The V8 Owners Forum -

Just writing in frustration here. I have not even attempted to examine the problem.

Just got the sodding mgb through its MOT this morning at the family home where I work on my car, then drove back up to home this afternoon. A stone flew up and chipped the windscreen which was highly annoying, but that's neither here nor there.

A weird noise started mid way up the A1. Got home, opened the bonnet and it was a ticking/tapping noise. Unplugged No2 cylinder and it stopped which makes me think it is pinking. Because it's only one cylinder my first thought is a cracked dizzy cap causing erroneous sparking, but I don't know.

Knowing my luck, the sodding engine will be about to go bang.

I thought this modded car business was supposed to be fun? I know it is probably only a minor problem but it's my everyday car and I need it!!!! I don't have the time to fanny about fixing one problem after another!!

Could it be something as simple as exhaut manifold gasket leaking

Im with r2d2hp, a leaking gasket can be a funny noise at best, and can really sound terminal.

ian.stewart wrote:Im with r2d2hp, a leaking gasket can be a funny noise at best, and can really sound terminal.

Yeah I thought about that too. As I said, I have not looked yet,. I just unpacked the car and went to the pub lol. In fact now you mention it, the bolts on no 2 exhaust flange do have a habit of working loose for some reason.

as said above sounds like exhaust gasket (no 2 most likely)
Mike

There were some loose manifold bolts. Tightened em up, but that aint cured it. Grrrr.

have you checked for a cracked spark plug?

only takes a barely visible hairline crack to the ceramic

Swapped plugs over so the suspect plug was on No4. Still made the noise on No2 only.

Have you tried listening with a piece of hose to try and tell where the noise is coming from.

ppyvabw wrote:There were some loose manifold bolts. Tightened em up, but that aint cured it.

The fact that the noise stops when the spark plug is removed means it is defo combustion related. If you have exhaust manifold gaskets, and one is breached, no amount of tightening will fill the gap.

Beyond that, what is the spark plug condition, maybe a clue there?

If you have a valve broken or piston ring probs, try compression or leakdown tests.

If its a tappet I dont know if that would quieten things down when the plug is removed - anybody?

ditto if the cam is worn, would removing the plug create silence.

[quote="ppyvabw"]A weird noise started mid way up the A1. Got home, opened the bonnet and it was a ticking/tapping noise. Unplugged No2 cylinder and it stopped which makes me think it is pinking. Because it's only one cylinder my first thought is a cracked dizzy cap causing erroneous sparking, but I don't know.quote]

Hi Alan.

Just a couple of questions.
Is it misfiring at all when it's ticking/tapping?
Has it noticeably lost power?
When you remove plug lead No2, as well as the ticking dissapearing, does the engine note change also?
And finally. SORRY I have to ask this question
To celebrate sucessfully getting a new MOT did you give it good thrashing? (I usually do )

Regards Denis

DEVONMAN wrote:
Hi Alan.

Just a couple of questions.
Is it misfiring at all when it's ticking/tapping?
Has it noticeably lost power?
When you remove plug lead No2, as well as the ticking dissapearing, does the engine note change also?
And finally. SORRY I have to ask this question
To celebrate sucessfully getting a new MOT did you give it good thrashing? (I usually do )

Regards Denis

Not lost power. Not misfiring, the engine note drops when you take the lead off.

And finally, yes. I did give it a good thrashing

Not lost power. Not misfiring, the engine note drops when you take the lead off.

And finally, yes. I did give it a good thrashing [/quote]

Based on your reply unless it is an exhaust gasket blown then it sounds like the problem is not in the head and somewhere below piston crown level.
That would leave piston rings, small ends or big ends or even a cracked piston

If it's piston rings the noise would be hard to notice unless you have a very quite exhaust system.
If it's a big end your oil pressure should be very slightly lower than before and the noise would be slightly less when the oil is cold.

If it's a small end then I think you would need to get an experienced
mechanic to listen to it before you think of stripping it.

Hope I'm wrong and it's something simple to correct.

Regards Denis

I don't think the tapping is heavy enough to be a bearing. And it's not coming from the bottom.

I aint stripping it, I will leave it until it goes bang and get my 3.9 built and put in.

ppyvabw wrote:I don't think the tapping is heavy enough to be a bearing. And it's not coming from the bottom.

I aint stripping it, I will leave it until it goes bang and get my 3.9 built and put in.

It would be a good idea to compare the compression on No2 with the rest.
This will at least help to rule out some of the possible causes of the noise.

As r2d2hp suggested, a piece of hose in your ear will help to pinpoint the area.

Regards Denis