I have always been a person to ask the question “Why?”
This post has come about through two reasons. The first, I have just bought Robsun’s 1300, original condition and low mileage, everything excellent about it but Robsun said the exhaust could need replacing shortly as he thought it was the original, no problem, the replacement would be stainless.
That got me thinking about a comment I think Carledo made in a previous post about the original Dolomite systems being a straight, through pipe on the drivers’ side without bends. Every car I have owned, Herald, Spitfire, Vitesse and Standard 10 have all been straight pipes and single silencer, in the case of the Standard 10 the silencer is under the drivers’ seat and the pipe goes over the rear axle (as per Dolomite), the rest are single silencer behind the rear axle. Why are the Dolomites different and so complex, same basic power unit etc as the cars mentioned?
I decided to go back to first principals and experiment. The downpipe, apart from the rear bend, on Robsun’s car is sound, we both thought the centre oval silencer was stainless so I started looking round for ‘off the shelf’ exhaust parts for the rest of a straight pipe system and found them.
Because the downpipe I had was sound I removed the bend to give me a straight pipe, joined it to the silencer situated under the drivers’ seat, then straight pipe to the back axle. To go over this I bought a couple of ‘off the shelf’ bends (I actually bought two sets just in case), then straight pipe to the back of the car and only ONE rubber mount at the back for the whole system (the front is held in the bracket on the gearbox).
The system is ALL clamped together, no welding.
The total cost of the stainless steel system, without downpipe, if I had had to buy a new silencer (available on line), about £100.
After I fitted the system I had to slightly weaken the mixture and reduce tick-over. The noise level is about the same as the two silencer multi bend original system but probably more economic in petrol etc.
Anyone wants more details of suppliers or photos email me. The spare pair of bends are also for sale, £25 plus post.
Now I will buy a new stainless downpipe to put in stock, should it be needed, IF, I can find one that is a correct OEM?
Again going back to previous posts an esteemed contributor to this forum mentioned the need for the pipe to be extended about the exhaust to manifold flange to create a gas tight seal, this extension sits in the recess in the manifold. Robsun’s downpipe has this extension (because the pipe is original), I tried a dry run without gasket, started the car, slight gas leak, gasket fitted, no gas leak.
For decades every exhaust I have changed on every Triumph the manifold to exhaust gasket hasn’t lasted because the exhaust and flange have been flush, no protection for the gasket and I didn’t realise the cause until recently. This includes downpipes from motor factors and the clubs I have been a member of, one to watch out for.