New crank in my future?

[daviss]

Finally got my crank out and am ready to take everything to the machine shop. I removed the bearings and saw .020 stamped on the bottom side. I guess I'm hoping the crank doesn't neet to be cut any more than it is. If it needs more than just a polish am I gonna need a new crank or are there .025 or .030 bearings out there. The crank isn't grooved or even rough to the eye or touch. How much material is removed with just a polish. I sure wasn't planning on buying a crank.

Any help is appreciated
Steve

 

[boostingbuick]

Cranks are not the strong part of our motors. And at the power your making I think it will be better to replace the crank now befor it breaks and takes out the block, rods, pistons and the trans. Sorry, but it will be worth it in the long run.

 

[BlownV6]

I agree with Boostingbuick , Might be time to do a little PM.
Pm sent Mike

 

[daviss]

Ouch, You know in the back of my mind that is what I'm thinking. I am hoping someone would have a miracle solution to save my crank. I really wanted to do a stroker anyway, but I wanted to give the stocker another shot before I went b@lls deep into something expensive. I guess I'll look for a stock crank for now.

Still open to any good news.
Steve

 

[Just a Six??]

I have put a lot of low 11 passes on a 20-30 crank & never worried about it. I'll bet there are a lot of 20-30 cranks out there. Just get 2 billet centre main caps. Just my opinion of course. You could also cryo treat it for $75

PS: No matter how strong you build them, detonation can take them out.

 

[daviss]

Now that's the positive thinking I'm looking for. I just happened to have all four billet caps sitting on the bench. I need to have the machine shop look at the stocker first to see if it needs any work before I buy a new one.

Thanks for everyone's input. Would like to hear from some more that are using .020 bearings or worse.

I do agree in doing it right to save the other parts.

Steve

 

[Lee Thompson]

polish

should only remove the high spots--I would not worry about a cut crank assuming it has not been abused.

 

[Just a Six??]

I personally know of two 40 under cranks that are doing ok but No Detonation & the main caps really help I think.

Same as when guys do pistons 40 over & people go Whoa!! But we are in most cases cruisers & not TSM & TSO kinda cars which are another animal.

 

[daviss]

should only remove the high spots--I would not worry about a cut crank assuming it has not been abused.

I guess it depends on what is considered abused. It has a handful of 11.30 to 12.0 passes and a little fun on the street but nothing I would consider abuse.

I'm going to take the crank to the crank shop here in town and have it gone over first. IF I need to replace it, I will probably scrap the whole project for now and reload on cash and either plan for a stroker build or start working on the 5.3 truck motor I've got. I really wanted one more shot with the LC2 at a 10.99 before I went V8 turbo.

I really appreciate all the input. My mind is somewhat at ease. I would still like to hear from more guys (or girls) that are running a crank cut .020++. I'm not planning on obscene boost levels or serious racing, just want to make sure I have all of my bases covered before I build a grenade.

Is it possible that the crank won't need any work at all. There are no visible or physical defects. The bearings were not really that bad either. I just wanted to freshen it up this Winter and opened up a can of worms.

Steve

 

[TurboCrazy]

If crank is ok, go for it. Put the 2 center steel main caps in the block and you will be fine. I ran one in a 4.1 stock block with steel center caps for 14 yrs. Beat the hell out of it, too! (always figured it would blow up:wink: ) It made about 550hp with a so-so set of ported irons on it. Would have made much more with good heads. Anyway, ran 27 lbs boost on it most of the time. It saw 6800rpm & 7400rpm when I took 2nd gear band out of the tranny!
BTW, the crank,rods, and pistons are still good and it would still be running if I hadn't done something stupid and screwed up the block. Stay out of the detonation and the crank will be fine. IMHO

 

[daviss]

Is there any insurance to be gained by using all four billet mains? I have a set I got a good deal on and was undecided as to using the front and rear or just the two centers.

Steve

 

[87GN_70GS]

When you go 30 you grind away the rolled fillets that are there for strength.

 

[Quick6'n'-K.C.]

Is there any insurance to be gained by using all four billet mains? I have a set I got a good deal on and was undecided as to using the front and rear or just the two centers.

Steve

Its your call, why did you tear it apart in the first place?

BW

 

[BetMinesFaster]

If ya got em and they are paid for ya might as well use em, sure wont hurt any! I have an uncut stock crank if your in the market as well!

 

[daviss]

Its your call, why did you tear it apart in the first place?

BW

Originally I pulled it out to clean up the engine bay and do a little housekeeping on the wiring. I planned on removing the heater box (done) and repairing the drivers inner fender well that got busted up when my tire blew. I was also going to pull the heads to see if they were the cause of my coolant overflow issue. While I'm at it why not pull the front cover to check the timing set. That's where it all went south. I found plastic in the pan and upon pulling the front cover found the cam gear to be completely destroyed. That's when I decided it was definitely time for some serious freshening and bulletproofing. Besides all that, I have never been inside this motor and had no idea what was in it since I bought the car four owners removed from the guy that built it. I found some good stuff inside. +30 Speed Pro pistons, ARP bolts everywhere, and finally got the specs on the mystery cam from Comp (too bad it's on its way out). Sounded like a logical progression at the time, now I'm hoping to have it all back together by Spring.

Steve

 

[daviss]

When you go 30 you grind away the rolled fillets that are there for strength.

I'm really hoping the crank shop will give it a passing grade as is (.020) considering it looks perfect. I'm just being careful and keeping all options open at this point. Thanks for the heads up though, I hadn't thought about that.

Steve

 

[Steve]

I had a T-Type that ran 10's for 4 years with a .020/.020 crank. It had stock pistons and rods also!

 

[daviss]

I'm gonna drop it off today @ the crank shop here in town. I should have an answer in a couple of days on whether it needs to be cut or just polished or maybe nothing at all. Thanks for the extra vote of confidence.

Steve

 

[Squid4life]

Well, what was the final answer?

 

[daviss]

Typical machine shop runaround. I dropped it off last week and it hasn't moved from where I set it in the shop. I guess they are not too motivated around the holidays. He did tell me it looked pretty good visually but he will let me know when they get around to it.

I will definitely post the results here.

Steve