348 Do 348 exhaust manifolds fail?

Hey guys, I was driving my 348 on the highway and while at cruise I started to hear a loud noise coming from the engine. As I slowed down, it sounded like my exhaust note was significantly louder and not in a good way. Car ran but it was a little rough. No white or blue smoke from exhaust.

Definitely coming from passenger side. Haven’t gotten car on lift to look at it. Pulled plugs and some fouling on passenger bank. Cylinder 2 looked worst. When I start car sounds like it overrevs a bit and settles into idle. I know the 355 has some issues with manifolds. Can it happen on 348 too? Any ideas on diagnosis?

Car has factory manifolds, x-ost muffler, and high flow cats

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I would first check the condition of the secondary air injection one way check valves, and the solenoids. You could have one that has failed and is open.

 

Is having just ONE that fouled a stuck injector?

sjd

 

I'll throw out a guess... One of your exhaust 'doughnuts'(round gasket) has failed at one of the cat connections= louder exhaust. Perhaps your o2 sensor is reading lean(because of leak) and telling the Motronic to increase fuel.

 

Early 348s only have 1 check valve per bank.

 

Good one! That's a possibility too. Though it would have to be on the header side of the cat.

 

I needed better grammar. Take 2.

"Only the one spark plug fouled? Would that be an indication of a stuck injector?"



sjd

 

Thanks for all the replies guys. I fired it up to take a look at some of these things and had it running for about a minute. It appeared that things came to a head. Engine stopped running altogether. Would not turn over anymore. This is the spark plug from cylinder two. Not good [emoji51]. Image Unavailable, Please Login


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Let me be the second to say "OH FACK"!

 

I have never seen an electrode fall. In the last 2 weeks this is the second plug failure I have heard about in a Ferrari. Prior to that I have never seen a plug fail but we replace them at service intervals just because.

So your battery is good and motor does not turn? Bump/rocking car in gear and pistons not moving? Man this is a bad day...

 

Battery is good. Motor does not turn. Bump rocking the car and it pretty much feels like the parking brake is on.

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Did someone gap the plugs before installing them?

 

No. Iridium plugs, left them alone


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Never seen that before, or heard of it happening!!!

You could put a fibre optic scope in there to see what’s what; but I suspect it will just delay the inevitable.

What make of plug are they (so I don’t put them in my 348!), how old are they and when/who put them in? (On the off chase there is any support!)

 

X2, Yikes, sorry to hear...

 

They look like NGK DR8EIX, that's what I use, looks like crappy ole champions are going in.
This is unfortunate, I wonder the linkage between the noise and this?

 

I wouldn't suspect the quality of the broken spark plug for the time being. As suggested by "A238W", I would first look inside the cylinders with a Borescope as it appears that the engine has jammed for some reason. The missing nose of the spark plug could just be a consequence of some impact in the combustion chamber.

 

To be clear, the engine sounded ill before I changed the plugs. It sounded like there was a noise coming from the passenger side bank which made me suspect there may have been a manifold or header failure. Clearly it was probably something worse.

At the start of the thread and you can see what the plugs looked like when I pulled them to see if I could get any information. They were changed with the last major in 2016. Since a few looked clearly fouled I switched them with the exact same plugs. NGK iridium.

Started back up and car sounded exactly the same. After running at idle for about a minute, that’s when it suddenly stopped. Pretty sure it is completely seized now. I’m probably going to get it towed to the dealer, but I fear what they’re going to tell me.


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OH!
Not good at all!

You need to have a look inside with a borescope to see if you can find the electrode. Hopefully you haven't any more damage than a busted spark plug.

 

For fun, here are the borescope pics. Focal length not great since piston at the top, first pic you can see debris and what looks like a valve. Second pic you can see the ceramic and electrode from the plug using a 90 deg mirror. Last pic is cylinder 4 for comparison. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login


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Oh geese!!!!

Sorry to hear this. I would do a compression test next to see just how bad it is.

 

Ernie,
That valve looks broken off and sideways, I think which made the engine jam and piston will not move. Probably not going to hold
compression. Tried rocking car in reverse to see if it will back off, no go. Have not been able to get a breaker bar on to try and rotate engine in reverse. My guess is either way that cylinder head has to come off. Not a good day man


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I wouldn't try to rotate the engine to avoid (possible) more damage. The head has to come off. Also, inspect the timing belt - the change in sound could have been due to a camshaft initially skipping one tooth and the "crash" when there was further skip.

(So many timing gear failures after majors)

 

Yes... pulley fence failure maybe the skipped belt....

 

Sorry for your trouble. Keep us posted with the tear down.