See attached picture. Looked at both heads, where number two would be I can see NO marks. Pistons have no 0.030 marking on them. Original? Thanks. Oh, it don't look as though the piston has been hammered on, just has the grooves.
Marks on #2 piston/ 340 engine
- Thread starter Louie70Dart
- Start date
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Cudaroy
Well-Known Member
Hi,Looks to me like SOMETHING was eating that piston. Did the engine sit for some time? How is the bore on that cylinder?
bad440
everything,all the time..
dont know what caused that like the last guy said has it been sitting outside?
Looks,like a loose belt sander,with 36 grit ,tun amuck. Run ,away from this please.
Its been sitting inside. People I got it from had taken the heads off to put oil in cylindersto keep it loose. When I got it it was locked up, but did not take a lot to get loose. Did not use anything extra for leverage and did not have to stand on it. Engine is loose now to where it turns over with one hand on balancer. Cylinder walls have some surface rust that comes off with brake cleaner and a maroon scotch-brite pad, and rust is not completely on all the cylinders. Going to rebiuld it back to factory specs as close as possible with new pistons at least cause of that, not sure about stock CR yet, may dop it one full point. Rods will get reconditioned and crank checked out, along with all the usual rebuild machining. Like I said this won't be a track warrior, but I do want it to last and move climb its way out of a wet paper bag. The 340 has more than enough ooomph on its own with some minor upgrades. Thanks.
Snake
Mopar Nut
I think I would more concern with that bolt broke off, top right if it was was.
.................looks like the dowl pin for the head gasket is broken off in the block.......kim.....
yeah it is the dowel/alignment pin and no its not broken thank goodness. I can hang the head on it with no problem. Thanks for the replies. Really!
I just went out and checked. Good bolt holes, thing is dirty greasy of course. I'll post the vin numbers I just got from the block and post it here on the site.
Crazy thought.... maybe someone took a belt sander to a domed piston making it a flat top.
moper
Well-Known Member
That looks like it was sanded - but it also has rust pits or detonation pits. Regardless - understanding the rusty/stuck nature too - I'd replace them. The ring lands have to be as equally ugly and that's where the rings have to seal...
Previous owner said it ran real good, but was making noise. Said it was pushrod? I rolled the pushrods on floor and didn't seem bent. I know it's not 100% accurate, but they weren't badly bent if at all. Here's a picture of #4 piston. You can see the circles from casting/machining. Can this still be original? I ask cause the pistons have no other marks on them other than the two slashes pointing to the front, both banks have these marks. When I rebuilt my '71 318 YEARS ago it needed to be bored 0.030 over. Replacement pistons has that size on them. This 340 doesn't, is that still original then? Ok, babbled enough for now. Thanks for listening.
moper
Well-Known Member
It's hard to see because the tops are so beat up - but yeah - it looks like it might have been kissing the valves on intake and exh.
airwoofer
Drivetrain limit explorer
Possibly the rod bearings on that cylinder (first pic) are worn enough to allow the piston/rod to float upward and contact the head. I say just take the motor apart and start cleaning and measuring things. You will have to eventually.
All 340 pistons have those valve reliefs.
moper
Well-Known Member
Louie - not the reliefs - what looks like marks inside the reliefs.
Ok, I see what you're saying now. Pictures are not always the best. I will go and check to be sure. Thank God I don't make a living as a photographer. Thanks.
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