Crank issues

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Dart Shawn

Dart Shawn

I wanna go fast!!!
Joined
Jan 17, 2009
Messages
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Location
Victorville CA
Got a dilemma on my hands guys and I want to know if you can point me in the right direction.

I bought what was supposed to be a brand new Mopar performance crank from Mancini racing out of New York, I just had the shop clean all the cosmoline off and I picked up the crank yesterday. I went to start plastiquaging the journals and found a nick in the 1'st main, then another in the last main and multiple spots of whats said to be from corrosion on the other journals-this coming from the guy that runs the shop I have had all my work done at. I took the crank back today and asked him if they could polish the nicks and spots out but he said he's not sure then said that as long as he polished out any sharp edges from the nicks and spots that the crank would be fine.

I have always been taught that if there's a nick in your crank then it needs to be polished or turned, same with my dad, he said that who's to guarantee that those nicks wont thrash the journals and bearings which I totally agree but also the shop owner makes a good point by saying the oil holes are the same concept, they are just ground and polished on the edges so that the holes don't trash the bearings which also makes sense. I don't know what to do should I just tell the guy screw it, have it turned .010 under and exchange my bearings, or have him polish out the sharp edges and call it good? remember there is no warranty as they can't promise anything.

What is best for my engine? I don't want to know what will get me by or what will make the engine run for now, I want to know the right way to do it but if polishing off the rough edges is just fine then I will stick with that.

Shawn.
 
I personally would contact Mancini with your concern's,don't pay for defects,rework as a last resort.I love the V8 Vega,always wanted one.Good luck
 
Yeah I know what you mean, the only problem is I have to have this motor built and in the car with in february, and I dont have time to send a crank back, wait for another then wait to have it cleaned and also hope there are no nicks in the next one, then if there arent any nicks begin the rebuild process and hope all goes smoothly I still have to do front end work on the dart also before I can even set the engine in, I just have the time nor could I afford to do it all so im stuck with polishing this'n or having it turned yet if I werent in such a crunch a return would have been warranted, that'd be my first choice for sure!

And thanks man if you want to see more pics of the vega or hear its story I'd be more then happy to show and tell =D.

Shawn.


Twisted72 said:
I personally would contact Mancini with your concern's,don't pay for defects,rework as a last resort.I love the V8 Vega,always wanted one.Good luck
Click to expand...
 
As far as polishing the nicks & using the crank, I'd have no problem with that. I'd still be a bit pissed about it though.
 
Oh I'm fairly pissed but so far this has been nothing but a night mare of wrong or bad parts so I'm just gonna polish it and be done with it, if the rebuild goes south then I'll pull the crank and turn it.

Shawn.
 
You should be fine with just a polish, as long as there's no sharp edges.
I would take pictures of it prior assembly, and contact Mancini as well and explain to them your dilema with the time frame...
Just in case something does go wrong, you can probably still get a replacement crank much cheaper, my .02.

All the best,
 
Measure it for taper. You may find turning it is a good idea anyway. Mancini, I am sure, would work with you on it. They can't see every crank, so call them. You never know.... Maybe if n othing else they can credit you some of the cost. Or was this bought 2nd hand?
 
Alrighty fella's thank's for the help! I now have another problem, the rear main seal I got in my gasket set is not marked in any way so I don't know whether the sealing edge goes towards or away from the engine, can yall lend me a hand with this'n to? it'd be much apreciated.

Shawn.
 
Hey Shawn,

I agree with Moper. Have it checked for taper and turn if so. But if it checks out otherwise, polish out the 'raised' part of the nick and use it. It will just hold some oil there, not a bad thing. As long as there isn't any raised nick above the surface it is good. Nicks that are below the surface will hold oil. Won't hurt a thing. IMHO, polish it out and you are good to go. Good luck.

Terry
 
The lip always faces the oil... So the sharp side faces the crank case. And the crank turns clockwise (look at the tiny vanes on the sealing surface)
 
Dart Shawn said:
Got a dilemma on my hands guys and I want to know if you can point me in the right direction.

