Exhaust Shield Damage or is this normal?

The shields are aluminum on my 308 GTB..they're crap construction and prone to be beat up. Unless you're the original owner and know they have never been abused.

 

I wouldn't call them crap construction. They get FU'd by people, hardly the fault of their construction. Mine are in great shape because I didn't F them up.

 

An act of human intervention. Looks like some gorilla needed to remove it at some time.

 

Looks very intentional. I wonder if this was an attempt to get them to stop rattling.

 

Looks to me like someone was progressively prying it out. But maybe you are right.

 

Yes, those dents look suspiciously intentional. I wonder if it worked?

I completely removed mine when I had the engine out. I don't know if I'd call them "crap construction" They were pretty darn tough to get off, I'll tell you that.

 

That is such a horrible prospect that it never even occurred to me. But I see it now.

And yes, Paul, I agree. I took mine off and they are tough. I envisioned a nice slice along all of the welds and pull the two halves off like clam shells. It did not go like that at all. Not even close.

 

Why did you remove them?

 

Mostly aesthetics, they were pretty beaten up and ugly looking plus they made the headers bulky and unwieldy, it was difficult to get on the upper flange nuts of the 5-8 bank and even when removed it was hard to maneuver them around to make clearance to lift the engine out during which time they got beaten up even more. So I had decided to remove them as well as the sampler tubes and get the headers ceramic coated.

I’m not saying everyone should do this. Despite how they look those shrouds are pretty stout and effective and getting them off was a real PITA. I don’t really know how effective ceramic coating is but I’m pretty sure it’s not as effective as those shrouds. Still, putting it all back together was a dream with all the extra room and they do look pretty sharp even though I’m the only one who ever gets that far down into things to see them. If I had it to do all over again I’d probably still remove them.

 

They are packed with asbestos....running rich or a misfire can melt them...I have had them drip molten metal on the road, at night..

I agree that was a mechanic trying to "tighten the void" caused by the asbestos packing, and it would definitely cause a rattle.
I bet they don't rattle!!

 

They can hide cracking headers...…..but do effectively keep compartment heat down, and exhaust header temps UP.

 

I know it’s not original but can the shield be remove and replace it with the header wrap and will that reduce heat inside the engine compartment?

 

I doubt a wrap would be as effective as the original design.

There's a LOT of asbestos in there, originally.

When my header shattered inside it, it blew the snow flakes everywhere and set the fan belts on fire....

 

My thoughts on the 308 in particular are that the shrouds are not there to solve a problem of heat in the engine bay, which is profusely ventilated compared to most vehicles, but are only there to retain heat in the headers and increase the efficiency of the catalytic converters - specifically during cold start and warm up periods.

When it comes to emission control equipment you'd be surprised at how much of it and to what lengths manufacturers were forced to go just to clean up those few minutes after a cold start. Also, most of those hoses and check valves and canisters and other clutter are just to ensure that not a whisp of unburnt fuel or oil vapor escapes into the atmosphere. I'm all for pollution control, it had to be done, but in the early days the solutions were nightmarishly crude. Look at today however, they have cars putting out 700+ hp with exhaust as sweet as a bay's breath.

 

You are correct. Thats why they are insulated but there was a large benefit and that was cooling down the engine bay, a problem on all rear or midengined cars. The non US 308s had lower exhaust temps and quite a bit more insulation around the engine bay. Really the US headers are a win and I never advocate removing the insulation.

 

Yup, seen that too but only on cars driven extensively with really poor running engines putting a lot of unburned fuel in the exhaust for long periods of time. Usually takes one or more dead cylinders ignored for extensive periods to put that much fuel in the exhaust.

 

I used to run the wrap on a rally car and it was by far the best.

 

Back in the mid 90's there was a SAAB ad that showed hooking up the exhaust of a 2 stroke SAAB to a then modern SAAB 9000 and measuring air quality at the 9000's exhaust, it was cleaner than ambient air.

 

Yea, like I said I did it mostly for aesthetics and don't advocate removal either. I also fabricated a few heat shields for the starter and fuel pump/accumulator in an attempt to mitigate the effects of removing the shrouds. I haven't noticed any I'll effects from the driver's seat but it hasn't been summer yet.

 

On a slightly related note: my car doesn't have the heat shield (which i believe used to be there) around the alternator area. I've flirted with the idea of fabricating something, but haven't been sure if it was actually worthwhile. Any thoughts?

 

Looks to me like a previous owner lived on a gravel driveway and loose gravel thrown up created the smaller dings in the first pic. The other bigger damage looks like it was run up on a kerb and scraped or dragged across it. If it was deliberate ie to solve a rattle the damage might be more contained and regular looking..

Just my 2cents

Mark

Actually looking at it again the smaller dings are too regular to be stone chips. Wow that rattle must have been pissing off someone!