"Ticking" noise when accelerating

[jimj]

Most twincams make tappetty noises, some worse than others, without any problems. Just rest a long screwdriver on the cam cover and put your ear to the handle end and see if that`s where the noise is coming from.
Jim

[Foxie]

One of the most obscure odd noises I've encountered was caused by the heater fan windmilling. Check by switching the fan on and/or changing the damper positions

Sean

[Barney]

Just to eliminate the electric petrol pump theory,
do you get a fast clicking when you turn on the ignition for the first time when cold that then slows down after a 5 seconds or so?

I once fitted a Morris Minor fuel pump to an Alfa Zagato without using rubber mounts - the sound through the metal bulkhead was very 'distinctive'.

Barney

[gerrym]

A broken valve spring can make a ticking noise. This would probably be present at all revs including idle but not necessarily. Check valve clearances and compare against previous readings.

Regards

Gerry

[greg.harvey]

Just to eliminate the electric petrol pump theory,
do you get a fast clicking when you turn on the ignition for the first time when cold that then slows down after a 5 seconds or so?

No, silence when it starts. Only under power. I'm going to have a much closer look this weekend.

A broken valve spring can make a ticking noise.

Bear in mind the noise has been there since I bought it, 6 years ago. I would hope that after 6 years of servicing, someone would've picked up on something like that... You never know, but I'd be both surprised and annoyed if it was a broken valve spring, as that sort of thing is supposed to be checked annually. That's what I've been paying people for!

[gwiz22]

Greg,
Well tonight I went to have a closer look at the the exhaust manifold where it connects to the head. Using a halogen light and a small mirror on a telescopic arm and carefully looked at every joint from underneath. On number two cylinder there was a trace of soot which looked as if gases had been escaping. I always thought this ticking was an exhaust leak and now I'm pretty sure this is the cultprit. So another job for the list.

I plan in the fullness of time to remove the manifold to make sure that my diagnosis is correct. At that time I will apply exhaust wrap to the manifold. I believe tubular exhaust manifolds emanate more noise than cast iron variants used on earlier Elans and hopefully the wrap will attenuate the noise somewhat.

Regards
Graham
'73 Plus2 S130/5

[greg.harvey]

Hi Graham,

Thanks for the update... one thing I'm wondering - from memory my ticking is not in time with the engine revs. Does that still make sense from a leaky exhaust manifold?

Rgds,

[gwiz22]

Greg,

You originally mentioned the noise was only prevalent when accelerating, which is exactly the same as I am experiencing. If you go for a run, get up to a decent speed then cut the engine, does the noise remain? If so, it's something in the running gear. I once had a ticking noise coming from the front nearside brakes, which stopped when I applied the brakes. I determined it was the pads lifting slightly in the caliper, then dropping back again.
If the noise goes away when the engine is cut then you know where to start looking. On mine the noise sounds as if it is coming from the top left hand side of the engine, exactly where the manifold is located. That was the first placed I looked but obviously not closely enough. So that's when my attentions turned to the bottom of the manifold to the Y piece and main pipe. I assumed the noise was coming up from the LHS of the engine bay and that is why it sounded as if it was coming from around the top of the engine. My money is on the manifold.

Happy noise hunting.
Regards
GRaham

[greg.harvey]

Thanks again, Graham - I think your money is well placed.

[greg.harvey]

Hi all,

I took a look at the exhaust manifold and head with a flashlight the other day and couldn't see any evidence of a leak. I also got this email from the Lotus specialist who usually services it:

Hi Greg,

It is most likely to be the non return vacuum valve on the brake servo. Try clamping the pipe and drive the car but bear in mind the servo will not work with the pipe clamped.

Interesting....

[gwiz22]

Greg,

Interesting indeed. However, I don't think that is the root cause of my problem. Of course yours may be different. After all we haven't actually compared noises only described them. The reason I don't think it is for me is when I first got the car the brakes occasionally stuck on after application. I disconnected the servo to try to isolate the problem, (and that problem did turn out to be the servo) the ticking noise was ever present. It sounds almost like a diesel when accelerating at low speeds.

Anyway, it's an easy check to do. I didn't clamp the rubber servo tube, I disconnected it from the metal tube that runs along the baulkhead and placed a bolt in the rubber tube and clamped it tight with a jubilee clip. It takes a bit longer to do but at least you are sure there is now vacuum getting to the servo and the pipe will not be damaged by the clamp.

Keep searching and let me know when you find it.

Regards
Graham

[gjz30075]

Greg (and Graham), if the exhaust leak doesn't fix it, here's another possible cause: Happened on a LoCort I owned some years ago and the ticking only occured under acceleration. Turned out to be one of the cam lobes just catching the side of the sleeve in the tappet bore. The sleeve wasn't installed too straight and the cutout for the lobe was not perfectly inline with the lobe. At idle, it wasn't a problem but under power, I suspect the camshaft moved, either fore or aft, and caused the lobe to hit the sleeve. With surgical cleanliness, I used a die grinder to open up the cutout in the sleeve and all was well.

Greg Z

[andyelan]

Hi There

Greg has just reminded me of somthing else to have a look at.

There should be two D-shaped washers under no 7 and 8 cylinder head bolts ( front exhaust and rear inlet - it's in the workshop manule where it shows the tightening sequence ). You'll have to look carefully as the flats are quite subtle, but if these haven't been fitted or are incorrectly positioned, (they were wrong on both my cars when I bought them) then the cam lobes will just catch on the washers. That could be a cause of your ticking noise.

Andy

[elansprint71]

It sound like your car is going like a bomb..........

I'll get me coat.

[gwiz22]

Greg,
I know it's been a few months since this topic hit the forum, but at the weekend I took of my exhaust manifold and as I had expected a number of the exhausts gaskets had blown. I think the reason was either, poor quality gaskets; they seemed very thin or when the manifold was bolted on the re-builder used flat washers. Due to the weld fillet at the point where the pipe meets the flange, the washer did not sit flat on the flange. I assume it was tightened up at the time, but over the years the washer probably sank some more. Whilst the nuts could not be described as loose, they were particularly easy to undo. I've replaced the gaskets, but not fired up the engine yet as I'm re-furbishing the steering rack. However, I'm sure this was the cause. How did you get on with your ticking?

I tried to update some pics, I keep getting and error

Regards
Graham