Posted by oscar on Saturday, August 10, 2002 at 4:07PM :
In Reply to: Just when I get it running, stuck valves!! Need help! posted by Drew M. on Saturday, August 10, 2002 at 2:32PM :
Whoa....
Before you punch out those valve guides and lape/grind the valves.... Try and get those valves unstuck. Get some wd40 - or liquid wrench. Yes - pull the head. Oil the guides and valve stem well, GENTLY tap on the valve with a SMALL plastic/brass hammer - repeat every 10 minutes or so for 4 hours or so. Make sure the cam lobes are down so the valve can move. The valve/guide is probably filled with carbon. You can also use a pair of vise-grips to GENTLY turn the valve so the liquid wrench can work down into the valve guide. Once you get the valve free you can remove it and clean the carbon out of the guide or replace it without taking as much risk of damaging the block.
We would measure the guide hole in the block and size the guide to a specific oversize using a lathe,. Then we would freeze (in dry ice) the guide and heat block (300 F) before inserting the guide. Then the guide stayed put. After inserting the guide you should ream it to the correct guide to valve stem clearance.Machining in a guide produces metal chips you'll need to keep out of the oil pan.
A stuck valve is not a major deal but Dad would pull the engine and do a full overhaul if the valves started to hang up.
If you just work the valve loose and then clean out the carbon out of the valves the engine may smoke a bit but you can put off tearing the whole engine down. Gun bore brushes work well as guide cleaners.
Remember the valve may be mushroomed a bit on the stem end so you may need to file the valve stem end a bit to remove the valve from the guide.
Good luck
Oscar
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