Cylinder has spark but not firing..

[no poseur]

I meant visibly... Will you be able to see the lifter compressed all the way.

if you pull the intake, since you have this with 2 different heads, I'd say your either looking at weak lifters or wiped lobes, pull the intake and spin the engine and watch the lifters and valves on the bad cylinders.

 

[Inertia]

I meant visibly... Will you be able to see the lifter compressed all the way.

prob not without the intake off..

Just loosen the bolts and start it,, if it runs better,, but not best,, loosen a couple of the next bolts a bit.. don't do this for very long, as oil will be flowing from the loosened bolts..

then you'll know the valves are/aren't closing sufficiently.. and spacers are/aren't in order..

It's an orderly process of elimination,, and relying on YOU to report accurately.. not just what you feel like doing, or guessing that this is so, or that should be okay..


hope it helps

 

[duey_roc]

prob not without the intake off..

Just loosen the bolts and start it,, if it runs better,, but not best,, loosen a couple of the next bolts a bit.. don't do this for very long, as oil will be flowing from the loosened bolts..

then you'll know the valves are/aren't closing sufficiently.. and spacers are/aren't in order..

It's an orderly process of elimination,, and relying on YOU to report accurately.. not just what you feel like doing, or guessing that this is so, or that should be okay..


hope it helps

It does very much so! thanks il give it a shot tomorrow and reply with what my outcome was.

 

[Cudafever]

Hahaha! I justmcaught that lol.:cheers: Yea ill give it a shot man. I'm not saying that's NOT the problem. I just thought that MIXING (lol) the pushrods around would put the misfire in another cylinder. That's what my buddy thought it was. He thought i had a slightly larger pushrod in one valve. But I'll definitely check that! Would it be noticeable if the lifter was compressed all the way? I'm just curious. :newb:

It would be difficult to see with out the intake off. I'm not saying take the intake off! try the bolt trick first!

 

[gliderider06]

You don't need to pull the intake off to see if the valves are opening. You can see if they are just by pulling the valve covers off and spinning the motor over and see if they move. You sure that the cam is not wiped out??? You did say that you had solid lifters on hyd cam or vise versa. I can't remember with the 100+ posts giving the same suggestions on what to check.

 

[Cudafever]

Glider, were talking about how far the push rod is sinking into the "Hyd" lifter body.

 

[/6 Matt]

Could it possibly have to do with him running hydraulic lifters on a mechanical cam and the ramp speed not pumping the lifters up?

Duey_roc, don't use the above question a reason to swap cams or lifters!ops: Unless somne comfirms its a possibility anyways.

 

[duey_roc]

Could it possibly have to do with him running hydraulic lifters on a mechanical cam and the ramp speed not pumping the lifters up?

Duey_roc, don't use the above question a reason to swap cams or lifters!ops: Unless somne comfirms its a possibility anyways.

lol cmooooon :cheers: No its a complete hydraulic setup in the engine right now. When i first got the motor, i put a solid cam in with the hydraulic setup just to see what would happen. It actually worked, but i was having this misfire issue so i went back to all hydraulic thinking that could have been one of the causes. :wack:

 

[magnumdart]

Just wondering if you changed out the distributor like you said you were gonna do, and what the result was. I'm thinking the shaft is bent, after all the dismantles and re-assemblies. If you keep loosening this, and switching that you will soon forget what you have done, and you will be on dis-assembly number four, to get it all back together right. I messed with my brothers Demon forever doing all the same things over and over again, thinking I was having a stupid attack. Then I walked over to my 'Cuda twenty feet away, removed the dizzy and popped it in the Demon. Started instantly and ran perfect.

 

[demoman3955]

got a new distributor that was good for a week, then it quit. turned out to be the condenser. I never would have guessed it. look for simple first.

 

[Cudafever]

Pushrods are all straight. Ill have to check the lobes on the cam. It is the original cam i know. I did check it briefly when the motor was apart but i didnt really mic it up and stuff. Wat about that distributor gear? what if when i pulled the cam out it rotated just slightly... wouldnt that affect the timing slightly?

