burnt valve

[VNexecutive]

hey everyone..

im looking at a vk with a 308 and when its idling it "puts" occasionally.

i was with 'xcop5l' at the time and he said it could mean it has a burnt valve.

how much work does it take to fix if it is that..?

thanks all.

[Boonz]

the manifold off, heads off, valve springs off, valves out,check valve guides,new seat grind, new valves in and springs back on, heads back on, manifold back on... few hundred bucks in parts and a bit in labour

[Not_An_Abba_Fan]

If it "puts" occasionally it wouldn't be a burnt valve. It would "put" constantly in time with the cylinder that had the burnt valve. An occasional miss at idle is perfectly normal on a carby car, there is never a perfect distribution of air/fuel vapour into all cylinders at idle. At worst, it would be electrical, maybe a dodgy plug or a crook distributor cap.

[xcop5l]

ok this vk has been running on lpg for a long time and as you should know lpg burns valves. it was a more than ocasional but not constant. if its a partial burnt valve it will put occasionaly because the valve turnsas its poened and closed

[cruzncommo]

my V6 has burnt valves =[ will it matter if i just leave it?

[Not_An_Abba_Fan]

Yes it will. The cylinders that have the burnt valves will be low on compression, and when firing, the combustion blows back into the ports if it is an inlet valve. It will be using more fuel, be down on power and worse case scenario, the cylinders will not be firing so the unburnt fuel will go past the pistons and into the sump.

[Pub247]

You should go get a compression test or a leak down test done on it. This will give you idea of how bad it could be

[cruzncommo]

its bad enough too head it quite clearly in the idle =[ sounds like only 1 cylinder is tho

[Tree cutter]

I would say it is either a crook spark plug or lead or the idle mixture is not set correctly. A simple check with a vaccum guage will tell you if it has a burnt valve or not.