berni82 Posted December 31, 2013 Share Posted December 31, 2013 Hi, I restore my opel 1.2l and I would like to ask you. I have piston with vertical gap (for cooling of piston). I dont know the orientation of piston in engine. The gap (cutting) on pistom must be in orintation of rotation of crankshaft or in oposite (generally)? Thank you for your opinion. Quote Link to comment Share on other sites More sharing options...
David Herbert Posted December 31, 2013 Share Posted December 31, 2013 I do not have Opel manual but my opinion is that the biggest force on the piston is from the power stroke which is downwards. If the engine turns the usual way with the crank moving down when it is on the left side of the engine, looking from the flywheel end of the engine ( looking forwards in a normal vehicle), the piston is pushed to the right side of the engine because of the angle of the connecting rod and so the split should be on the side with less force - the left side. The reasion for the split is not cooling but so that when the piston gets hot it does not get so much bigger so the fit in the cylinder can be closer when cold. I hope this is of some help, good luck! David Quote Link to comment Share on other sites More sharing options...
berni82 Posted December 31, 2013 Author Share Posted December 31, 2013 Ok, If I understand, you mean, when engine turn to left- gap on the left site; turn to right-gap on the right site? Thank You! Quote Link to comment Share on other sites More sharing options...
wally dugan Posted December 31, 2013 Share Posted December 31, 2013 l think the attached may help you understand the principal of the split skirt piston Quote Link to comment Share on other sites More sharing options...
berni82 Posted December 31, 2013 Author Share Posted December 31, 2013 Thank You Wally, hmm, ...."When assembling split-skirt pistons onto the connecting-rod it is important that the split side of the skirt is on that side which bears against the cylinder during the compression stroke, so that the unsplit - and stronger-side takes the greater side-thrust during the power strokes"....but I am not technically able:c) and my not very goog english :c). What means "split side of the skirt is on that side which bears against the cylinder during the compression stroke?" - it is in compliance with my previous sketch, isn´t it? The function of split-skin piston I understand now-the piston can be tighter in the cylinder when it is cold. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 31, 2013 Share Posted December 31, 2013 Thank You Wally, hmm, ...."When assembling split-skirt pistons onto the connecting-rod it is important that the split side of the skirt is on that side which bears against the cylinder during the compression stroke, so that the unsplit - and stronger-side takes the greater side-thrust during the power strokes"....but I am not technically able:c) and my not very goog english :c). What means "split side of the skirt is on that side which bears against the cylinder during the compression stroke?" - it is in compliance with my previous sketch, isn´t it? The function of split-skin piston I understand now-the piston can be tighter in the cylinder when it is cold. Berni, To make it simple for you; Stand in front of the engine looking at front pulley, the engine will turn in same direction as a clock (clockwise) The thrust side of the engine will be the left side as you are standing, so the split goes to non-thrust side on your right. So I think your last drawing is correct. regards Richard Quote Link to comment Share on other sites More sharing options...
berni82 Posted December 31, 2013 Author Share Posted December 31, 2013 Super, The best way how to explain it for me:c)). (by the way, when I bought this engine and I started the dismantling, the piston was in inverted positin. I suppose -all thinks indicated it - that this engine is right side rotated. Maybe, the previous ovner make wronk motor mounting.) Quote Link to comment Share on other sites More sharing options...
Chrisg Posted December 31, 2013 Share Posted December 31, 2013 Isn't it also that the non thrust side is the camshaft side Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 31, 2013 Share Posted December 31, 2013 Isn't it also that the non thrust side is the camshaft side Camshaft can be either side, it has no bearing on piston thrust Quote Link to comment Share on other sites More sharing options...
Chrisg Posted December 31, 2013 Share Posted December 31, 2013 Camshaft can be either side, it has no bearing on piston thrust The memory not what it was Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 31, 2013 Share Posted December 31, 2013 The memory not what it was Hi Chris, Manuals will often say, split to cam side or opposite to cam, just a way of making the positioning easy for the mechanic. cheers Richard Quote Link to comment Share on other sites More sharing options...
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