Loose tappet guide

[ALAN COCHRANE]

Hi Everyone

After a total of 250 miles this weekend the car has developed what I thought was an engine rotation related squeek. This varied in volume at idle and disappeared under load as the engine revved.
I checked the usual suspects-water pump and alternator but the noise seemed to eminate from the inlet side of the cylinder head.
Once home I ran the engine in the garage and the noise became very loud and this time it sounded like a loud pinging noise.
I'm beginning to suspect that one of the tappet guides has come loose and the sound is it hitting the corresponding cam lobe.
Do any of these symptons tie in with this assumption or is there another explanation? Would the noise disappear ats the revs increase?
I'm going to remove both cam covers to check for signs and as a matter of course fit the hold down kit.

Cheers

Alan

[abowie]

Never heard that boise but if it's cam related it should occur at half crank RPM.

[ALAN COCHRANE]

Well I've removed the inlet cam cover and everything seems in order. I'm assuming that the camshaft would show obvious signs of damage if there was a loose tappet guide? The following image shows the state of play:-

There were some lumps of hylomar in the oil which had been squeezed off after I'd replaced the seals 6 months ago.
I also wondered if the cam had suffered from oil starvation and this was the the cause of the noise. The reasoning for this was that I'd previously removed the oil feed pipe bolt and discovered that the oil delivery hole was covered in ptfe tape. I have to hold my hand up and admit that I was the culprit. I'd wrapped the ptfe tape around the bolt threads in an effort to stop the thing leaking and this had worked it's way up the shank when it was screwed back in.
One last question-where does the oil feed emerge inside the cam housing, somewhere near the rear camshaft clamp I presume?
Anyway I'm no closer to discovering the source of the noise so more investigating tomorrow.

Cheers

Alan

[christopher storey]

Alan : have you siphoned oil off from the wells beneath the camshaft ? If you have not done so, then there is something very wrong with the oil feed, as the camshafts should be bathed in oil with the wells almost full when you take the cover off. I think it unlikely that you have loose tappet guides, as if this is going to happen it is much more common on the exhaust side . You need to examine the top i.e. inner side of each guide, which is the part that the cam lobe will meet ( and batter down ) in the normal direction of rotation if there is a loose guide on the linlet side ( vice versa on the exhaust side ) . If there has been oil starvation, I would rotate the engine until the valves adjacent to each bearing cap in turn are both closed , - so that there is no local load on the camshaft - and then remove the cap and have a look at the upper bearing shell and the exposed part of the cam journal . If all is well you have probably got away with it

Addendum : the oil feed on the cars with hollow camshafts ( which IIRC yours should be ) is through oil holes on the camshaft journals and the back of the cam lobes which are fed under pressure from the hollow centre of the shaft

[ALAN COCHRANE]

Christopher

The picture was taken after I'd cleaned a lot of the oil out when removing the hylomar deposits.
My next move is to clean out the head completely and then turn over the engine on the starter and check for good oil flow. Hopefully I can see this happening before everything gets sprayed with oil.
I used an oil stone on the rear face of the cam housing as part of my ongoing attempts to stem the oil leak at the external oil pipe bolt. I was very careful to clean away any of the slurry created but cannot be 100% sure if some didn't get pushed into the threaded hole.
I'm assuming that blowing compressed air down the oil feed way with the cam out is the preferred method of cleaning out any blockage?

Cheers

Alan

[kingzetts]

Alan,

I don’t recall if you have had head work done recently, but check out this thread viewtopic.php?f=3&t=10992 which details my issues last year which sounded like a loose guide or dropped seat and turned out to be a very odd issue with the valve stem collets sitting too low in the valve spring upper retainer. Worth checking.

[ALAN COCHRANE]

John

Thanks for the link.
Thankfully my symptons don't match yours. The noise only happens at idle and then disappears at anything above this. I had noticed that the engine sounded more tappety before this happened.
I'll check the clearances as well, although I reshimmed the head two years ago and it has run like the proverbial sewing machine ever since.

Cheers

Alan

[PeterCrespin]

A squeak sounds dry. A tappet guide hit by the cam sounds like very loud clattering. It is rare on the inlet side and the cam lobe usually looks normal except perhaps the edges. The tappet guide sustains the worst damage.

All cams are hollow and feed the shells. They are best plugged at each end (later ones are as standard) but your Hylomar/PTFE exploits may have plugged a feed somewhere and any noise would be likely to be overwhelmed by a rev increase. Did the feed pipe get a crimp by touching the bulkhead seam during engine installation?

Does your car have the sprung belt tensioner?

