White Deposits In The Exhuast Ports/Back Of Exhaust Valves 1978 SC 3.0L

[Philbey]

Hi there all,

I pulled the headers off my SC motor and noticed white deposits in most of the exhuast ports. There was also some buildup on the back of the valves. Take a look at the pics.

Anyone have any idea what this might be? I've never seen it before, but i assume it's something to do with lean burning, similar to tuning by sparkplug colour.

To add to this, my motor still had the air pump piping fitted, but no smog pump. Piping was capped where it passes into the engine compartment but not that well. I've since plugged the ports as you can see. I wonder whether this may have something to do with it?

also I've been running a valve seat recession fluid in the fuel, otherwise all fuel I run is 98Ron.

[James Brown]

If it were the good old days of leaded fuel I would say it was running great. But might be a little lean on unleaded fuel. So, what fuel in Australia? What is valve recession fluid? my guess it's full of lead. That lubricates valves and seats.

[D911SC]

Originally Posted by James Brown

If it were the good old days of leaded fuel I would say it was running great. But might be a little lean on unleaded fuel. So, what fuel in Australia? What is valve recession fluid? my guess it's full of lead. That lubricates valves and seats.

When you fill up here (Aus) you can buy a lead replacement additive since leaded fuels and lead replacement fuels are no longer available. Leaded fuel was phased out around 2000 and LRP fuels around 2004.

Most pre 1986 cars will run fine without a AVSR (Anti Valve Seat Recession) additive, although the disclaimers always point you to the manufacturer for their official comments. I use just 98RON on my 83SC on the advice that I don't need an additive for normal street driving.

Sorry Philbey - can only answer James's question, not yours.

[James Brown]

Im sure your engine will run fine without the lead additive. It will turn a dull black in no time.