74 Valiant 318 Backfire when hot

[MOPAROFFICIAL]

Just look for a rocker arm that ain't movin "much". There's your huckleberry.

Always liked that movie, tombstone..a doc holiday line

 

[RustyRatRod]

I edited that. ;)

If she's obese enough, it's gonna be a shart.

 

[RustyRatRod]

Always liked that movie, tombstone..a doc holiday line

Best Doc Holliday act ever......although I thought they made him sicker than he was early on in his life. He was from Georgia, so I've done a lot of reading about him. Once he got out west, he improved greatly.....for a time. Then once he got sick again, he went pretty quick. They had him sick throughout, which wasn't true......but then we only got about 2 hours. lol

 

[Woody500]

Here's a simple one then, fire it up let it idle until it's fully warm, then take a screwdriver handle, the plastic kind... and drag it against the exhaust manifold right up next to each port on the head. If the handle slides melting like butter, it's firing just fine and there's probably no issue.. if it sticks or drags roughly across the manifold then that's the cylinder with the problem.

This is easier with headers, but works with manifolds.

If you find the problem cylinder, pull the valve cover and rockers... and simply see if the valve stem height matches the others...if so, then check the plug , then onto a leak down test... or you can put a piece of paper up to the tail pipe and if it goes from blowing the paper away to.. sucking the paper to the tail pipe.. that is a burnt valve. It could have a section melted and broken away.

The boys can surely be on to something, just figured id offer my approach.

You can tell one is cooler with spit (old-school ) or a drop of water & evaporation time . Some will be cold to the touch, and if you do it upon cold start up, you can touch them all & tell quickly.
Or. Got a laser thermometer? $40 at Wal-Mart Pharmacy Dept. One from HF junk & returned it.

 

[mygasser]

You can tell one is cooler with spit (old-school ) or a drop of water & evaporation time . Some will be cold to the touch, and if you do it upon cold start up, you can touch them all & tell quickly.
Or. Got a laser thermometer? $40 at Wal-Mart Pharmacy Dept. One from HF junk & returned it.

even if hot spit on your finger tip and dab the header tube. it should boil off immediately with a tsss sound, lol.
neil.

 

[PRH]

What are the odds that we hear how this one played out?

 

[mygasser]

What are the odds that we hear how this one played out?

slim to none