86 C10 Loping

[Like]l[A]l[Rock]

Hey just joined the site, I have a 86 c10 with a crate 350, it runs and drives ok but it lopes at idle and I have to adjust the carb and distributer frequently, I was curious if the timing chaing could be off? Any help would be appreciated.

[Irish_Alley]

is your distributor bolt and clamp tight? there's only so far you can move your distributor before the plug wires hold it back, are you verifying your timing with a light

[Like]l[A]l[Rock]

I hvnt even messed with the chain yet I wanted to verify that was the problem before I did anything, but Ill give the the distributer a look, but even with the the di and carb adjusted properly it still lopes.

[Irish_Alley]

if your chain was kept going off you wouldnt be able to adjust the timing to stay running by the distributor. something is moving and you seam to be fixing it by moving the distributor.

[bd]

Hey just joined the site, I have a 86 c10 with a crate 350, it runs and drives ok but it lopes at idle and I have to adjust the carb and distributer frequently, I was curious if the timing chaing could be off? Any help would be appreciated.

Remove the distributor cap and crank the engine until the rotor approaches #1 cylinder.  Rotate the engine in one direction by hand until the 0 degree timing marks are aligned.  While watching the rotor, rotate the engine in the opposite direction until the rotor just barely starts to move.  Measure the separation between the 0 timing marks (approximately every 0.1" relates to ~2 degrees).  This reflects the slop in your timing chain.  Conservatively, if slop is ~0.4" or more (8+ deg) the timing chain has outlived its service life.

Did the 'lope' just start?  Running rich will also cause a lope at idle, as will valve overlap.

[Stewart G Griffin]

Unfortunately, a worn cam could also cause a lope.

[Like]l[A]l[Rock]

Ok, because it starts and runs fine without adjusting the carb or distributor, it runs better after the adjustment but still lopes

[Irish_Alley]

so your saying it gets worse the warmer it gets?

[Like]l[A]l[Rock]

It runs the same cold or hot, im not really worried about the carb or distributor its the loping im curious about

[bd]

It runs the same cold or hot, im not really worried about the carb or distributor its the loping im curious about

     What if the lope is caused by excessive fuel delivery?  Are you still not interested in the carb?


To check the timing chain...

Remove the distributor cap and crank the engine until the rotor approaches #1 cylinder.  Rotate the engine in one direction by hand until the 0 degree timing marks are aligned.  While watching the rotor, rotate the engine in the opposite direction until the rotor just barely starts to move.  Measure the separation between the 0 timing marks (approximately every 0.1" relates to ~2 degrees).  This reflects the slop in your timing chain.  Conservatively, if slop is ~0.4" or more (8+ deg) the timing chain has outlived its service life.

[Like]l[A]l[Rock]

Im checking the timing chain on the morrow ill let you guys know what the deal is

[Irish_Alley]

loping can come from timing being retarded. your timing is adjusted byu the distributor, loping can also be caused by like bd stated excessive fuel. just trying to narrow the choices of what the problem could be. and if you have to keep adjusting the distributor and carb to compensate for a lope than means the problem keeps occurring. and as far as i know, if you chain stretches ifs not going to keep on stretching causing you to readjust the carb/dist. if you jump the chain same deal if you keep jumping no matter how much you adjust the distributor your going to run out of adjustment in a couple inches

[bake74]

      Like]l[A]l[Rock, here is a couple of things to consider that the guys were trying to tell you.  You asked about loping at idle.  Everyone here has been trying to give you things to check and the symptoms that will occur with the given problem.
     To diagnose and eliminate problems, 1st check your timing and make sure it is correct, if not correct it.  Use a paint pen and mark your distributor base and where it mounts so you can see if it moves in the future.
     Then use the procedure that bd suggested on checking your timing chain for slop/looseness.  If both of these check out then then also as bd suggested, you could be getting to rich a mixture from your carburetor, which in turn you will need to adjust your carb. or rebuild.
     I can not help after reading this whole thread that you might be hoping it is something simple, it does not seem in this case it is. 

[Hinkv10]

Not much to add but to reiterate what others have said. Check your timing and for chain stretch/slop. I play around with mine and if I retard the timing the Rpms drop and I get that cool loping sound. I learned this by playing around. It sounds cool but has much less power. I also upgraded my distributor and advanced the timing which improved power and throttle response further. Check the basics first and then report back.

[greasemonkey54]

vacuum leaks can cause a lope as well