aluminum colored.

View attachment 1715016874

View attachment 1715016875
Click to expand...

I don't think that is the culprit. J.Rob
 
I wish you luck, but I think if that plug is left out oil does not go out to the filter much, but you said you had good oil pressure. how did all the oil passages check out
 
RAMM said:
I don't think that is the culprit. J.Rob
Click to expand...


Now that I think about it...off the top of my head I think you are correct. That passage lets unfiltered oil to the engine, but it's not a flow loss. Need to get a drawing out to remember for sure.


Most people don't take them out and I don't always but I've had to do it.
 
Looking at the drawing, that plug just stops dirty oil from going back to the engine. It lets oil bypass the filter.
 
yellow rose said:
Looking at the drawing, that plug just stops dirty oil from going back to the engine. It lets oil bypass the filter.
Click to expand...

Like I said--not the culprit. I'd bet $$$ on the main feed passages not drilled the correct diameter to the full depth. J.Rob
 
I had a coworker leave a plug out of his 406 chevy that nobody ever takes out. Didn't take long for it to eat itself. His oil pressure was crap though.
 
RAMM said:
Like I said--not the culprit. I'd bet $$$ on the main feed passages not drilled the correct diameter to the full depth. J.Rob
Click to expand...

You would surely have a better handle as to why this happened but I still have to wonder about the history of the block and was there ever a problem prior to rebuilding it? Could a passage have gotten clogged from machining debris?

JW
 
Exactly how many cam bearings were damaged, and if not all, then which ones?
The missing plug, as noted, just redirects oil to the filter. The cleaned oil re-enters that very same passage, just above the plug.
BUT
I don't recall if there is a step behind it to prevent it from being driven in too far. I remember on my build to pay particular attention to the exact location of that plug. I do not recall a step. In fact I drilled out all those passages before it went to hot-tanking.Those as well as most or all of the others. If that is possible, the plug could find it's way up further into the main gallery, where it would severely restrict oilflow, which would only become apparent with rpm. The pressure would remain the same,as the oil pump went into bypass, while the volume would stall.With the inadequate oil-flow,the hydrodynamic wedge would collapse. 70psi oil pressure could blow that plug right down to the end of the horizontal passage, or more likely,up the vertical passage.
I would make every effort to find the missing plug. It may not be missing at all.
 
Last edited:
Good copy, All.
I'll chat with the shop next week about the additional concerns and advise.
Thanks for the input, as always.
I'd really like to get the Dodge back and on the road again.
 
AJ/FormS said:
Is supposed to stop at the step.
What if somebody tried and failed, to get it out and just left it up in there somewhere? That is my question
Click to expand...


I'm sure that's possible. There are things I've seen that I thought were impossible.

Hell, I've had stuff happen that was impossible, broken the unbreakable all the stuff that isn't supposed to happen.
 
With all sincerity, good luck with it and let's hope it lives a long life now.
The plug you noted forces the oil through the filter. Nothing more. If it was there, but driven in too far, that might do something negative to the oil delivery. But missing it just means oil was not directed to the filter.
 
moper said:
With all sincerity, good luck with it and let's hope it lives a long life now.
The plug you noted forces the oil through the filter. Nothing more. If it was there, but driven in too far, that might do something negative to the oil delivery. But missing it just means oil was not directed to the filter.
Click to expand...
RGR that; I am just so glad to have it back and running properly.
 
You must log in or register to reply here.
-

Back
Top