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I have bought a used big valve head, complete with camshaft fitted.
I took off my old head as per manual and lined up the camshaft sprocket using the tool with two pins at TDC on Cylinder 1. (12 O clock)
However, my new head on putting the sprocket on is significantly off (pins are about 2 O clock).
How do I fix this?
Did you put everything at TDC before you removed the old head? Are you sure the crank is exactly at TDC? One tooth can make a lot of difference. You say you lined up the cam shaft sprocket but then you say when you put the sprocket on it’s off. Did you put the sprocket on the cam before trying to line up the crank with it?
I think I have figured it out, just over thinking it. It's a used BVH I'm fitting and it came fully assembled, but in a different orientation than the one I took off.
I am going to remove it again and index it until it fits the same tool I used to set the head that I took off, they should then be in the same place / orientation. This should make the marks line up when I refit and put the sprocket back on.
Since you marked your chain and sprocket, just loosen the bolts on the rocker shafts to take the tension off the cam and rotate the cam to the orientation that best matches the chain. Once the chain is on and guides are in, tighten the rocker shafts back down.
Not my dog, but to clarify. By reducing the tension on cam at the rockers and spinning the sprocket and cam so that they match timing then tightening the rockers you allow the valves and springs to make the adjustment? Is that the thinking?
I am looking at doing a head swap within the year, so I am very interested. Thanks for the clarification.
Not my dog, but to clarify. By reducing the tension on cam at the rockers and spinning the sprocket and cam so that they match timing then tightening the rockers you allow the valves and springs to make the adjustment? Is that the thinking?
I am looking at doing a head swap within the year, so I am very interested. Thanks for the clarification.
Basically, normally the Cam doesn't come tightened down. And since it's a non-interference engine, you simply mark both the chain and the sprocket prior to removal, , do your disassembly taking care to keep tension on the chain and bottom sprocket, (some or one bungee attached to the bonnet usually does the trick except when actually removing and replacing the Head, just make sure to prop the bonnet so it can't accidentally close. I've also zip tied the sprocket to the chain as well) remove the sprocket, remove the Cam, remove the Head. Reinstall the Head, lay the Cam in the saddles, align the sprocket with the chain, spin the Cam until the sprocket lines up with the dowel, then set and tighten you Cam caps and Cam bolt.
