I Need Help!

[Rolling_Thunder]

Alright... i know my stuff but maybe i am overlooking something here...

fresh engine build (Big Block Mopar 452" stroker)

problem: Cylinder #2 is dead

Work done to solve situation:
1. replaced spark plug wires
2. replaced the spark plug
3. replaced distributor car
4. replaced distributor itself

I ran a compression check and it was putting out 170psi

I see no reason why it should not be firing...

am i overlooking something here ?

[Bigblue73]

Is the intake valve opening? No gas....nothing to fire. You never mentioned if you have any spark or not at the number two hole.

[MrQuick]

start from scratch. fuel, fire then go on.

You pulled all the rags out of the holes right?

[Bad Bowtie]

Thunder,
Just last week I ran into this same kind of issue with a friends boat powered by (2) 350 engines . He brings it to me with one engine running perfect and one engine misfiring on # 2 & 3, he tells me he has changed plugs, wires, cap and rotor to no avail. I run a compression test and find the two cylinders with plenty of compression to fire the cylinders so I started looking for a vacuum leak and found none. I double checked to see if it had fire at the plug tip and it did. I decided to switch the carb from the good running motor to the misfiring one and guess what it picked up those two cylinders that were dead. I tore apart the carb that was on the "bad" motor and found that it had a lot of trash & gook, and some of it was blocking one of the jets. Put the carb back on the motor and all it ran perfect. You might want to try a carb swap if you have another one to try. Keep in mind these were Q-jet carbs but may be possible with Holley and other square bore carbs. Hope you find it, keep us posted.
BB

[Rolling_Thunder]

I am getting spark - The carb is a fresh out of the box holley... I'll throw a different carb on there tomarrow i guess...

it is getting gas though - as when i pull the plug out if is soaked in the stuff...


pulling rags out... unknown... This is the ONLY enigne I have not built in the shop and it is coincidentaly the only one to give me problems... it was delivered assembled without ignition... looks like tomarrow ill throw on a different coil (only electronic i have not replaced just for laughs) and a carb... if that does not solve it - I will be tearing the top end off...

[Rolling_Thunder]

UPDATE! Solved.... Well I pulled the intake manifold to check lifter condition and cam and noticed something... the engine builder did not install gaskets between the heads and the intake... he only used the factory valley pan (soft steel) - the cylinders only dropped off after about 1 minute of run time... it all makes sense now... a massive vacumme leak formed when the heads and intake heated up... allowing a crap load of air to cylinders 2 and 4... more air and little fuel made it an unburnable mixture.... installed my special little gaskets (4 of them) and now all cylinders are firing...

Thanks for all the help guys - I guess now I have seen it all!

[Bad Bowtie]

Thunder,
Glad to hear "problem solved'. I haven't been around big block mopars in awhile, wasn't the metal valley pan used as the intake gasket back then. If I remember right didn't the valley pans have an embossed area around the ports. I think i remember some of them eventually went to some type of gasket material bonded to the valley pan. Like I said it's been awhile. I have a 440 stuffed under a shelf in the shop just haven't had any mopars to use it in. Thanks for the update.
BB