Very stiff inlet cam on N/A??

[ChrisSZ]

Finally managed to get the relevent bits of the car apart to change the cam belt and noticed that while the exhaust cam is relatively easy to turn with a spanner, the inlet cam is stiff as hell:(

 

Anyone got any ideas as to why/how this might happen?

 

No grinding noises or any kind of roughness when turning the bugger so I'm somewhat at a loss:( :(

 

Next plan is to strip down the inlet system and get the cam cover off for a visual inspection - any ideas what I should be looking out for please??

[Digsy]

Off the top of my head:

 

Check that the correct cam caps are in the correct position (I'm assuming that they'll be be numbered).

Look for crap in the bearing clearance, burrs, or signs of scoring on the bearing surfaces.

Make sure you follow the tightening sequence exactly when you re-assemble.

If the caps aren't individually dowelled in place, use a blob of grease on the cam journal to centre the cap hydraulically as you tighten it up.

[ChrisSZ]

Cheers. May have a look this evening - kinda pissed-off with it at the moment:( Sems to be one thing leading to another - each more expensive/time consuming

[ChrisSZ]

edited - found it

[ChrisSZ]

OK, got the cam off and found that the very front cap/bearing thingy is filled with black gunk and scored to hell!! As soon as I released that one the cam turned quite easily - got them all off (only managed to lose one bolt!) and looked at the lower bearings and the very front one (just behind the cam wheel) is knackered!!

 

Are these replaceable or am I looking at a new/replacement head?

 

Also, what might have caused it??

[Digsy]

Unfortunately the cam caps will be line-bored with the head, so you can't buy a front cam cap individually. New cam journals in the head means a new head.

 

No idea what may have caused it. Starvation of oil to the front bearing maybe, but cam bearings can run on cock all oil with little problem. Its the front ones that take all the loads from the drive pulleys, so they get the hardest life. The front bearings are also the only ones to take any load in the downward direction, so wear on the bottom half fits. All the others should be loaded upwards from the force of the valve springs.

 

I suppose you could try cleaning everything up and just reassembling as is it to see if it turns freely, but it does sound like something has gone a bit Pete Tong somewhere.

 

Hope you get it sorted.

[ChrisSZ]

Cheers mate, Migster's popping round tomorrow to have a quick look for me. He thinks we can possibly salvage things by gently sanding the lower journal and he has a new upper anyway. Gonna give it a go and try to flush all/any shit out with a couple of oil changes - loads of cheap Halfords stuff to flush through followed by a filter change and quality oil.

 

Fingers crossed :)

[Kranz]

If Mig has an upper cap that helps, but as Digsy says the cap and the bottom bearing in the head are inline bored together and are matched.

 

What you can do is get the bottom of the 'new' cap & all the other caps skimmed so they sit lower on the head.

 

The bearings can then be inline bored back to spec, taking the material out of the head (bottom) bearing. This will make the cam sit a few thou lower, but a shim adjustment can sort this.

 

Or get a second hand head??