Quick crank question

[nightspeed87]

On my rebuilt motor the ( 6bolt ) the crank shaft was the only original part in the motor ( mainly because I ran out of money to replace that too )
Well anywho, the crank was taken to the machine shop because it came out of a blown motor, and after going over the specs of the crank the machine shop guy said something about a bad journal and it had actually grinded, or may I say welded its way onto the crank slightly almost like it kind of fused into it. Well therefore then they micro polished the crank shaft, so im assuming this means removing some of the metal embedded into it, and they smoothend it out and also knife edge it... ( Ive heard about knife edging dont know the real benefits of it but i think it has something to do with sharpening it to help it turn through the oil faster? ) And on top of that I dropped off the whole block to them and they said they had to make custom bearings specific to the needs of this " micropolished/knife edged/ salvaged crankshaft" and they actually needed the block to help get exacts... Well to make a longer story short, does any one see any problems in this ( once again didnt have money to buy a new crank )
Supposing the machine shop did everything right, and to perfect spec will this affect the longevity and/or performance with all this micro polishing and custom crank bearing work? Has anyone else ever had to get their crank machined like this?
( By the way, this wont matter much but the crankshaft also got cryotreated to make it more durable. )

 

[fourreGsixty3]

Ok for knife-edging the crank it takes...I read 4-7lbs off the crank, it just reduces the amount of rotating weight. As for the crank, if its all done properly it should be fine. Micro polishing doesnt take that much material off, so I wouldn't worry about that. Yes, cryotreating it will make it stronger by cooling it down to -330*f to change the crystal structure of the metal, magnafluxing the internals strengthens them as well. Also here is a remaned crank>>> http://www.slowboyracing.com/more.php?id=1715&, pretty cheap as far as cranks go.

Dustin

 

[dsmjoe123]

it should be fine. my buddy did it and he hasnt had any probs

 

[DankDSM]

the journal bearings are the holes in the crank where oil gets pumped into the bearings lubing them up and letting everything rotate. Usually if the journal bearings are messed up you should scrap the crank and go to the junk yard and find another one. And for the money you spent getting the crank knife edged and cryotreated i am sure you could of gotten a new crank. But since you already did all of that the shop you sent it to is probably going to order so specific bearings because your crank is no longer standard size. It is probobly like .1 under or even less and they have to make sure the clearances are right or the engine will spin a bearing. Good luck and if you are paying someone to do all this make sure they check the clearances. GOod luck

 

[nightspeed87]

the journal bearings are the holes in the crank where oil gets pumped into the bearings lubing them up and letting everything rotate. Usually if the journal bearings are messed up you should scrap the crank and go to the junk yard and find another one. And for the money you spent getting the crank knife edged and cryotreated i am sure you could of gotten a new crank. But since you already did all of that the shop you sent it to is probably going to order so specific bearings because your crank is no longer standard size. It is probobly like .1 under or even less and they have to make sure the clearances are right or the engine will spin a bearing. Good luck and if you are paying someone to do all this make sure they check the clearances. GOod luck

Yea see that was the kind of answer I was looking for, but your saying as long as the clearances are ok, the machining was right and bearings were specific to the crank I should be ok right?
Will this is affect the durabilitly and how much horsepower I can make on that crank? ( Or if everything is done properly can it still be just as good as any other dsms crank? ( as far as longevity and durability )
How bad does this look to you guys that all that work needed to be done, I mean I dont know to the extent of the damage, I just know one of the journals were bad and they had to micropolish it out basically.

I payed 120 for the micropolishing and maching work, ( couldnt use my old crank because it was a 7bolt crank. ) and I didnt pay anything for the cryotreating.
But still all the cranks Im seeing is 300 and up, and there arent any turbo dsms in the junkyards around here, and Im kind of on a time limit and definitly on a budget with getting this engine done... Im not putting together any of this, the guy whos building my engine is. Im thinking maybe the machine shop can warrenty that crank work? Im going to call and find out, thanks a lot I appreciate it. If anyone else has any more input Id like to hear it...

 

[ericbev]

magnafluxing the internals strengthens them as well.

Just for clarification, magnafluxing or MPI (magnetic particle inspection) as it is also called, is a process in which a part is magnetized and dusted with an iron powder to find cracks that may be hard or impossible to see with the naked eye. This does not strenghten the part.

 

[92awddsm]

the journal bearings are the holes in the crank where oil gets pumped into the bearings lubing them up and letting everything rotate.

The journal bearings are actually the bearings. The holes you are referring to are called oil holes. The oil holes and journal bearings are 2 different parts. The bearings are replaceable, the oil holes are not.

 

[nightspeed87]

The journal bearings are actually the bearings. The holes you are referring to are called oil holes. The oil holes and journal bearings are 2 different parts. The bearings are replaceable, the oil holes are not.

that makes the most sense...

From what Im figuring according to what your saying is they probably micropolished the cranks oil holes because
one of the journal bearings embedded into it a little i guess, so they had to machine all of that out.
But questionably, why would they need to order custom, so specific bearings to the crank? What would one assume?


Any more wisemen have any input on this situation ?
Anything I should be concerned about with this as far as spinning a bearing, longevity, or
any abnormalities relating to this crank work that I could possibly run into?