patman Posted February 18, 2014 Share Posted February 18, 2014 Please bear with me here as hope this makes sense.....took my head of today due to knowing by research I need to change the valve stem seals (bearing in mind before I go on my starlet had a full engine rebuild with receipts which I have less then a year ago) a week a go a compression test was done all about the same in the last 150's so that's fine, anyway back to, today, head off then we looked at the pistons just to see while the head is off, when we rotated the crank pulley so 2 pistons were at the top there was alittle play in both pistons 2 and 3 and also same with 1 and 4 when they were at the top too when I say play they moved up and down a mm or 2, (never had piston slap before it knocking when the car was running) also my mechanic done some leak test what ever he put in each bore just to see if it would go down, and in time it did very very slowly though, whatever it was it was very thin, not as thick as oil, which of course has gone into the sump, to me is it the rings? Everything else seems fine, I can only think seing as it's been rebuild in less then a year ago it has the wrong size rings on? It's kind of got me thinking alot here, as what I have just said May be normal on starlets just need to know before everything else goes back on, sorry for the long story hope it all makes sense.Thanks Pat Quote Link to post Share on other sites
patman Posted February 18, 2014 Author Share Posted February 18, 2014 Hopefully someone who knows these engines inside out will know 👍 Quote Link to post Share on other sites
Rob H@RCH Engineering Posted February 18, 2014 Share Posted February 18, 2014 Is the play in the pistons up/down or side to side in the bores? there is supposed to be some side to side movement to allow for expansion in the piston, and also you will have a small amount in the bearings some in the big end and some in the little end (gudgeon pin) to allow for the oil, the oil takes up the slack and acts as a cushion between the surfaces. Thin oil will get past the rings in time too this is normal, rings act more as a friction seal there not completely air tight same again this allows for a thin coat of oil to form on the bores.If every thing was good before you stripped it down it should be fine now. Quote Link to post Share on other sites
patman Posted February 18, 2014 Author Share Posted February 18, 2014 Thankyou so much rob for that information I think you have totally nailed this on the head, also since I had the car and owner before both used 5w 40 fully syth oil maybe I was thinking there shouldn't be any play at between the piston and the bore seems to be up and down that's when we checked it when pistons were at top of bore, pistons and rings in there are only about 8 months old, plus bore been honed etc etc when it got done 8 months ago Quote Link to post Share on other sites
Rob H@RCH Engineering Posted February 18, 2014 Share Posted February 18, 2014 no prob mate! Quote Link to post Share on other sites
kp61wannabe Posted March 16, 2014 Share Posted March 16, 2014 Do a search on piston rock should set you right lad Quote Link to post Share on other sites
patman Posted March 16, 2014 Author Share Posted March 16, 2014 Too late mate everything's stripped out now ready for a full engine rebuilt 😄 Quote Link to post Share on other sites
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