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PISTON PROTUDING FROM BLOCK??
Posted: Sun Feb 05, 2012 7:14 pm
by conar22
Hi there-im after some help/advice....ive got my block back from machine shop after getting new liners pressed in and honed to size-however after putting in the crank and conrods/pistons ive noticed the pistons protude the block by around 1.1mm. In my opinion this is wrong and could lead to serious engine damage when started-so now im not sure what to do....go back to the machine shop and get them to machine a bit off the top of the pistons? Or is this a common occurence and im worrying about nothing? Its a 144 engine if thats of any significance.
Thanks,conar.
Re: PISTON PROTUDING FROM BLOCK??
Posted: Sun Feb 05, 2012 9:49 pm
by Brian
If you have been supplied Perkins parts it is possible that you will have to have the new pistons machined down. This was a common occurance on Perkins engines and perfectly normal.
If you are using the original pistons and the engine was running OK, then it should still be OK, the liners should have no protrusion above the block face so will not affect the piston travel, so that is how it was originally. Unless the block has shrunk in the cleaning processes!

Re: PISTON PROTUDING FROM BLOCK??
Posted: Sun Feb 05, 2012 9:53 pm
by conar22
Ah i see-good to know im not the only one this has happened to. Thanks for the reply

Re: PISTON PROTUDING FROM BLOCK??
Posted: Mon Feb 06, 2012 11:56 am
by llanfair
Hi Conar22
I had my block fitted with Vapromatic pistons and liners these pistons were also proud of the block, i contacted an ex perkins engineer who told me the pistons should be machined level to 0.01mm below . Using a gauge to make certain of TDC i used a large file and emery tape so that they were level. Engine has now done about 15hrs
on road runs, Starts runs and sounds perfect.
Hope this is of some help,
LLANFAIR.
P S Make sure you block all ports and stud holes to avoid fillings entering.
Re: PISTON PROTUDING FROM BLOCK??
Posted: Mon Feb 06, 2012 6:26 pm
by conar22
ok,thanks for the info-much appreciated.
Its bit of a bugger none the less-i wanted her running this weekend past-suppose thats the joys of restoration....the saying 'always expect the unexpected' has never had so much meaning in buying a hedgerow special! Nothing seems to be straight forward
