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BJ7/BJ8 Exhaust Systems

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BJ8Healeys

BJ8Healeys

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I have had a stainless exhaust system from Moss on my BJ8 since 1986. The car has developed a rattling noise under the driver's seat, becoming obnoxiously loud at idle, but not noticeable at speed. It sounds like a baffle might have broken loose in one of the mufflers. To my knowledge, no one is going to sell me just a matching muffler by itself and I'm not inclined at this time to replace the whole system. I haven't investigated the feasibility of a repair yet. and I haven't yet proceeded to remove the BJ8 system.
A few years ago, someone who was getting out of the Healey world gave me an apparently-new BJ7 exhaust system from the manifold to the rear, exiting on the driver's side. I've seen a lot of BJ8s with that configuration, so my question is: are the hanging points of the BJ7 exhaust system the same as those for the BJ8, minus the two mufflers across the back? The parts manual shows different part numbers for the two downpipes from the manifold to the mufflers between BJ7 and BJ8, but if the bends are different, I'm hoping I can use the BJ8 pipes to mate up with the BJ7 muffler (which has two inlets and two outlets).
Anyone done this who can share any words of wisdom?

Thanks!
 
Thanks for the response, Steve. I believe it is the inboard muffler that's rattling, but I won't know for sure until I remove it. Assuming that I can find another stainless muffler that I can buy separately from a complete system, my concern would be whether a replacement would fit into the space allowed and is the same length. It would be nice if it had the same general shape, too.
 
Is there a noticeable sound difference between the mild steel and Stainless muffler systems on a Healey?
I'd assume the mild steel would sound more similar to the original Healey's, being originals were steel. Don't know what type and thickness the originals steel was. I've read the reproduction mufflers are a different design then original. I would think that may change the sound too.
Interesting that the usual suspects charges more for the Healey exhaust in mild steel vs SS. Most mufflers in SS cost extra.
 
AUSMHLY said:
Is there a noticeable sound difference between the mild steel and Stainless muffler systems on a Healey?
Click to expand...

I installed a stainless system after going quickly through two mild steel mufflers (not the original design). In those days, I was driving the car frequently to work -- 3 miles there and three miles back -- so that the exhaust system never really heated up and condensation rusted out the steel pretty quickly. I don't remember any particular difference in sound when I installed the stainless system. There is a difference in sound between BJ7 and BJ8 systems, probably because the BJ8 has two more mufflers crosswise across the back, and there is a only a single muffler for two pipes under the driver's seat. Some people have installed a BJ7 system on their BJ8 because they like the sound (I do, too). I've seen a lot of BJ8s with BJ7 systems and I was hoping someone out there had done that job themselves and could tell me if there are mechanical things to consider in doing the work.
 
a

Well

In some cases the baffels inside have losened in the muffler , some success at quieting was to install SS clamps over the outside of the mufflet at three equally spaced distances.

You could try it
 
Keoke said:
a

Well

In some cases the baffels inside have losened in the muffler , some success at quieting was to install SS clamps over the outside of the mufflet at three equally spaced distances.

You could try it
Click to expand...

Yes, putting a clamp on the muffler would change its resonant frequency and could work to quiet it down. What kind of clamp would you recommend, Keoke? The restricted space around the muffler would require some kind of band clamp, but the muffler is 13 inches in circumference. That's a hefty clamp!
 
The roadster muffler is 17" around - I had no trouble buying this size clamp at the hardware store:

screenshot.1966.jpg
 
AUSMHLY said:
Is there a noticeable sound difference between the mild steel and Stainless muffler systems on a Healey?
I'd assume the mild steel would sound more similar to the original Healey's, being originals were steel. Don't know what type and thickness the originals steel was. I've read the reproduction mufflers are a different design then original. I would think that may change the sound too.
Interesting that the usual suspects charges more for the Healey exhaust in mild steel vs SS. Most mufflers in SS cost extra.
Click to expand...

I bought the mild steel muffler from Healey Surgeons last year. With UPS to California it was about $215.

I had bought a Moss TT system in order to get the muffler, as I didn't need the tailpipe or down pipes - the muffler blew out immediately and it was loud with a nasty resonance at 2500-3500 rpms on the freeway. Moss said they had problems with the original batch and had switched (Chinese) manufacturers and the replacement they sent me (in photo above) was approximately the same soundwise as the Healey Surgeons UK-made* mild steel currently mounted on the car. Inan at HS says these mufflers last a long time. It'll probably outlast me.

I tried at least 5 of the above clamps on the loud muffler and they didn't make any difference in the loudness. I did not, however, have a loose baffle.

Edit: *most likely the AHspares muffler referred to by Derek below, as HS sells AHS products in the US.
 
