buring valves

How can intake and exhaust valves burn. And how would you know this of happening?

I'm saying this cause my buick 350 is really running like crap right now. i put on a new intake and a 600cfm carb and when I had on the 2bbl it seemed faster. But really the new setup is faster just less torque. Also my timming keeps on jumping. Which is kind of pissing me off. So In goes a new cam and a new EFI ignition. Also Dual exhaust and maybe 3.55 rear gears with a 200r4. Than maybe the grandma car will have a more umph. Also what year was the first 200r4 installed in any car. I went to autozone and they sayed they want 1100 for a 200r4 out of a grand national. Thanks for any help

Brett

 

Brett,
You might want to check out your timing chain. If your timing is jumping around then it might be your timing chain is stretched out

Rob

 

that or the plastic teeth,if its the original, are starting to work their way south.

as far as the valves its not that hard to tell. the car will start missing BAD. if it's an exhaust valve it'll miss throught the exhaust. if it's an intake it'll pop through the carb. one way that i know of checking is to pull the wires one at a time, while running, at the cap. if the hole is firing it will go to a dead miss and pick up as soon as you put the wire back on the cap. if you pull a wire and there is no change in the sound of the engine,note it and move on to the next hole. when you have narrowed it down to say number 6, start checking the simple things first,plug, wire,etc.if that doesn't clear it up you may want to check into the valves. oh yea and be ready when you start pulling the wires like this cause your gonna get "hit". i do everytime,:af: at least. no big heart stopping bite but it will get your attention,,,:grin:

sounds like an ignition thing to me might wanna start there and see what you can find.

later..............................

 

listen too the advice about the teeth on the original timing set when i pulled the oil pan because my distributer and cam wasnt turning the first thing i see is the chain off the cam gear and when we pulled the pick up tube there were more teeth in it than at a tooth pullin contest at a dental school.

 

do a compression check, if one cylinder is really low, it could be a burned valve. I had a burned valve on my old 77 dodge aspen, slant six motor. if i gave it WOT from idle it would hesitate really really bad. Compression check showed all cylinders at about 125 psi, except for one that was at 75. A leakdown test will narrow it down exactly. I was lucky enough to have a spare head lying around, so I took one of it's valves. The reason I had burned a valve, was I had like a bazillion vacuum leaks, and it was running really lean, which creates very high combustion chamber temperatures, which is what burns valve.