start here going clockwise 1,8,4,3,6,5,7,2.
Cylinder has spark but not firing..
- Thread starter duey_roc
- Start date
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Two cylinders are not firing, so this is not an accurate statement.
foxmopar585
Well-Known Member
HOW are cylinder 3 and 5 the csrb one side gives gas to 2358 the other giv gas to1467 check carb.may be vac leek
Dartnut
Don't hate me because i'm beautiful
Change the intake and see what happens then.
Are the angles off on the heads or intake from being resurfaced?
Check that out, if wrong, it would result in a vacuum leak as well.
Are the angles off on the heads or intake from being resurfaced?
Check that out, if wrong, it would result in a vacuum leak as well.
duey_roc
Well-Known Member
No **** sherlock haha.:finga: My plan is to check the intake and see if this is the issue on my next day off. Like i said, i'm someone whose learning. I'm not a master at this, but im going off of what i have as symptoms.
What i meant by everything is working as it should be is I'm getting spark, i have compression, all wires are in firing order, carb is tuned to the best i could get it, and its timed as best as i could.
I've done my research and i've read that if i have compression, spark, air, and fuel but i have a misfire in one or more cylinders, chances are its a cracked intake manifold.
Yeah, I think Del had the right idea. Later dude.
Try this and it won't cost you a dine.....maybe a valve cover gasket if it gets damaged.
it will only take you 10 minutes and save you a set of intake gasket and a lot more then 10 minutes
loosen the right rear rocker shaft bolt, 1/2 of a turn.
Do the same to the left front rocker shaft bolt.
start it and see if them two cyl come to life. if they do you can buy some rocker pedistal shims and fix the problem or spend the $$ to buy some pushrods that or .020" shorter.
if neither cyl come to life, then take the intake off just to be sure.
it will only take you 10 minutes and save you a set of intake gasket and a lot more then 10 minutes
loosen the right rear rocker shaft bolt, 1/2 of a turn.
Do the same to the left front rocker shaft bolt.
start it and see if them two cyl come to life. if they do you can buy some rocker pedistal shims and fix the problem or spend the $$ to buy some pushrods that or .020" shorter.
if neither cyl come to life, then take the intake off just to be sure.
duey_roc
Well-Known Member
Lol! Where's peoples class nowadays? Sheesh
I was wondering the same thing. I very rarely use the smileys on this site and have never used that bird flipping one. It's just rude. Nor would I have talked to someone like you did who was trying to help. I hope you get it fixed. If you do, it will be without my input from here on out.
Oh and goodbye.
duey_roc
Well-Known Member
You see here's the thing brother, I understand youre trying to help, and im very appreciative. but youre coming off as this mechanic God and youre stomping down on people who want to LEARN more about this. I dont know anywhere near as much as you, or many other people on here, but when you treat me like a boy and be a smart ***, I dont care who you are, im going to treat you the same way. Seriously, yes i know not everything is in proper working order. duh. That's not what i meant by that, and im sure everyone else understood what i meant. Thank you for your assistance i really mean it.
Never been a "mechanic god" and the only place that's coming from is you. I'm the most humble person you'll ever meet.....or could have. Good luck.
Just because someone is trying to point you in the right direction doesn't mean they are trying to be a "god", it may mean you're taking it the wrong way.
Just because someone is trying to point you in the right direction doesn't mean they are trying to be a "god", it may mean you're taking it the wrong way.
Lonewolf3165
Living the Dream!
Typical order of misfire diagnosis;
1- check spark, you said you did this.
2- check for vacuum leaks, you said you found no external leaks.
3- check compression, you said you did this.
4- perform cylinder leak-down test. You didn't mention doing this(unless I missed it) so I would recommend doing it if you haven't. It will tell you much more than a compression test will.
5-verify your ignition & valve timing (individually) aren't fluctuating because of mechanical problems. (Worn distributor, timing chain or gears, camshaft etc).
Take a vacuum reading with a gauge connected to manifold vacuum & watch for flutuating needle & low vacuum.
If you still suspect a cracked intake manifold or other vacuum leak you can get an ordinary propane torch & feed some propane into the air cleaner or top of the carb while the engine is running & see if it smooths out or stumbles worse. Smoothing out would indicate a lean condition(like a vacuum leak) & stumble worse would indicate its over-rich.
I would suggest either replacing or thoroughly cleaning the plugs before further diagnosis since they may be fouled due to the misfiring & may not respond to any of the testing correctly.
You need to approach this issue with a more clear & precise method rather than tearing into it & making guesses.
I hope this is of some help to you. Good luck.
1- check spark, you said you did this.
2- check for vacuum leaks, you said you found no external leaks.
3- check compression, you said you did this.
4- perform cylinder leak-down test. You didn't mention doing this(unless I missed it) so I would recommend doing it if you haven't. It will tell you much more than a compression test will.
5-verify your ignition & valve timing (individually) aren't fluctuating because of mechanical problems. (Worn distributor, timing chain or gears, camshaft etc).
Take a vacuum reading with a gauge connected to manifold vacuum & watch for flutuating needle & low vacuum.
If you still suspect a cracked intake manifold or other vacuum leak you can get an ordinary propane torch & feed some propane into the air cleaner or top of the carb while the engine is running & see if it smooths out or stumbles worse. Smoothing out would indicate a lean condition(like a vacuum leak) & stumble worse would indicate its over-rich.
I would suggest either replacing or thoroughly cleaning the plugs before further diagnosis since they may be fouled due to the misfiring & may not respond to any of the testing correctly.
