Crankshaft will not rotate. Help please!

[dt1903]

Hi all,

I'm in the process of my first build and this has involved a complete engine rebuild. All has been going well until now. I have reached the top of the engine, put the cam cover on and tightened the bolts to the specified torque specs. Then when I went to turn the crank ,to begin checking valve lash etc, it won't budge. I took the cover off again to check I'd installed everything right to this point and all was well. Then replaced the cover and same thing happened. I then loosened the bolts just slightly and the crank was then able to turn but the bolts are not at the minimum torque spec. I'm a bit baffled and wondered if anyone had any ideas?

So basically it all turns over nicely BEFORE the cover is on. It's only when I put it on that things go wrong.

Any help is hugely appreciated. Thanks

 

[drewpy]

sounds like the timing is out 180'.

go back and check the correct piston is at TDC and that the cam lobes are not pushing on the followers causing the vales to open on the piston

 

[dt1903]

Hi drewpy,

So when I was installing the cam I made sure the atu pin was at 12 oclock and the sprocket matched it, and with the rotor lined up with the LT mark in the right place. I checked to make sure the left piston was at TDC and it seemed to be. Is there something else im doing wrong?

 

[drewpy]

I seem to remember a similar thread and the tooth was out by 1 or two.

what you described is accurate, just make sure the camchain slack is taken up the right way as per haynes

 

[dt1903]

ok cheers mate. I'll give it another go over the weekend

 

[dt1903]

Drewpy,

Had another go at this and it is still happening. I'm really baffed. I've tried moving the chain along a tooth or so but what I don't understand is how this makes a difference? Because I have everything lined up right and there are specific holes for the cam sprocket to go into. Still, the crank won't turn when the cover is tightened down.

I've also put the chain guide and tensioner in and they seem to be in the right place.

Is there anything else you can think of in the sequence that I might have missed?

 

[dt1903]

Also should mention this is with the valve covers off as well.

 

[xschris]

When you rebuilt the engine did you replace the crank bearings?

 

[drewpy]

Also should mention this is with the valve covers off as well.

then it can't the timing as the valves will be flat in the head. Must have something sticking out and it catches.

was else was removed? starter chain baulking?

 

[dt1903]

chris: I actually can't remember as this has been going on for so long. Only able to do little bits in my spare time. I'll check the receipts. If I haven't, that could sink the crank enough for this to happen?

drewpy: everything was taken apart. right down

 

[xschris]

I say this because if the bearings are the wrong size it could be binding.

 

[dt1903]

Ok. well serves me right if it is that and i didnt change them. if you think of anything that it could be where i dont have to go to the bottom again let me know! it would be much appreciated.

 

[drewpy]

try disconnecting the clutch plates so the engine can turn over separately from the drive train, if it still locks, then either something stuck down the tunnel, starter clutch side is bindingsomehow or the crank as xschris says.

start easy and work your way inwards

 

[dt1903]

ok. will do. thanks for the help
I'll let you know how it goes!

 

[dt1903]

Mystery solved.

I thought about all the possible solutions and nothing was making sense to me as it was working fine before I put the case on.

Then, I realised that during this whole thing the parts from a 250 I too apart got mixed up with my 400 parts. so I tried the other lid and it worked fine.

You may send any abuse now!

Thanks for helping out anyway both of yous

 

[xschris]

It's always a good idea to label stuff Good to hear it's all sorted now

 

[drewpy]

 

[dt1903]

Yea yea....

 

[Greasey Fingers]

Ah you may have helped me here a little with your problem.. I was trying to work out if theres a difference between the 360 and 250 heads/rocker covers, because they look the same when I gave them a quick eye ball. But it sounds like they are different

 

[dt1903]

Yea, they look the same but are only mm in difference.

Glad something good came out of it! Ha.