Cylinder has spark but not firing..

[duey_roc]

Figured it out

 

[Oklacarcollecto]

Figured it out

And what is the answer?

 

[duey_roc]

So it turns out it was the intake manifold being cracked underneath. I went and got a new intake and put it on. Fired right up. All 8 cylinders running good and the carburetor can adjust like it should!

 

[duey_roc]

Guess my diagnostic skills arent as bad as some people on here think

 

[cudascott]

That's great:cheers: now drive the crap out of it

 

[70aarcuda]

Guess my diagnostic skills arent as bad as some people on here think

maybe on post number 1 ...if you would told everyone that the intake had been welded to fix a water leak....just maybe...the thread would not have 250 post..

 

[67Dart273]

So it turns out it was the intake manifold being cracked underneath. I went and got a new intake and put it on. Fired right up. All 8 cylinders running good and the carburetor can adjust like it should!

I say without proof it didn't happen

 

[iw378]

I say without proof it didn't happen

LOL. Pics or it didn't happen. Just messing around.
Let's see the crack. Glad you got it going duey

 

[TrailBeast]

HOLY CRAP, now it's even more confusing.
From the plugs picture it looks like cyl 1&4 would be the ones missing, and the other cylinders running too rich.
There seems no rhyme or reason to the lean and rich mix of the plugs.

If it was a booster leak, then why is number 1 lean?
If an intake leak, then why 1&4 ?

Maybe it is the intake cracked.

You checked for tennis balls in the runners right? :-D

So it wasn't tennis balls? :-D
That cylinder 1 and 4 lean was a dead giveaway.

Conratulations.

 

[RustyRatRod]

I say without proof it didn't happen

We have a winner.

 

[3406pk]

Congratulations on solving the problem. Enjoy the cruising.

 

[duey_roc]

Actually now that I'm looking at the intake, I don't think it's cracked. I'm not really seeing a crack visibly. I think it may be warped.

 

[duey_roc]

I say without proof it didn't happen

LOL. Pics or it didn't happen. Just messing around.
Let's see the crack. Glad you got it going duey

We have a winner.

Ok heres the proof i guess. I set a straight edge on the lower part of the intake making sure that it was straight across and not swaying up or down. Here is what i got. I was able to get a .010 feeler gauge in between it with ease and my flashlight in behind. The first pic is on the PASSENGER side rear and the second pic is on the passenger side #8 cylinder runner where i was having problems. I made sure to put the straight edge on the lowest part of the intake so its not going straight across the runner openings. :burnout:

 

[sireland67]

I question the straight edge, what did you use?
That looks like an old piece of steel, not a granite table or machinest straight edge.
But glad you fixed the problem.

 

[Cudafever]

Congratulations Duey.

Your gut instinct was right!!!! :thumbrig:

 

[magnumdart]

Wonder if someone took a belt sander to it to clean it up.

 

[fishmens67]

So ive had this 360 torn apart 3 times now and im going to scream since ill most likely be doing it again. Heres whats going on...

I have a brand new set of J heads on the motor. I had them put new hardened valve seats in, valve grind, and surfacing all sides of the heads. For some reason, nothing happens when i pull #2 and #8 plug wires out. They're giving spark but im not getting any action into the cylinder. Ive tried multiple sets of spark plugs and they all do the same thing.

The bottom end is stock. Original rings and bearings. I haven't gotten around to doing a compression test on it, but im thinking i have bad piston rings. If i have spark, and i know my cylinder heads are good, i can rule those out. The only other thing i can think of is low compression caused by bad piston rings. What does everyone think? angry9:

this! lol no mention of intake, I wonder!

 

[mopar head]

I question the straight edge, what did you use?
That looks like an old piece of steel, not a granite table or machinest straight edge.
But glad you fixed the problem.

That`d be a highly precision drywall T square:coffee2:

 

[Dartnut]

Good for you.
I wish someone would have mentioned this in one of their posts.

 

[duey_roc]

That`d be a highly precision drywall T square:coffee2:

:glasses7:

 

[/6 Matt]

Well I'll be damned....

Take the intake to a machinist and have them mill it true and it will be ready to go again. Wonder if the welding caused the warpage?

 

[duey_roc]

Well I'll be damned....

Wonder if the welding caused the warpage?

Good point that could be the case. Now to go to HEI :toothy3:

 

[magnumdart]

What if the crack was caused by the manifold warping? Will the new manifold warp also?

 

[/6 Matt]

What if the crack was caused by the manifold warping? Will the new manifold warp also?

Also a possibility. As long as proper torquing sequence is followed and the engine never reaches critical temperatures, the new manifold should be just fine.

 

[duey_roc]

Since you are dead set on changing the intake because it is your problem, I will be interested in buying it from you, for the right price. post a picture of it and I just may purchase it from you.
Let me know when you sell that intake.

Hey buddy you still interested in the intake?? haha! I actually re measured the other side of the intake and it was warped bad. Like .030 at least. Its warped on the side of the welded water jacket. I think he got it too hot and it warped the metal...

Heres the new one installed on the car. Runs great!