You need to approach this issue with a more clear & precise method rather than tearing into it & making guesses.
I hope this is of some help to you. Good luck.
problem is, you are not listening to a thing anyone is saying. good advise is given and you go off half cocked in the wrong direction. Rob and Del are pretty good troubleshooters,
Damn good.
Damn good.
duey_roc
Well-Known Member
A leak test is when you loosen the rockers back and blow air into the spark plug hole right? If air is coming through tailpipes, its a bad exhaust seat. Air through the carburetor is bad intake seat, and coming through crankcase breather is rings. Or is that something else? lol
I havent done this yet. Wouldnt bad rings give me low compression? I know my seats are ok. These heads are rebuilt and never ran.
Lonewolf3165
Living the Dream!
Don't fall into the trap that just because the parts just came back from the machine shop or just came out of the box that they are okay. Even the best machinists can have a bad day & make a mistake. I don't rely on compression readings alone because the tester only reads peak pressure. A leak down test will tell you everything a compression tester can & much more. I've seen too many engines with bad valve springs or seats leaking that showed up in a leak-down test but had good compression test readings.
Inertia
Well-Known Member
^^^^^^^^^^^^ try this,, it is a good lead,, been there..
duey_roc
Well-Known Member
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
You did what with the push rod??? Not making fun of your spelling, I'm probably one of the worst offenders here!
OK now that I'm a little bit more awake. You Mixed the push rods around, Right? If all the push rods are the same, moving them around will change nothing.
Your lifter will only work in the middle of it range(I'm taking about how far the push rod collapses(sp) or compress the spring inside the lifter.
If the pushrod is two far down, or up, it can cause a noise lifter. BUT, if the push rod is pushing all the way into lifter body it acts like a solid lifter. Then you start the eng and the lifter tries to pump up and hangs the valve open. Just enough to loose compression and not start. your cranking compression is good! but your running compression my not be good at all. No Compression, no fire!
Even though you don't thing it will work. And you have a logical reason why(in you mind) it won't work. Try it.
We all can, over look things because it cant be that.........then later, as we understand a system better, find that it really could have.
let me give you a example
My buddy decided to shave his 360 head down to get some compression out of his stock 360. has the head shaved, and all ready to install.
the shop said that it should be find but that the rocker arms may need to be shimmed. both of us look at each other and say OK. Not having a clue what that is.
While he is at work his younger brother decides to do him a favor and install the heads for him. it won't start and spins like there is no compression. His brother gets the blame and the heads are pull off but have no problem. reinstall and same problem.
Take them back to the machine shop to check for leaking valves. machine shop said they were good. but he insisted on havering a valve job done.
installed on car, same problem:mumum:
After pulling the head back off and taking them back to the machine shop again and demanding they fix it! he ended up coming back with these small shims that goes under the rocker arm shafts and head.
Guess what, It started and ran GRATE! and has for many of years.
I'm not saying this is the answer, BUT, you have to try the 1/2 turn loose rocker arm bolt trick to prove it Right o Wrong!!!
Quit trying to come up with reasons why it won't work, have faith in some one, and try it.
Your lifter will only work in the middle of it range(I'm taking about how far the push rod collapses(sp) or compress the spring inside the lifter.
If the pushrod is two far down, or up, it can cause a noise lifter. BUT, if the push rod is pushing all the way into lifter body it acts like a solid lifter. Then you start the eng and the lifter tries to pump up and hangs the valve open. Just enough to loose compression and not start. your cranking compression is good! but your running compression my not be good at all. No Compression, no fire!
Even though you don't thing it will work. And you have a logical reason why(in you mind) it won't work. Try it.
We all can, over look things because it cant be that.........then later, as we understand a system better, find that it really could have.
let me give you a example
My buddy decided to shave his 360 head down to get some compression out of his stock 360. has the head shaved, and all ready to install.
the shop said that it should be find but that the rocker arms may need to be shimmed. both of us look at each other and say OK. Not having a clue what that is.
While he is at work his younger brother decides to do him a favor and install the heads for him. it won't start and spins like there is no compression. His brother gets the blame and the heads are pull off but have no problem. reinstall and same problem.
Take them back to the machine shop to check for leaking valves. machine shop said they were good. but he insisted on havering a valve job done.
installed on car, same problem:mumum:
After pulling the head back off and taking them back to the machine shop again and demanding they fix it! he ended up coming back with these small shims that goes under the rocker arm shafts and head.
Guess what, It started and ran GRATE! and has for many of years.
I'm not saying this is the answer, BUT, you have to try the 1/2 turn loose rocker arm bolt trick to prove it Right o Wrong!!!
Quit trying to come up with reasons why it won't work, have faith in some one, and try it.
duey_roc
Well-Known Member
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:
Inertia
Well-Known Member
Yeah ! ! .. it'll run like yours.. lol
Dartnut
Don't hate me because i'm beautiful
Get a factory service manual for the specs and start MEASURING things like the push rod length, lift at the cam, lifter length, valve spring installed height, valve length, rocker arm ratio, etc. until you find something that doesn't add up. Do you have solid and hydraulic lifters mixed up on the cam?
Pictures would go a long way here......
duey_roc
Well-Known Member
Ill shoot some pics tomorrow. from what i know i ts a factory hydraulic setup. Ill start measuring stuff as well. Thats a good idea.
duey_roc
Well-Known Member
I meant visibly... Will you be able to see the lifter compressed all the way.
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