Kagnew66 15 #1 Posted August 14, 2018 All cleaned up. Painted. Ready to start. So I thought I would pour a little MM oil in the cylinder, while I installed the new carb, points and condenser. Well, the engine turns over, has compression, but the piston isn't moving. What am I missing here? I'm a greenhorn, but I thought you should see the piston moving up and down when you turned the crankshaft. Thanks for all the help you can give me. Share this post Link to post Share on other sites
Ed Kennell 35,809 #2 Posted August 14, 2018 What makes you think the piston isn't moving? Share this post Link to post Share on other sites
Kagnew66 15 #3 Posted August 14, 2018 I couldn't see any movement, so I inserted a chop stick and put a mark on it. The compression seem good though, blew out a foam plug I had put in the intake for painting. Share this post Link to post Share on other sites
JAinVA 4,619 #4 Posted August 14, 2018 (edited) I'm with Ed.You can't have compression unless the piston is moving.With the engine buttoned up there is almost no way to see piston movement.Pull the sparkplug and crank the engine.You should feel air coming from the plug hole in the head. Edited August 14, 2018 by JAinVA Share this post Link to post Share on other sites
Kagnew66 15 #5 Posted August 14, 2018 Well, that's pretty much the definition of a mystery. I am looking at the top of the piston, when I remove the plug on a 161, correct? Share this post Link to post Share on other sites
JAinVA 4,619 #6 Posted August 14, 2018 (edited) It depends on the head.Some heads have the spark plug over the valve area.Looking down the plug hole you may not see any motion at all,except maybe a valve.Crank the engine over with the plug out.If air comes out the plug hole then the piston is going up and down.Mystery solved! Edited August 14, 2018 by JAinVA 2 Share this post Link to post Share on other sites
Kagnew66 15 #7 Posted August 14, 2018 Sounds good to me. I don't see anything moving in the plug hole. I know the valve is moving. I can feel that through the intake. I'm going to try my loupe tomorrow and continue assembling. Thank you guys for the help. Share this post Link to post Share on other sites
SPINJIM 1,978 #8 Posted August 14, 2018 When you look into the spark plug hole, you're NOT looking at the piston. You're seeing the space between the valves and the cylinder. It's a small area, but that's where the fuel and air meet the spark. The spark plug is not immediately above the piston like on car engines. If you have compression, the piston has to be moving. Jim 3 1 Share this post Link to post Share on other sites
Kagnew66 15 #9 Posted August 14, 2018 Thanks, Jim. I've learned something. That's why I love this group. 2 Share this post Link to post Share on other sites
Ed Kennell 35,809 #10 Posted August 14, 2018 Like Jim said, the spark plug hole is not over the piston. 1 2 Share this post Link to post Share on other sites
Kagnew66 15 #11 Posted August 15, 2018 Thanks. I'll go back to work on it and let you know if it runs. Next project is a Wisconsin, that came with a customized Suburban. I know I'll need help with that. Share this post Link to post Share on other sites