4 replies to this topic

[lsto]

Afternoon all. Just replaced the head gasket on my 91 1275. When I had the head off I lapped in the valves and replaced the seals as you do.
Anyway couldn't help but notice my exhaust valves had a white deposit, unfortunately I took no pics. I assume this means its running lean and cooking the valves?
This is what it would mean on the motors at work but they are big 12 litre td lumps lol.
The valves were a little pitted which don't help...
Anyway I have tweaked the carb a touch and see what happens.
Advice appreciated, petrol motors ain't my usual business and college was a long time ago lol

[KernowCooper]

White deposits on the exhaust valves are pretty normal its carbon deposit and the heat makes it whiter on the exhaust valves, When I was in a Vauxhall Dealership doing decokes standard cars would have exactly the same deposits. Did you spin the deposit off on a rotary wire brush.

 

Take a plug reading or if you have a CO meter to see if its actually weak is my advise.

[IainStallard]

This what you mean?

[lsto]

Yeah that's it, yeah I cleaned it all off. All it was is on the big diesels its usually a sign of running hot or a blocked crt, but its been a long while since I worked on petrol motors, my brain is a little rusty lol.
Unfortunately I don't have access to a CO meter, just a smoke analyser.
I'll just adjust my carb back then, lucky I marked it

[miniman24]

To my knowledge it means the engines running well and is in good condition, kind of the same colour you get on healthy spark plugs. Mine was the same, nothing to worry about :)