ticking noise from engine

[djm16]

This has been bothering me for some thousand miles. The car is only just back on the road, so it is a little hard to says exactly when it started.

The ticking is exactly once per 2 engine revolutions, it coincides with firing from cylinder 4. It is virtually inaudible at slow tick over. It is loudest at fast tick over and disappears above about 1500.

The sound appears to come from inside the block.

I have have the valve covers off and re-adjusted the clearances to both inlet and exhaust. Made no difference and in any case I really do not hear the noise as coming from a valve. Moreover I tried adjusting the clearance to zero of the exhaust valves and (briefly) ran the engine - no difference.

My thoughts:
does this sound like worn cam chain / tensioner? oil pump relief valve sticking?

[Welsh Warlock]

If its a V8 it is well documented that a leaking exhaust manifold can cause a ticking noise.

To check, use a listening tube and move it around near the exhaust manifold on the side of the engine where the noise is emanating from and it should be obvious if that's the issue and would be a relatively easy and cheap fix with new exhaust manifold gaskets.

[Roy of the Rovers]

Could also be if a spark plug is coming loose or not tightened correctly. Less common but I have had this myself.

[Phil Nottingham]

I had number 1 plug actually blow out whilst driving - it often worked loose before that but not since

Exhaust manifold ticking is both P5 and P5B problem - easier on a P5B as a gasket may all be needed as they can be fitted dry.  P5 is because of warping through incorrect assembly and will need refacing if not done before

[Welsh Warlock]

Interesting that the ticking noise from exhaust manifold also afflicts the 3 litre. I didn't know that.

The issue is discussed almost weekly on the various Pistonheads TVR V8 forums so it is very common and it really doesn't sound like a blowing manifold; more of a metallic click.

[terryvanman]

I've had this problem, tried all the tricks above with no joy...so it's in the garage for major work....going over there tomorrow to chat with the guy and see whats what. will get back with a report.

Terry

[eightofthem (Andy)]

Could it be the pushrods just catching the cylinder heads, especially if heavy duty rods have been used without enlarging the holes

[djm16]

Thanks for the above suggestions.

I also have had cracked exhaust manifold and a leaking spark plug hole give similar noises. So I have already checked these. Most notably the noise is independent of throttle opening and does not go away on removing any plug leads.

A more experienced engineer than me has suggested an inlet vavle fouling the top of the piston if the cylinder head has been skimmed too many times.

[enigmas]

A clearance issue? Carbon build up on the piston head touching the squish area of the cyl head. (An engineer mate of mine (cyl head specialist) found this situation on a BMW after the factory mechanics had given up)

Checking the cyl head to piston deck clearance may resolve the problem. Unfortunately a time consuming task on a 3 litre engine.

[djm16]

I agree with the possibility of a clearance issue. I had a similar problem on a 95 again with a Weslake head. Several pistons were making contact with the cylinder head, but only when the engine got too hot. This one does it when cold too.

Now does anyone have a fibreoptic scope handy?
eBay for me!

[Phil Nottingham]

Have you tested the exhaust manifold face for flatness - this is quite a common issue which even the manual identifies although it does not give the symptoms. It is usually obvious on removal anyway as carbon tracking can be seen on the gasket.  Gasket cement should never be used either as the joint must be able to slide for expansion and contraction

I have had this on every IOE Rover engine from time to time and have heard of others pulling the engine apart before checking this simple cause

The other cause can be a flat spot on a roller tappet

[djm16]

Thanks Phil,
Yes, I had the manifold skimmed. It has been on and off several times, and there is no evidence of carbon tracking.

You are likely right about the flat on the camshaft. But I am still hoping it will be something a little cheaper and easier to fix.

[terryvanman]

This is the reason for my tick

[Phil Nottingham]

The camshaft should be OK - the roller tappets are actually cam-follower an slip out when vales are removed but you can inspect and turn them in situ

[djm16]

roller tappets

Got it. Did not read your post correctly first time.

[djm16]

Update on ticking noise.

With the help of a local friend with some experience with these engines I have narrowed it down a bit.
Closing off the gap in each inlet tappet in turn led to the discovery that the ticking was associated with inlet number 2. Since the tappet clearance was exactly 6 thou, the problem had to be at the other end, namely the camshaft and followers. Yes, I know you told me already!

It is possible to remove each of the inlet roller followers simply by removing the rocker gear from the head and pulling out the pushrods.

What I found was on number 2 inlet roller there was a crack in the case hardening that extended across the width of the roller (pictures to follow). Quite bizarre and hard to see how this could make the ticking noise, but it seems likely to be the cause.

We get to put it all back together again Saturday when I have a NOS roller to put in.

While we were there we pulled out the number 1 inlet follower too. To my dismay the case hardening in the roller was also pitting as was the corresponding cam shaft lobe. But that was not the one that was noisy. So it looks like if and when I get around to rebuilding the engine I am going to need a new camshaft too. But then again, maybe it will do another 50,000 miles.

[Phil Nottingham]

It will do another 50k miles - will you (in it) that is the question?

[djm16]

part number
Can some kind soul with access to a parts book tell me if the roller cam followers in the 3 litre are the same as in a Landrover 2.25 / 2.5 and 6cyl?

This would be the part number from Land Rover Parts Australia: 90517429

[djm16]

OK, here are pictures of the offending articles.

Clearly the cam has seen better days. I am showing the most damaged cam lobe. It coincides with the ticking noise, and also the damaged roller cam follower. When I do get around to rebuilding the engine, assuming I am still alive in 50,000 miles, then the cam will need a regrind.

Although it does not exactly make sense to me, replacing the damaged roller cam follower made the ticking noise go away. The visible defect on the roller just seems too small to cause so much noise.

[Phil Nottingham]

I am pleased you have found the problem - the flat on the roller could well have damaged the camshaft but I would still not bother replacing the shaft just the damaged rollers to see how the perform/last 

It sad that the roller tappet did not cure fully the excessive camshaft wear the 5 bearing engines suffered with just a plain rocker pad. This is a not uncommon affliction with both 2.6 and 3 Litre 7 bearing engines

[projectrover]

Jan 3, 2016 3:47:06 GMT djm16 said:

OK, here are pictures of the offending articles.

Clearly the cam has seen better days. I am showing the most damaged cam lobe. It coincides with the ticking noise, and also the damaged roller cam follower. When I do get around to rebuilding the engine, assuming I am still alive in 50,000 miles, then the cam will need a regrind.

Although it does not exactly make sense to me, replacing the damaged roller cam follower made the ticking noise go away. The visible defect on the roller just seems too small to cause so much noise.

I have the same problem, Ticking above 2000 rpm. Stripped it down And replaced the 3 slightly worn followers and shafts which were worn. And decided on a reprofiled cam as well. But getting the cam out is proving a bit tricky. It moves about 1/2 an inch then clunk! No set screws in bearings all move. Its stumped me at the mo. any ideas gents.