2012 Camry: Eyesore under the hood

The headers do have the heat shields on them. What Toyota has done is integrated the shields with the manifolds. It's pretty spiffy if you ask me.

That manifold was clearly designed to be covered. The mechanic confirmed that.

" snipped-for-privacy@hotmail.com" wrote in news:a4926744-6440-485a- snipped-for-privacy@hb4g2000vbb.googlegroups.com:

What you're referring to is called a "heat shield". This device traps heat inside the manifold so as to aid in keeping the A/F sensor (and the cat) as hot as possible so as to comply with federal emissions-laws.

The new car has double-skinned manifold runners. The old car had a separate sheet-metal shield. Same function, different approach. The new method is more expensive, and will be FAR more difficult to fix when it rusts. But it's better at trapping heat, and better at emissions-law compliance.

" snipped-for-privacy@hotmail.com" wrote in news:8481b00f-f016-4331- snipped-for-privacy@z31g2000vbt.googlegroups.com:

He's wrong.

See the little tab above the #1 cylinder's runner? See how it has a pictogram of a hand with an "X" on top of it? That's what remains of the old heat shield. The rest of the shield has been wrapped around each individual manifold runner.

Gona need to see the paper work on this statement cause I ain't buyin' it!

That hot surface icon is usually on the shield/cover. They had to put it somewhere when they got rid of the latter. Whatever, that area looks like crap without the cover. And wait till the manifold starts to discolor and rust, it'll look like something on a tractor's power plant.

Where else on a car do you see welding in your face like that? The thing was originally intended to be covered. The black plastic on top of the engine was supposed to meet the cover close to the block. Now it just hangs over the block looking like something unfinished. The bolt holes for the cover are plainly visible on the block as well. It sucks big time IMO.

On Feb 10, 9:28 pm, Tegger

I'm gonna have to call you on this one also.

Here is a pic of a 2011 Camary:

You can see it has a "heat shield." You can also see where the two top bolts are.

In this pic of the 2012 in:

...you can plainly see that the "heat shield" has been removed. It looks like it was bolted to two tabs on the exhaust manifold. One of the tabs has been cut off, (drivers side), and the other one has been used to bolt the "warning placard" to. The first and easiest give away is how god awful ugly it is. They don?t do that these days.

no way wrote in news:f121aa92-5f2d-4376-9694- snipped-for-privacy@l1g2000vbc.googlegroups.com:

There has been nothing "removed".

The picture with the traditional heat-shield shows a "non-PZEV" 2AR engine.

The "eyesore" picture shows a "PZEV" 2AR engine.

"PZEV" is an EPA acronym which stands for "Partial Zero Emissions Vehicle".

PZEV engines are built to stricter emissions-standards than non-PZEV. To meet PZEV laws, it is necessary to have extremely tight control over exhaust temperatures; the traditional single-wall manifold and heat-shield are not good enough for PZEV. That's why they went to the "eyesore" double- wall manifold. Even the pipe between the front cat and the rear cat are double-walled for PZEV.

I am not sure, but I believe PZEV engines are primarily California-market.

no way wrote in news: snipped-for-privacy@eb6g2000vbb.googlegroups.com:

See my other post.

I think the PZEV laws in question may not be federal, but instead CARB or CAL EPA.

but but but

1. tegger likes to guess and then present those guesses as fact.

1. tegger /doesn't/ like it when people say things like #1.

2. tegger has such a stick up his ass about emissions, it warps his other sensibilities. and he doesn't even live in kalifornistan, the birthplace of emissions regulations where those of us who have to live with it on a daily basis seem to get by ok!

the stuff about keeping the cat "as hot as possible" is just bogus - excess heat kills cats - it causes the noble metals to diffuse into their ceramic substrate. same for the sensor - they need to be kept hot enough to work, but not so hot they burn out too quick. in fact, the electric heater circuit is controlled by the engine computer [pwm] to /prevent/ it overheating, so making that job harder with some kind of thermal insulation makes no sense.

point conclusively proven.

sorry tegger, you don't know squat about the california market.

pzev is not a "law" thing dude, it's a manufacturer competition thing because these guys don't want the cost of the hybrid, but you can have some of the benefits by just switching the engine off when the car stops moving. "partial zero emissions" means the engine's not running!

forgot to comment - this is bogus bullshit too. double-walling is in no way a feature of just switching the engine off. i've got double-walled headers on part of my non-pzev 89 civic system. you probably have on your non-pzev integra. you're just wildly guessing.

I disagree.

- snipped-for-privacy@eb6g2000vbb.googlegroups.com:

Let me clarify. When I said,?gonna need to see the paper work?, I was referring to your explanation/definition of a ?heat shield?

Your statement was, ?What you're referring to is called a "heat shield". This device traps heat inside the manifold??.

That isn?t true. A ?heat shield? keeps heat away from other objects. A ?heat shield? is not designed to ?retain? heat.

I know you won't believe me, so here:

I have a feeling your going to try and talk yourself right on this anyway, so I'm done with ya on this.

What you're looking at is not a cast iron manifold - that's hidden under an insulating jacket. This is a rather expensive way to do it but if that's w hat Toyota engineers want to do, it's fine with me. Obviously, they felt th e need to keep the heat within the exhaust stream instead of heating the en gine compartment. If you say it looks like shit, I can't disagree. My Hyund ai has a nifty chrome and black engine cover - just like the expensive cars . It's pretty! A Camry should have one too.

no way wrote in news: snipped-for-privacy@w4g2000vbc.googlegroups.com:

I think you'd better read your own comment a bit more carefully. If the shield is to keep other things from getting hot, then it can only do so by retaining the heat that's inside of it.

Compliance with emissions laws require that as much exhaust-heat as possible be retained in the exhaust system until the gases have passed the rear-most cat. PZEV specifications are /so/ strict that the open shields used for lesser designations are insufficient in retaining heat.

Open shields allow air movement through them, which allows more heat to be conducted away from the manifold, especially when the vehicle is on the move. This makes it more difficult to achieve the numbers for PZEV designation.

On the PZEV 2AR engine, Toyota has, therefore, dispensed with open shields in favor of double-skinning the entire system from exhaust ports down to the rear cat.

The Wiki article tells only half the story. See my first paragraph.

no way wrote in news:05b72d59-b979-47b1-896d- snipped-for-privacy@dq9g2000vbb.googlegroups.com:

My, you're a persistent one.

I have images of the non-PZEV and PZEV systems from the factory Service Manual. You want 'em? Email me.

tegger (at) tegger.com