Exhaust manifold

[cal44]

This is an exhaust manifold from an early Elan. Do they fit later Lotus engines as well? Such as a 1973?
Or,
Other than Federal cars are the exhaust manifolds the same up thru '74?
Thanks in advance,
Mike

[peterako]

I would 'guess' that they do. The head didn't 'change'.

Though the evolution to the later exhausts brought performance improvements......

Peter

[RogerFrench]

There were 2 cast iron manifolds and one tubular as standard, depending on year and model. The later cast iron version has 2 squarish outlets rather than 1 round.

[jcocking]

Topic moved to Engine/Exhaust.

[Bud English]

If it helps to place the change (as much as that can be done with Loti), my early 70 +2 had/has the double square ports as what I believe to be original (second owner).

[cal44]

Thanks guys. Unless I haven't found it (or old age made me forget), I am trying to get a timeline on changes to Lotus bits. Each time I obtain a piece, I mark down not only what I purchased but try and get a timeline of manufacture.

Since my weapon of choice is the Plus 2 I am curious if the single round bore exhaust came on the Federal cars in early years. Or was it always the two square bores........Federal

And......what were the earliest Plus 2's imported to the U.S. 1970?
The info is probably in a book.........

Mike

[types26/36]

I believe the square two port cast manifold came with the Elan SE engines (118hp) but not sure how it relates to the plus two time line.

[rgh0]

As said above the engine exhaust manifolds related to the engine specifications

Cast with Single round outlet - standard 105 hp
Cast with Double square outlet - SE 118 hp
Welded tubular steel - Big Valve 126 hp.

I thought all the early Plus 2 came with the SE 118hp engine until the introduction of the Big Valve engine in the Plus 2S 130.

In the USA the various emissions changes may have resulted in some differences from this that I have not seen.

cheers
Rohan

[types26/36]

Cast with Single round outlet - standard 105 hp
Cast with Double square outlet - SE 118 hp
Welded tubular steel - Big Valve 126 hp.
Rohan

This is also how I believe Lotus did it but there is a slight anomaly, when I had a JPS Europa Special (rated at 126hp) it had the cast square ported manifold from original so did the fabricated manifold actually make any difference or was it just a cost saving exercise from Lotus?

[rgh0]

Potentially the layout of the Europa special exhaust with it going down under the engine was the reason they adopted the cast manifold. Or maybe they just had a stock of left over ones they want to use up

Technically with its longer primary pipes the tubular manifiold should be a little better but your only talking about a few hp at most.

Most of the hp increase in the Big Valve 126hp engine versus the SE 118 hp engine came from the carbs and cams and compression ratio. The "big valves" and tubular manifold exhaust were minor contributors

cheers
Rohan

[Uboat]

This is How my manifold looks like. I'm not sure if it was the original extractor (1974). My mechanic think that som of the bends are too angular or tight so they restrict the flow.
/Ulf

[rgh0]

The primary pipe down to the collectors look like the standard arrangement. The flanges after the collectors look like a later modification to make removal and installation easier.

cheers
Rohan

[Uboat]

would you experts agree that the tight bends and to angular joints will restrict the flow?

[Mazzini]

I believe the square two port cast manifold came with the Elan SE engines (118hp) but not sure how it relates to the plus two time line.

I'm just about to pull the engine out of my S3 S/E, I've not owned a car with type of manifold before, it looks like a pain to undo the three bolts holding the manifold to the down pipe in situ or is it possible to remove the transverse pipe and then pull the engine, manifold and down pipe out as one unit?

Thanks!

[types26/36]

I had problems with both the down pipe flange and the flange on the manifold and yes it is a real PITA to get at/remove the three fixings (they may be Allan headed set screws or studs with nuts)
You could try first removing the engine mount then the nuts securing the manifold to the head, move the manifold away from the engine which gives you a little more space.
I don't think you can get the manifold off complete with the downpipe attached to it if the head is on, I know you can refit it attached to the downpipe with the engine still in if you have the head off as I just did it although I have not refitted the head yet.
If you are going to strip the engine why not remove the head while the engine is still in the car, its also so much easier to remove the engine with the head off.
A word of caution, be carful removing the three bolts on the flange, the cast iron is very brittle and a piece can break off very easily as I found out! I managed to source another one but they are quite scarce.
Here are a couple of threads that mention the manifold.
engine-exhaust-cooling-f39/exhaust-gasket-s3se-t22784.html
engine-exhaust-cooling-f39/exhaust-manifold-bolts-should-use-locktite-t22985.html