Quite the straightforward question.. I'm rebuilding an 850 T5 engine, but I can't get the cylinder head off. I got the top off and the cams out, but then the cylinder head is attached to the block with 12 very big bolts, and they are just too tight.

I gave it all force I could, struck it with a hammer a few times, then stuck a metal tube to the end of my wrench and gave it all from that with an arm of about 1 meter - i bent my wrench and the bolt is still very well tightened.

How do I get these bolts loose? Will a pneumatic impact wrench help at all, is this a good investment? Or is there another method?

 

Half inch drive breaker bar, then use a long, steel pole, 1 inch thick, about 4-5 feet long, leverage!!!

 

I did that and ended up bending the breaker bar.

 

With all due respect, you'll most likely end up damaging the aluminum head. Shouldn't require Supermanlike force. Good luck. Don't break those bolts, you'll be up a creek...

 

If they are that tight most likely an air gun will not work either. Slide the pipe all the way on to the head of the breaker bar. They can be really tight been there done that.

 

Might want to go with a 3/4" breaker bar and a 4' pipe. My son broke two 1/2" breaker bars on his axle nut before we bought the 3/4". He bought the sockets and bought the bar. Harbor Freight has them for a fairly cheap price.

 

Ok so before I read this thread again, I borrowed myself one of those impact wrenches and started undoing the bolts. In hindsight not the best idea, but ok.. It took quite some time per bolt for them to come loose, after about 5 seconds they started to give a bit, and then they slowly came loose. So they didn't snap loose and it didn't seem to have caused any damage, luckily..

This is what it looked like afterwards:




One question though; all pistons seem to have 2 'dents' in them, at the exact places where the intake-valves are positioned. Are these dents there because they should be there (for better flow dynamics of the combustable mixture perhaps?), or have they been caused by bad timing and hitting the valves, actually denting all pistons?

Now I've got the block apart for the most part. All pistons are out, all very nice! Only thing is, I can't get the bottom off the top. In the next picture, the block is upside-down and I'm trying to get the top off, but it doesn't seem to want to get loose. It's about 3mm separated from the cylincer block, but still sticks to something.



I removed the wheel you see in the picture (impact wrench did come in handy there), and the 4 torx screws behind that. Checked that nothing was still attached to both halves, but it seems to stick to something very close to that wheel I removed. I can't seem to figure out what though..

 

Maybe the rear main seal or oil pump?

 

Glad you got it!!!! 4 valve pistons are ok.. Hope you find what's holding you up soon! What exactly are you trying to break lose??

 

After some looking-around in Vadis and tutorials, it indeed seems like I haven't yet disconnected the oil pump. This sits directly on the crankshaft, right? This afternoon I'll go back there and disassemble the final bits. After that, they're off to the machine shop