Cost to Replace Cam Belts in So Cal

[Privateer]

7000 sounds nuts.

What is the service interval for belts, anyway? I know on my car it's 160,000km, which blows my mind.

I was always told 2 years or 12k miles.  I will throw out, however, I let a set of belts go about 30,000 miles just to see what would happen (props to ExactFit belts).

[alibaba]

2009 M696 - As I recall the first and only time I replaced my belts I just set the marks to change the horizontal cylinder and then marked the location of the vertical cam gear on the gear and the case.
I didn't move the engine at all.  Don't understand why the engine has to be rotated once set in place and all is marked?

[Howie]

If you didn't get it right and you hit the starter  ,  gently, by hand will give you a second shot.

[brad black]

you set the belt tension with the cylinder at tdc firing.  so you fit, tension horizontal, rotate engine 270 degrees, tension vertical.

well, I fit them, turn the engine over several times with the belts at approx. tension to have them work they way into where they want to run (and so you know nothing hits), then go to the tdc firing positions to tension.

[alibaba]

Thanks Brad, but let me be sure I get it.  The belt tension is dependent on pistion position because there is more tension on the belt at the location I slide in my 5mm Allen wrench when the valve is being opened or closed?  Even though there is no valve spring to tension the belt?

I would have thought that sans valve springs, the tension was pretty much constant at any piston location?

[suzyj]

There's a keeper spring on the closing rocker. That's what fights you when you spin the camshaft with the plugs out.

[alibaba]

Thanks Suzy - I was aware that spring existed but never having seen one, I thought it was a small weak spring that would not effect belt tension.

[Privateer]

[Thermite]

BTW, on 4V testastretta engines, does the allen wrench method still work??

No, you use the tuning software.  Easy free download stuff but you need a remote microphone to get in the case.  Tune each cylinder at TDC so the valves are closed with no spring pressure.

For the 4-valves it's important to have a cam-locking tool.  You *can* get the belt on without it but it's not worth the savings.

[BK_856er]

Thanks Suzy - I was aware that spring existed but never having seen one, I thought it was a small weak spring that would not effect belt tension.

Here's an example of tension vs. position (not my data!):



BK