"A" series camshaft endfloat

Here's one for you: I have got a second hand 1275 engine from a scrappy, to go into my 950 sprite. I've checked the internals, crank, bores etc, and found that it had had a new liner fitted, and some other work and was gennerally in good shape. I got the feeling it had been hastily assembled, just to sell it, as there were no rings on the pistons, most of the bolts were finger-tight etc. but all in all a good start for building a good motor. new rings, shells etc fitted, and then I found the camshaft wasn't held in very well. it has a retaining plate with three bolts, but about 40 thou clearance, not the 6 thou required. it has the spider type oil pump drive, that slots in ok, it just sits 40 thou under the level of the front mounting plate. I am wondering if maybe it has been assembled with a wrong retaining plate? was there a different one with a bit of meat that dropped down to locate the shaft better? any ideas?

Reply to
Charlie
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Heard of this on OHV Fords. Groove in cam wears, cam floats, eventually it breaks the cam followers.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

Reply to
Peter Hill

From what you say about the engine assembly I would suspect poor assembly. I have not heard of excessive wear like you are mentioning but that doesn't mean it can't happen.

The cam location plate rides against the end of the cam, which has a square shoulder. The camshaft sprocket has a step in it which goes into the location plate and is clamped against the camshaft by the retaining nut. It is the depth of the step on the camshaft sprocket facing the block that controls the endfloat, ie it should be about 0.006" deeper than the width of the retaining plate as you mention. So if inspection of the end of the cam shows little or no wear and the same for the camshaft sprocket then I would presume poor assembly.

Reply to
David Billington

Thanks for that. If I understand you correctly, the endfloat can only be mesured once the cam sprocket is on? I was looking at the bare end of the cam, without the sprocket, and seeing it move in and out decided I had something wrong.

Reply to
Charlie

Yes, you need to have the camshaft sprocket fixed in place to properly gauge the camshaft endfloat. This can be measured at the front or back of the engine. Hope this helps.

Reply to
David Billington

There's a steel plate which bolts to the cylinder block that the cam bears on one side, the sprocket the other. So this needs to be assembled to check the end float - but the only adjustment is by replacement. The figure given in my Midget WS manual is 0.003 - 0.007" The crank sprocket is adjustable by shims to line up the chain correctly.

I hope you got the engine cheap - sounds a right bitsa. ;-)

Reply to
Dave Plowman (News)

If the engine was just bolted together, is the oil pump gasket fitted?

Reply to
Richard Porter

Thanks for the help, Richard, and Dave. it's been over 25 years since I last rebuilt one of these engines. It all went together fine, once I realised the sprocket had to be on. I have replaced the oil pump gasket anyway. It is for sure a bitsa, but as long as it all works in the end, that's ok!

Reply to
Charlie

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