How to loosen crank bolt with engine on a stand?

[M42lover]

My spare engine is getting a very nice set of used timing components, courtesy of a member on the  R3V board. Problem is the engine was pulled and the crank bolt was not loosend (sp?) at the time. Do you guys think a impact  and compressor would do it?

[1991 E30 M42]

Depends on how tight it is and what kind of impact you have. I tried using a brand new 1/2 in drive Ingersoll Rand and couldn't get it loose so I put the flywheel pin in and had a friend hold onto the rotation handle on the stand and put a bit prybar on the bolt.

[Cobra Jet]

If your impact gun cannot break it loose, you will need a second hand so that person can hold the flywheel from rotating as you manually break the bolt free.  If I remember correctly, I think that bolt is torqued to something like 240 ft. lbs.

[Asserti]

I heated the bolt quite hot with a ?gaz burner?
Don't know the english word for it, a very little flame thrower :p

Then a big impact gun made it loose

[Abrax]

Some time ago I had the same problem and it became obvious, that even 3 person holding the flywheel were not able to hold it.... So we've pulled the oil pan and with long wooden plank, we've blocked the crank.

2 persons were standing on the engine block and two other were pulling the key with 1,5 meter lenghtened arm. And finally we've forced the crank bolt to lose...

But I think, that impact gun would do the same...

[DZick]

There is a pin hole that locks the Flywheel... and also sets the engine to TDC.
 
Just shove a BFScrewdriver in there and go at it! I beleive the hole is covered by a yellow cap that you just pull off.

[kowalski]

i just bolted a chain to the crankshaft that was bolted to the engine stand. then i used an 8 foot breaker bar, had absolutely no troubled removing it by myself.

If thats mark, which i'm pretty sure you are, then i can come show you if you don't understand what i mean.