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A


Is there a noticeable sound difference between the mild steel and Stainless muffler systems on a Healey?--

-YES there is : mild steel has a lower resonant frequency.​
 
DerekJ said:
AHSpares sell mild steel silencer boxes which will be the same size and shape as the originals.
Click to expand...

Here's a photo from Moss's catalog that shows what I believe the original front silencers looked like. #4
58981FD2-3B20-40D6-A640-3217608205DA.jpg
Here's a photo from AHSpares. Doesn't appear to be as the originals. Looks like what moss and other vendors sells, simple oval shape.
AB2F712F-C1EF-4B92-9B6F-E501778E9CF5.jpg

In my quick search for original Healey exhaust photos, I came across this.
Anyone looking for a slightly modified Healey? Owner seems to like the cove's of the Corvett vs Healey. Check out the center console too. More mods, I dare you to click on the link.

1967 Austin Healey 3000
Running driving car, 289 ford motor (runs good but is tired)C4 automatic trans, top chopped 3",seats lowered through the floor 3", custom tuck and roll interior, front wheels widen 1" and rear wheels widen 2", have original grill and some chrome pieces that will come with the car. Some minor paint chipping, headers need to be painted. Small exhaust leak from 1/8 inch hole in pipe. The taillights have a break in the line but work with rerouted line. Solid car, owned for 30 yearsby owner who did all the work.
C3723DCD-FE20-42DE-BC2E-6A78C7F63A7F.jpegA5C024B1-49CC-4CA2-9911-DAACD21F77C8_4_5005_c.jpeg
https://mfpclassiccars.com/austin-healey/53010-1967-austin-healey-mk3-modified.html
 
OMG thats horrific !!!!!!!!!!
 
DerekJ said:
I believe you are overthinking this. If AH Spares are selling them, they are going to fit.
Click to expand...

Hello Derek, I agree, they are going to fit. (disclaimer, nothing on a Healey will fit without a little work).

My question wasn't if it will fit, rather the design change. "Don't know what type and thickness the originals steel was. I've read the reproduction mufflers are a different design then original. I would think that may change the sound too." You replied, AHSpares has shape as the originals. I simply pointed out, they don't and provide photos of the original and AHSpares. Not a fit issue, a curiosity if the tone changed where as the external shape is slightly different (4 corners of the silencer) I'll assume the baffle design might be modified too.
 
Steve,
The BJ8 downpipes are spaced a little bit more from each other than the BJ7 single muffler inlets. You probably should replace the downpipes to match the BJ7 system. You also might encounter some clearance issues beyond the muffler with the raised rear chassis mods on later BJ8s, but easily adjusted at the mounts.
Good luck, Bob
 
Purchased a mild steel muffler from AH Spares last month for my BT7.
Total cost was $160 with DHL shipping. Arrived in two days.
 
Hi Steve,

First, when you hear the rattle, is it only at a low rough idle and disappear at a higher smoother idle RPM. Can you hear the rattle when going slowly over a rough road? If your answers are Yes and NO and the rattle sounds like something mettle that is loose and banging around)? This is what I have been looking for but not finding for a while now. Some of my friends helped look for what was making this noise and suggested it was a sinking motor mount that caused my exhaust down pipe to hit the frame. However, I was not convinced and now your description seems located in the same area and hidden sufficiently to be difficult to find.

As far as similarities between your resonator-equipped BJ8 exhaust and the BJ7, if your BJ7 muffler is a single unit with 2 intakes and 2 exits, you may need to use the BJ7 exhaust pipes for proper exit spacing and cut them to fit the the BJ8 pipes for the turn to the resonator. This should not be a big issue and I would try it before buying new muffler/s, parts, or a replacement system. Also, I expect the modification would be to the BJ7 exhaust pipe, the least expensive component, only and all original BJ8 components should not need modification.

Last, there is a difference in sound between stainless and soft steel exhaust systems. I have an Ansa soft steel system, purchased from Moss and installed back in the mid 1980s as part of my overall Healey redo. Since my Phase 1 BJ8 is quite low, I had to weld metal runners along the bottom of mufflers and resonator to gain some protection for bottoming hits. To date, they have no rust and still perform and look quite good painted flat black.

If you intend to follow Keoke's suggestion, I would go to someplace like home depot and look for strap clamps in the plumbing department that are sometimes used to secure rubber interconnects onto waste pipes.

Good luck,
Ray(64BJ8P1)
 
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dezand said:
Purchased a mild steel muffler from AH Spares last month for my BT7.
Total cost was $160 with DHL shipping. Arrived in two days.
Click to expand...

That's good news. I obviously paid a markup to Healey Surgeons. Of course if I had a problem I wouldn't have to ship it back to the UK.
 
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