[Healeys] BJ8 Exhaust Systems - BJ8 or BJ7?

[Bob Spidell]

On 6/15/2011 6:24 PM, Robert Blair wrote:
> Hi Listers, The time has arrived for a new exhaust system on my BJ8.  Banged
> up rear boxes are holed/rusted thru - just age and bottoming out.
>
> Would like the List's collective experience.  ...
Have given this subject lots of time, thought, money and frustration.  Even read a book called 'Scientific Design of 
Exhaust and Intake Systems' (if you ever have trouble sleeping ...).

I'm currently running a system cobbled together from 20+-year-old Ansa pipes and generic glasspacks.  The pipes--where 
they haven't been clobbered--are in perfect condition, but I rarely start the car unless I'm planning an hour or more of 
mostly highway driving.  It's noisy--somewhere between a stock BJ8 system and a straight-piped Harley, but surprisingly 
quiet at highway speeds.  I've wrapped the downpipes--which some claim will lead to their early demise--but the main 
casualty seems to be the front mufflers--I've had to replace them after only 15K miles or so.  I believe most, if not 
all of the current aftermarket products are glasspacks and not baffled ('turbo') systems (the Ansa mufflers were 
glasspacks).  The glass/steel wool will deteriorate over a few years; the extra-hot exhaust gas from my wrapped 
downpipes exacerbates the problem.

Have heard--have no hard data--that the longer BJ8 system actually improves low-end torque (but may limit top-end HP).   
Something to do with natural resonances at certain engine speeds.

When I get tired of welding new glasspacks in I will look for a good-quality mild steel system (I believe Walker brand 
has been recommended).  Or, Moss has a new, polished SS system that has gotten good reviews for other LBCs (however, 
these are glasspacks and I suspect the packing will be gone before the metal goes).   I would scuff the SS and coat 
black.  This stuff works very well:

http://www.designengineering.com/category/catalog/design-engineering-inc/exhaust-wraps-accessories/ht-silicone-coating

It needs to be 'tempered' at 400degF--after applying I go over with a propane torch with spreader.  Holds up better than 
any paint I've tried.

Bob

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Bob Spidell           San Jose, CA            bspidell at comcast.net

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