55 Fargo Posted July 30, 2009 Report Posted July 30, 2009 Here is a the engine internal green horn:eek: ? of the day. What exactly is a burnt exhaust valve:o? Is it the valve and seat burnt to not allow a good contact and seal? What are the symptoms:confused:? What are some causality:confused: Is there any snake oil for sticking valves, to add to gas or oil:D? Just pondering this, I have something going on in my engine, when at an idle when warm, she misses a bit, but runs well other wise, the miss sound come from the exhaust, and is not noticeable at the engine.....Fred Quote
Plymouthy Adams Posted July 30, 2009 Report Posted July 30, 2009 the majority of bad exhaust valves I have seen in these engines are coming from the rebuilder where they grind the exhaust valve face without regard to retaining enough margin on the valve edge to displace heat..the minimum specification are in the book...if marginal..for the few dollars they cost..they are cheap insurance... Quote
dezeldoc Posted July 30, 2009 Report Posted July 30, 2009 Good point tim, look at the one in the pic kinda thin on the edge. Quote
grey beard Posted August 1, 2009 Report Posted August 1, 2009 My engine had one low hole - 65 psi -and when I tore it down, I found it to be the very front exhaust velve in #1 cylinder. The guide was shot, but I was amazed to see that the valve itself was still okay. Had all the valves refaced and redid the seats, then knurled all the guides - except that one bad one that had to be replaced. Works fine now. Fred, the only way to know if valves are bad is a compression test. If you find low holes, squirt oil into those holes and check 'em again. If compression comes up, the cause is likely rings. If it stays the same - low - it is most probably the valves that are the cause. Check compression with all the plugs out, and a big screwdriver down the carburetor to keep both choke and throttle plates open. Give each cylinder the same number of compression strokes - you can hear them and count them as you do each cylinder. Write your readings down, and then tell us what you got, okay? Good luck Quote
Don Coatney Posted August 1, 2009 Report Posted August 1, 2009 Check compression with all the plugs out, and a big screwdriver down the carburetor to keep both choke and throttle plates open. This is not required. There are always 2 or more intake valves open and with the spark plugs removed there is no restriction at the carburetor. Quote
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