2000 Honda Civic EX-G (Canadian Model) Exhaust issues **Need Help**

Hi. I've got a bone stock 2000 Honda Civic EX-G with the execption of
a K&N air filter and platinum Bosch sparkplugs. In the past year,
I've cracked my exhaust manifold twice. I had it replaced last June,
and now it's cracked again. Since my car isn't the most powerful, I
tend to compensate by being a little heavy on the throttle. The car
has automatic transmission, which could also be a factor.

I'm fairly sure (correct me if I'm wrong), that these cracks are
caused by the restrictive stock muffler and cat. In an effort to
avoid having to replace ths exhaust manifold in a year's time, I'm
considering replacing the stock exhaust with something that flows a
bit better. Any recommedations? I'm not looking for something ultra
aggessive, but a bit louder than stock is ok. Also, should I be
replacing the manifold with OEM again, or something aftermarket.

Can anyone recommend a reputable shop in the Toronto/Mississauga area
of Ontario? What should I expect in terms of cost?

Thanks,

saneboy.

I've never heard of a manifold cracking due to back pressure. Since air is
compressible, then the "back pressure" would build up and effect performance
to the point of killing the car.
Heat problems, poor mounting, bad motor mounts may be causes.


--
Stephen W. Hansen
ASE Certified Master Automobile Technician
ASE Undercar Specialist



"saneboy" > wrote in message
...
> Hi. I've got a bone stock 2000 Honda Civic EX-G with the execption of
> a K&N air filter and platinum Bosch sparkplugs. In the past year,
> I've cracked my exhaust manifold twice. I had it replaced last June,
> and now it's cracked again. Since my car isn't the most powerful, I
> tend to compensate by being a little heavy on the throttle. The car
> has automatic transmission, which could also be a factor.
>
> I'm fairly sure (correct me if I'm wrong), that these cracks are
> caused by the restrictive stock muffler and cat. In an effort to
> avoid having to replace ths exhaust manifold in a year's time, I'm
> considering replacing the stock exhaust with something that flows a
> bit better. Any recommedations? I'm not looking for something ultra
> aggessive, but a bit louder than stock is ok. Also, should I be
> replacing the manifold with OEM again, or something aftermarket.
>
> Can anyone recommend a reputable shop in the Toronto/Mississauga area
> of Ontario? What should I expect in terms of cost?
>
> Thanks,
>
> saneboy.
>

Steve wrote:
> I've never heard of a manifold cracking due to back pressure. Since air is
> compressible, then the "back pressure" would build up and effect performance
> to the point of killing the car.
> Heat problems, poor mounting, bad motor mounts may be causes.

------------------

Like Steve said. Has nothing to do with back pressure, but since I don't
live in Toronto, make it as loud as you like :-)

'Curly'

On Wed, 15 Jun 2005 14:57:39 GMT, "Steve" >
wrote:

>I've never heard of a manifold cracking due to back pressure. Since air is
>compressible, then the "back pressure" would build up and effect performance
>to the point of killing the car.
>Heat problems, poor mounting, bad motor mounts may be causes.

Strange. I'd always attributed this to my "heavy-foot" driving style.
As a point of reference, I also had a crack in the exhaust manifold in
my previous vehicle, a Jeep TJ 4.0L.

Thanks, for you input, though.

saneboy > wrote in
:

> On Wed, 15 Jun 2005 14:57:39 GMT, "Steve" >
> wrote:
>
>>I've never heard of a manifold cracking due to back pressure. Since
>>air is compressible, then the "back pressure" would build up and
>>effect performance to the point of killing the car.
>>Heat problems, poor mounting, bad motor mounts may be causes.
>
> Strange. I'd always attributed this to my "heavy-foot" driving style.
> As a point of reference, I also had a crack in the exhaust manifold in
> my previous vehicle, a Jeep TJ 4.0L.
>



It has nothing to do with how you drive.

