On a '79 cj5 with a 258 do I have to double check that when #1 is tdc the timing markers are on zero degrees or is there no chance that it can be 'off' ?
If so, what is the best way to set #1 TDC and check it is (without taking the head of)
Well, when I shut the engine off sometimes it will just rotate another few revolutions with what it seems fuel igniting. Also there is a chance that fuel mixture is blown into the exhaust and ignites there (causing a loud bang) The engine is not pinging I think. Uhm, No EGR anymore.
The "old de-carbon the cylinders trick".. wel.. when we took that
258 aparrt to put a 4.0 head on, we didn't see any carbon. So no sense in doing the "old de-carbon the cylinders trick", right?
I want to see and check if my engine is running right.
First thing I wanted to check is to see if the ignition timing is correct. (I do realize though, that with the 4.0 head, headers, different intake and carb, the timing setting might need to be different than stock.
After I figured out timing I want to check and see if it is idling ok and not running too lean or rich.
Ron
urned off =A0has nothing to do with ignition timing, since the plugs are no= longer firing. If the engine was "pinging" on acceleration or part throttl= e cruise, then I would look at the timing or EGR if so equipped. =A0
ater down the carb when the engine is at about 3000 rpm and see if that hel= ps. lets us know what you figure out. Good luck
Idle is definitely too high. Fast idle is about right (according to Haynes/Clifford) but curb idle is way too high, just a few rpms lower than fast idle.
However, I noticed that the hot wire for the choke never had any power because of a blown fuse. that might make a difference. (Although I believe that when you hit the accelerator the choke should fully open, on a Holley 390?)
Fast idle is about right (1500-1600 rpms). Now I'm going to try to get curb idle around 700 rpm.
After I have those two right I want to get the advance(s) right
curb idle timing advance I can set moving the distributor around.
I have the crane vacuum advance on the HEI distributor,to get the timing advance correct at higher rpms than curb idle one has to tinker with the advance weight springs and the adjustable vacuum advance. right?
I'm all for keeping it simple too
is not caused by the spark plugs firing. For some reason, you have hot spo= ts that are igniting the fuel mixture after the key is turned off. Electron= ic fuel injected engines don't due this because the injectors stop spurting= fuel once the key is turned off, but a carbureted engine is still getting = fuel sucked into the cylinders. Make sure the idle is not set to high, as t= his lets in more fuel/air mixture than you want, and can contribute to "die= seling" when the key is off.
eading correct TDC, I would use a dial indicator in the spark plug hole of = # 1 cylinder to find the exact TDC of the piston and then see if the crank = pulley is indicating TDC or zero. BTW, when someone says 38 degrees timing,= they are talking about total timing advance, not timing (reading) at idle = or 1500 RPMs.
y is to put the jeep on a dyno-smog machine and read the 5 gases coming out= of the tail pipe under load as well as idle. Short of that, drive the jeep= for a couple of days, then pull out a couple of spark plugs and see if the= y are carbon fouled (too rich), nice brown/tan (normal-OK), or white cooked= (lean). Just like checking an old dirt bike after a carb or jet change, sa= me principle. Try to keep things simple...the same thing that makes a model= "A" run, makes a brand new Corvette run. Just different (better) delivery = and control methods. =A0 =A0
turned off has nothing to do with ignition timing, since the plugs are no = longer firing. If the engine was "pinging" on acceleration or part throttle= cruise, then I would look at the timing or EGR if so equipped.
water down the carb when the engine is at about 3000 rpm and see if that h= elps. lets us know what you figure out. Good luck
the choke never opened because of a short with the electric wire that powers the electric choke. I think it caused curb idle to be really high and also, after shutting down, fuel mixture to ignite in the exhaust header.
I have to play with the choke 'timing' a little because it stays on a bit too long.
Other than that it seems to be running fine
btw: why is the timing slightly different for a jeep with an automatic vs manual transmission ? Is that because the torque converter causes somewhat of a load ? I'd rather expect a bit higher curb idle than a different ignition timing.
is not caused by the spark plugs firing. For some reason, you have hot spo= ts that are igniting the fuel mixture after the key is turned off. Electron= ic fuel injected engines don't due this because the injectors stop spurting= fuel once the key is turned off, but a carbureted engine is still getting = fuel sucked into the cylinders. Make sure the idle is not set to high, as t= his lets in more fuel/air mixture than you want, and can contribute to "die= seling" when the key is off.
eading correct TDC, I would use a dial indicator in the spark plug hole of = # 1 cylinder to find the exact TDC of the piston and then see if the crank = pulley is indicating TDC or zero. BTW, when someone says 38 degrees timing,= they are talking about total timing advance, not timing (reading) at idle = or 1500 RPMs.
y is to put the jeep on a dyno-smog machine and read the 5 gases coming out= of the tail pipe under load as well as idle. Short of that, drive the jeep= for a couple of days, then pull out a couple of spark plugs and see if the= y are carbon fouled (too rich), nice brown/tan (normal-OK), or white cooked= (lean). Just like checking an old dirt bike after a carb or jet change, sa= me principle. Try to keep things simple...the same thing that makes a model= "A" run, makes a brand new Corvette run. Just different (better) delivery = and control methods. =A0 =A0
turned off has nothing to do with ignition timing, since the plugs are no = longer firing. If the engine was "pinging" on acceleration or part throttle= cruise, then I would look at the timing or EGR if so equipped.
water down the carb when the engine is at about 3000 rpm and see if that h= elps. lets us know what you figure out. Good luck
Change your oil. A choke that never opens can suck enough gas out of the carb to wash raw gas right past the rings and into the crankcase. I had a Malibu with the V6 in it that did that to me. I only noticed the problem when the level on the dipstick started to _rise_.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.