Race Engine Forum UK

Following my request elsewhere on this site for a TC exhaust gasket, I actually managed to find one in an 'old' headset I had 'in stock' from a 125 engine. I was rather surprised that the standard exhaust gasket for a 1608cc unit is also specified for the 1438cc, and fits the 1995cc exactly. Perhaps I should have realised this after more than 20 years around Fiat twin cams?!?!

I was searching for an exhaust gasket as I believed that the one on my Racing's engine was blowing. After removing the exhaust manifold and carrying out all of the associated draining down of coolant, etc, I found that the gasket had indeed blown, so my time wasn't wasted, but after reassembly and running up the engine again I find that there is still a 'ticking' noise from the engine.

At first I thought it was still the gasket, but a thorough inspection has found that the exhaust system is air tight. I am now lead to believe that it might be a tappet. The noise is worse from the 'inlet' side of the engine, and seems to occur when one specific cylinder (although I don't know which one!) is firing, a sort of '1 in 4' noise.

My queries are

1) Is it likely to be a tappet?
2) Could it be an 'induction' noise? Could this sound the same as a tappet?
3) What else could it be? (suggestions)

I realise that this is a very open query, with many potential answers, but I'm concerned that there may be something obvious that I'm missing.

The car is due an MoT in a couple of weeks and will fail if the tester believes it's the exhaust.

Thanks

Simon

Well, Simon

the most obvious thing to do without delay is check the valve clearances, I set them at 16/18 thou" in/ex, +/- 2 thou.

Also check the condition of the cam lobes, they should have a nice smooth radius, but go 'pointy' and elliptical when worn. The cam/bucket rattles quite badly when the clearance is loose.

I have shim tools for sale if you need one and can supply shims on mail order readily enough.

GC

Simon.
A blowing inlet gasket can make a "ticking" noise too. I had a 127 which did exactly this. It sounded like a tappet but was the gasket blowing in the middle of the manifold and causing the noise.

Andy.