I bought what was supposed to be a brand new Mopar performance crank from Mancini racing out of New York, I just had the shop clean all the cosmoline off and I picked up the crank yesterday. I went to start plastiquaging the journals and found a nick in the 1'st main, then another in the last main and multiple spots of whats said to be from corrosion on the other journals-this coming from the guy that runs the shop I have had all my work done at. I took the crank back today and asked him if they could polish the nicks and spots out but he said he's not sure then said that as long as he polished out any sharp edges from the nicks and spots that the crank would be fine.

I have always been taught that if there's a nick in your crank then it needs to be polished or turned, same with my dad, he said that who's to guarantee that those nicks wont thrash the journals and bearings which I totally agree but also the shop owner makes a good point by saying the oil holes are the same concept, they are just ground and polished on the edges so that the holes don't trash the bearings which also makes sense. I don't know what to do should I just tell the guy screw it, have it turned .010 under and exchange my bearings, or have him polish out the sharp edges and call it good? remember there is no warranty as they can't promise anything.

What is best for my engine? I don't want to know what will get me by or what will make the engine run for now, I want to know the right way to do it but if polishing off the rough edges is just fine then I will stick with that.

Shawn.
Click to expand...

Might I ask what crank it was?
 
FYI......Mancini Racing advertises big time about their Mopar heritage but I have been to their place near Detroit....I was pretty bummed to walk in and see virtually nothing Mopar in there! Plenty of Ford and Chevy stuff.
I'm thinking they can't be the original owners.....
 
First time I've checked their site in a long time. They do have a lot more stuff than they used to.
Killer deal on Pro-form carbs.
 
The lip would be the sealing edge the seals egainst the crank?

Shawn.

moper said:
The lip always faces the oil... So the sharp side faces the crank case. And the crank turns clockwise (look at the tiny vanes on the sealing surface)
Click to expand...
 
Looking at the end of the seal 1/2... you'll see there is a peak, or lip, that is the sharpest point on the seal and just below it is slightly undercut. The lip is what rides on the crank surface to seal it.
 
Your best bet is to have it "index ground". What that means is they will verify that the stroke is correct AND that the throws are 90 degrees apart. It's the only right way to have a crank ground for a performance engine.

In my opinion, Mopar Performance parts should be considered cores at best. Their QA is non-existent.

I wouldn't put one of their cranks in my engine without magnafluxing, index grinding and balancing it. Also check to make sure all of the oil holes are properly drilled.
 
Interesting,

Not to hijack (butt) if one was to want a very good crank (purchase new) whose would you suggest?

Bob
 
Rbob said:
Interesting,

Not to hijack (butt) if one was to want a very good crank (purchase new) whose would you suggest?

Bob
Click to expand...

A lot of guys use Eagle cranks. I personally have not used them. I tried to look at their catalog online real quick, but their online catalog sucks beyond compare. You might look at Crower, too. Scat is another popular crank manufacturer.
 
Rbob, only one crank I ever measured was flawless IMO. That was a Callies Dragonslayer 4". There are more expensive manufacturers, but dollar for dollar Callies makes a really good product. That beign said... NO crank, from anyone, should be used without soemone measuring it properly. We don't all have the mics to do it. PLastigage is not really the best way. Think of it like using a rifle or a shot gun to shoot a target. Mics are a sniper rifle, plastigage is a sotgun.. or better than nothing. No cast crank is really machined taht great now. most are usable and within manufacturers' specs. So they work. But to get it all perfect, they would almost all need to be turned undersize by someone who is really trained on a crank grinder. Take any cast crank you want and have it chucked up in a grinder and measured with an Arnold gage... If mics are a sniper rifle, the Arnold gage is a laser for cranks. I can measure to a ten thousanth of an inch (.0001) with my mics and sometimes they make me cringe a little...lol.
 
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