new timing chain fitted still slack

[S1-crysis]

hi all i apologise r if there is alresdy a thread on this but from my searching i csnt serm to find one. anyhow recently fitted a new engine to my yaris as the previous one had an issue eith timing chain slip and then pistons met valves spark pluged died etc anyhow wheb fitting the new engine i decided it should have a new timing chain due to the engine being out only issue is iv had to re fit the chain abet 7 or 8 times now because i cant remove all the slack no matter what i try. it will basicly be fitted tight seem all gd everywhere then i manually rotate engine and then chain becomes lose then gos tight then loose etc the engine is a 2sz-fe 1.3 vvti if that helps. im currently under the impresion the tenshioner although new is causing the issue altho i do hav to turn the vvti camshaft back slightly due to it not wanting to stop tdc without me holding it there untill chain is tensioned thanx josh oh yh the timing chain kit is a Dayco if that helps 

[Madasafish]

The timing chain is tensioned by an oil pump mounted near the rear of the engine. Wear in it causes chains to rattle.. the seals go in the pump.

BUT - when I replaced chain in son's Yaris  (and the pump) I had the same issues and rang our local Toyota garage (where I had bought the parts). Mechanic says : once assembled - and timing is ok.. DO NOT rotate the chain/crankshaft manually as there is no oil pressure , therefore no tension and chain slips. 

 

SO I did as advised, reassembled and all ok.

[bathtub tom]

I don't see the difference between turning the engine manually and starting it. I wouldn't have thought the oil pressure would build sufficiently to tension the chain for a few revolutions when started.

[Madasafish]

Frequent very slow turning of the engine does not develop enough oil pressure to make the tensioner work...It is spring loaded . Edit .. and the engine oil pump delivers minimal pressure at low revs  so frequent slow turning probably empties some of the oil galleries - judging by the time the oil pressure light took to switch off when we got the engine to run...

[S1-crysis]

thank you for the replies been pulling my hair out trying to sort it since posting iv got hold of a freind who now lives 2 far away to help in person :( who said wheb hes changing chains on Nissans he makes sure there is no slack at all on the opposite side to the tenshioner from which he said to basicly turn the vvti cam which for me has a tendency of not stayin tdc unless held in place with a spanner till tensioned so there is an extra click to help remove the last of the excess slack so then the oil pressure can take the last little bit of play out the chain hopefully will have it sorted 2moz thabk you for the replys :)