Cam journals worn........

[simonbuk]

It appears that my cam journals are worn (or so I've been told by my mechanic). It has a 'rattley' sound and increases under load.

My father reckoned it was piston slap (he was in the trade for many years) but my mechanic says it is top end noise.

What are my options on this ?

1) live with it for a while (does/will it get significantly worse when only doing 2/3k miles a year)
2) new cams
3) second hand head
4) what else ?

I've read some other threads about ticking/rattling noises and can confirm that the engine is running fine so don't believe its plugs/leads/fuel rail issues. Recently got very good mpg on some long runs and good mpg touring around generally. Timing was set correctly a few months ago.

Merry Christmas folks !!

Simon

[alan e]

what oil are you using ?

[simonbuk]

According to the literature I have with the car the last couple of changes was Mobil 1 10W 60.

We have just put a slightly thicker oil going to 10W 40.

[lotusflasherman]

Not making much sense to me - cam journals are the perfectly circular bits that support the camshaft and just go round in the circular bearings... if they were so worn that they rattled, you'd have a 'lack of oil pressure' problem showing itself, and the load on a camshaft is related to the number of valve springs it's working against and the revs, so will be there in neutral with no engine load of any significance.

The cam (or cam lobe) is the eccentric lump that opens the valves. The Elan has hydraulic tappets (a.k.a. cam followers) where oil pressure is used to alter the length of a telescopic tappet to achieve minimal valve clearance.
Much more likely that you've got some 'crud' in the oil either stopping the tappet expanding or the ball valve isn't seating properly so your rattle is excessive valve clearance.

How many miles has the car done and how old is the oil?

I have an SE that's been on SORN several years and was firing it up from time to time but I left it quite a while and it developed a rattle on start up due to a 'sticky' tappet. I left it ticking over till it got hot enough for fans to kick in while I cut the grass and the rattle had gone when I turned off the mower. Few months later it rattled again for several minutes from cold but went as it warmed up so I treated it to an oil change and it's been quiet on start up since (touch wood !).

When my wife had a Ford Escort with CVH engine that suffered from a stuck hydraulic tappet rattle. Some use a circlip to hold the assembly together but Ford crimp a collar like a 'crown cap' on a bottle and in theory are 'not maintainable' so I bought a new one and fitted it. Then out of curiosity prised the collar off the old one to see what was inside - oil was a bit like treacle so washed it in petrol and cleaned the ball valve and oil ways and filled with clean oil and it was good as new and not too tricky to recrimp the collar - so I worked my way along refurbishing all the others and removing 'the treacle' ...
ended up with a spare refurbished one which I've still got even though we sold the car decades ago.. (New Year Resolution - clear out the obsolete rubbish!)

[lotusflasherman]

According to the literature I have with the car the last couple of changes was Mobil 1 10W 60.

We have just put a slightly thicker oil going to 10W 40.

huh??? 10W 40 oil will be thinner when hot, not thicker.

Both behave as SAE10 when cold so will appear the same out of the can, but when hot (at 100°C) the Mobil will behave as SAE 60 so will remain 'thicker' than the SAE 40. (Higher the number, the thicker it is.)

[alan e]

According to the literature I have with the car the last couple of changes was Mobil 1 10W 60.

We have just put a slightly thicker oil going to 10W 40.

huh??? 10W 40 oil will be thinner when hot, not thicker.

Both behave as SAE10 when cold so will appear the same out of the can, but when hot (at 100°C) the Mobil will behave as SAE 60 so will remain 'thicker' than the SAE 40. (Higher the number, the thicker it is.)

its worth changing the oil for a 10w 60

[simonbuk]

So will be there in neutral with no engine load of any significance.

Think it is, meant the noise increases under load doesn't disappear.

How many miles has the car done and how old is the oil

76K mikes, just had an oil change - no difference to noise so not oil related. Last oil had only done a thousand miles if that, same as the oil before.

It did have a head gasket failure a couple of years ago so probably suffered some oil starvation at some point.

[simonbuk]

Meant to add that the noise is constant, no amount of leaving it until hot or driving it around for hours makes the noise disappear so no sticking tappet etc.

[Jamie N]

Ultimate solution Simon.... K20 Type R it!.

[muley]

Hmm.

I know next to bugger all about oil.

But, I would try running it on 0W40 (Mobil 1 preferably) for a bit. This is recommended in some of the earlier service notes. The thinner(when cold) oil might clear out junk from the hydraulic followers - it's worth a try.

I normally use this but switched to a 5W30 (just to flush it really) and I was surprised to see the pressure reduced a fair amount..

Stands by for flaming.

Have a Merry Christmas.


Jim

[HJ2]

Since the noise is constant...
Are you sure that you don't have a noisy CAS assembly? (worn bearings)

[simonbuk]

Since the noise is constant...
Are you sure that you don't have a noisy CAS assembly? (worn bearings)

How can I check for this ?

[muley]

Since the noise is constant...
Are you sure that you don't have a noisy CAS assembly? (worn bearings)

How can I check for this ?

Try using a stethoscope, or piece of pipe. If you grasp the CAS you might feel it grumbling in your hand.

Jim

[simonbuk]

Ok cheers. If it is worn bearings in the CAS assembly are these replaceable or is it a new one ? (I believe these are the things that are about 300 quid if you can get them ?)

[Simon_P]

To check cam journals take the cam cover and a cam cap off and have a look. I expect that it will all look ok.

Check the belt tension - slightly loose will cause the top end to rattle.

[simonbuk]

Researching CAS assemblys it says there is 3 parts to it but none of them mention a bearing in it ? Is the bearing a seperate part ?

Looking on SJ's and Deroure the whole CAS is about 260 quid (probably need to add VAT and postage still). Is there an Isuzu part that works ? Tried Rockauto website but its not listed.

I'm going more with the CAS being more noisy than anything else at the minute !

[alan e]

I think that HJ2 replaced the CAS bearing that he got on Ebay and I think he put a link to it on posting , it may be worth sending PM good luck.

[Simon_P]

There is a write-up on how to change the cas bearings.

If there is a rattle it is more likely that it is caused by the cam belt not being tight enough - This might also sound like cam bearings as the noise can be heard across the length of the cam.
You can check the belt tension for nothing.

[simonbuk]

Thanks just found some threads regarding the cas bearing replacements.

Can't believe the belt is loose as it had its timing checked (and adjusted) not long ago but I will check tomorrow.

[alan e]

Just been into my garage to check the part number of the bearing I have for the CAS its a SKF explorer 6000-2RSH.
and good luck removing the belt cover to see if the belt is loose its not easy