LB7: How bad is this?

[catman3126]

I'm no machinist by any means but Ido this exact thing onshafts all the time and Ihave never got one that far out. its just takes a little time to get it right. Ibet the guy set the end mill down int he dowell hole, forgot to lock the ways and started cutting. it moved once the cutter started cutting and he just went for it. a person likehis should not be doing engine machine work.

 

[catman3126]

The could make a stepped key and cutting the key way wider and making the step the size of the keyway in the other part but i would say then get me a good crank and you can fix this one and sell it to someone else and I'll take my good crank elsewhere.

 

[S Phinney]

Make them buy a new one.It would only be rigging something to make it work and that isn't how you should do it.

 

[Big Block 88]

Dont let them try and fix it, they need to replace it. This isnt some small little sbc crank that will see 250 horse. The gear isnt even keyed from what i see.

I have screwed stuff up on a mill but i have never let it get that bad... Someone did the set it and forget it and the machine wasnt locked down and the head wandered to the path of least resistance.

The more material they remove the weaker that snout will be

 

[dirtydmax]

That's what I figured,now they are trying to wiggle out of it but with the amount of B.S I have gone through with this build im not going to let up now.I wont settle for a bandaid fix on something like this,Thanks for the info and encouragement guy's.Should I ask for a recondishoned crank replacement?

 

[S Phinney]

No. It would have to be standard bearings size and I would have to know a history before I would except a used one from them.

 

[dirtydmax]

No. It would have to be standard bearings size and I would have to know a history before I would except a used one from them.

Good call,forgot that a recon will prob be ground so new is the only option.I priced them out today and they retail for $15xx.xx but my price is $1197.97 tax in cad.

 

[WolfLMM]

Ok, now I'm not an engine machinist, but I know my way around a machine shop. But couldn't this be fixed by machining a larger key way in the correct location and doing the same for the gear? It won't be weaker, it would be stronger. So am I missing something here?

 

[andy-stevenson]

Don't scrap it! JB Weld it!

 

[Big Block 88]

Ok, now I'm not an engine machinist, but I know my way around a machine shop. But couldn't this be fixed by machining a larger key way in the correct location and doing the same for the gear? It won't be weaker, it would be stronger. So am I missing something here?

The keyway may be stronger but the snout would lose more material. Im no engineer but less material=weaker. Now with the gear on the snout and key in the keyway, i understand that the voids are filled, in turn the gear would be holding the crank snout so the load spreads out to the gear also helping the snout.

Im just a welder fabricator who runs a mill on occassion though. You may have a better mind set than myself wolf...

We need FINGERS!!!

 

[catman3126]

The keyway may be stronger but the snout would lose more material. Im no engineer but less material=weaker. Now with the gear on the snout and key in the keyway, i understand that the voids are filled, in turn the gear would be holding the crank snout so the load spreads out to the gear also helping the snout.

Im just a welder fabricator who runs a mill on occassion though. You may have a better mind set than myself wolf...

We need FINGERS!!!

I really doubt there would be a breakage issue out there on the crank since theres not much load out there.

 

[dirtydmax]

I always wondered about keyed cranks vs breaks,would heating that gear red hot on the nose of the crank cause some issues with crank breaks and how many broken cranks were keyed?Andy...jb weld it isWho needs a key!

 

[dirtydmax]

If they were to fix it would it be better to have a step key to allow for the reluctor wheel to still have the orig 5mm key and a wider one in the crank or have the crank and reluctor machined to allow for a bigger key.The balancer fits fine in the first key way.

 

[Awenta]

I wouldn't deal with it. You shouldn't either with as much crap as this build has given you.

Get a new one. The key is tried and true. If it ain't broke don't fix it.

Plus I wouldn't feel comfortable letting a shop that did this in the first place try again. If they want to try again they should do so on a new crank.

Sent from my SM-N910V using Tapatalk

 

[WolfLMM]

Stepped key would be easier IMO. I would have a hard time trusting them to broach the gear in the correct location. That's significantly more involved then aligning a key with a dowel hole on an external surface.

 

[dirtydmax]

Stepped key would be easier IMO. I would have a hard time trusting them to broach the gear in the correct location. That's significantly more involved then aligning a key with a dowel hole on an external surface.

I cant trust their work now,I don't think they could give me a warranty or guarantee that their key wont cause damage down the road and end in catastrophic engine failure,Worse case sinario I know but this whole thing sceeers me now.This crank IS NOT going to be used,too many what if's.

 

[Fingers]

Personally, I would have them make me a stepped key. At least if they f(&& that up, they just ruined the key, not the crank. Beat on them till they get it right. Up to you how much to get back $$ wise for the screw up.

Keys do weaken the crank, but defiantly not an issue here.

 

[S Phinney]

It really comes back to indexing. How are you going to know after they cut it for a step key that everything is back in the right spots.

 

[dirtydmax]

I broke down and decided to pull a comacazi move and stripped a short block I was saving.Pulled the crank and it's perfect,journals are spotless so I am dropping it off to the builder and he is going to key this one.The other one I am picking up and giving back to the shop that wrecked it.If they cant figure it out this time they own it!

 

[Harbin_22]

I would have him key the timing gear too. Do all three of them