Cam chain tension,I

[Triton]

 I needed to lift the cams to take 3 shims out for  grinding to get correct clearance,  I backed off the chain tensioner and cable tied the chain to the cam wheels. I am unsure about the chain tension, book saying  1/2" slack on chain between cam wheels, there is no slack but if i push down on the chain i can get about 1"  to 11/2"..  Is the 1/2" measurement  before or after i push down on the chain,   Hope this explanation make's  sense.  Thanks  Stuart..

[4129R]

Turn the engine backwards by rotating the bottom pulley from underneath. You can only do this with the car up in the air on ramps under each wheel, or on axle stands.

When the engine goes slightly backwards, (from underneath rotate the pulley anti-clockwise) there will be slack between the exhaust and inlet cams.

When rotating the normal way, the crank pulley tensions the chain taking out the slack.

[Triton]

Thanks  4129R for the advice.  I  jacked a rear wheel up and put it in top gear to turn the engine.  I think i had been running with the chain a bit slack. Sounds ok ,does not whine.  Stuart....

[Fotog]

The 1/2 in. of deflection between the two chain sprockets is with the chain tight otherwise; ie. between the intake sprocket, crankshaft sprocket, jackshaft sprocket, etc.  If you can make 1-1.5 in. of slack I think that's too much.

I'm a fan of jacking a wheel and turning it to turn the engine with the gearbox in top gear.  Just be careful if there's a chance that anything is out-of-whack that you don't bend a valve.

[jbcollier]

He has backed off the chain tensioner thus the excess slack.  Do NOT turn it over with the chain slack!  Mark the cam position of the cam you want to remove so you can get it back in the same place.  Undo its cam bolt and carefully remove its sprocket.  Use something to keep the sprocket/chain tensioned do the chain stays on the same position on the Jack shaft sprocket.  I always do this at TDC so it is easy to put back together.

[Fotog]

Always good to hear from my guru on these topics.  I'm not exactly clear, but I think that's what I tried to do; but despite trying to keep some things fixed, I kept finding that I had to move the chain 'another tooth'.  Exactly for or what, I can't recall, but it seemed necessary at the time.  I was a bit uncertain, yet ultimately I got it right .

[Triton]

Before i started i backed of the chain and marked the original setting.  After fitting the cams and caps i returned the tensioner back to original position.  I turned the engine over a few times with a wheel jacked up  to check valve clearances and everything ok.I am used to setting cam belts and chain tensions on the longest run but on the Twin Cam you can only see about  5" of chain. I realize now that i had been setting it too slack. I started the car and engine running fine. Thanks again for the advise and information,   Stuart