[updated:LAST EDITED ON Jan-15-06 AT 06:31 PM (CST)]ok guys (an gals) question for the real technically minded of you. brittish guy here with a '50' 3100 with a '55' 235 in it (or was in it) ive stripped the engine for inspection and she was running fine but im not sure about the exhaust valves. the engine seems to have had a bit of work done on it not so long ago, and over here in uk leaded gas is not available and additives are expensive, so im not sure if i should change the ex valves and seats for lead free ones. are there any tell tale signs that it has been done already? are the lead free valves markedly different? are they heavier or lighter? different shaped face? be a shame to invest in all that work for no reason, any ideas? ps, ordered bunch of stuff from chevy duty monday night 9-15pm uk time, on my doorstep thursday morning 10-30!!!!!!!!!!! i cant get deliveries as quick as that from suppliers in my own country!!!! cant tell you how impressed all of my friends and even my wife were. i was just blown away. thanx all at chevy duty. he may have made the earth and heavens in 7 days but it must have taken a little longer to make my truck! ________ Teen Girl
First off, I have to agree with the speed that CD delivers. I have actually had stuff delivered the next day! But I live considerably closer to KC than you. As for your problem, if you decide to do anything at all, it is change the valve seats, the valves themselves do not need to be changed. Not sure how you can tell if you already have hardened valve seats. But you really do not have a problem unless you are really working the truck, lots of (relatively) high speed driving, carrying large heavy loads, or maybe just long distances. Otherwise do not worry, you will have no problem. Lots of guys here in the states do not change out their valve seats, and we do not have leaded gas either. And additives are just wasted money. You cannot buy tetraethyl lead anymore. The usual wisdom is, if you are already doing a valve job for some other reason, go ahead and have the machinist change out the exhaust valve seats, but otherwise, no.
RE: lead free valves Not sure why you'd take apart a ' fine running ' engine but in any case . As long as it's apart I'd go ahead and have Stellite seats , stainless steel exhaust valves and all bronze valve guides installed , the labor isn't much but the parts are going to be a bit . These engine have been running just fine on unleaded fuel since we discontinued it 30 years ago but once the engine is open it's silly not to upgrade it , this way it'll never give you any troubles . For the rest of you reading this and wondering : DO NOT screw with it unless a valve seat receses , you'll know as the valve will go tight (zero clearance) and then close up again about 2,000 miles after you adjust it , after several adjustments there will be no more adjustment possible . BTW : for those who refuse to do routine valve adjustments , you'll know when the valves are tight by a persistant engine miss @ idle that shows up as the engine reaches operating temperature . If you do a valve adjustment you'll be pleasantly surprised by the improved idle and ease of starting , cold or hot , fuel economy increases to and no worries about burned valves as that is caused by lack of adjustment... -Nate
RE: lead free valves Thanx for the reply. reason i asked was the guy who sold the truck mentioned that 1 cylinder was down slightly on comp test and i discovered the head gasket was starting to blow into an oil gallery, and as im now doing a total rebuild on the truck i thought it wise to tear it down for the sake of a gasket set. tell me, i have been told that the original seats on the head were part of the casting and not inserts? and if it has seat inserts its been converted. he may have made the earth and heavens in 7 days but it must have taken a little longer to make my truck! ________ Threesome mwm
