Tapping noise when cold Griffith 500 serp

[chris52]

A little help needed
Just noticed this morning that my Griff has developed a tapping noise which is quite load but only noticeable when the engine is cold. The car is also very hesitant and jerky when at low speeds even when hot.I did have the car out for a 220 mile run the other day and it ran without fault. The oil pressure is fine although it does take a few seconds for the needle to rise when first started up. The cam was changed and a full engine rebuild was done at 42,000miles its now done 67,000. I havn't realy had time to have a close inspection yet so I supose it could be anything, but if any of you guys have some pointers of things to start looking into and changing it could save me a bit time and cash.

Many Thanks
Chris

[davetherave1970]

First thing I'd look at would be the fannymold gaskets. They know to spring a leak and make a ticking sound.
If that's not the fault then I'd have to get it looked at by someone else

[Tonto]

Yep, sounds like exhaust gasket or the actual manifold itself could have s pin hole or 2. Get a feather or similar and hold it over the manifolds, soon spot the problem if its that.

Edited by Tonto on Monday 30th March 23:49

[Ballistic Banana]

Yeah check the manifold gasket, if not maybe a loose trumpet rattling around...
Does the noise change with engine speed?
Also check ht lead isn't shorting onto the manifold this can make this noise and a loss in power.. Stuttering/shunting sensation.good tip is torun theengine in the dark and you may see it sparking... Don't touch it if it is untill engine is off

BB

[chris52]

Cheers for the swift replies.
The noise is pretty weird realy as its only there for a few minutes. you start the car and its nice and quiet ( if a tvr can be such a thing) no tapping. Drive for a couple of minutes and its starts, sounds very much like a single noisey tappet. The tapping increases with revs, then when the car gets up to full temp it just disapeers. I have only just bought this car and compared to the last griff I had it seems quite a bit slower and less responsive, but this may be down to the fact the other had a sports exhaust and just seemed quicker with the extra noise.

I am going to have a good look over it today and see if i can find any manifold leeks.

Was also thinking of getting rid of the pre-cat, just to confirm though that you dont need to do anything with the lamba sensor when just removing the pre-cats

cheers again
Chris

[chris52]

Had some time today at work to check out the car. No air leaks from the manifold, no rogue sparks coming off any of the HT leads, also filled up the tank with fresh fuel just in case it was poor fuel. Had a good listen to the engine with a screwdriver to my ear and touching various parts of the engine to see if I could hear any adverse noises, it was a little noisier on the left side of the engine near to the back but as the tapping only apears for a short time its very hard to say for definate.
I definatley have a hesitation/lumpyness at about 2000rpm and the engine seems a little lumpy at idle.

It has a lucas distributor cap and rotar arm. New coil and ign amplifier so I dont think its electrical. Oil pressure is fine but it does have for some reason a halfords oil filter and it runs on mobile one oil.
As said before the cam was replaced at 42k and its done 67k now so can't see it being the cam, any other sugestions would be really helpful

Chris

[zippy500]

Could it be just tappets/rocker parts filling up with oil and hence clattery for a little while. Then once oil has got around it goes. If it were leaks or wear, I think you would hear it a whole lot more and when warmed up also.

[chris52]

Perhaps its just me being over critical, I have just checked throgh the history and the car did have new cam followers and hydraulic lifters only 26000 miles ago. the car does drive great and the noise is not realy that loud, the last Griff i had had a sports exhaust so chances are I wouldn't hear anything. I will get it to a specialist at some point to check it out and get an opinion. thanks for all the help and advise

Chris

[lewton]

Not one of the steel pads fallen off one of the rockers,causing the hydraulic tappets to take longer to take up the slack???????

Edited by lewton on Tuesday 31st March 22:57

[Miss Tree]

I know I have one tappet that is slow to come up to full size that shows exactly this kind of tapping noise (no sign of the low speed shunting though). You may two issues at work.

Once it is up to full size after a minute or so the engine runs nice and quietly. It often goes away completely after an oil change but returns after a couple of thousand miles.

[chris52]

Took the car round to Andy Turner today who had a good listen to it. Turns out its just a sticking injector. A bit of aditive lubricant in the fuel and with a bit luck and a few miles of running it should be all good.

Thanks everyone for your advise and help

Chris

[Ballistic Banana]

that's a relief and glad you got it sorted

BB