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[JamesV6CDX]

Just wondering

I'm fitting some replacement heads to my 3.0 Project.

Now - should I use the camshaft shells that came with the replacement heads, or the original ones from the car, with the original camshafts?  

[sassanach]

camshaft bearing caps are matched to the cylinder head they were removed from.

[hotel21]

If you can, shells that came with the shafts, I would think.  Running surface to running surface, not mounts....

[sassanach]

the caps are bolted to the heads and then line bored at  the manufacturing stage.they should not be interchanged.

[hotel21]

the caps are bolted to the heads and then line bored at  the manufacturing stage.they should not be interchanged.

That changes things.....

How does that setup intend to accomodate a failed bearing or replacement camshaft?

[Kevin Wood]

A mate of mine was once forced to use different shells (long story, but he ended up having to rebuild a Cosworth YB in hicksville, mid-US due to his engine taking exception to some rubbish fuel).

Anyway, he sourced a head but without shells. Figured he'd try the ones from the old head and a camshaft snapped as he torqued the bolts down.

End of his journey, oddly enough.

Always use the original shells, in their original locations and orientation.

Kevin

[sassanach]

if a  cap fails your supposed to scrap the head,however you can skim the  mating face of the caps and then re line bore the brgs.cost however would limit this procedure to rare items, omega heads are plentifull in comparison

[hotel21]

I can see the advantages for initial construction but that places a massive confidence in the design to ensure that no failures result.....

If you are stuck in the arsehole of nowhere, its relatively easy to be sent a set of camshaft shells by pigeon post and then blue/cut them suitably then into place....  More difficult with a few pounds of cylinder head and associated gasket requirements etc....

[JamesV6CDX]

Looks like I'll be using the ones from the new heads, then!

In itself, that's not a problem. Location won't be an issue, because they are marked and I know where they should go.

Not sure about orientation, though  

[hotel21]

No wipe/smear marks on the running faces?

[JamesV6CDX]

No wipe/smear marks on the running faces?

I'll certainly check

[sassanach]

all down to cost saving, and another good reason for regular oil changes.as for orientation of caps,they are marked front to back,the front cap can only go on one way.

[Kevin Wood]

Looks like I'll be using the ones from the new heads, then!

In itself, that's not a problem. Location won't be an issue, because they are marked and I know where they should go.

Not sure about orientation, though  

IIRC, they are numbered on one side. If this includes the front one with the cam oil seal housing on it, it will establish what side should be where. Number to the outside of the head rings a bell. I know it was a pain to see them.

If you really can't figure it out, put them on each way and feel for a step inside the journal where the cap meets the head.

Kevin

[JamesV6CDX]

Looks like I'll be using the ones from the new heads, then!

In itself, that's not a problem. Location won't be an issue, because they are marked and I know where they should go.

Not sure about orientation, though  

IIRC, they are numbered on one side. If this includes the front one with the cam oil seal housing on it, it will establish what side should be where. Number to the outside of the head rings a bell. I know it was a pain to see them.

If you really can't figure it out, put them on each way and feel for a step inside the journal where the cap meets the head.

Kevin

they are marked

R1
R2
R3

and L1
L2
L3

Etc etc...


there will be no confusion about the passenger bank, cos that has the cam sensor

Not sure about the drivers bank, though, as I guess the front caps appear interchangable on this side...

[Marks DTM Calib]

the caps are bolted to the heads and then line bored at  the manufacturing stage.they should not be interchanged.

That changes things.....

How does that setup intend to accomodate a failed bearing or replacement camshaft?

If the bearing has failed then the reast of the engine will be in a very poor way.

If a camshaft fails around the bearing area there wont be much left of the top end!

Reality is that line boring is by far the best method becuase it ensures excellent line accuracy and good strength.

Cam bearings as per the likes of the Rover V8 are a pain in the arse....almost imposible to get them all truely aligned and the result is they wear!