I picked up a 1010 with a broken crank Purchased a used crank that was turned down 10 rebuilt the engine but I cannot time the engine with the existing marks. When I use the existing marks my exhaust valve opens on the compression stroke. When I use the marks I'm not at top dead center on the flywheel but it seems I am at the 26 degree used for ignition timing.
Any ideas??
valve timing on my 1010
Re: valve timing on my 1010
Are you talking about match marks on the crank and cam gears or external marks for timing? Are you assembling the engine and see the two don't match? I can't say for that engine, but the two sets do not always coincide. Were the cam and crank gear marks matched to gether when the crank or cam was installed?
A two-stroke engine compression stroke is every time the piston "goes up". On a four-stroke engine, like your 1010, the compression stroke is only every other time the piston goes up. A four-stroke piston "goes up" on the exhaust stroke just like it does on the compression stroke, except the exhaust valve is open to allow the burnt gases out of the cylinder. So having an exhaust valve open every other rotation of the crank is correct for a four-stroke engine. Your description sounds to me like the exhaust valve is opening on the exhaust stroke. Are both valves closed, if you rotate the crank a full rotation to the compression stroke? (Rotate the crank in the direction it turns when running as much as you can to keep the slack out of the gears as it would be in operation.)
Do you have the 1010 service manual and are you using it to guide you during this assembly?
A two-stroke engine compression stroke is every time the piston "goes up". On a four-stroke engine, like your 1010, the compression stroke is only every other time the piston goes up. A four-stroke piston "goes up" on the exhaust stroke just like it does on the compression stroke, except the exhaust valve is open to allow the burnt gases out of the cylinder. So having an exhaust valve open every other rotation of the crank is correct for a four-stroke engine. Your description sounds to me like the exhaust valve is opening on the exhaust stroke. Are both valves closed, if you rotate the crank a full rotation to the compression stroke? (Rotate the crank in the direction it turns when running as much as you can to keep the slack out of the gears as it would be in operation.)
Do you have the 1010 service manual and are you using it to guide you during this assembly?
Re: valve timing on my 1010
I do have a service manual and I am timing with the marks on the cam gear and the crank gear. The cam shaft and gear are original with this engine The crank is a replacement. When I time it using the marks on the two gears I get popping out the exhaust and the exhaust valve is opening too soon in my opinion. I am wondering if there was a change in crankshafts in the 1010 series and I have a different crank. Something isn't timing properly. I had the engine assembled and ready to run but it wouldn't start and the exhaust had a popping noise. I took the front cover off and the valve cover so I could watch the valves through the cycle. Soon after it crosses top dead center the exhaust valve is opening. I appreciate you time and energy in responding to my post. I'm just baffled!
Re: valve timing on my 1010
The parts catalog shows the cranks and cams were different for gas and diesel. By chance could the crank you got be for the wrong fuel? Did you compare the broken crank and the one you got, as well as look for casting numbers? It might be the keyway for the gear is in a slightly different location. Without going through every related part, it appears they used the same bearings and gear on both cranks.
Who is online
Users browsing this forum: No registered users and 77 guests