Sudden Engine Noise Series 2

[SimonBrown]

Just started the E Type up ready for a show tomorrow and wish I hadn’t!
It was very difficult to start and sounded as though it was missing a couple of compressions. It did eventually start but was very lumpy as though flooded.
Suddenly it started running smoothly on all 6 but has a loud tappet type noise from the top of the engine, somewhere in the middle I would say. Previously quiet.
It was running perfectly when last used a couple of weeks ago.
The engine was rebuilt 1500 miles ago, although about 5 years. Oil is clean and fresh.
Any ideas as I think it not wise to continue to run it with the noise?
Thank you

[dxke38]

This sounds worrying, although if it was running on all six cylinders its hopefully not serious. I think I would take off the cam covers and check valve clearances, it could be valve trouble or perhaps a loose cam follower guide. I suggest you don't try to start again until checked further.

[SimonBrown]

Thanks Derek,
It runs as smoothly as ever on six cylinders. I have checked compressions and all are equal.
I have restarted it, and the noise seems a little quieter but is only audible above about 600 rpm.
If I hold it at about 1500 rpm it is quite noisy and sounds like a noisy tappet. I don’t think it is from the front end of the engine, it is difficult to determine whether it is on the inlet or exhaust side.
I wonder if it may be a valve seat come loose but would have thought this would show poor compression
Appreciate your help
Simon

[Allrand]

It could be a sticking valve, but more likely a loose or migrating cam follower sleeve. I had that on my Mk 7. Check for marks on the edge of the sleeves and cam lobes. There are hold down kits available these days, but I solved it by drilling, tapping & fitting small cap bolts hard up next to the lip of the sleeves such that the bottom edge of the bolt heads tightened down onto the top edge of the sleeves. I'd try some Valve Ease or something similar first before going the hold down route.

[dxke38]

Yes it does sound like a cam follower sleeve that's moved and is allowing a cam lobe to tap against it. The only way to find out and be certain is to remove the cam covers and check all 12 of them. If that is what's causing the noise then you will have to decide which way to secure it back into the head. I wouldn't think it was a valve seat that's loose. I have heard an engine with that problem and it was more of a rattle than a sharp tapping noise.

[SimonBrown]

Thank you for ideas.
Checked valve clearances, all okay.
I have narrowed the noise down to cylinder 5 or 6 inlet valves (front of engine)
There are no witness marks on the cam follower guides, so don’t think they have moved.
I suspect a slightly sticking valve, only when the engine is hot and over tickover.
Does anyone have any experience with Valve Master or Redex, or be able to recommend an upper cylinder lubricant?
Hoping this and a gentle run will cure it
Thank you
Simon

[mgcjag]

Hi Simon.....check out the timing chain...you noise was a sudden incident.....a pad comming off a tensioner or damper could give this type of noise...an endoscope would be handy to look....Steve

[abowie]

As Simon has said it may be your upper timing chain needs tightening. 1500 miles after rebuild would be a likely time to need this too.

It would be worth attending to this prior to looking elsewhere as you might just get lucky.

[dxke38]

Hi Simon, If you don't manage to find the problem then I have one suggestion. I had a similar noise on my 3.8 which took an age to find. It turned out to be a broken inner valve spring which with just the outer spring allowed the valve to bounce. You could probably check this quite easily by testing the springs by pushing down on the cam buckets of the suspect cylinders to see if one of them has less tension. It's a long shot but hopefully won't come to that.

[SimonBrown]

Hi Derek,
Thanks for this, which sounds possible. I don’t think it is timing chain as the noise is just too much like a tappet.
I will try running for a while with some Valve master plus and see if it clears (hope)
If not I will remove cam cover again and check valve spring tension.
Its odd that compressions are all okay and noise appears as the engine warms at over 600 rpm
Cheers
Simon

[mgcjag]

Dont be do quick to dismiss the timing chain it can sound like a tapping noise...and its simple to check. ..Steve

[SimonBrown]

As I seemed unable to resolve my tappet noise, valve clearances all correct, compressions fine and even, I enlisted the help of my local Jaguar Specialist. He has removed the head and found most of the inlet valves were severely gummed up as per the attached photo.
It would appear to be caused by petrol going off. The car has been used regularly but has only covered 1500 miles since the engine was rebuilt four years ago.
I think in future I will be using Suuper unleaded E5 combined with Valvemaster plus
Gutted and a lesson learned
Simon