Good GAWD. One step at a time. Compression seems fine. Do you have a volt ohm meter? Measure the resistance of the two wires on the skipping cylinders and see how they compare to the rest. They will be different because of the difference in length, but if they are stupid different then you have plug wire issues. Lets rule the simple stuff out first.

Just thought id throw this in there too... I have points on this motor. Would this matter?

Even if the motor came factory with electronic?

Nope that's pretty much it man lol. I got the motor from a 78 Cordoba. The previous owner of the barracuda put a new points style distributor in it with new points cap and rotor. I'm converting to electronic tomorrow to see what happens. I planned on doing it anyways I guess now would be a good time

And yes I've had this motor apart in 3 different situations. It's been kind of an experiment just to see out of curiosity. For example I wanted to know what would happen if you ran a solid cam on a hydraulic lifter. It actually worked but decided to switch to a stock cam. I've had the heads redone so I pulled the old heads and put the j heads on. I've had to take the intake off twice alone because of vacuum leaks. Then i tried running the motor with the stock 318 torque converter. That doesn't work because the 360 is externally balanced and I didn't have weights on the converter. So now I'm at this and I'm still learning. I've just never had this problem before. Gonna try converting to electronic ignition tomorrow and see what happens

You did not happen to leave rags or paper towels in the ports when putting it back together?

What is the resistance of the #2 and #8 plug wires?
Check the simple stuff first.

It is possible to have a plug wire that won't fire a spark plug under compression if it has too much resistance but you can still get a shock off it.

Ill give it a shot man thanks! I dont think its a machining issue though because ive had 2 different heads on the motor and am having the same issue in both head sets. The only thing i havent actually fully played with is the intake.

Actually, now that i think about it, thats not it lol. I purposely mied the pushrods and lifters around in the engine too. (i know thats not recommended) I still had the same issue. Same 2 cylinders acting funny... Crazy lol

lol cmooooon :cheers: No its a complete hydraulic setup in the engine right now. When i first got the motor, i put a solid cam in with the hydraulic setup just to see what would happen. It actually worked, but i was having this misfire issue so i went back to all hydraulic thinking that could have been one of the causes. :wack:

OK here we go!

You said that you have tried 2 different heads and nothing changed
Probably not the head.

You did not answer this question
Originally Posted by gliderider06
You did not happen to leave rags or paper towels in the ports when putting it back together?

have you replace you distributor or is it still point type dist?????

Have you invested in a vacuum gauge, or volt ohm meter yet?
You should,.... A leak down test is a good idea, but i don't thing you will ever buy on.

now let start with the vac. gauge.
I'm trying to get you to loosen a couple of bolts(half a turn only!) to see if the push rod is two long and holding up the valve while running.
With a vac gauge you can check this with out pulling the valve cover.
It can also tell if you have a vac leak causing a cyl to drop or not fire.

buy on, and i will show you how to use it for this and may other things.

Now for the volt ohm meter, a spark will still jump or spark out side the motor. but when under compression, it WILL NOT. if the plug wire has to much Resistance, the voltage will not be high enough to to fire the spark plug inside of the motor.

Now here is some stuff that I'm not so clear about so PLEASE help me out

#1 You said that you tried a hyd lifter on a solid cam or was it a solid lifter on a hyd cam????

#2 You said that you have the stock cam back in it now with the stock lifters...........did you install new lifter on the old cam or the original lifter back in the block

Now that i have side all of this: it will still cost you 0 dollars to pull the valve cover and loosen the back rocker shaft bolt on passenger side and front rocker arm shaft bolt on drivers side.

And just in case you didn't click on the link provide you.
I thing its is of value


Odd driver side, even passenger side. Attached Images

Happy holidays!!

 

[Woods74]

Merry Christmas!

 

[teringer]

I,m new here so I got to get my 2 cents in sometime to. nice to meet so many people that have real experience working on mopars. you said you used a ld4b intake with 360 j heads, what intake gaskets are you using? the smaller intake ports on the ld4b can leak on some combinations ,are you using good aftermarket gaskets, fel/pro ect. not the metal ones. also I agree with the leak down should be done. the only thing cyl.4/8 have in common is the pos on the dist cap. and dist cam that opens the points, also is this miss only at idle or high speed. does the engine shake at idle ,does it smooth out when a cylinder is canceled,?

