18 replies to this topic

[1977 Loud_Mini]

Hi all i have a bit of a problem. 3 of my 1380 pistons are in the correct way round, with the numbers on top facing you as you look at the engine in the car. The other piston which is piston number 4, clutch end is 180 degrees out so the numbers are at the top and upside down. I was going to try ad swap this over but have heard i need a press to get the gudgeon pin out. The pin is free inside the piston but tight in the conrod, now i would have thought it was supposed to be the other way round? Will it matter that the piston is sort of upside down if you like. It has new rings and the bore looks like it has possibly been re honed.
I also noticed the bottom ring has a spring holding it out onto the bore built into the ring, is this correct?

Any help would be greatly appreciated.
Thanks, Evan.

[Cooperman]

It doesn't matter which way round the pistons go as they are solid skirt. It only matters with early 850 split-skirt pistons.
The gudgeon pin should be tight in the rod end and move within the piston.

[Paul Wiginton]

As Cooperman says - as long as theyre not offset dished

[Ethel]

It doesn't matter with a fresh build, but once they are bedded in they should be kept the same - put it back as you found it.

[1977 Loud_Mini]

Thanks for the help everyone, you've been great. There's no offset dish and the gudgeon pin spins in the piston while being tight in the rod. I would have thought this would wear out the piston?
Now i've got to go out and buy either a big jubilee clip or a proper ring compressor to get the piston back in.

[me madjoe 90]

Thanks for the help everyone, you've been great. There's no offset dish and the gudgeon pin spins in the piston while being tight in the rod. I would have thought this would wear out the piston?
Now i've got to go out and buy either a big jubilee clip or a proper ring compressor to get the piston back in.

Big zip ties
work sometimes

[1977 Loud_Mini]

Yeah hadn't thought of that, could work.

[mike.]

You can get a piston ring compressor for about a tenner from halfords. Oil it up well and it worked great for me.

[1977 Loud_Mini]

You can get a piston ring compressor for about a tenner from halfords. Oil it up well and it worked great for me.

Thanks for that will buy one tomorrow if they have it in stock.

[bmcecosse]

Just use your fingers - and 'feel' the rings in. That way you know they aren't broken!

[1977 Loud_Mini]

Just use your fingers - and 'feel' the rings in. That way you know they aren't broken!

I did try that but couldn't squash them tight enough. Do the rings usually break when using the proper compression tool as i would imagine they just push in quite nicely once the tool is wound up?

[mini_mad69]

Just use your fingers - and 'feel' the rings in. That way you know they aren't broken!

I did try that but couldn't squash them tight enough. Do the rings usually break when using the proper compression tool as i would imagine they just push in quite nicely once the tool is wound up?

I've never had a problem.

Although have broken a ring using the jubilee clip trick.

[samsfern]

Just use your fingers - and 'feel' the rings in. That way you know they aren't broken!

get a proper ring compressor, oil the bores, pistons and ring compressor with plenty of oil, sit the piston in the bore, ring compressor on, very gentle tap with a bit of wood, dont force it though and job done.

The gudgeon pin is suppose to be tight in the conrod, its an interference fit, and loose on the piston, if you look at a gudgeon pin youll see it is a bit thicker in the middle.

Edited by samsfern, 17 November 2010 - 08:33 PM.

[1977 Loud_Mini]

Thanks for all the help, i'll give it a go tomorrow and if anything goes wrong i'll be sure to post it up

[1977 Loud_Mini]

Right went to halfords and bought a ring compressor for the grand total of £13 so that was ok. Now here comes the problem (nothing ever seems to go well) the piston nearest the radiator end, so numbr 1 piston has what looks to be 2 chips on the piston skirt at the bottom rear i think of the piston. They aren't sharp and are of equal size, basically looks like a letter m witt about a cm in between each cutout.
Will this be ok to put back in as is as i'm not really sure if funds will allow new pistons. I thought it may have been a way of balancing the pistons but seems strange?

Evan.