Rotating A Piston In Situ?

[mhyphenl 10 1 Cars]

Hi,

 

Second question of the day. Just read a nice inspirational 8V rebuild thread and just realised I've made a bad error!! If just finished the lump as well!! I've put the pistons in with the DIST arrow pointing to the distributor/ flywheel end. Doh! Is it possible to take the sump off, undo each big end, push the piston up and rotate in position??

 

Thanks

[Paul_13 212 1 Cars]

I can't see there being a problem as long as you don't touch the valves!

[Paul_13 212 1 Cars]

Make you put the bearings back in the right way.

Have you run the engine.

[mhyphenl 10 1 Cars]

Hi, no not run it, I'm going to take the head off so I can make sure I have got it wrong, I hadn't thought about the bearing so thanks for that! I'll just do two at a time, rotate the crank, undo one fully down and push it up out the way, rotate and change the bearing and pull it back down. Hopefully there's enough clearance to get my hands in and do it! I'll make sure I clamp the liners down so I don't disturb but as it hasn't run yet it shouldn't matter!

[SweetBadger 94]

To save you taking the head off get yourself a little usb camera and stick it down the plug holes - should be able to see whether the pistons are the right way round with that.

 

Should be fine rotating the piston in situ if necessary

[Tom Fenton 1,542]

I'm not sure there is room in the block to spin the rod. Happy to be told I am wrong though.

[dcc 855]

I think you can but the crank being in the way is a mega pain iirc.

[mhyphenl 10 1 Cars]

it's the crank that'll be make or break on this, to be honest the worst case is going to be popping the piston out the top of the liners and turning, I got washers and bolts that are sized so I can clamp the liners down but still remove pistons If I haven't run the engine and take the head off am I going to need a new head gasket??

 

To save you taking the head off get yourself a little usb camera and stick it down the plug holes - should be able to see whether the pistons are the right way round with that.

Should be fine rotating the piston in situ if necessary

 

are USB cameras cheap? I'm fairly sure I have got them wrong but it's one of those 'have I locked the front door or not' situations, once the thought entered my head I can't risk it!!

[welshpug 1,661]

check where the tabs on the big end bearings are.

[jackherer 543]

are USB cameras cheap? I'm fairly sure I have got them wrong but it's one of those 'have I locked the front door or not' situations, once the thought entered my head I can't risk it!!

 

Yes, look on ebay or somewhere for borescopes. Just make sure it has a narrow enough diameter to fit down a spark plug hole.

[pug_ham 244 3 Cars]

The only problem I could see with rotating them in-situ is the positioning of the piston & oil control ring gaps mentioned in Haynes might not stay how they are supposed to be.

 

g

[Juttie205 123 2 Cars]

You cannot turn if the crankshaft is still fitted as not enough room.

[mhyphenl 10 1 Cars]

You cannot turn if the crankshaft is still fitted as not enough room.

This man has the correct answer! there just isn't enough width between the main bearings. However I think the easiest way to fix the issue is to remove the head and pop the pistons out, put them back in the right way round. Interestingly you can see enough of the crown of the piston by looking through the spark plug hove with a torch, didn't need a bore camera. The reason it's easier to take the head off is that I've bonded the spacer, put the crank oil seals in etc, I think I'd rather buy a new head gasket than take all that apart and clean it all up again!