 

[gliderider06]

I really don't think the OP is listening to what is being told to him, for what to check. Pull the VC off rotate the motor and see if both intake and exhaust valves move. if they do, losen the shafts and see if it runs. If it does you will need to shim the shafts as told many posts ago. If the rockers do not move as much as the others on the head I would suspect a wiped cam, especially if you keep changing things around that do not work properly together.
Are the plugs on the cylinders in question oily? If you think the intake is cracked on the underside of it, while running it will also pull oil into the cyl.
You are making this much harder than it really is, to fix this car.

 

[Bad Sport]

I really don't think the OP is listening to what is being told to him, for what to check.

I get that impression too. Bouncing around too much instead of focusing on one step at a time.

 

[duey_roc]

I really don't think the OP is listening to what is being told to him, for what to check. Pull the VC off rotate the motor and see if both intake and exhaust valves move. if they do, losen the shafts and see if it runs. If it does you will need to shim the shafts as told many posts ago. If the rockers do not move as much as the others on the head I would suspect a wiped cam, especially if you keep changing things around that do not work properly together.
Are the plugs on the cylinders in question oily? If you think the intake is cracked on the underside of it, while running it will also pull oil into the cyl.
You are making this much harder than it really is, to fix this car.

Yes i did this today. I pulled the valve covers and rotated the motor to see if ALL the valves open and close. They are opening and closing. Then i loosened the rocker arm assembly slightly and still had the same issue. No difference in those 2 cylinders. Those two spark plugs are oily as well i noticed today as well.

 

[duey_roc]

OK here we go!

You said that you have tried 2 different heads and nothing changed
Probably not the head.

You did not answer this question
Originally Posted by gliderider06
You did not happen to leave rags or paper towels in the ports when putting it back together?

have you replace you distributor or is it still point type dist?????

Have you invested in a vacuum gauge, or volt ohm meter yet?
You should,.... A leak down test is a good idea, but i don't thing you will ever buy on.

now let start with the vac. gauge.
I'm trying to get you to loosen a couple of bolts(half a turn only!) to see if the push rod is two long and holding up the valve while running.
With a vac gauge you can check this with out pulling the valve cover.
It can also tell if you have a vac leak causing a cyl to drop or not fire.

buy on, and i will show you how to use it for this and may other things.

Now for the volt ohm meter, a spark will still jump or spark out side the motor. but when under compression, it WILL NOT. if the plug wire has to much Resistance, the voltage will not be high enough to to fire the spark plug inside of the motor.

Now here is some stuff that I'm not so clear about so PLEASE help me out

#1 You said that you tried a hyd lifter on a solid cam or was it a solid lifter on a hyd cam????

#2 You said that you have the stock cam back in it now with the stock lifters...........did you install new lifter on the old cam or the original lifter back in the block

Now that i have side all of this: it will still cost you 0 dollars to pull the valve cover and loosen the back rocker shaft bolt on passenger side and front rocker arm shaft bolt on drivers side.

And just in case you didn't click on the link provide you.
I thing its is of value


Odd driver side, even passenger side. Attached Images

Happy holidays!!

Ok i see i missed a lot of questions here lol. No there is no rags left anywhere... I am using the original points and condensor, however they are new. New as in a new points style distributor, cap rotor, points, condensor, etc. I havent done the vacuum test because i dont have one yet lol. The auto shop is closed today for obvious reasons. I do have a voltmeter, but, in all honesty, im not sure how it works. :newb:

To your hydraulic question: I tried using a solid camshaft with hydraulic lifters.
And im using the original lifters on the original camshaft. Meaning, Im using the original hydraulic cam with the original hydraulic lifters now.

