Camshaft End Float

[AndrewMAshton]

Hello, still bolting the engine bits back together and the next hurdle is the camshaft, with the camshaft fitted (new), bearing in place and cam sprocket bolted on there appears to be no endfloat, in fact the cam sprocket is tight up against the front cam bearing and it won't turn, I have searched on here and read both manuals and information is scarce.  Looking at the setup I think I have to remove a few thou off the rear of the cam bearing to get my end float, the front can't be changed as the cam sprocket is hard up against the bearing, am I right?, as always, thanks, Andrew 

[ntc]

1 hour ago, AndrewMAshton said:

Hello, still bolting the engine bits back together and the next hurdle is the camshaft, with the camshaft fitted (new), bearing in place and cam sprocket bolted on there appears to be no endfloat, in fact the cam sprocket is tight up against the front cam bearing and it won't turn, I have searched on here and read both manuals and information is scarce.  Looking at the setup I think I have to remove a few thou off the rear of the cam bearing to get my end float, the front can't be changed as the cam sprocket is hard up against the bearing, am I right?, as always, thanks, Andrew 

What engine are we talking about and who’s cam?

[AndrewMAshton]

4 cylinder, piper cam, I bolted it together off the engine and I have no clearance between the rear of the cam bush and the face of the cam, Cheers, Andrew 

[BlueTR3A-5EKT]

1. Ask  Piper why.

2. Do it as you have suggested, carefully lap the rear face of the cam bearing that touches the cam flange to get the desired end float, that figure ideally is the same as the crank end float.  So, the crank when thrust forward, does not pull the cam sprocket forward, thus running the chain out of line between the cam and crank sprockets.  The cam and crank sprockets must be in alignment, done with shims on the crank nose etc.

Peter W

[John L]

Do you have thick gasket under the engine front plate? Have you bolted up the 3 bolts at the camshaft to compress the gasket a bit more perhaps, is the front bearing new?

Surely you could ease the front of the bearing perhaps to allow the gear to seat?

John

[ntc]

Don’t touch it send it back imho 

[BlueTR3A-5EKT]

2 minutes ago, ntc said:

Don’t touch it send it back imho 

+1

[Drewmotty]

In my experience it’s quite normal to have to lap or machine a few thou off the cam bearing to get the correct end float. I would expect cam manufacturers to make the bearing area length a bit short so that we’re not faced with too much end float which would be difficult to resolve. 
The end float can be measured and sorted out on the bench prior to assembling to the engine. Just slip the front bearing over the cam and nip up the sprocket. You may need to start with a measured spacer behind the sprocket in order to give you some slack to measure. 

[AndrewMAshton]

Hello, an update, a bit difficult to send it back as it has been on the shelf in the garage for 3 years (it's a long story).  I have a piece of float glass and various grades of emery paper so have now got the clearance to 5 thou, all spins as it should.  Of course one thing leads to another and crankshaft end float is just outside the acceptable, 8 thou, I will fit one pair of 5 thou oversize thrust washers on the clutch side of the housing, so we should be within a couple of thou of spot on, it is not a racing engine, I am rebuilding it to try and resolve a number of oil leaks, as always, thanks for your advise, cheers, Andrew

[Lebro]

Andrew. I have a set of 4 unused thrust washers +5 thou left over from my rebuild Moss part No. CW2004 005.

You are welcome to some or all of them.

 

Bob 

[AndrewMAshton]

Bob, a kind offer, I have just ordered a set, although I now have another problem, I need to replace one of the cam bearings, I am learning a lot!, cheers, Andrew