Timing belt tension spring's purpose AFTER belt install?

[awmccready]

I have two sets of instructions for changing the timing belt on a 97 camry le, 4 cyl. Both say to torque the timing belt tension (upper) idler pulley bolt to 31 ft-lbs, after installing the timing belt and just before installing the upper timing belt cover. However, doing so, appears to freeze the belt tension applied by the spring. I thought that the spring was to continuously apply tension to the belt and dynamically adapt to operating conditions, particularly belt wear.

Is the upper idler pulley bolt supposed to stay torqued? If so, doesn't that mean that the spring has no effect other than to position and freeze the upper idler pulley at the timing belt's installation time?

I am leery of leaving the spring "out of the loop", but both sets of instructions appear to say to do exactly that. Obviously, if the bolt were left loose, it and the idler pulley could at the least rattle, and at the worst eventually allow the upper idler wheel to fall out.

[88 LE]

Originally Posted by awmccready

Is the upper idler pulley bolt supposed to stay torqued? If so, doesn't that mean that the spring has no effect other than to position and freeze the upper idler pulley at the timing belt's installation time?

Yes and yes.

I am leery of leaving the spring "out of the loop", but both sets of instructions appear to say to do exactly that.

Read the instructions again.

It says to remove the spring and check it for tension. Your better off just replacing the spring, its only a few bucks.

But nowhere does it say to leave the spring out. The tensioner spring must be installed.

[awmccready]

Sorry. By "out of the loop", I did not mean physically removing the spring. I meant that torqueing the upper idler pulley bolt to spec freezes that pulley. That is that torqueing of the bolt keeps the pulley from being moved by the spring, effectively (not physically) taking the spring "out of the loop", until the bolt is again loosened.

You are right about replacing the spring, it was less than $3, and that is what I had already done. However, the Toyota dealer parts guy sold a new spring to me (which I installed) that is noticeably shorter than the original spring. Since the instructions said the free length of the spring was to be precisely 1.811", the length of the new spring "muddied the waters". So, I am now trusting the parts guy that Toyota made an engineering change to the spring, for some hopefully good reason.

Thanks for your time and response.

[asm]

I know this is a old thead, but since I have just finished doing my timing belt on 5S-FE, so here is my guess...

If you look closely at the upper timing belt cover, you will notice a rubber plug. Remove the rubber plug will reveal the bolt for the tensioner pulley. Perhap, by leaveing the spring in place, would allow adjustment to the belt tension without removing timing belt cover??

ASM

[cneculae]

so a regular toyota dealer in the US would have a tensioner spring for a 1992 toyota paseo?