SJ Exhaust Manifold

[Big Vern 121]

Has anyone ever used this one from SJ, my S/S manifold pipes do not line up properly to fit to the 4 section. Its the 2nd time its happened so im looking at alternatives now..... i just want to get the old girl back on the road as soon as now. Starting to lose the will.........

 

[slewthy 249]

I bought the 4 - 1 ST ST from SJs and fitted it in the car. I too could never get the collector to fit down on the primaries far enough to completely seal.

Spoke to Steve who advised me to send back the primaries and they sent new ones FOC. Trial fitting with engine out looking good.....

I'll let you know how I get on over the next week or 2 as I reattach everything.

[Daniel 265]

I'm going back with standard.

I bought 2 standard manifolds and I'm going to choose the better of the two and get it ceramic coated by zircotec.

[silverfrost 1,390]

I still do not understand why SJ or Mike at lotusbits has not made an intermediate Stainless exhaust manifold ?   The tubular manifold is lovely system and very well made but the  price of the full tubular systems are a little hard to swallow for some people which is understandable.  

I just cant see why none of the above 2 companies have not made a stainless manifold to the same dimensions as the cast one,  so you could just bolt it on to the rest of the standard exhaust system.  

Two parties imo,  some will go for the Tubular system for longevity and bhp gain.  The other party does not want the increased cost and is not bothered by bhp and keeps replacing the cast one.   To me this leaves the middle man who like Brett are sick of the cracks in the standard manifold but do not want the aftermarket tubular system. 

Come on Steve or Mike,  get the Jig built and knock one up, Get the price right and it will be like printing your own money imo 

[monkey man 17]

Hi all 

I got the sj exhaust it looks like the no.3 pipe that don't line up

[Big Vern 121]

Thats exactly the same as the problem i had, it took attempts but SJ got it right enough to fit in the end. Apparently it was a common problem that they are aware of.....

[silverfrost 1,390]

Does SJ not stamp the number on these things or somthing to aid fitting them in the correct postion,  not that these are fitted wrong, just always wondered how long folks have to fiddle about while trying to puzzle it all out if they are not marked up 

[slewthy 249]

Wow - they look way off! Yes - they are numbered but in fact, its hard to get the wrong way around!

They do of course need to be 'loose' before fitting the collector or it is just too difficult. In the end, I kept one tight and 3 loose so there was at least a solid starting point.

I'll try and take a pic of mine tomorrow as I fit it.

[GTK 691]

On 22/08/2017 at 15:19, silverfrost said:

I still do not understand why SJ or Mike at lotusbits has not made...   ...a stainless manifold to the same dimensions as the cast one

It'd be way more expensive to produce matey so probably wouldn't fall into the middle ground price wise. Casting SS is more demanding than casting iron, and to produce a 4-2 tubular manifold in the space between the block and the standard main section of exhaust would be very labour intensive so again expensive.

My guess is you're better off with a tubular system regardless of the metal used or shape. The problem with the cast manifold seems to be the different rates the alloy of the block and the cast iron expand, so you get blowing and movement and cracks. The thin metal of a tubular system must heat quicker and so stay in better sync with the block. My impression of things anyway. Seems there are consistency issues with the SJ tubular system but then I'd imagine it's produced by a man, rather than by an automated process. Can't be easy. The jig for No.3 must be off if it's a common thing.

Edit: we're lucky by the way. The standard manifold probably cracks because of warping. In other engines I've experienced instances where the cast manifold warps but is too strong to crack and so shears stud or pulls them right out of the head! Imagine having to pull the head off the car to sort a measly exhaust stud.

[silverfrost 1,390]

Hi George, 

  I did not mean cast SS manifold,  Just simply a sort of recreation of the standard cast iron manifold,  but made in from stainless steel tubing 

So it would be a complete stainless steel cut manifold face flange, with tubualar pipes welded on,  This would result in a far greater weight saving than the lotus one, but far less complex and thus less labour time than the complex ss tubular one on the the market atm imo.  

I will have to take the stainless one of one of my spare audi v8 engines and see if the flanges can be altered, as not only are they pretty light weight and compact, they also have an outer shield build incorperated that reduces heat,  you can litterally touch the manifold for a few seconds when the engine has been running for a while ! 

Regards Danny

[Big Vern 121]

It would be good to hear how you got on Wayne, my garage should be tackling the exhaust soon too as the engine and gearbox are now back in the car so ill keep you updated on progress too. Should be interesting...

[slewthy 249]

EVENTUALLY!

Engine back in car and exhaust fitted. All now running well, no leaks.

Change - sent original 4-1 back to SJs who replaced. Also, assembled with Granville assembly paste - what a difference! Much easier to slide back.

Very low and boomy now (no central silencer)

Happy.

[sprog 3]

Another update to the exhaust saga! Having spent endless hours trying to resolve the issue of exhaust vibrating against the chassis and trying to align the mid box so it does not touch bodywork, I finally found a stainless steel exhaust specialist in Cardiff to sort it. He cut at the point after the 4:1 reducer and created a new section which now does not foul the chassis. He also sorted some issues with the back box and mid box. Will get some pics when I am next under it, will probably put some exhaust wrap on there too. To be fair he spent hours doing it and now it all seems to be fine. Just think the carbs need setting up now as it seems to be running a bit flat and they have not been adjusted for well over 15 years.

[Big Vern 121]

Will look forward to some pics soon Wayne!

[jonwat 459]

On 18/06/2019 at 22:22, sprog said:

Just think the carbs need setting up now as it seems to be running a bit flat and they have not been adjusted for well over 15 years.

You'll probably find the idle mixture screws will have seized, I'd drip some WD40 on them & leave them to soak for a week or so before trying to adjust them. ☺