SE - strange noise on warmup

[Sparky]

Here's a weird one - did a cambelt on Paul's SE (Doulou) a couple of weeks ago. Found the vacuum pump virtually hanging off, so remove/refit of pump and bracket to ensure all was secure. On first startup, several random 'cracks' were heard, seemingly emanating from around the cam towers area. Sounded just like a lead or plug arcing, but no obvious signs, and it stopped once the engine was warm. Found nothing. Paul has just heard it again on warmup. Plugs/leads have been eliminated from enquiries and engine does not falter when this happens, so I have no idea what it could be!

Any thoughts?

[Advantage]

Dodgy earth strap or alternator grounding etc?

/guessing/

[Doulou]

Dont think the crack sound is electrical really hard to explain but I think it's mechanical

[Wilf]

Something expanding as it heats up? No idea what it might be though!

[Bibs]

Is the car stored outside in the damp?

[Advantage]

Good call Bibbo. Mine does that if left outside overnight (water droplets exploding from the heat of the exhaust manifold).

[Bibs]

My NA did exactly the same if it was left outside overnight.

[Doulou]

You might be on to something chaps! When Sparky did the belts, it was p*ssing down all day for sure some water may have got on the manifold as the poor bloke did it outside. And the same for me yesterday the cars been outside at home since, with a god chance of rain water dripping in. Funny, today I started her nice and dry "nothing"

I'll keep an eye on it

Thanks guy's and thanks Gary.

Regards

Paul

[Sparky]

I'm hard, me. Rain? Pshaw.

That would make sense, actually. It was a tad damp that day, and I was relegated to outside because that bloke internets stole my nice cosy spot.

Trevor came up with another possible cause - static discharge from the newly tightened belts. Again entirely possible, but let's see what happens...

[910Esprit]

Could be onto something. Deffo no ancilliary earrth leads missing or broken? It may be acting as a Van der graf generator....

[cjtpb13]

You have to love this forum...how many other forums would anyone know what a Van Der Graaff generator is much less what it performs.

However if it sounded like bacon popping in the hot pan...I will go with the bit of water down in the spark plug area...as I get this constant after a good wash.