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[Markie]

Mate has bought a head off ebay for pug 106 spi 1.1 8v single cam.

All loks okay however the cam ( yes single cam) rotates - when i say rotate i mean by hand - not spinnning freely all the time

Now any head i have ever had removed on has not allowed the cam(s) to rotate, yes the sprocket under torque will rotate cams....

So is this normal/ semi normal or does it suggest a more sinister issue with the head....

All else seems okay with it - valves seated properly etc etc

thanks

[hotel21]

Valves opening when being rotated by hand?  If not, hydraulic adjusters empty of oil?  If the valves are opening, does seem odd but no experience of these engines....

[Jay w]

i would have thought the valve springs would have provided a decent amount of resistance

[Markie]

Yep it is strange, im inclined to think it okay.

If you take a typical twin cam rover k head, each cam has a relationship with 8 valves when it "rotates" ( explanation as the eye sees it!)

On this pug head the cam goes down the middle of the head with 4 valves on either side however the cam cant/wont/ doesnt come into contact at all with the valves......

So it seems to work differently

if that makes sense  

[theolodian]

Yep it is strange, im inclined to think it okay.

If you take a typical twin cam rover k head, each cam has a relationship with 8 valves when it "rotates" ( explanation as the eye sees it!)

On this pug head the cam goes down the middle of the head with 4 valves on either side however the cam cant/wont/ doesnt come into contact at all with the valves......

So it seems to work differently

if that makes sense  

Sounds iffy to me.  I suppose it could be collapsed lifters, but still.  If the cam lobes look fine, and all the hardware is there between the cam and the valves, then start by looking at the lifters.  Either way it needs to be taken apart and checked.

[Kevin Wood]

Sounds like a TU engine.

IIRC, the valves are operated by rocker arms under the camshaft so the camshaft doesn't bear directly onto the followers and then the valves but things are separated horizontally. Can't remember if there are hydraulic or manual adjusters.

Since the cam shaft operates all 8 valves it won't be as hard to turn as a cam on a DOHC head because the effort opening one valve spring is offset by another valve that's closing, IYSWIM. I wouldn't expect it to "spin" by hand, though.

Maybe it does have hydraulic followers that give little or no valve lift when deflated? Sounds very odd to me, and must make it a pain to start after an overhaul?

Actually, the more I think about it the more I think this engine has manual valve clearances anyway... :-/

Kevin

[lee4206]

It is possable that the seller has ajusted the rockers to take the pressure off the cam to check it rotates.  check the valve clearences if they are correct it could have worn springs.