timing belt: tight

[tima01864]

Some where in this thread I was advised, One from a Member and one from the guy who built back my cylinder head.
If you can twist the belt 45 deg or so between intake and exhaust pulleys (May of been a reference to Croft) Then the belt is not too tight.
90 degrees or so between Aux and intake not too tight I asked about tensioner pulley and exhaust but got no reply.
So the long and short of it I could do this.
Like the Geospider the original poster poster, I added to this only because he is the only member to comment on a tight to get on belt. Same problem as this and I think he has a stock engine.
Was worth investigating

[Nut124]

I inspected my loose belt w/o removing it. I ended up leaving it in after adjusting the tensioner.

The tension is now just about how tima01864 described in his post; 45deg between the cams and 90 at the long run.

I figured that had I replaced the belt, I would have to check and adjust tension after some driving anyway as it seems some break-in does happen between a new belt and the Vick pulleys.

Below are a few pics of my 2-piece front cover that made this job easy:

[RRoller123]

I did that 2 piece front cover and IT IS A NO BRAINER. I don't understand why everyone doesn't immediately do this. What a convenience, saves a huge PITA!

[Nut124]

Earlier, I had found my timing belt quite loose. I tightened it to a point where I thought it was still on the loose side, with engine cold.
After some length of driving tonite, I checked the belt tension with a hot engine; It feels tight.

With engine cold, the belt, on the long run from intake to aux pulley, seemed to have a good 5-8mm of free deflection.

After hot driving tonite, the belt has zero slack and sounds tight.

So, I would say, when cold, set belt tension such that there is 5-10mm free slack in the longest span. Seems loose but it tightens up when the block, head expands, apparently.

Or, this 25mm belt from AR behaves differently.

Has anyone else observed this hot/cold tension difference?

Or, maybe the aluminum pulleys thermally expand, but the OEM plastic ones do not, and require a loose belt when cold.

[18Fiatsandcounting]

Has anyone else observed this hot/cold tension difference?

No, but what I have observed is a difference in belt tension when the engine is turned off, and the tension is checked. Depending on where the crankshaft/cam pulleys/aux. pulley end up in their rotational cycle when an engine is turned off, certain segments of the belt can seem loose.

Very simple to correct. Turn the engine off. Loosen the two nuts on the tensioner. Turn the intake cam by hand (with a wrench on the nut if necessary) so that the run from the crank pulley to the intake cam pulley is tight. Now turn the exhaust cam (with a wrench on the nut if necessary) so that the top run between the intake and exhaust cam pulleys is tight. Pull on the tensioner with a screwdriver behind it to tighten things, tweak the intake and exhaust cam pulleys, and tighten the two tensioner bolts.

That's all I've ever done. No issues.

-Bryan