Many of you know our set-up: bolt-on C5 with OEM lift/duration cam. Runs mid-11s NA. Car has a wet system which we have dyno'd but yet to sort out on the track.

I picked up a Tick SNS Stage III Torquemax cam and was going to install that with new injectors along with a stand alone and get it retuned on the dyno. Goal is solid 10s NA and 9s on (up to if necessary) a 200 shot. Was going to try to achieve this with the stock untouched 241 heads and LS6 intake.

While pulling the balancer Monday (engine is still in car) the ARP crank bolt came out like this:




Crank bolt went in fine 3 years ago and we've run the car hard over that time with no issues. Not sure what happened but the crank threads are toast. Tried to run a tap through to clean them up but no go. Thought about a helicoli but having a balancer exit the engine compartment at 7,000 rpms scares me!

So ... what to do. Pull the engine of course but then what too achieve our goals of solid 10s NA and solid 9s on nitrous? Repair the stock crank at a machine shop and add forged rods and pistons, all new bearings and rings, and a good set of heads and intake? We just bought a new house and have one in college so money isn't unlimited (when is it ever?) but I don't mind spending some and doing it right once and be done with it.

What would you do to get it right the first time?

Scott

 

Sorry to hear this Scott. The tap was worth a try......

Ron

 

Thanks Ron. Like the kids are saying these days ... it is what it is. If you mess with these things long enough and tear them apart enough times something like this will happen. Oh well ... no use crying over striped threads.

I don't think I need to go the route we talked about to achieve my goals. However, if I had deeper pockets and wasn't so cheap that's how I would proceed. We'll see.

 

Cranks are easy to find.

 

You pulled your pulley on with the bolt didn't you?

 

Used a balancer installation tool if that's what you're asking.

Talked to ARP yesterday. Guy was really nice and said he'd send me a free replacement bolt hoping that I could get the threads cleaned out. Also told me the GM cranks are crude at best on their threads and that he sees this more times than you'd think with both OEM and ARP bolts. It just happens unfortunately he said. Looking back when it got tight coming out I should have worked it back in and out gradually instead of just putting more muscle to it.

We'll get it figured out one way or another.

 

I had that happen to one of my engines. Not with the balancer bolt, but with my install tool.
I got a long drill bit and cleaned it out. Ran a tap down through it. Installed a new balancer bolt and went on my way. Still running strong.

Good luck with the repair Scott.

 

Going to try this as well as some other things this weekend.

Thanks for encouragement. It will be back on the road ... I mean track ... soon! Last day of school is today so I have 3 months off to figure it out.

Scott

 

This. They may be crude but they are going on 14+ years..
Good luck with your repair..

 

I double pinned mine. After 2 cam changes and an oil pump swap I felt like my threads were taking a beating.

 

He said he used an installation tool. You people don't actually READ the responses before throwing in your $.02 do you?

 

We have to give you something to do!

 

Can you use a bolt with larger threads & retap the crank snout? I'd try that and a pin kit.

 

Well, I found and purchased a 16mm x 2.0 tap ($$$) but it wouldn't bite and start. Then I used a cut off wheel and grinder and turned my damaged ARP bolt into a "thread cleaner". Crank is too far gone to clean up apparently. Ordered a time sert kit ($200) and will install that when it arrives as well maybe a pin kit. Talked to a few reputable machine shops and LS engine builders and although helicolis scared them they said a time sert would be fine.

 

I'm with this guy. We had to do this to mine. It's been running strong this way for 3 years. I spin the motor to 6900 rpms no problem pin it tap snout for bigger bolt and plenty of red lock tight. Should be good to go