Cam Chain Timing Mark Drawings

vocky

here's the cam timing drawings

this is what you get in the timing chain kit

this is why the old jet blocks

old oil jet and new larger oil jet

simon1

is there any locating slots on the back of cam sprockets as from the pic they dont seem to have any key way slots.

Daz

Yes there is m8...they will only fit on one way too..

vocky

here is the timing marks for the balancer chain

Matte

Ehh.... don't know if I musunderstanding things here but. Is It like 1mm hole on the the old oil jet and 4mm on the new one? :shock:

They just take the insert in the jet away?!

vocky

yes that is all GM did, remove the brass insert :roll:

Pauls_150_sri

I have somehow totally lost the valve timing after fitting a new cam chain. Is it possible to reset from scratch ? When I line up cams with marks on chain the cams appear to be in the wrong position. I thought that engine was TDC no 1 cylinder when I removed old chain, moved nothing, put new sprockets on and nothing would match up. How can I now be sure that no 1 piston is at TDC and get valve timing right. Any assistance would be much appreciated

blue_se2

How far out are the marks 1-2 teeth or a lot more? prob get away with tuning them into position if only out 1-2 teeth
You could reset from scratch you will have to put the crank 90 degrees BTDC ( making sure the valves are not going to get hit when turning the crank)so the pistons are all half way up the bores then reset the cams the turn the crank to TDC then refit the chain.

Pauls_150_sri

Thanks for that. I have reset the chain and sprockets according to the coloured links and timing marks. For some unknown reason the inlet cam sprocket was nearly half a turn out. This wories me as I thought I took extreme care to locate TDC for No 1 cylinder. I have now got the chain sorted, by the method you suggested and the pistons 1 and 4 are at TDC. How can I check that the crank is in the correct position and not a complete turn out? Many thanks for your help so far.

vocky

the crank doesn't matter, as long as 1+4 are tdc

blue_se2

Got this sorted now paul?

ace24

hi
am just on with the chains.
i put balance chain on as shown in your pic
i got told to turn a full rev & it says if crank pulley marks dont line up, remove chain & re-align
ive done about 3 times & still out of line so started putting timing chain on.
have i done something wrong ?
any help will be well pleased
andy

vocky

you will never re-align the marks in 3 turns :lol:

it's something like 700 turns for the cam chain and proably 400 for the balancer chain !

once aligned the marks will all move by the same amount of links, so just count the difference, all three should be the same

ie; 2 links, 2.5 links or whatever

ace24

thanks for that i was getting a bit worried as i have put both chains on now & done a full turn to see if piston/valves were ok etc.
yeh when marks didnt line up at 1st i was a bit worried but you sorted my head out lol
thanks

misterY

Re:

vocky said:
yes that is all GM did, remove the brass insert :roll:

Is this the only attribute you can differ the old chain kit from the new one? My mate here had an engine blow up. The previous owner said, he changed the chain, but he has no bill or journalisation in the service book. So he is interested to check if there was the new kit fitted.

vocky

old chain kit had the brass insert in the oil jet and also the chain timing mark links are silver and bronze

the new chain kit has no brass insert and blue and purple timing mark links on the cam chain

misterY

vocky said:
old chain kit had the brass insert in the oil jet and also the chain timing mark links are silver and bronze

the new chain kit has no brass insert and blue and purple timing mark links on the cam chain

Thank you very much. Your can is just invaluable. :thumbup:

karl_hodder

hi just wondered if anyone can help, i'm trying to line up the timing marks on the balance chain and the timing mark on crank sprocket (pin hole) seams to be out half a link and doesnt completly line up with the mark on the chain, the timing mark on the sprocket is between teeth, is there any other way i can line up the bottom pully without this mark? i originally had chain slap and noticed that the tensioner wasn't put in right, would this cause the chain to jump as the engine seams restricted. notsure.gif

vocky

the mark is between the teeth and the centre of the coloured link should align to it :thumbup:

karl_hodder

vocky said:
the mark is between the teeth and the centre of the coloured link should align to it :thumbup:

yeh found it, just my eyes playing tricks as i had never timed a chain before, and living next door to unconsiderate noisey bastards dont help as i didnt get sleep for 2 days. but all back together to find out now that rings need replacing, just wait for the flex hone to turn up and on with the project, thanks for ur help anyway appreciate it very much.