411 (Series 3-5) Exhaust Tailpipes

[John Keighley]

Many thanks to all who responded with these suggestions. On Monday I'll take the 410 to Cooma and the workshop with the only exhaust fabricating and pipe bending capability in town will blank off four metal tubes, weld these up, cut a hole in the bottom of each and then fit chrome caps over them to tidy up the job. As we have discovered, there are no exhaust tips of this type available Australia, so we will have to fabricate them. When all is complete I will post results and photos and let you know how we got on. Now armed with this information, I can throw some light for the workshop people on how the set-up should be. Many thanks for the photos, Kevin.
John Keighley

[UK6]

John,
It will be an exhaustive solution!

Brett

[Kevin H]

Originally Posted by John Keighley

.... On Monday I'll take the 410 to Cooma and the workshop with the only exhaust fabricating and pipe bending capability in town ....

Cooma ? - I bet they don't see many Bristols there :-)

[exgasman]

From memory the pipes on my 412 S1 pointed slightly up and had rectangular holes about four inches from the end on the underside and I'm quite sure they were not blanked off.
The mystery deepens!!

[Peter.Kent]

When I first had it the (non-standard) ss pipes were pointed upwards. No problems with fumes. But they seemed a small bore. The current ACCS items have the oblong slot at the bottom and blanking in the outlet.
PS: the rear window in the Imp was for loading luggage etc into the back. V practical it was too ...as was the car in other areas as well. And did it go if properly tuned. Peter

[lansdownplace]

My 412 had on odd aftermarket exhaust which branched off in a Y shape splitting from the Diff so the exhausts protruded at the right place but pointed outward at about a 30 degree angle and cleared the rear bumper a little. The previous owner had attached lip spoiler to the rear bumper to stop fumes coming into the back of the car when the hood was down as his passengers had apparently noticed this. He said the bumper spoiler did the trick.

When it was rebuilt BCL fitted new SS exhausts (which are very quiet) with their stainless steel tips. These are blanked off internally and have the slots cut underneath as described elsewhere in the thread. The 'spoiler' was removed. I have done at least three thousand miles with the roof down and passengers in the rear with no complaints or comment, so this must work. I sprayed the interior of the tips with matt black barbecue paint so that you don't notice the blanking discs.

I have put my winter top on and as the S2 doesn't have vent slots the back of its hard hat like the Beaufighter of the car is pretty airtight. This does mean that you don't get a good airflow through the cabin though unless you crack a window open slightly hence the modification when they did the Beaufighter. My Brigand had vent slots in the parcel shelf to the wings and I am pretty sure that there are also breather panels in the parcel shelf into the boot, although I am happy to stand corrected on that. The 412 definitely doesn't have this.

Paul

[browning l]

Just a sidenote to the tailpipe question - and everyone may know this already:

The four pipes on my '79 603 S2 are blanked off, and have holes on the bottom side, from which the exhaust issues. This is easily seen from both the vapor emissions, and the moist spot on the concrete garage floor under the pipes.

[John Keighley]

Many thanks to all those on this forum who were able to help resolve this problem. Armed with the information given, the people in the workshop facility in Cooma were able to fabricate suitable tailpipes from four 2 ½ inch tubes. These were bent up to about 5-6°, the ends were blanked off about two inches in and holes cut into the underneath. The chrome tips we initially had installed were then relocated to the ends of the new pipes. A couple of photographs illustrate the modification.
The end results look quite respectable but I haven’t been able to really test the new arrangement to see if it works because it was raining on the trip home. Kevin, it’s funny that you should say that about Bristols rarely being seen in Cooma. There were more visitors to the service facility than usual on that day, apparently the 410’s presence caused a bit of interest.
It’s interesting to note that the solution to the issue of these cars creating areas of low pressure around the rear can be quite complex.
This exercise also illustrates how valuable a forum such as this can be to operators of these cars – thanks Kevin!
John Keighley

[Kevin H]

I'm glad you found this site useful John. Looks like the guys in Cooma did a good job. Let us know if it solves your problem with exhaust gases getting into the cabin.

Regards,
Kevin

PS. I have a "roadworthy" test appointment on Monday morning for the 411 and an appointment with Vic Roads to get it re-registered on 22 Dec (this year!), finger crossed it passes the roadworthy!

[John Keighley]

Kevin, Good luck with the roadworthy. I thought that almost three years for me was a test of patience to get a Bristol back again but for you, that time would pale into insignificance! I gather you've abandoned the idea of fuel injection for the time being. Are you running it on the original induction setup?
John Keighley.

[exgasman]

Just a point of interest I've recently spoken to the guy who had my 412 S1 before me and he was the person who removed the blanking discs in order to create a “venturi” effect through the bottom slots to improve the exhaust flow.
All I can say is that I very often ran with the back section of the soft top down but with the middle section of the roof in and never had the hint of fumes in the cabin.

[John Keighley]

Kevin,
That's bad luck. Hopefully, you can get the leaks sorted out and hopefully its not the main seal at the rear of the crank - it's a rope seal and if that's leaking, I am told that the crank has to come out.
All exhaust fumes in the cabin seem to be now eliminated. I've had a good opportunity to test is and there's nothing noticeable.
I do however, have to upgrade the seal along the back of the boot lid as the one that is there isn't providing an adequate seal. It is where the lid joins the lower part of the body- where the locking mechanism is located.
There is a story (a brief history thereof and a brief description of the refurbishment on this 410 published in the current BOCA Club Express magazine.
John K.

[John Keighley]

Finally,
I have been able to take some photos of the completed work to the exhaust tailpipes. Pictures 005 & 006 show the finished work. I have also added a picture to show the arrangement when the car first came back. Why I chose a 411 quadruple tailpipe arrangement is that it looks far less ungainly than the original system and significantly neatens up the appearance of the back end of the car. Although not frequent, I've been in it enough to confirm that there are no exhaust odours in the cabin now. The one thing I do need to attend to is the rear boot lid seal which isn't sealing the boot all that effectively and that will settle any other exhaust seepage issues.
John Keighley.

[armandjones82]

Try to really research if you could have the best Tail Pipe for your 411. Try also other forums and websites to really see what you can have in your Bristol Car. I, myself don't own one, but you can find one in order to really see what your car can have.

[bristolboy]

i know its not the full real deal but we fitted a rolled tail pipe to our car and it did the jobs in terms of looks. we got it from a company called aftermarketsounds heres the link anyone else just wanted a simple tail pipe Rolled Tail Pipes - Car Accessories - AfterMarket Sounds really did tidy the car up