You guys ever seen this? I got this 78 351M idling good and running relatively smooth, but as soon as I put it in gear (manual transmission) it runs like junk and bucks like, well, like a Bronco. It then runs like absolute **** until it has had an opportunity to sit and cool down. Any ideas? Vacuum leak? Bad timing? ****ty 2 barrel Autolite carb? It's a Ford? Your help is greatly appreciated as at this point I'm planning on taking it to the local mechanic and hang my head in shame.
Yes..........sounds like theres a problem...........probably gas..........water in gas.......if it idles smooth........everything is functioning as it should at low speed............... 2. next check would be timing..... 3. make sure the valves aren't too tight........ 4. and yes.............check that carb.......... Take your time.........do it one at a time........it should show itself farely fast.......
Fresh gas yesterday (delivered by an outboard tank I rigged up. Fresh fuel filter. Timing was set about 15 degrees above stock setting (CHiltons says correct timing for that is 8* BTDC and it's on the money) Replaced bent pushrod and lifter couple days ago and torqued all rockers down to factory specs.. wailed on the valve with a hammer to make sure it wasn't stuck. Ran a can of SeaFoam through it and it ran BEAUTIFULLY for about 20 minutes until I put it in gear. Changed the oil to get the seafoam out. Fiddled with idle to just get it to stay running...
OK................. 1. check and make sure you got a blue spark........if not.....fix.......... 2. Check and make sure you got good compression on all cylinders........ 3. If all the valves are doing their jobs.....you got compression and spark.......only other thing is the carb................
Oh.....before I forget.....if your doing the colum shift......make sure when your shifting.....your not pinching any wires.......like the ign. wire or wire erom the ign. switch..........that would cause a cutout when going into gear.......... Isolate the systems........then isolate them to when the problen is occurring............. if its fine idling.........see what NOT makes it fine when you put it into gear........like sloppy motormounts letting torque movement pull on wires..........or.......... A bare wire down by your starter touches your headers when you go into gear..... You gotta check all those kinda things when your a hot riddin'!!!!Ha!
Does the idle return to normal when you take it out of gear?? You said you just replaced lifters, did you run a compression check after?? I would also go back and check the torque on everything again
Does not return to idle after back in gear. I just replaced the one lifter that had bounced out (long story) and pushrod on the oce cylinder.
I chased a problem around like this for a long time. I ruled out vacuum leaks and bad fuel. I even changed the cam... same ****. The problem wound up being the timing. The balancer had spun a few degrees, and when I would set initial timing, I simply use the mark for reference. However, when I pulled the plug in #1 and manually felt for TDC, the mark was about 20 degrees retarded. I set that to 0 degrees, advanced it from there and that was about 10,000 miles ago. Even 20 degrees retarded, the engine would fire and idle, but once in gear, would stumble, buck and pop to the point of stalling.
the reason I ask is bent or chipped valve/s can cause this type of problem and what Joe said is a great idea as well.. manually check the timing
The Jalopy Journal
