Puzzled!

[CUUDA]

2007 3.5 used with 80,000 miles that sat on my engine stand for nearly a year.

First installed after new head gaskets, timing belt and waterpump. I do this on all used engines.

Ran great after install. Parked it for a couple months waiting on other parts. Went to crank it and made all kinds of racket and sounds like it has no compression. Spins freely as if valves are open??

After several cycles and revolutions the thumps of compression start to return and it will fire up.

Engine light flashes random misfires.

Kill it and restart it a time or two and allow it to warm up and it cleans up and runs perfect!?? No Noises!!?? Drive it around without issues for the rest if the day.

Next morning same damn thing!!!!! 😡

The noises sound like banging rods and a loose flexplate or a rattling catalytic convertor.

EVERYTHING was torqued to spec and it did not do this until it sat for 2 months waiting on parts.

I am leaning towards the lifters loosing prime overnight. When I spin it over enough the oil pumps back up and compression is back up then it fires up. Once warm it runs perfect.

I am about to riddle it with 12 gauge slugs!!!

[CUUDA]

https://i.imgur.com/Xz7VXBF.jpg

[reefstar]

https://i.imgur.com/Xz7VXBF.jpg

It very well could be the rocker arms. Did you replace them?

[CUUDA]

[QUOTE=reefstar;5184714]It very well could be the rocker arms. Did you replace them?[/QUOT

Yes I did... But not the lifters!

[reefstar]

[QUOTE=CUUDA;5184717]

It very well could be the rocker arms. Did you replace them?[/QUOT

Yes I did... But not the lifters!

I’ll bet the lifters had orange caps on them. Do you remember?

[CUUDA]

Don't remember. The one I pulled has the orange but those were silent. That engine has a light bottomend knock. I have a crank kit for it.

I just walked out there and hit the key and the sonuvabeach cranked and ran perfect! 🙄

[reefstar]

Don't remember. The one I pulled has the orange but those were silent. That engine has a light bottomend knock. I have a crank kit for it.

I just walked out there and hit the key and the sonuvabeach cranked and ran perfect! í*½í¹„

Still sounds to me like the rocker arms. Chrysler has upgraded them a couple of times, the new ones have yellow caps.

The reason the car just started fine was likely because when you turned off the engine last time, the lifter wasn’t under pressure, so it didn’t bleed down.

[reefstar]

Don't remember. The one I pulled has the orange but those were silent. That engine has a light bottomend knock. I have a crank kit for it.

I just walked out there and hit the key and the sonuvabeach cranked and ran perfect! í*½í¹„

Here’s a simple trick you can use to help isolate sounds. Take a section of garden hose or any kind is tubing. Hold one end up to your ear, and then aim the other end at different points of your engine. You’ll be surprised how easily you can isolate where a noise is coming from.
Also a cheap mechanics stethoscope is worth WAY more than it costs.

Mechanics Stethoscope Engine Diagnostic Tool Amazon.com: Mechanics Stethoscope Engine Diagnostic Tool: Health & Personal Care

[circ1977]

Don't remember. The one I pulled has the orange but those were silent. That engine has a light bottomend knock. I have a crank kit for it.

I just walked out there and hit the key and the sonuvabeach cranked and ran perfect! ������

Cant explain away the knocking noise but i had one 3.5 in for service that sounded like every other broken timing belt I've ever heard, except it wasn't ! I would of bet all the money in my pocket at the time that is what it was , it ended up being ****ty gas ! It left me dumb founded but it was a car from a auction yard that had old or contaminated gas in it , that was all that was wrong with it. Sounds like this car has been sitting for awhile, any chance that gas is trash?

[reefstar]

Cant explain away the knocking noise but i had one 3.5 in for service that sounded like every other broken timing belt I've ever heard, except it wasn't ! I would of bet all the money in my pocket at the time that is what it was , it ended up being ****ty gas ! It left me dumb founded but it was a car from a auction yard that had old or contaminated gas in it , that was all that was wrong with it. Sounds like this car has been sitting for awhile, any chance that gas is trash?

That’s a reasonable thought. It’s worth a shot. Top off your tank with some 92 octane and see if it helps (if you can’t drain it). Sea foam it at the same time.