camshaft alignment, did I do it right

bobsnow100 · Post by **bobsnow100** » 06 Oct 2006, 09:37

Ozark Lee,
thanks for the info, You were wondering why I took off the cam pulleys off. Reason why was because I had 10 bent valves due to a water pump breaking,so since I put in a new water pump, new head gasket, took out all the valves ,cleaned or replaced and lapped them all, installed new valve seals, new dist. cap,rotor, etc, it just made sense to replace the cam seals since it was all apart. The only way to replace the front ones is to remove the cam pulleys. I also polished up the cams with crocroise(spelling) cloth. I didn't know I would have this timing problem.
Sntee
How I made those pull down tools for the cam cover,I wrote how I did mine a couple of responses back in this thread, I bought air adaptors from Napa Auto and it worked beautiful. If you need more info ,just let me know

I borrowed the actual volvo tool from a volvo mechanic, He also gave me another tool which lines up TDC from a hole behind the starter. seems like this tool goes into a hole behind the starter and stops the flywheel or something at the exact spot. He said it is better than using the crank mark

bigshot · Post by **bigshot** » 11 Mar 2007, 21:19

What I have to say may save all of you a lot of wasted time and frustration.

Forget about timing marks, they are more trouble than they are worth. If you are changing a timing belt on an 850 then follow this procedure for setting up the cam timing. Trust me, I've been a mechanic for 20 years and have just had to do this myself from first principles.

If you haven't taken the cam belt off, wind the engine over to number 1 TDC, check it with anything that you can place down the spark plug hole and make sure the piston is exactly at TDC. At this point, if you take off the cam angle sensor plate from the exhaust cam and the rotor button / drive plate from the inlet cam, you will notice that the drive grooves are about horizontal and above the bolt hole in the end of the cams. I say almost, because for them to be lined up perfectly horizontal, the crank needs to come back 1 tooth on the crankshaft pulley, which gives a static timing of about 5

sntee · Post by **sntee** » 13 Mar 2007, 17:58

I may be misunderstanding Bigshot's advice in his posting, but he seems to be stating that the timing marks (or any other kind of alignment for that matter) on the Cam pulleys, are irrelevant.

If this is the case, and if you have had to remove the pulleys, how do you ensure correct timing of the inlet and exhaust cams? Given that each pulley has about 7 degrees of rotational freedom and that just a degree or so of misalignment, can have a significant effect on engine performance.

Before removing my pulleys, I scribed a line across the end of each camshaft and onto each pulley. This gives you a very accurate method of re-aligning them to the same position when you put everything back together.

dnfrick · Post by **dnfrick** » 15 Dec 2007, 08:51

I beg to differ with Bigshot on the bar alignment tool for holding the cams by their end slots. The slots are slightly off-center, so the bars that fit into them have to be offset by some amount if the slots are to be held parallel in the correct position. Does anyone out there have the proper dimensions for the width of the slots and the amount of offset? I would like to make this tool before I get in there to replace cam seals.

Post by **Ozark Lee** » 15 Dec 2007, 09:21

The offset distance is the thickness of the slot in the end of the cam itself. Usually bar stock has enough give in it that it really doesn't matter to build the offset into the tool.

My method of marking the cam sprockets was to use spray paint on the face of both pulleys over each of the three bolts. The outline then gives you something to line back up with. If you are not removing the top half of the cam tower I really don't see any need to lock them in place just to replace the seals. I didn't on mine and it worked fine.

The only other tip I can give is, after the spray paint dries, hold the opposite cam sprocket by hand and crack the sprocket bolts to just loose before removing the timing belt. The bolts then come out easily without moving the cams.

The front seal on the exhaust cam is a bear to remove and a bear to replace due to the limited space between the shock tower and the front of the engine. The intake side is easier to get to.

...Lee