Undoing crank bolt

[E30Adam]

Does anyone have any tips for undoing the big bolt in the front of the crank, or more to the point, how to lock the crank. I've tried sticking big drills and screw drivers in the other end to lock it but it's just bending them.

[billgatese30]

if the other end of the crank is attached to the flywheel then could some sort of flywheel lock up tool not be used, of course this relies upon the lfywheel being accesable (i.e. out of car) and if the engine is droped out then the flywheel must not be already removed. if not then all i can suggest is a bigger screwdriver or ask your nearest machine shop if they have any offcuts of decent stainless steel bar(the correct size of course) that you could have, or anything else that is quite tough(not hard and brittle) that you could use.

hope this helps

[DawieM3]

Adam,

I`ve just undone the front bolt on my Alpina 2.7 Lump. It was bloody tight.
Engine is out on stand and conrods, sump removed. I placed a wooded block and used it to wedge the crank from turning. Applied a little heat, and used a socket with a power bar. Bolt came undone.

Hope it helps.

regards,

Dave.

[E30Adam]

The engine is actually out the car and on an engine stand at the moment, it's basically just a bottom end with no ancilliaries or head. There's no flywheel attached because you can't fit it to the stand with a flywheel fitted. The one on the ETA block just came undone really easilly but I know they're torqued up pretty high.

[bmv]

try not to use heat as it alters the tensile strength of the bolt,the best way i have found is bend a valve 90 degrees, or use a peice of angle iron in the flywheel to a bolt in a bellhousing bolt hole to lock it.
you will have to drop the engine i on the floor and pop the flywheel back on but it will be a lot easier than struggling

[E30Adam]

try not to use heat as it alters the tensile strength of the bolt,the best way i have found is bend a valve 90 degrees, or use a peice of angle iron in the flywheel to a bolt in a bellhousing bolt hole to lock it.
you will have to drop the engine i on the floor and pop the flywheel back on but it will be a lot easier than struggling

That's a pretty good idea, I'm gonna give that a try tomorrow!!

[Guest]

The old way of course is to feed some soft rope in the spark plug hole, turn the crank and the compression will lock it solid (but careful of the valves though).
You could of course try and borrow an Impact Wrench from someone, best tool in my tool box!

[E30Adam]

The old way of course is to feed some soft rope in the spark plug hole, turn the crank and the compression will lock it solid (but careful of the valves though).
You could of course try and borrow an Impact Wrench from someone, best tool in my tool box!

What's an impact wrench, sounds like it could be a useful addition to my toolbox.

I would have tried the other method but there's no head on it, it's just a block.

[E30Mark]

Adam,

If the sump is off the block, then wedge a decent sized lump of wood between the crank and side wall.

This is a b!tch of a job, and really should be done with the engine in the car..... much easier then but i'm sure you didn't want to hear that

or alternatively

[M3GTR]

Yep..block of wood is the way to go Adam..I just did mine not long ago. Impact wrench is ok for smaller bolts, but in this case, a long handle and brute force is much better imho.

[andyp]

make sure you eat 3 shredded wheat first in the morning,

[Demlotcrew]

how would one do this with the engine in the car?

Andrew

[Toby_Unna]

you make a tool (i.e. a long bar) that bolts to the front crank hub. then bolt this on so the bar is pushing against the ground when you try to turn the crank. then use a breaker bar on the crank nut.

the m30 nut is even tighter than the m20 one, in the end i welded an old propshaft to a spare crank hub to make a tool.

[andyp]

how would one do this with the engine in the car?

Andrew

pull the handbrake up and put the car in gear

[Toby_Unna]

pull the handbrake up and put the car in gear

that didn't work for me. unless you take the bonnet off you don't have much room to move the long breaker bar round, and i found that by the time i'd got past the slack in the drivetrain i'd run out of room to move the bar. and when you let go it springs back again.

maybe the m20 is less hassle, but i think the torque spec on the m30 3.5 is 360lb ft, and that's plus what it takes to crack the threadlock bond. much more torque than the engine makes, probably not great for the mechanicals either. bmw use a tool as described.

[Demlotcrew]

Think ill let Birds do mines.

[Jimbob]

Wow, what kind of job do you have whilst you're at Uni to have a place like Birds do the work?!

[Guest]

E30Adam
An Impact Wrench is the same thing those Kwikfit monkies use to whack your wheel nuts off with. They can be air driven (via a compressor) or you can get half decent electric/battery one nowadays fairly cheaply (I got a 240lbft 19Volt Sealey battery one from Fleabay for about Ԛ£140 all in, they used to be Ԛ£500 for a good one!!).
Brilliant tool and saved me getting the compressor out and hooking up my air one (sold it now, don't need it with my battery one).
I have tried spanners, rachets with poles on the end before on some nuts and ended up with bent spanners and broken rachets....two minutes later with the impact wrench the nut was off.
If you are going to do a lot of shifting of old, rusty or stubburn nuts then it's well worth investing in one for the time saved.

[Demlotcrew]

Wow, what kind of job do you have whilst you're at Uni to have a place like Birds do the work?!

I work at Next, doing the accounts and paperwork for the shop.

Andrew

[E30Adam]

Wow, what kind of job do you have whilst you're at Uni to have a place like Birds do the work?!

I work at Next, doing the accounts and paperwork for the shop.

Andrew

Oooh can you get me discount, I pretty much live in Next clothes.