Camshaft Installation...can't align the DOTS

[Wez_]

Grr....This is so annoying!!!

The timing mark is at 1.4, the camshaft is secured with 3 bearing caps. The sprocket is rotating on the shoulder of the camshaft. Im trying to make sense of the bigger picture here so I can repeat this process in the future. The digital service manual obtained from here is different from the book....so to me, I want to develop my own understanding on this....and importantly...document it somehow...

What do I do?????

Every time I move the sprocket one tooth either way....Either the dots end up way off, or there is slack in the chain and when the chain is tightened, the sprocket shifts ever so slightly enough so that afterwards...

Other observations:

Depending on which way I rotate the sprocket...The slack shifts to the other side of the sprocket, making things more complicated....so....AMC please help!!

Here is how I want to secure the assembly.....but....



The chain slack is on the right side in these pictures...and the slack makes the chain want to rotate clockwise.
Once the chain slack is removed at the back of the motor, here you can see the DOTS end up ever so slightly off



Which way should I entertain rotating the sprocket? Or should I give up and run while I can??...jk
I tried to mark the chain and sprocket as a reference so maybe I can be told which way to move...ugh..

 

[dirtdigger]

You could always slot the sprocket retaining bolt holes so they are adjustable. Then you could line up the marks perfect to factory spec. Otherwise chain wear and sprocket wear combined with if the head and block were milled will throw your cam timing off if you must try to use stock non adjustable sprockets. Even from the factory they will never be absolutely perfectly lined up....stack up of manufacturing tolerances will make them off ever so slightly even with all brand new parts. If you dont go that route you are just going to have to split the differences and go with the position that makes them the closest...not the best for top performance but it should get it running.

 

[amc49]

You can't even try to tell without both bolts in the sprocket and clearly not done on the second pic. If anything then you end up like pic #2 if using used chains which retard the cams to rotate the sprockets clockwise as looking at that side of them. HOWEVER, if putting the bolts in then puts things off worse, that is possibly not chain on correct teeth either.

With used chains you never are able to 'split the marks' and out worse on the front as the run is longer with more chain pins in it.

Post #2 is correct but make both sprockets any error the same way, making one go one way if closer and the other the other way could get you bent valves if you pick the wrong clash there.

So, front chain ends up with clockwise moved sprocket and the rear clockwise too but less of it. But both as close as you can get without going counterclockwise to pass split marks the other way.

 

[Wez_]

You could always slot the sprocket retaining bolt holes so they are adjustable. Then you could line up the marks perfect to factory spec. Otherwise chain wear and sprocket wear combined with if the head and block were milled will throw your cam timing off if you must try to use stock non adjustable sprockets. Even from the factory they will never be absolutely perfectly lined up....stack up of manufacturing tolerances will make them off ever so slightly even with all brand new parts. If you dont go that route you are just going to have to split the differences and go with the position that makes them the closest...not the best for top performance but it should get it running.

YES!!!....THANKS DIRTDIGGER!!! This is valuable information bud!! Never thought about slotting the sprocket. Are there aftermarket slotted sprockets available? That's an interesting consideration! But the tolerance stacking and used chain stuff makes perfect sense too. I was starting to go crazy.

 

[Wez_]

You can't even try to tell without both bolts in the sprocket and clearly not done on the second pic. If anything then you end up like pic #2 if using used chains which retard the cams to rotate the sprockets clockwise as looking at that side of them. HOWEVER, if putting the bolts in then puts things off worse, that is possibly not chain on correct teeth either.

With used chains you never are able to 'split the marks' and out worse on the front as the run is longer with more chain pins in it.

Post #2 is correct but make both sprockets any error the same way, making one go one way if closer and the other the other way could get you bent valves if you pick the wrong clash there.

So, front chain ends up with clockwise moved sprocket and the rear clockwise too but less of it. But both as close as you can get without going counterclockwise to pass split marks the other way.

Thanks AMC! I have had the bolts in and out of the sprocket so many dang times, I have almost memorized how the dots will end up...
Picture # 2 is how the sprocket ends up after the bolts are installed and the slack removed from the chain. Basically, it does not get worse than pic #2
Interesting point about the front being longer with more chain pins!

I'll take you and dirt's advice and work on the intake camshaft now. Hopefully I can recreate the same offset and split the difference on the intake camshaft.
Updates soon. Thanks again bud!

 

[amc49]

To my knowledge there were never any slotted sprockets for these, the racers always made them themselves. Front sprocket is cast and not hard to machine but the single rear one is quite a bit harder material and harder to work on. I forget what year talked about here but some very early ones have a different size pilot hole in center of sprocket and Honda changed to a different hole size later. Meaning if you have an early one you may have fits finding replacement sprocket if you screw up there. Just a caution.

The chain pins are what wear to add length to the chains. The teeth on both parts add to that too.