Removing gudgeon pins

[TNT ANDY]

Hi all I said I'd do a quick write up, so here it is. You've got to imagin the con-rod in place as I didn't have a spare one kicking about.

Before first - whenever you are taking pistons and liners and big end shell and caps etc apart, do yourself a favour. Working from 1-4 take many photos and reference each set of photo's making note of positions and orientations of all parts. Pay attention to keeping all number 1 parts together, number 2 parts together etc. Note which way pistons are on rods in respect to where the flywheel is. Get this wrong and you could be fannying about for ages trying to get it right. Believe me, I've written the book on it.

First - you need a good vice.

second - you will need an old liner that you are prepared to smegg up.


Drill about a 25mm - 30mm hole through both sides of the liner keeping them both level and at 90 degrees from the flats as this will help keeping things level and flat when pushing the pins out. Remember to clean up the insides up so that later on when you're pushing brand new pistons in, they, or your new rings don't get damaged by the burrs created when drilling.

http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4122.JPG

http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4123.JPG

Next place this liner in the vice and block it up so that the holes are in line with the jaws of the vice.


http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4124.JPG

[TNT ANDY]

Next get yourself a piston in there (imagine it has a rod on it) doesn't have to have rings on it and line the holes up with the pins.


http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4125.JPG

http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4126.JPG

You can just see the pins through the holes.

Next get yourself a drift - in this case, a 13mm long reach socket is just the ticket, it's also worth noting that a cam follower is exactly the right size also if you are initially tight for space.

http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4127.JPG


next you want to get some wood behind the liner so that it takes up any indiscrepencies in levels and flatness, this will almost certainly avoid cracking the liner and damaging your piston / rod.


http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4130.JPG

Sorry not the best picture but you get the drift.

The wood has a large hole drilled out of the middle to allow for the pin to come out.


Now start pushing away, ie tighten the vice up. do only a few turns then let off a bit and re-align and tighten again just to keep the thing level.

http://www.rtoc.org/files/Miscellaneous/Stotto/puching%20pins/DSCF4128.JPG


It will be immensely tight, I had a 3 ft bar on my vice handle, but you can feel it pushing out nice and smooth. Takes a bit of getting used to, but it will feel ok after a couple of goes. I'm not sure if heating anything up helps out or not, but I found I did not need to, other might have a different story.

[TNT ANDY]

Pushing new pins in is exactly the same process if you're doing it cold as I did (well I say cold, I heated the rods to 250 deg C (removed shells 1st) and froze the pins. It was still incredibly tight getting them in. There has been talk of heating the small ends until getting them cherry red and simply pushing them in with your fingers but I have not tried that. I'll have a go at that next time.

But remember which ever way you do it, make sure that all the right parts are with all the right parts and pointing in the right direction.

[Tony Walker]

If heating the rods to cherry red you need some gauntlets to place the rod in the appropriate place for the gudgeon pin to be inserted, and may still need some pressing in force via a vice.

[olidaviesuk]

Great guide mate, only point that I'd make is that you should not fit new gudgeon pins cold. I know some people have done it with success but you can create all kind of probs including microscopic cracks in the skirt and piston body by cold pressing. Heating rods in oven to 250c is deffo worth the extra effort (so the way you're doing it is 100% right) and although a bit trickier because you need to wear welding gauntlets etc is the best and correct way to do it. Again cherry red has been mentioned by people as a way of getting all together without a press, but shouldn't be putting that kind of heat into the metal as weakens it..

[TNT ANDY]

If heating the rods to cherry red you need some gauntlets to place the rod in the appropriate place for the gudgeon pin to be inserted, and may still need some pressing in force via a vice.

Here Here - thanks Tony, I did have these on myself when they where only at 250 Deg C.

[TNT ANDY]

Great guide mate, only point that I'd make is that you should not fit new gudgeon pins cold. I know some people have done it with success but you can create all kind of probs including microscopic cracks in the skirt and piston body by cold pressing. Heating rods in oven to 250c is deffo worth the extra effort (so the way you're doing it is 100% right) and although a bit trickier because you need to wear welding gauntlets etc is the best and correct way to do it. Again cherry red has been mentioned by people as a way of getting all together without a press, but shouldn't be putting that kind of heat into the metal as weakens it..

Thanks fella - this is what this thread is about - I'm no engineer (no **** TNT Ross is saying as reading this:laugh:) and it's exactly this kind of thing I'm looking for to help others out.

[Matt@CodeRedMotorsports]

I don't mind renting out my Renault tools to do this job...:laugh:

[HAndy]

is that the crack in the liner you where on about the other week( fifth pic from the top):(

great little right up there by the way:agree:

fluffy will be flying next year, quicker than the haribo kid dare i say:D:laugh::laugh::laugh:

reference the couple of fives that want to meet you in twisties, you better replace those hero ditch finder rubber you've got on her first, dont want a repeat of the blyton corner king do we ;) :laugh::laugh::laugh::laugh::laugh: