PITA Crank Bolt

[Devin]

I'd be very careful when using a non-automotive grade bolt. I got a very strong bolt from Tacoma Screw Products to replace one of the ones in my front motor mount. I didn't even get it to the correct torque spec before the head snapped right off. That one wasn't very hard to get off, but I'm not entirely convinced it'll be easy to extract a shank out of the crank! I think that bolt is one of the hardest metals on the whole car.

 

[SHO GoDz 89]

The SHO crank damper bolt is a real odd animal.

It's M14-1.5mm pitch, the shank length to the back of the ****** is 50mm.

The ****** is 47mm diameter and 6.3mm thick. It has to be this large to apply compression force to the damper ****** that slides over the crank snout. The radius on the back side of the ****** to the unthreaded shank is quite large, which tells us something about the forces transferred into the ******.
Click thumbnail to enlarge.

The large, strong ****** applies a compressive force to the inner sleeve of the damper, which is actually sort of soft material. This causes the damper sleeve to compress and deform a little bit, so it fits very tightly around the crank snout. This is why you can often push the damper onto the crank snout, but once it's been bolted down for awhile, you need a puller to get it off.

You aren't going to accomplish the above with a regular bolt and a flat washer.

Here's a possible solution that a SHO parts vendor could undertake. Source a bolt like this: M14-1.5 X 60mm at McMaster. Then have a machine shop make a ******, 47mm O.D. and 10mm thick with a clearance hole for a 14mm shank. Get the ****** hardened and sell a replacement crank bolt assembly. M14-1.5 is unfortunately a little bit uncommon, and it may take some searching to find something with more tensile strength then prop class 8.8, 116,000 psi tensile.

McMaster Carr is wayyyy too far from me to just go out and get one. I've been there a few times already but going there for a bolt is out of the question.

This will have to be a temporary solution until I get a real crank bolt. But for now I have no choice. I bought a hardened m14x1.5, hardened m14 fender washers (2), and a hardened lock washer.

 

[shoon]

Ran into the same problem with a crank bolt, so I looked up one of those mobile tractor trailer tire repair trucks in the phone book, and had some guy come out.

he had a heavy duty air compressor on his truck, and a 3/4" drive impact gun

5 seconds and $20 later and the bolt was out.

 

[Brett]

I never seem to be doing it until the motor is out and on the stand. Then you have to secure the flywheel side too. I do have a compressor and gun, 120psi, pb blaster, and a long, LONG time later it was out. I hate the crank pulley bolt.

 

[SHO GoDz 89]

This crank bolt makes me want to an hero.

 

[NebraskaSHO]

Starter bump got mine free back in June. Still a gigantic PITA though.

Good luck with all that's going on with yours.

 

[hawkeye18]

Uh... I'm not sure you read the ED article right. An heros need to commit suicide. Generally, though, they don't. That's the problem. Anyway, an heros are people who ruin a good time by letting the guy/girl getting pranked/recorded doing things to herself that they're being watched/messed with...

 

[gmorrell]

I'd be very careful when using a non-automotive grade bolt. I got a very strong bolt from Tacoma Screw Products to replace one of the ones in my front motor mount. I didn't even get it to the correct torque spec before the head snapped right off. That one wasn't very hard to get off, but I'm not entirely convinced it'll be easy to extract a shank out of the crank! I think that bolt is one of the hardest metals on the whole car.

What is an automotive grade bolt? I'm not yanking your chain, but I'm an engineer, and I make a very good living from knowing this stuff and how it works in real world, bolted-joint situations. Would that be automotive grade pre or post auto industry bankruptcy?

Metric bolts are generally available in 3 grades, or property classes:
8.8 is typically 115,000 psi tensile.
10.9 is typically 150,000 psi tensile.
12.9 is typically 174,000 psi tensile.

The best bolts that Ford supplied on the SHO were 10.9, with 8.8 in lower stressed areas. When I was actively open tracking my SHO, I would replace mission critical suspension fasteners annually with 10.9 or 12.9 bolts.

