6 cam shaft end-play shims req'd - unsual?

[squidmarks]

I'm reassembling my '82SC engine. As per instructions in Wayne's book, I'm aligning the cam shaft sprockets to the intermediate shaft sprockets. When I took the engine apart, I kept the respective cam shaft sprocket assemblies (including shims) in separate zip-lock bags. Because the engine does not appear to have been previously rebuilt, I expected that I would find the cam sprockets properly aligned when I reassembled them. The left side sprockets are spot on, but the right side is about 1mm out which will require two additional shims be added to align the sprockets. Both sprockets were properly torqued down when the alignment measurements were made.

A couple questions - is it unusual to find sprockets out of alignment on reassembly if the original shims were used? Also, both sprockets originally had 4 shims, so the total number of shims req'd to align the right side will be 6. Is that an unusually high number?

Thanks.

Geoff

[ChrisBennet]

Geoff,
It's almost always 3 shims on one side and 4 on the other. I suspect your measurement technique is letting you down. Personally, I've found it impossible to get reliable measurement of parallelism without using a tool to hold the straight edge.

Look at your old sprockets; does the wear point to a misalignment?

Where in Mass are you? I'm working in Bellerica, maybe I could loan you the tool.

-Chris

* 964's seems to come from the factory with 2 & 2, but measure out like they should have 3 & 4. Don't ask me why.

[squidmarks]

Chris,

I thought it might be my technique as my initial measurements with a wobbly straightedge I wasn't able to get consistent readings. Today, tho, grabbed a nice steel straight edge from work. I've measured both sides at least 10 times holding the straight edge at various angles and get very similar numbers each time (+/- 0.1mm).

I get 51.7mm for the front of the case to the first intermediate shaft sprocket, 50.7mm for the right cam sprocket (the left is spot on).

Oh! Major brain fart! After typing those numbers I just realized that since the distance b/w the case front and right sprocket is smaller I need to *remove* shims, not add them. Ok, so to bring them into alignment I'll need to remove two shims bringing the total on that side to 2 shims.

BTW, I work in Milford, live near Worcester.

Geoff

[john walker's workshop]

2 is still unusual.

[squidmarks]

Ok, more measuring and re-measuring. Three shims on the right side sprocket brings it to within 0.1mm of the intermediate sprocket.

So, after all that, it originally had 4 shims on the left and 4 on the right, and now it has 4 shims on the left and 3 on the right side to bring it into alignment.

Geoff