Timing belt deflection / play

[Got Boooost]

Hey guys,
I built my motor about 4 years ago and maybe put 10,000 - 12,000 kms on it. I installed an HKS timing belt, and new tensioner at the time. with my motor cold and i push the timing belt all the way down (the part of the belt that is in betweem both cams) mark that spot, then all the way up, there is about .75 - 1 inch on play, should i be concerned? i know were aloud some play just not sure how much.

Thanks for the help

Vern

 

[gsxtasy]

I wouldn't be too concerned. The belt between the cams will naturally develop slack at rest because of the tension from the valve springs holding the cams in a certain position. The slack is even worse with bigger cams.

 

[1gAWDlaser]

I wouldn't be too concerned. The belt between the cams will naturally develop slack at rest because of the tension from the valve springs holding the cams in a certain position. The slack is even worse with bigger cams.

This is correct. Try bumping your starter real quick then check the play it should be gone after bumping the starter. The cams do relax some not sure the exact measurement.

 

[DSM1G90]

Also, the tensioner pulley also has give due to the autoadjuster also to allow this slack between sprockets.
When things are rolling, everything is running in a correct balance.

All OHC motors - both chain and belt - HAVE to have this slack, otherwise, the belt or chain will snap or rip in a heartbeat, esp on startup.

Even with OHV motors with the cam is below the compustion chamber where the cam is driven by a chain and sprocket from the front of the crank, there is slack down there also.

-DSM

 

[forcefed_90tsi]

Thanks for that helpful information guys. It was one of my concerns also.