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340 from Hell!

DetMatt1

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I am posting this thread for @B.Mike Roberts
He inadvertently sent it to me in a pm instead of starting a thread so this is a copy and paste of his post to me.

Guys thanks for the previous info on 340 numbers Helped a lot
As I,m disassembling my 340 out of my Challenger I have to give a little history on this Engine It’s a 71 out of unknown
I had it rebuilt several years ago by R&R Engineering in my Area in Lombard Illinois,when I got it back I installed it and it ran Hot but good I ran a FlexFan with a 4 core Aluminum Radiator(Junk) and Chrome Headers which glowed red all the time even at idle All this was done at least 15 years ago,moving forward I never drove the Car on the Road but regularly started it to keep the blood flowing with the exception of Driving it down the road down my street just to test the Shifting I would say I accumulated about 6 hrs of start up time in all,then the terrible thing happened due to my Leftie Wife who loves Animals(probably more than people) She used to keep Birdfood in a bucket next to my Car untill one day she saw Mice in the Bucket that couldn’t get out,so what does she do She put in something like a Ladder for them to get out Which I found Hilarious that is untill One day I opened my hood and noticed a bunch of Birdfood in my Sixpack,needless to say I cringed and soon after I got over thinking about killing her I removed my heads to see what got in the Engine and was surprised that nothing went below the intake,then Bad times hit me and I let the Engine sit without heads which later caused some Surface rust in the jugs,fast forward to a about a week ago I pulled the Engine and one by one I bottomed the Pistons and Filled them with Cider Vinegar drained them and cleaned the Vinegar residue with a Scotch pad Turned out really nice ,so then I found out a couple of Issues as I took all Pistons out of the Engine ,first my NR1 has a slight mark on the Journal whic shows that when Rod was installed it left about 4 thread imprints on it,I knew this wasn’t my doing first I was super carefull removing second they were real easy to push out and third the marks are also on the Bearing,they are very slight and not really noticable to the naked eye then as I took #5 piston out I noticed another problem on the piston wall ,a noticable but very fine spot of pitting half way down the bore and on inspection of the piston It looks like something corrosive ate the top Edge and top side of the piston I couldn’t even remove the Top compression ring because of the Corrosion untill about an hr ago It finally came out with carefull prying
I scraped out the groove and lots of a Powdery substance came out,It reminds me of Metalergy class of putting Aluminum and Steel together much like the front Cover always has when removing it,finally my question is can the Rod Journal be Polished out or do I need to get the Crank turned again It is now 010 over and can this also be done to #5 piston wall as both area s are hardly visible Keeping in mind to all you good people out there that the Engine always had 80 PSI Oil pressure on Start up dropping to 60 on Hot Engine Also if anyone can answer this I bought a set of Cam and Lifters originally from Larry at Mopar City that was a Purple shaft did anyone manufacture these for Mopar or was it Factory done The Box it came in was Mopar and my Cam on the Front says Crane?
Just to correct some members who commented on Crankshaft Casting numbers during some research that have said that there aren’t any Casting numbers on Forged Cranks only Cast cranks I would have to say that’s not the Case
my Casting # is 253 2457 and a possible 4 followed by 9 so 25324574 9 and for those people that said they couldn’t find one on their forged ones I found mine on the first counterweight of Journal of Cylinder 3 and 4
i hope I helped someone with that
Thanks to All
German Mike
 

DetMatt1

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@B.Mike Roberts It should be obvious now how to upload photos to this thread. You were having trouble doing that because it’s not an option in a private message.
It’s all yours from here…
 

Steve340

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The pistons are your biggest problem. Any wear or damage to the ring lands that engine will pump oil like a choo choo train.
Polish the crank, replace the bearing shells and a few pits in the bore will not be a problem.
They most likely nicked the journal while assembling the engine.
To strip and give everything a good clean is probably a good idea. If there is not a lot wrong it is just time and a few gaskets.
 

Xcudame

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Send some pictures Mike. They will give us more information. I used to grind and polish crankshafts, so once I see a good photo, I can comment on whether it can be polished or the rods all need to be reground. Same for the cylinder wall. You're going to need new bearings and a set of rings! And inspect the piston ring grooves like Steve340 mentioned.
 
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