Timing chains and sprockets.. which is best?

[TVR Beaver]

I've been playing around with cam timing for about a week now! (on and off)... I have an adjustable top sprocket set bought from Power and I'm trying to get 111.25 deg on my 885 cam....
When I nip the thing up I can get it spot on.. but then torquing the screws to 20Nm, it moves and retards the setting by .7 deg... so it's not easy to set.. also I think the 4 threads are pulling out a bit on the top outer sprocket so not 100% happy with the thing...

I'm aware of the 9 key units that get's you 2 deg on the crank so 1 deg on the cam.... (I think)

Just wondering if anyone else had had this problem and whats best to use?...

cheers

[spend]

TVR Beaver said:

...but then torquing the screws to 20Nm..

Lock it off with 2 hex keys + bar across them on the top gear, torquing against the chain will just throw it out.

You are limited as to which verniers will fit under the cover & over the retainer (to the one you have IIRC).

[spitfire4v8]

What is your allowance for differential expansion rates of the alloy block and steel chain,timing chain whip, and chain stretch ??






timing a cam to 0.25deg? are you nuts? When you tighten the bolts up is it close enough (ie less than a degree out)? if so leave it. You will never notice the difference.

[TVR Beaver]

yes.. got it to 0.5 deg last night, thats taking the lash out the chain and shiming the keys a tad (as they move about 0.5 deg)... so got it to about 110.9 (target is 111.25)
when you consider bearing bedding and chain / sprocket bedding I'm sure this will do...
Now just going to cross drill the thing and put a M5 cap head on it to ensure it don't move!
As you say, what does the chain expand at temp?? I know for sure it's not that consistant when it's cold