Pressing liners out of a Perkins P3 TA

RUSTY_RELICS · Post #1 by **RUSTY_RELICS** » Tue Feb 12, 2013 12:42 am

Hello all,

Has anyone any experience or tips for pressing liners on the early "P Series" P3/4/6's. I have a Allis-Chalmers B with a P3 conversion, which I've added to our "Perkins diesel conversions section" in our collection. The tractor runs well but breathes heavily and is a pig to start !! It has a lip in the bore like a door step. :arrrrgh:

Agri-line Products sell the pistons and liner kit for the Ferguson T20 conversions which uses the same P3 engine as in my Allis for £195 + £8.50 P&P which isn't out of the way, so long as the liners come out with out any hiccups !
Any Help greatly appreciated ....

Thanks, Carl

Kenham · Post #2 by **Kenham** » Sun Feb 17, 2013 2:19 pm

Hello Carl, I take it the liners are dry liners ? In my friends machine shop he usually takes the old liners out by boring them with the boring bar. When they get thin enough you can then break them out. Push the new ones in with a hydraulic press and then bore / hone to size.I think you have to bump the pistons on a P3 when fitting new but I could be wrong. Ken

FOWLER MAN · Post #3 by **FOWLER MAN** » Sun Feb 17, 2013 7:42 pm

Kenham wrote:Hello Carl, I take it the liners are dry liners ? In my friends machine shop he usually takes the old liners out by boring them with the boring bar. When they get thin enough you can then break them out. Push the new ones in with a hydraulic press and then bore / hone to size.I think you have to bump the pistons on a P3 when fitting new but I could be wrong. Ken

Hello Carl,
This is all good advice. It's difficult to remember detail but I did several Perkins "P" and "R" series engines in the 1960s and we did sometimes have to bore out the old liners. :think:

To bump the pistons it was necessary to install the pistons, tighten the big ends and measure the height of each piston relative to the top face of the block.
They are all likely to be different and I remember turning off between 0 and 80 thou. on one P6 engine.

Mark each piston, remove it and turn off the piston crown in the lathe to obtain the correct height.
I,m not sure now, but 40 thou. below block face rings a bell :?:

Then of course youll have to build it all again. :roll:

You need only put the rings on the pistons for the final assembly. :thumbup:

I never realy understood why this was necessary.

You would have expected the throw of the crank, the length of the rod, and height of the piston above the pin to be constant so that the piston crown height would be be fixed at manufacture.

Don't be tempted to take a chance :!:

The pistons will probably hit the head and knock like hell. I remember rebuilding a customers knocking R6 after he had fitted new pistons and rings into the existing bores without checking the height. :doh:

Fred

RUSTY_RELICS · Post #4 by **RUSTY_RELICS** » Mon Feb 18, 2013 1:25 am

Thanks for the replies Guys,

Fred: someone did say something to me about "bump" testing each piston in the cyl, before attempting to fire up the engine. I will have to research the clearances

Thanks, Carl

RUSTY_RELICS · Post #5 by **RUSTY_RELICS** » Mon Apr 01, 2013 10:58 pm

Hello everyone,
Well here is a few pictures of our progress, we (me & dad) have a non- ferrous scrap yard and we used the horizontal action of our scrap baler to press out the Liners and the new ones in, we turned a alloy blank from a billet to fit the liners to push on. Does anyone have any information regarding "Bump Clearance" for these early P3's ??? As this is the point we are now up to ...

https://plus.google.com/photos/111063970018410088464/albums/5848983558502712801?banner=pwa&authkey=COTQoMf7hoOz6wE

Thanks, Carl

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