Timing chain question

[Emma-Knight]

I was wondering how the timing chain tension is measured:

- trying to move it between the cam sprockets - maybe 3mm up to down
- giving it a stronger pull (so the inlet cam rotates a few degrees - much more than the 1/2 inch stated in the manual (I think the tension sprocket plunger compressed the spring) Due to cam/tappet friction, it stayed that way.

So - what is the correct way to check?


By the way: watched "from Venus with love" - the first appearance of the S3 in the Avengers - even in the middle of nowhere (so the car must have been driven that day) it throws oil on acceleration and gear changes - I think many of us would not have bought it used....

Anna

[frearther]

Anna,
According to the manual, the play in the timing chain is measured between the cam sprockets. The specified amount is 1/2 inch English, about 13 mm. But when you rotate the intake camshaft and get that large amount of play that you mentioned, you're actually compressing the spring on the idler plunger. Measuring the play in that manner would give you a false reading - perhaps dangerously so (for the life of your pistons and valves).
Your 3 mm. movement seems to be about one-fourth of the specified amount.

[garyeanderson]

If its too tight it will start to sing, too loose it will rap on the cam cover. If its not doing either its pretty close.

Gary

[rgh0]

I have always interpreted the 1/2 inch movement specified in the manual as the maximum that is present under a load sufficient to fully compress the spring on the adjustment plunger. Works for me and when set this way the chain does not slap as to loose or whine as to tight.

cheers
Rohan

[Dag-Henning]

- Rohan is right. ( - if I understand this strange language correct... )How can you possibly get 1/2" play between the sprockets otherwise... ?!

DH

[frearther]

I'm now convinced that I need to go back and readjust the chain tension before finishing my engine! Thanks, Rohan. That also answers my question (not asked on the list) about the possibility of changes in valve timing with that much play in the chain.

Dag-Henning, you're correct. English can be a strange language. But, of course, the Norse are partly to blame for it - no disrespect intended,

[Dag-Henning]

- believe you......" They used to come in wooden ships, - now they come with low priced Irish planes and buy our plastic cars......"

DH