camshaft too tight maybe

[Tez]

I've just trial assembled the cam into the case of my type IV, and it seems it may be a little tight, you can turn it with one finger through the crank bore but it takes a bit of effort, you can turn it easier with an open ended spanner in the oil pump drive slot but I'm not sure if its ok. I've clearanced the thrust bearing and the cam spins fine in each case half before bolting the case together, just seems a bit tight, is this normal? Cheers.

[Clatter]

Mount the cam in the bearings and case, and torque the case half bolts.
Leave the cam plug and oil pump out.

Reach in with a drift and smack the cam with a hammer once from each end.

See if it doesn't twirl free at that point..

It also might grow a couple thou end-play, too.
Best to do this before sanding the bearing thrust for end-play, BTW. (FWIW )

Let us know if this helps!

[Tez]

Hello there, tried what you suggested but it didn't change things, I guess what you suggested doing was intended to loosen up the thrust clearance? I've been turning by hand via the oil pump drive slot and it seems to be freeing up so I'm going to keep giving it plenty of turns over the next few days and see what its like, cheers for your advise

[Type 4 Unleashed]

Are you running the dbl thrusts cam bearings ? There is some times core shift and when dbl thrust are used to get end play the outer thrust on one case half is clearance and and the inner thrust is clearance on the other case half.

You should have the same amount of end play after the case is bolted together, that you had before it was bolted together, and you should be able to push the cam back and forth with your fingers unless something is wrong, and hammering it back and forth with a drift isn't going to clearance the thrust any more than it already is.

[Clatter]

Oh, yes, I misread what you were saying a bit.
Often times the thrust will make things feel tight unless you seat it home with a wack.

Even with a bit of light oil, it might be a bit 'sticky' to get started turning by fingering the cam bolts (Or even worse rivets) along.

If you can twirl it around with a big straight-slot screwdriver, you're likely good to go.

The bearings are going to pound in once you start it up.

Thanks for checking back in and sharing what you found.
We all learn this way!

[Tez]

[quote="Type 4 Unleashed"]Are you running the dbl thrusts cam bearings ? There is some times core shift and when dbl thrust are used to get end play the outer thrust on one case half is clearance and and the inner thrust is clearance on the other case half.

You should have the same amount of end play after the case is bolted together, that you had before it was bolted together, and you should be able to push the cam back and forth with your fingers unless something is wrong, and hammering it back and forth with a drift isn't going to clearance the thrust any more than it already is.

Hello there, I'm using straight cut gears so only got a thrust bearing in one case half, the cam spins very free in each half of the case but tightened up quite a lot when the two were bolted up, I've got it turning ok now though, I welded an half inch washer on the end of a scissor jack handle and turned it via the oil pump drive slot, after a few 60 second bursts it now turns nicely and I'm confident it will be ok, thanks for you input and all the best from England!