[nikitino25]

So my buddy and I were re-installing my manual trans after replacing the clutch (335is unit) and when tightening one of the single use aluminum bolts that bolt the trans to the engine, one of them snapped in half. Luckily we were able to get the broken half back out after pulling the trans back off but I had to order a new 5 bolt set (we had already torqued one other one also) because I didn't want to re-use the old bolts since they are one use only. For you guys who've done this, how did you torque the aluminum bolts to spec which is 72nm (53ft lbs)? You have to use such long extensions that I think it skews the torque wrench accuracy......Also, I see no way to fit a torque wrench on the top two bellhousing bolts which were the hardest to get off.....

[peter91118]

I haven't done this myself in an e9x but could you use a torque stick instead of a regular torque wrench?

[j1gilles]

Extensions should not effect torque wrench accuracy. Try a "crows foot" for the top bolts

[pwr hungry]

Originally Posted by j1gilles

Extensions should not effect torque wrench accuracy. Try a "crows foot" for the top bolts

Extensions will not, but a crows foot will increase the torque being applied.

[mankytron]

What is the logic behind bmw using these aluminum one use bolts as they seem like a problem waiting to happen. I have never seen this in any other brand, even including older bmws.

[nikitino25]

Originally Posted by mankytron

What is the logic behind bmw using these aluminum one use bolts as they seem like a problem waiting to happen. I have never seen this in any other brand, even including older bmws.

Tell me about it, they are also now discontinued if you look them up on real OEM or ECS tuning site. I found some at a semi local dealer but still had to have them shipped....what happens when they are all gone, surely they must make a replacement.....

[nikitino25]

Originally Posted by j1gilles

Extensions should not effect torque wrench accuracy. Try a "crows foot" for the top bolts

That's not a bad idea for the top bellhousing bolts but these are Torx bolts...where on earth could you get a crows foot torx wrench I wonder? The Sudatenland?

[Aerotest]

Originally Posted by pwr hungry

Extensions will not, but a crows foot will increase the torque being applied.

Not if you set the foot 90 degrees perpendicular to the plane if the torque wrench, so not to increase the moment. If in plane then yes you are correct.

[deltalima0]

Originally Posted by nikitino25

Tell me about it, they are also now discontinued if you look them up on real OEM or ECS tuning site. I found some at a semi local dealer but still had to have them shipped....what happens when they are all gone, surely they must make a replacement.....

They went to steel I put in a new transmission and used the new steel ones.

[Myrder]

Originally Posted by j1gilles

Extensions should not effect torque wrench accuracy. Try a "crows foot" for the top bolts

Extensions twist and create a spring effect which will throw off readings from a torque wrench.

[robc1976]

Originally Posted by Myrder

Extensions twist and create a spring effect which will throw off readings from a torque wrench.

totally agree.

[j1gilles]

Originally Posted by Myrder

Extensions twist and create a spring effect which will throw off readings from a torque wrench.

100 % false.... Hardened steel or chromoly steel will not twist enough to generate rebound torque.. Especially at the torque applied for bell-housing bolts. I've had this debate a million times back in my wrench turning days. Test it, take a torque wrench (I used a digital Snap-on) and put an extension on it. Put another torque wrench (same brand/type)in a vise and put a 3/8 socket on it. "Attach" the two and slowly turn the torque wrench with the extension on it while watching the torque reading on the other one... There will be little to no difference one the 2 readings. I've tested this up to 100 ft lbs.

[j1gilles]

Originally Posted by pwr hungry

Extensions will not, but a crows foot will increase the torque being applied.

Correct and you can compensate for the "extra" torque.. Got this from my old Ford stuff. Here is the formula for anyone that needs it. The formula for calculating the torque with a crows-foot. E- Effective length of extension - measured along the center-line of the torque wrench. L Lever length of the wrench - center of grip to center of drive. T(W) - Torque set on the wrench. T(E)- Torque applied by the extension to the fastener.

T(W) = T(E)* L/L+E
T(E) = T(W)* (L+E)/L

[robc1976]

Originally Posted by j1gilles

100 % false.... Hardened steel or chromoly steel will not twist enough to generate rebound torque.. Especially at the torque applied for bell-housing bolts. I've had this debate a million times back in my wrench turning days. Test it, take a torque wrench (I used a digital Snap-on) and put an extension on it. Put another torque wrench (same brand/type)in a vise and put a 3/8 socket on it. "Attach" the two and slowly turn the torque wrench with the extension on it while watching the torque reading on the other one... There will be little to no difference one the 2 readings. I've tested this up to 100 ft lbs.

this I agree 100% I was referring to the extension moving inside socket slightly. Good info here.

[Myrder]

Originally Posted by j1gilles

100 % false.... Hardened steel or chromoly steel will not twist enough to generate rebound torque.. Especially at the torque applied for bell-housing bolts. I've had this debate a million times back in my wrench turning days. Test it, take a torque wrench (I used a digital Snap-on) and put an extension on it. Put another torque wrench (same brand/type)in a vise and put a 3/8 socket on it. "Attach" the two and slowly turn the torque wrench with the extension on it while watching the torque reading on the other one... There will be little to no difference one the 2 readings. I've tested this up to 100 ft lbs.

Fair enough. I know with excellent tool set this is agreeable. When using some cheaper extensions and sockets you will get a twist. I don't believe its 100% accurate then. You lose some torque if you use a universal joint, which is needed on a lot of hard to reach areas.