Fitting the exaust manifold with the body in place

[chrisawyer]

In my rush to get the chassis ready to mate wit te body after the latter was painted, I made the cardinal mistake of not fitting the tubular exhaust manifold during engine installation. And, to make it even more fun, I left it off when the body was hoisted back onto the chassis. This has stopped me dead in my tracks. However, while reading an article online about a different Lotus model, I came across a link to S & J Sportscars, and looked at their exhaust systems for S4 Elans. My question is this: Does anyone know if their two-piece tubular stainless steel manifold (or similar) can be fitted to a car with the body and chassis joined up? Or am I well and truly screwed?

I am including the link just in case.

Thanks.

https://www.sjsportscars.com/parts-and- ... 6S0004.htm

[pharriso]

My advice Chris, buy the SS manifolds from Paul Matty, beautiful & I fitted mine without too much of a struggle:

Post wasn't too bad either

p.s. if not clear, engine & gearbox were in the car... just swapped manifolds...

[steve lyle]

Don’t know about the linked manifold, but you’re not screwed.

I’ve fit my one piece steel tubular manifold with the body on multiple times.

1. Place a jack under the engine, with wood block to spread the load
2. Remove the engine mounts.
3. Move the engine as far as it will go to the right side of the bay
4. Fit manifold.
5. Reverse steps 3, 2, and 1.

This is how Ed replaced an Elan manifold on Wheeler Dealers as well.

[The Veg]

it may also help if you switch from studs to bolts.

[chrisawyer]

Thank you all! This is great news. I tried the block of wood, etc. method before with the help of the former Ford engineer brother, but unfortunately we could not get things to work as planned. Since he's no longer available to help, I've let it sit. I think I may get the Paul Matty manifolds, as suggested, but would like to know more about replacing the studs with bolts. I'm guessing just a simple one-to-one replacement with a bolt of the same size, thread count and length?

(As you can tell, Ive gotten a bit gun shy...)

Also, it turns out this is a Sprint. Other than the straight pipe between the header and muffler, were there any other differences -- other than the Sprint rubberized bobbin, that is. The previous owner used an off-the-shelf muffler and self-bent straight pipe. What muffler did it use, the twin-pipe?

Thanks again. You guys are the best.

Chris

[ericbushby]

Hi Chris.
I changed from studs to Allen head set screws when I had the engine out last year.
The thread is 5/16 UNC and I think the screws were 1" long but check that.
I cleaned the threads in the head carefully with a plug tap and used something anti- seize.
Using a 1/4" long reach ball ended Allen key I could fit the screws easily.
I would have had great difficulty fitting the exhaust with studs still in the head.
Best of luck
Eric in Burnley
1967 S3SE DHC

[Foxie]

Hi Chris.
I changed from studs to Allen head set screws when I had the engine out last year.

Eric in Burnley

I've been using Allen head screws for some time now. Makes the job a doddle !

[englishmaninwales]

Hi Chris.
I changed from studs to Allen head set screws when I had the engine out last year.

Eric in Burnley

I've been using Allen head screws for some time now. Makes the job a doddle !

+1
The downside, however, is damage to the threads in the CH in the long term. I think that next time the CH is out of the car I will consider fitting thread inserts, if that is possible, or helicoils
Malcolm

[richardcox_lotus]

My advice Chris, buy the SS manifolds from Paul Matty, beautiful & I fitted mine without too much of a struggle:

IMG_0921.JPG

Post wasn't too bad either

p.s. if not clear, engine & gearbox were in the car... just swapped manifolds...

How loud are they Phil ? Especially is it a drone on long runs ? I have a stainless silencer, with the rest of my manifold and main pipe being mild steel. The silencer gives a bark which is tolerable, but I wouldn’t want it any louder, and am curious as to those who run a complete stainless system get on, as I have leaks elsewhere in the system that may mean replacement.

Thanks
Richard

[friedy]

A question for those that have changed to caphead allen screws, did you use stainless screws or plain steel ?
Alan.

[lotusfan]

Stainless

[pharriso]

Hi Chris.
I changed from studs to Allen head set screws when I had the engine out last year.
The thread is 5/16 UNC and I think the screws were 1" long but check that.......
Best of luck
Eric in Burnley
1967 S3SE DHC

You sure about that thread? My notes show 1/4 UNC x 1 SHCS

[ericbushby]

Hi Phil.
You may be right. I looked up my ebay purchase history to come up with that. I will check the removed studs tomorrow.
It`s late now and a little too much whisky and I would not trust myself to measure anything just now, night, night.!
Eric in Burnley

[mbell]

You sure about that thread? My notes show 1/4 UNC x 1 SHCS

You might want to correct that note Phil.

I just clean the threads on the studs on my engine using a 5/16unf thread cleaner. So the studs are certainly 5/16" and I'd expect the thread into the head to be unc not unf.

Personally I haven't found it enough of a problem fitting the manifold with car in the engine to swap out the studs. I have standard two piece manifold on my car and the studs do get in the way a bit but not too bad. I'll probably regret saying that when I get to refitting the engine....

[mbell]

A question for those that have changed to caphead allen screws, did you use stainless screws or plain steel ?
Alan.

I probably would go with zinc plated.

My main concern would be galvanic corrosion, which might be an issue with stainless steel:

https://www.marshfasteners.com/can-stai ... -together/

Whether it a real issue for the use I don't know but twin cam heads aren't a cheap thing to experiment on.