Exhaust manifold cracking is normally due to structural weakness or unusual
physical load. Some cars are prone to this.

Does your year have a welded steel-tubing manifold or a tin cast-iron one?

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

On 15 Jun 2005 19:26:44 GMT, "TeGGeR®" > wrote:

>saneboy > wrote in
:
>
>> On Wed, 15 Jun 2005 14:57:39 GMT, "Steve" >
>> wrote:
>>
>>>I've never heard of a manifold cracking due to back pressure. Since
>>>air is compressible, then the "back pressure" would build up and
>>>effect performance to the point of killing the car.
>>>Heat problems, poor mounting, bad motor mounts may be causes.
>>
>> Strange. I'd always attributed this to my "heavy-foot" driving style.
>> As a point of reference, I also had a crack in the exhaust manifold in
>> my previous vehicle, a Jeep TJ 4.0L.
>>
>
>
>
>It has nothing to do with how you drive.
>
>Exhaust manifold cracking is normally due to structural weakness or unusual
>physical load. Some cars are prone to this.
>
>Does your year have a welded steel-tubing manifold or a tin cast-iron one?

No idea. I'll have to remove the heat shield to find out. Is one
stronger than the other?

saneboy wrote:
> I'm fairly sure (correct me if I'm wrong), that these cracks are
> caused by the restrictive stock muffler and cat.

my WAG would be the engines running too hot. backpressure shouldnt crack
a manifold, but excessive heat might.

saneboy wrote:
> Strange. I'd always attributed this to my "heavy-foot" driving style.

which might mean times of excessive heat buildup, followed by a cooling
period, then another "Hotfoot" burst of heat.

> As a point of reference, I also had a crack in the exhaust manifold in
> my previous vehicle, a Jeep TJ 4.0L.

yeah, my friend did too. 6 cyl, right? i attribute that to a POS
manifold design, but he kinda had a leadfoot too.
>
> Thanks, for you input, though.
>

saneboy wrote:
>>It has nothing to do with how you drive.
>>
>>Exhaust manifold cracking is normally due to structural weakness or unusual
>>physical load. Some cars are prone to this.
>>
>>Does your year have a welded steel-tubing manifold or a tin cast-iron one?
>
>
> No idea. I'll have to remove the heat shield to find out. Is one
> stronger than the other?

id imagine the welded steel tubing might be more forgiving. cast iron is
pretty brittle.

saneboy wrote:
> Hi. I've got a bone stock 2000 Honda Civic EX-G with the execption of
> a K&N air filter and platinum Bosch sparkplugs. In the past year,
> I've cracked my exhaust manifold twice. I had it replaced last June,
> and now it's cracked again. Since my car isn't the most powerful, I
> tend to compensate by being a little heavy on the throttle. The car
> has automatic transmission, which could also be a factor.
>
> I'm fairly sure (correct me if I'm wrong), that these cracks are
> caused by the restrictive stock muffler and cat. In an effort to
> avoid having to replace ths exhaust manifold in a year's time, I'm
> considering replacing the stock exhaust with something that flows a
> bit better. Any recommedations? I'm not looking for something ultra
> aggessive, but a bit louder than stock is ok. Also, should I be
> replacing the manifold with OEM again, or something aftermarket.
>
> Can anyone recommend a reputable shop in the Toronto/Mississauga area
> of Ontario? What should I expect in terms of cost?
>
> Thanks,
>
> saneboy.
>
where are the cracks? at the head end or the colder end? where the
castings have small radius or large? has the vehicle ever been crashed?

my money's on the latter - if the vehicle has been crashed & the repair
incomplete, the engine may not be sitting straight and that will strain
the exhaust system leading [eventually] to cracking.

excess back pressure or temperature are /most/ unlikely. chances are,
your manifold is cast and the main reasons castings are used in this
location is precisely because of ability to withstand heat. even if the
exhaust is extremely blocked, there is little practical ability to
create excess pressure sufficient to crack a manifold because the
engine stops running first.