69 427 idler pulley

[dick foehringer]

here is another question for all. does the idler pully ride on the outside of the belt pushing it towards the pulleys or does the belt run over the pulley pulling it tight by what i would call the normal way to tighten the belt? the reason i ask is the picture in the assembly manual shows the belt over the idler. but here is the question. the idler wheel has no belt groove in it. it is just a flat surface. so if it has the belt riding over it what stops the belt from jumping off? is it the fact that its so close to the crank pulley it stays on? i dont get it? the car has a/c and PS so it has a 3 groove waterpump pulley and a 2 groove crank pulley.
thanks, dick

[Joe L.]

Re: 69 427 idler pulley

Dick-----

The 1969-74 idler pulley rides on the outside of the belt. I expect the reason for the confusion in the AIM is that there may be some vestige of the 1968 configuration present in the drawing used for 1969. The 1968 configuration used a conventional style, grooved pulley on the idler. This was a 1968-only feature.

[dick foehringer]

Re: 69 427 idler pulley

joe thanks again! i figured it had to be something like that. what was the purpose of that belt and the idler? it looks like all it does is add a second belt from the crank to the water pump? maybe because the water pump pulley drives the A/C?
regards dick