 

[duey_roc]

I,m new here so I got to get my 2 cents in sometime to. nice to meet so many people that have real experience working on mopars. you said you used a ld4b intake with 360 j heads, what intake gaskets are you using? the smaller intake ports on the ld4b can leak on some combinations ,are you using good aftermarket gaskets, fel/pro ect. not the metal ones. also I agree with the leak down should be done. the only thing cyl.4/8 have in common is the pos on the dist cap. and dist cam that opens the points, also is this miss only at idle or high speed. does the engine shake at idle ,does it smooth out when a cylinder is canceled,?

Yes the LD4B was made for the 273 and 318 intake size ports. Im using the blue Fel Pro gaskets. And the miss is constant. Its only running on 6 cylinders all the time. It feels that way anyways. I revved the motor to 3000 rpm and pulled both plug wires to those cylinders and i had no difference in performance.

 

[Cudafever]

Ok i see i missed a lot of questions here lol. No there is no rags left anywhere... I am using the original points and condensor, however they are new. New as in a new points style distributor, cap rotor, points, condensor, etc. I havent done the vacuum test because i dont have one yet lol. The auto shop is closed today for obvious reasons. I do have a voltmeter, but, in all honesty, im not sure how it works. :newb:

To your hydraulic question: I tried using a solid camshaft with hydraulic lifters.
And im using the original lifters on the original camshaft. Meaning, Im using the original hydraulic cam with the original hydraulic lifters now.

There is nothing Wrong with not knowing how to us something!:cheers:

You need to turn the meter to ohm and in some case you need to put the post lead into a different slot in the meter its self.

Then you remove the ign wires one at a time and put the red lead on one end and the black lead on the other end(dont' matter which way you do this
The meter will send a small voltage through the wire(ign wire) and will display how much Resistance, in ohms.

Snap a picture of your volt/ohms meter,and post it up, and i will help you out some more.

The test i ask you to do is BOGUS with a wet plug. get some fresh plug in #2 and #8 and test it again. If the plug is wet i will not fire, even if you close a valve and raised the compression.

now to your cam swap
Did the lifter go back into the same lifter bore or did thy just get installed randomly?

 

[Robbie2734]

Yes i did this today. I pulled the valve covers and rotated the motor to see if ALL the valves open and close. They are opening and closing. Then i loosened the rocker arm assembly slightly and still had the same issue. No difference in those 2 cylinders. Those two spark plugs are oily as well i noticed today as well.

Just another opinion, oil on the plugs is probably coming from the lifter gallery. I think your intake is sucking air from the lifter gallery.

 

[duey_roc]

Just another opinion, oil on the plugs is probably coming from the lifter gallery. I think your intake is sucking air from the lifter gallery.

That's my thinking. But I'm gonna go out and try the ohm reading and see what happens

Where do I touch both ends of the ohm meter?

 

[Bad Sport]

Where do I touch both ends of the ohm meter?

Undo each end of the plug wire, one at a time and one lead to one end and the other lead to the other end. Do that for each wire, all 8, and write down your readings. Specifically noting what you get on the two bad cylinders.

Just because you get a shock on a plug wire doesn't necessarily mean it's good.

 

[duey_roc]

Undo each end of the plug wire, one at a time and one lead to one end and the other lead to the other end.

Ok so for example i would do between the cap and the beginning of the plug wire. Then i would do both ends of the wire. And then i would do to the end of the wire to the spark plug. Correct? Just trying to make sure im understanding lol

 

[Bad Sport]

Ok so for example i would do between the cap and the beginning of the plug wire. Then i would do both ends of the wire. And then i would do to the end of the wire to the spark plug. Correct? Just trying to make sure im understanding lol

Unhook one wire at a time from the cap and the plug, hold one lead to one end of the wire, the other lead to the other end of the wire, write down the readings. Do this for all 8 wires. I'm curious what you get on the two bad cylinders. This is done without the engine running, all you are doing is checking resistance on each wire.

Check your coil wire too.

 

[duey_roc]

Unhook one wire at a time from the cap and the plug, hold one lead to one end of the wire, the other lead to the other end of the wire, write down the readings. Do this for all 8 wires. I'm curious what you get on the two bad cylinders. This is done without the engine running, all you are doing is checking resistance on each wire.

Check your coil wire too.

Oooooooooh gotcha. Ok hang on