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| | | | Joined: Feb 2011 Posts: 7 New Guy | | New Guy Joined: Feb 2011 Posts: 7 | Good afternoon all. I'm having trouble with my 250. It was running well a week ago, now it won't start. It cranks, but won't fire. It has spark and plenty of gas. A few things that I noticed was that air is puffing out of the carburetor. I suspect the cam has jumped a tooth or two, but is that even possible with these engines? The ignition rotor does not point at the #1 terminal when the motor is at TDC. It is closer to the #4 terminal. Compression is all over the place from 30 psi to 80 psi. Is there anything else it could be besides the cam being out of time with the crank? | | | | | Joined: Jun 2004 Posts: 8,597 Riding in the Passing Lane | | Riding in the Passing Lane Joined: Jun 2004 Posts: 8,597 | That sounds like the problem but it is rare on that engine. They dont use achain but the 250 comes out with a fibre cam gear. Take the valve cover off & check the location of the valves when at TDC. When you are at TDC the valves on #6 Or #1 should be overlapping. Like the exhaust closeing & the intake opening. If that is correct then your dist. has jumped time.
They say money can't buy happiness. It can buy old Chevy trucks though. Same thing. 1972 Chevy c10 Cheyenne SuperIn the Gallery Forum | | | | | Joined: Feb 2011 Posts: 7 New Guy | | New Guy Joined: Feb 2011 Posts: 7 | Yeah, I remember that about the 250's. I forgot. Thatnks for reminding me. I will take the front cover off and have a look. I will report back. Thanks again! | | | | | Joined: Feb 2011 Posts: 7 New Guy | | New Guy Joined: Feb 2011 Posts: 7 | The cam gear is aluminum. It's in perfect condition and in time. I will take the valve cover off tonight just to see if there is anything fishy. After that, I guess I should be preparing for a rebuild??? The motor smokes when warm and there is a good bit of blow by. I suspect the rings are bad and that's why I have low compression. That would definately make it not start, but it's weird that it was running a week ago. Any other suggestions? | | | | | Joined: Jun 2010 Posts: 188 Shop Shark | | Shop Shark Joined: Jun 2010 Posts: 188 | Put the timing mark at zero, take the distributor cap off, turn the dizzy to line up rotor tip on #1. Should be easy to turn the dizzy cause I suspect your hold down bolt has loosened. I had the same problem. Timing kept changing till I figured out the clamp with the bolt going thru it was on wrong. | | | | | Joined: Feb 2011 Posts: 7 New Guy | | New Guy Joined: Feb 2011 Posts: 7 | Thanks, I got it running. The ignition timing was off. I haven't a clue how that happened, but it's running good. Thanks for all the help.
Last edited by stealth908; 05/05/2011 5:49 PM.
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