[christopher storey]

Alan : a good way to check the oil feed is to use a garden sprayer - 5lbs/sq.in /0.3 bar is ample , with some engine oil in, and plug it into the oil gallery running along the right side of the block at filter level ( there are 2 or 3 spare blanking plugs ) . Within 2 minutes or so you should see oil oozing out of the bearings and the lobes. If you had to clear oil away, however, it sounds as though the feed was ok anyway

[ALAN COCHRANE]

Christopher

Your earlier diagnosis appears to have been correct. I cleared out all the oil in the housing and then replaced the cover. I then ran the engine for approximately two minutes and after that checked the oil level in the cam housing. There was no evidence of new oil.
It appears the oil I found originally had been there for a while and was not freshly pumped in.
I checked a couple of the cam bearing shells and one looked like this:-



I replaced all the shells just over two years ago so would not expect to see this type of wear. Fortunately the cam journals appear undamaged
I'm fairly certain this is the source of the noise.

I might try your suggestion,although I now need to remove the cam to replace the shells so I'll take the opportunity to thoroughly clean out the oil way. I suspect the blockage is actually between the external feed bolt and the rear cam shell.
As I stated in an earlier post I think I am the one to blame for all this. I think some of the slurry I created when using the oil stone has managed to get into the oil way and cause the blockage.

Fingers crossed this will be the end of my investigations.

Cheers

Alan

[abowie]

FWIW do you have the original cam oil feed pipe fitted or did you go with the braided replacment style? The braided hoses have a smaller ID and deliver less oil.

[ALAN COCHRANE]

Andrew

I have the braided hose pipes. The originals had developed leaks at the brazed ends.
I’ll also check that the oil pipes aren’t blocked. Although this is unlikely since the exhaust cam is bathed in oil and there’s a perpetual leak at the inlet side bolt. This is what started this saga off- my attempts to stop it!
I should have listened to a friend’s advice- it’s a Jaguar so it leaks!

Cheers

Alan

[abowie]

Andrew

I have the braided hose pipes.

We have stopped using them. They are some sort of hydraulic fitting which is OK for transmitting pressure but no good for flow. The orifice diameter is considerably smaller than the original and flow is proportional to the 4th power of the radius.

[ALAN COCHRANE]

Well I've finally sorted the cam oil feed problem.
The cause of the oil blockage was ptfe tape riding up the threaded section of the external feed bolts. This stopped the leaks but also stopped the oil feed! The ptfe tape gathered behind the first sealing washer and covered the oil hole in the bolts. Luckily it only affected the front hole on the exhaust side so that camshaft was unaffected.
As an experiment I wrapped two turns of tape around one of the bolts and tightened it into the block. Even this small amount ended up being pushed back towards the front oil hole. So no ptfe tape this time around.
I ended up having to tighten the upper timing chain as well. What a dreadful din a loose chain can make. Anyway the oil feed is most definitely restored to the head. I only tightened down four of the inlet cam cover bolts in case I needed to take it off again. The result was a nice puddle of oil on the garage floor via the front of the inlet side.
So the moral of this story is live with small oil leaks and be very careful with ptfe tape.

Cheers

Alan

[phil.dobson@mac.com]

I don’t want to state the obvious BUT... pfennig has no place in an engine. Just my humble opinion. and remember a dry jaguar engine is an empty jaguar engine ;-)
Best regards

[christopher storey]

Phil, what does the reference to pfennig mean - or is it a typo ?

[ALAN COCHRANE]

Phil

Have to disagree about ptfe tape. It's very useful in the right places, obviously not on the cam feed bolts.
In an earlier post Christopher recommended it's use on the thread of the rearmost sump bolts and it works.
I've used it many a time to seal coolant leaks on various cars.

Cheers

Alan

[phil.dobson@mac.com]

ooops typo sorry guys. should have read ...ptfe tape has no place in an engine.

[chrisfell]

ooops typo sorry guys. should have read ...ptfe tape has no place in an engine.

[rfs1957]

Sorry to hear of your travails Alan.

I only ever use PTFE on brake bleed nipples where it - somewhat curiously - works wonderfully to stop fluid leaking past the threads when you're bleeding the brakes.

I cant think of anywhere else on the car that there isn't a better product than PTFE for sealing really ?

My main reason for posting, except to try not to be assumed dead, is that the leaks on the rear head-feed banjos would never be cured anyway by any attention paid to sealing the threads themselves.

The leaks can only occur on the sealing circumferences of the banjos, and whatever happens around the threads is irrelevant.

No ?

Somebody supplied me super thin Cu washers for this which had the added advantage of giving another half a turn of thread of bolt in the head, and I think I read that you can get longer bolts for these fittings as short ones can quickly strip. It is definitely worth checking a head that's off, and fitting helicoils if need be, as its a head-off job to fix otherwise.

There is NO reason to tolerate leaks here anyway, save them for more difficult-to-cure areas !

Good luck.