Removing the TCS stock exhaust manifold

[Grumblebuns]

Or specifically the exhaust down tube. In the middle of my engine removal I hit a snag this past summer and fall trying to remove the down tube from my TCS, 3923R. I let the problem sit all winter hoping to hit upon a solution next time I start working on it. Went back to work on the car this morning and nada, I'm hitting a brick wall in trying the remove the most outboard nut on the down tube. The only tool that will fit on the 1/2" nut is an open end wrench which starts to slip and round off the nut any time I put any torque on it.

My last resort is to remove the exhaust system as a unit. I believe it can be done if I support the engine and remove the left hand motor mount bracket. The down tube is held on by three studs on the manifold. The problem fastener is the most outboard nut which is so close to the tube that there is no clearance to slip a socket on it.

Anyone else run into this problem?

http://lotus-europa.com/manuals/tcparts/s/index.htm

Joji Tokumoto
Fallbrook, Ca


 

[BDA]

I'm not that familiar with the TC exhaust system but I wonder if a very thin-walled box end wrench might be helpful. It might require you to carve up a wrench or socket just for this purpose. You might also try to split the nut with a chisel.

[jbcollier]

Stubborn, hard to get at, exhaust flange nut solutions:
- heat the nut up and use a worn 12 mm wrench (1/2" = 12.7 mm). As soon as it gets stiff to turn, heat it again,
- no heat? Freeze it,
- nut splitter,
- small cut-off saw on a dremel,
- if you are practiced, you can take a nut off with a cutting torch and not touch the stud underneath.
-

[EuropaTC]

Hi Joji,

It's many years since I had to do that job due to a leak at the flange, and I seem to recall I ended up taking the manifold and downpipe off as a unit. It was so messed up with rusted studs they needed replacement and it's easy once it's on a bench with new studs to hand because you can just hack it off - cutting disc, drill the nut, whatever you like.

Brian

[4129R]

Can you get small mole grips on the nut?

They can grip very tight.

[Certified Lotus]

Joji, mine was a bear to remove too. Just did it a couple of months ago. It was completely rusted and between the odd angle to remove it (and I had my car on a lift so was underneath it) and the rusted/heated in place I could not remove the nut. Finally took the motor mount bracket off to get better access and that didn't help much. Then removed the entire header and cut the exhaust pipe under the transaxle. took off the bolts in the clamp on the floor of my garage with an air powered cutting wheel.

The header went into my spares box as I am replacing with tube headers and the rest of the exhaust got trashed as it was completely rusted.

[Grumblebuns]

From Brian and Glen's experience, the entire exhaust manifold can be removed as a unit. I think I'm done wasting time trying to remove the nut with the manifold in place. I'll remove the entire exhaust system and work on removing the nut afterwards. Thanks for all of the tips.

I will try using vise/mole grips first, if there is enough room between the down tube and the frame, and see if that will loosen the nut, otherwise the exhaust come out. I've attached a couple of pictures showing the issue with the down tube nut.

[EuropaTC]

Yep, that has got to be one of the worst designed flanges ever. If anything that looks even worse than mine, but then again it's a long time since I took a look down there !

As an aside, when I replaced mine I modified the lower section slightly to improve the sealing.  I kept blowing the joint which I put down to the lower section being all stainless with a relatively thin flange and apart from the expansion coefficients being different, it had also warped slightly. I ground away the bores in the cast iron upper section and welded small extensions on the lower 2 tubes to form a spigot & socket type of joint. Only thin steel but when coupled with paste & gasket it sealed first time and has undisturbed ever since.

Yours looks like a mild steel section and quite chunky so you shouldn't have the same problem, but it was an easy mod to increase the security of the joint given how difficult it is to get at again.

Brian

[Grumblebuns]

The down tube shown in the pictures are a newfactory spare I picked up a while back. The factory welds on the down tube flange section are crap, the reason why the bolt appears to be cocked a bit. When I re-install my replacement motor, I plan on using a tubular header and high balance intake manifold. With the cross over tubes removed, I always thought the left over holes and studs on both manifolds detracted from the appearance of the motor. I'm having a pair of high balance manifolds made up by my machinist. If anyone is interested in getting a pair, let me know and I'll send you his email. Just be warned that he is very slow, he's been working on mine since last fall.

Joji Tokumoto
Fallbrook, Ca

[EuropatcSPECIAL]

Has anyone sourced a stainless steel system for a tcs in the uk? I bought one last year from a specialist and it would have fitted a tractor more easily  Thanks

[EuropaTC]

The only ones I've ever seen advertised have been at SJS and Banks but it wouldn't surprise me to find they both resell from an independent exhaust manufacturer, so they haven't got much control over the final fit.

Double S used to make stainless systems for the Elan and I have one of their exhaust boxes on the Elise, both fit reasonably well. Unless your previous system came with a double S badge on it, it might be worth giving them a call ?

Brian 

[4129R]

I am about to get 3 made locally in Norfolk when 3089R is sprayed in about 2-3 months time.

I will take the car with the engine in, to the manufacturer, and they can make copies that actually fit properly.

I have a loose one as a pattern.

Alex in Norfolk.