4B11 or 4B12 Exhaust Manifolds

peregrine

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Is there any gain or benefit, in fitting a 4B12 manifold to a 4B11 engine, or are the exhaust manifolds identical?
Simple question but noted an unresolved dispute, elsewhere. I can't imagine it being different but?
 
If the gasket is the same then it should bolt onto the engine. Then it's just a matter of finding out if it's the right length. Doubt there's any benefit in it though
 
If the gasket is the same then it should bolt onto the engine. Then it's just a matter of finding out if it's the right length. Doubt there's any benefit in it though

Hi rigby, thought I had answered this! Part numbers are different, as are the manifolds. Looks like no go.
 
Even if they were different, why would you bother doing this?

Just buy a set of extractors/headers and you will get better results!
 
Agreed, but 4B12 manifold could have avoided warranty hassles!
However as it now seems its possible that 4B12 wont fit. No point in going any further with this until proven.
 
An exhaust won't void a warranty if it's carried out by a reputable workshop and you keep the same amount of o2 sensors and *poo*
 
It could be argued that any modification that takes away from normal settings of ECU etc: and or increases power and torque, causes more stress
exceeding the limitations set by the manufacturer to ensure the viability of their warranty and therefore represents a reasonable breech
of that warranty! Fortunately most manufactures don't push that hard a line and as with me over the years have accepted anything reasonable
put to them. Evan had GM H give me a new motor when mine blew up, for my 1965 HD Holden, after 20000 plus miles and after a year
when warranty was only for 1 year and 12000 miles. So next car I bought was another new Holden a 1969 HT. next car Magic Machine
top of the range 1974 P76 V8 just $5000 fully optioned new.

PS Lookout if they want to get tough!
 
only reason a warranty would be voided is if the dealer and/or manufacturer can deem the aftermarket part the cause of the issue.
 
Agreed, but 4B12 manifold could have avoided warranty hassles!

You'll still get grief from the dealer come warranty time for an engine issue if they work out that the manifold is different....

An exhaust won't void a warranty if it's carried out by a reputable workshop and you keep the same amount of o2 sensors and *poo*

It really is a grey area and depends on what exactly the fault is that you are trying to claim warranty on. The CJs also have two O2 sensors (the Californian models actually had 3 atleast back in the early days), so they can give you a bit of grief if you change the exhaust manifold. There are work arounds but they essentially involve making the rear O2 sensor see a false reading.


only reason a warranty would be voided is if the dealer and/or manufacturer can deem the aftermarket part the cause of the issue.

Yes that is correct, but dealers and car manufacturers think they are a law unto themselves. Unless you have a good relationship with your dealership, there is a good chance they will try weasel out of warranty jobs by blaming your mods. The onus will then be on you to fight them.

When a friend's CJ had an issue, her local dealership told her that they couldn't help her because her stereo (amp and speakers) was interfering with the MUT-III scanner and they wouldn't do anything for her until the stereo was removed. Needless to say, I got a different response from the dealer when I went with her and told the dealer that my Jaycar OBD scanner had been able to read the error code. Her car had a new MAF sensor installed the next day...
 
Thanks all, play it safe and wait another 3 plus years till warranty runs out. Just found out I had to notify insurance re fitting a front tower strut brace
Whiteline, as it is termed a performance modification. Did so, no worries or alterations. Asked about chrome Bling and sound deadening, no interest.
 
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