The crank bolt is probably 10.9, but it's difficult to tell, as there is no prop class on the bolt. At 85ft-lbs, assuming this bolt has a nominal (working) diameter of 12mm (we use the thread minor diameter to make things a little closer to worst case), and dry threads (torque factor, K=0.21), we're looking at maybe 60Ksi tensile in the bolt shank, which is halfway to the specified strength of a prop class 8.8 bolt. So if my math is even halfway close, Yamaha put in a 2X safety factor.

When I buy high grade bolts, I ask for country of origin. A good fastener house knows where their bolts are manufactured, and will tell you. Most will show you the certification paperwork on high grade fasteners. I'll buy bolts made in Canada, the US and Japan, I will not buy bolts made in China.

I wouldn't even put your kid's swingset together with Chinese bolts. :swing:

Cheers,

 

[SHO GoDz 89]

Uh... I'm not sure you read the ED article right. An heros need to commit suicide. Generally, though, they don't. That's the problem. Anyway, an heros are people who ruin a good time by letting the guy/girl getting pranked/recorded doing things to herself that they're being watched/messed with...

How about you an hero then?

Go lose your ipod

 

[itwonder]

Ran into the same problem with a crank bolt, so I looked up one of those mobile tractor trailer tire repair trucks in the phone book, and had some guy come out.

he had a heavy duty air compressor on his truck, and a 3/4" drive impact gun

5 seconds and $20 later and the bolt was out.

Good move. Shop air setups, including mine, that use the standard 1/4" fittings and 3/8" hose have no chance of flowing enough air for any impact wrench to generate enough torque to pop that crank bolt.

If a standard 14 mm bolt and washer is adequate, wouldn't Yamaha have used one? The penalty for the kludge not working is only crank cancer, so why worry?

 

[1995mtxsho]

If you are MTX then gigantic ass breaker bar, 5th gear and someone on the brakes. If not then I don't know what to tell you. With my ATX the starter bolt trick worked on the very first try.

Yup, Already covered that...

Put it in 5th gear....
Have someone stand on the brakes...
Use a breaker bar to break it loose...
Only works with an MTX... But DOES work...

 

[AREA 91]

How about you an hero then?

Go lose your ipod

I got the bolt out for John yesterday. He also has a replacement from me.

 

[ManySHOs]

I normally reach down and use my fingers to remove the crank bolt. If that doesn't work, I'll use my teeth.

Ahh, I think it's time to revive the old "real man" thread.

Ian

 

[hawkeye18]

oh my god, not the 'real man' crap...

I clamp my ******** around the bolt to get it off, cos I'm a real man.

 

[ManySHOs]

oh my god, not the 'real man' crap...

I clamp my ******** around the bolt to get it off, cos I'm a real man.

Wow, what just happened here?

 

[SHO GoDz 89]

I got the bolt out for John yesterday. He also has a replacement from me.

:thankyou: Thanks a lot for that. You guys are awesome.
I put the SHO back together and got it running...but unfortunately I'm having the same problem. I talked to Matt about it already today.
I've got some used ignition parts laying around, I'm hoping my problem is just something incredibly stupid like the MAF or ignition.

 

[gmorrell]

Ahh, I think it's time to revive the old "real man" thread.

Ian

You ******* and your bolts...

Let's talk welding. When I'm welding, I don't even use a helmet, I just close my eyes and guide the arc with the tip of my finger.

 

[SHO GoDz 89]

You ******* and your bolts...

Let's talk welding. When I'm welding, I don't even use a helmet, I just close my eyes and guide the arc with the tip of my finger.

I guide the arc with my pen15. I'd like to see you tig weld like that.

 

[blckstng96]

you can't just order that bolt from the ford dealer? they always seem to be able to get whatever i need.

 

[SHO GoDz 89]

By the way, use the hole saw trick. Area 91 (Brian) got it off in like 5 minutes.