I think I'm going to try to replace the timing belt on one of our cars. Does anyone have a cam locking tool that they want to sell? If so, pm me.

 

You don't really need the tool to do this job. I bet you could make one yourself for less also.

 

Probably not, but if you move any of the sprockets.... I bought one for my first timing belt and found it to be a great little tool. Line up the camshafts, push in the tool, check the crank, do the belt.... It takes all the worries away because you cannot move the sprockets when the tool is installed. BTW, I've done 5 timing belts so far.

 

I have never used one on any of the volvo's and done tons of t-belts.

 

Yeah, the tool's not really necessary... if you really want one, IPD has theirs for something like $25

 

I guess I'm used to having the camshaft move while putting the timing belt back on (other engines), but I guess it's not so for Volvos. If I'm ever without the tool, I won't have to worry.

 

DOHC 4- cylinder engines are kind of notorious for having the camshafts be smack in the middle of a couple lobes when at TDC, so the cam will slip as soon as it's just a tiny bit off, because each cylinder fires in a kind of square- wave pattern, 180 degrees from each other, so while cylinder #1 is at TDC, #4 is at the end of its exhaust stroke, which makes the exhaust cam slip, and #3 is at the end of its intake stroke, which will make the intake cam slip, thus making a cam locking tool almost essential if the engine manufacturer doesn't put the timing marks at some other point to compensate. However, on our 5- cylinder engines, the cylinders aren't at perfect 90 and 180 degree angles to each other, so the cams are not in a position to slip when #1 is at TDC.

 

Exactly. Awesome little write up, thanks for the info Carrot.

 

I don't think cylinder #1 is at TDC when the crank and cam reference marks are aligned. I thought this was the case until I was re-assembling my motor and wanted to put the head on without a cam locking tool(there are lobes aligned nearly straight down, hence the need for the locking tool). If you align the crank with the mark on the oil pump, piston #1 is a few degrees before TDC. From what I could see TDC is when the crank mark is straight up.

I've change 3 volvo timing belts and used no cam locking tool( in fact I think it's almost impossible to get the belt cogs to rest in the sprocket cogs with the cams locked). But I've always had respect for the mechanical relationship between the valves and the pistons. So I would say line everything up with the existing belt and remove. when replacing, don't move the crank the cams may have to be adjusted a few degrees but only by hand, never use any force, just remember the valves can be very close to the tops of the pistons.

 

Ok. So I would have to TRY to mess this up. I'll give it a shot without it. Thanks for the info.