Timing question

[wehey]

i have nearly finished rebuildng my 1.3 from the crank upwards. (Complete engine strip down) incl a head skim.
I was rotating the crank pulley to check and double check the cam timing which is spot on.

I did however notice that if I rotate the pulley anti clockwise that the pulley rotated but the cams take a bit of time to catch up, about 20 degrees on the pulley before the cams begin rotate.

At first I panicked thinking that I had attached the bottom chain incorrectly and would have to strip it down again.
Would I be right in saying that when I rotate anti clockwise I am firstly taking up the slack in both chains?

 

[skymera]

i have nearly finished rebuildng my 1.3 from the crank upwards. (Complete engine strip down) incl a head skim.
I was rotating the crank pulley to check and double check the cam timing which is spot on.

I did however notice that if I rotate the pulley anti clockwise that the pulley rotated but the cams take a bit of time to catch up, about 20 degrees on the pulley before the cams begin rotate.

At first I panicked thinking that I had attached the bottom chain incorrectly and would have to strip it down again.
Would I be right in saying that when I rotate anti clockwise I am firstly taking up the slack in both chains?

Yes. I was told you should never turn a chain driven engine backwards..?

 

[wehey]

Yes. I was told you should never turn a chain driven engine backwards..?

Oops...lesson learnt
Thanks for the help

 

[mrjackmich96]

Yeah clockwise only can score bores in worse cases other apprentice did it in my work we nearly smacked him

 

[wehey]

I don't really get it that it scores the bores?
Pistons go either up or down. If you turn the crank anti clockwise they can still only go up or down?

 

[frank]

the only way you can do any damage is if there is a load of slack in the chains, my old skimmed and cammed engines would lock up (piston-valve contact) when turned backwards

 

[mrjackmich96]

Piston slop was out guess as we were striping the engine and the fact he was turning it with an air ratchet the dim wit