Bearing abuse

[67 dartgts]

Hello:
  Thought some of you would find this interestering...recently I pulled apart a 383 from a doner car..here is a photo of half one of the rod bearings.    A New bearing on the right for comparission.



Maynard

[73swinger]

is the crank ok? I had some bearings that looked like that in my 383 too....killed the crank

[67 dartgts]

Hello:
  I really kinda doubt the crank is gonna be ok.....getting it checked out but it looks terminal.

    Maynard

[73swinger]

Hehe, I guess you don't need anymore excuse for building a 438 or 496 (I built the latter)

[67 dartgts]

Hello:
  mmmmmm now why didn't I think of that..

            Maynard

[PureGTS]

Ya know it's bad when the bearing material is ooozing out the sides between the crank and the rod next to it.

[67 dartgts]

Hello:
  Well it just goes to show that Mother Mopar built them to take punishment.  How many Hyundais (or however you spell that) do you think could that kind of abuse.

            Maynard

[bwells]

Those look pretty good.  About 2 weeks ago I pulled my seized 318 apart, and the bearings didn't look nearly that bad, and it ran for almost 15 minutes without oil, until it seized.  The bearings I pulled out hadn't eaten the ends yet, and I had to have the crank journals turned 20 down. 

[Jim_Lusk]

Unless the crank is cracked it can probably be fixed. An old machinist friend of mine told me that Chrysler cranks had more material and could be turned down farther than the Brand-X stuff he normally sees.

[pwmax]

There are bearings available for most cranks, including mopars, that allow them to be turned .060. Yes, .060. I have told that to guys, that shriek in horror, but, then I say, well, what about a .165 off-set ground stroker crank? That means that .165 is taken off, all at the botom, Or, taking a 440 crank, turning the mains down to 400 size, thats common. Then, they say, "Oh, yah", I guess I didn;t think of that. Grinding the rod journals that much, will allow a good crank grinder, to possibly get some radius in the fillets also.

Frank

[67 dartgts]

Hello:
  Well i'm not a machinest so I have to go by what he tells me.   When I took it to my machinest this morning he said before we take it out of the truck let me get my "mike".  A check with the mike reveled what I feared...It's already as close as we can tell .020 under...he said "usually when a rod goes south like this it also bends the crank some".  I looked at him and said "boat anchor?" ....He said "boat anchor"....
  Now it's decision time I have a 383 crank thats been turned 0.10 x 0.10....Or I have a new 440 crank and rods to drop in and make a 426...
  not to hard to figure which way this is going.
Oh by the way, anbody want to try to salvage the bad 383 crank...pay  the freight and its yours.

  Maynard

[slimer68]

Hello,

I build a mild 340 for my sons `64 Barracuda. He run it at the track and put around 3000 street miles on it.
We checked a bearing (while changing cam and convetor) and the bearings looked kinda like yours. Machine shop said the crank was bent, so they straitened it, we put it back together and now cold it has 55psi oil psi
and hot it has 10psi or less. Any ideas what happened?

[67 dartgts]

Hello:
  Give me a little more information please.   When they corrected the crank did they turn down any of the Main or Rod journals?  Possibly they turned some journals and you were unaware of it?  So (for example) you put STD. size bearings on an under size journal resulting in too much clearence.  Your high pressure cold with extremly low pressure hot is usually due to excessive bearing clearence.

I'm assuming you put new bearings in?

    Maynard

[slimer68]

 Yes we replaced rods and mains with mich.77 bearings. Also had the crank turned and checked clearance with plastic gauge and looked good. I had the block flushed and cam bearings replaced. Oil pump is new also. Could the crank have cracked?

[Mopar Tom]

Hey Maynard,
If that motor came from a certain blue 68 Coronet 4 door that an old buddy of ours now owns  for donation of Charger parts,,,,,,,,,,,,,,,,,,then I,m surprised as it looked like a pretty clean car . Coarse just cause it's clean on the outside don't mean they ever changed the oil,,, -------------------Mopar Tom