MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Improve the existing exhaust manifold

I am shortly going to have some work done on my F and I wanted to take this opportunity to try and improve the existing exhaust manifold. I was reading Dave Andrews's K-Series web site http://members.aol.com/_ht_a/DVAndrews/kengine.htm#exhaust and found this quote. “It is important not to underestimate the affect a properly designed exhaust can have on an engine, the stock manifold that comes with the K series as installed in the Elise is pretty awful, having very short primaries and a lot of welding clag in the inside of the manifold flange, the very least you should do with one of these is to fettle away the weld build up inside the manifold.”

I don’t really want to replace the exhaust this time so this seems a good and cheap option!

Has anybody done this on their F?

If so do you have any pictures?
Did you notice and difference afterwards?
What did you use to do the work?
How far down inside the pipes did you go?

Cheers
Steve
Steve

I believe Mike has a refined manifold section which may be of interest to you?

Leigh
Leigh

i was at Dave andrews for my second fettled manifold. It's actually quite easy to do with a little dremmel type tool and a tungsten carbide bits. The trick is not to take too much meat away from the weld. Mike favours welding externally to strengthen the flange up again and I can see the point after my first manifold suffered a fracture around the weld after fettling, However it is possible to survive without the external welding if you're lucky.

Getting the manifold off is the fun part the bolts to the block are not too difficult but you will find that the studs will probably unscrew rather than the nuts. that is not a problem but you should separate the nut and stud and re-insert them with a stud inserting tool. The nuts/studs fixing the the flexi are the difficult ones. and for these what is really useful is a wiggle joint socket extension (try www.drapertool.com) this will allow you to get to the nuts past the sub-frame.

When I did this last weekend lying on the floor of dave andrews driveway I found it useful to unbolt the flexi from the CAT to allow a bit of movement and to remove the bolts from the head before undoing the manifold/flexi nuts. the wiggle extension my obviate this.

Expect to spend a good 3 hours for this and you will need a mate to assist. Rob did take some pics so I hope he may have them on his website very soon.... Over to you Rob... (how's the finger.... must try that trick next time... :0)
tim woolcott

Don't try the finger trick at home kids - spent two hours waiting in casualty - d'oh! But Tim did fit my bumpers for me ;o)

will sort something regarding the manifold - but all the pix were on your camera Tim. Can you forward them to me?
Rob Bell

Posted 12 October 2003 at 19:51:46 UK time
Rob Bell, North London
Don't try the finger trick at home kids - spent two hours waiting in casualty - d'oh! But Tim did fit my bumpers for me ;o)

will sort something regarding the manifold - but all the pix were on your camera Tim. Can you forward them to me?

Two Hours Rob......?! Did you enter some kind of space-time-continuem.....? In that time I managed to fit a flexi-pipe, mend one of your fog-lamp brackets, fit front and rear Bumpers and polish off a bucket load of tea...... I never realised I could work that fast.

Oh and Andy Bates fitted two pairs of door mirrors so must have been longer than 2 hrs.... ;0)

Tim

Oops forgot the pics were in My camera, I'll forward them to you both tonight if I remember.
tim woolcott

The time and motion committee have noted your efficiency, and will expect similar hard work from you in the future... ;o)

[Reference: Peter Seller's B&W masterpiece - "I'm alright Jack"]
Rob Bell

Looks like all this stuff is THE way to go

I must get out and get greasy with my F!

Rob, you must do ALL this stuff to your car I recon it will make a fundemental difference.

I have had 2 cars gas-flowed (and would always recommend it as a "pure" way of extracting bhp) the cars were :-
1. a mini I did myself with the aid of David Vizard's book "How to modify your mini" (remember that?) and a huge "shaping" machine at Uni!!!
2. A Lancia HPE that Mr Andrews did the honours on the head one evening at his place ...up to and beyond midnight

They were both different cars once the work was finished!

Dave's
work was desribed as "Magnificent!" by an old Lancia hand.

My work was described as "Brutal!" by the undertaker who eventually bought the car!!!!
Neil W

Dave's
work was desribed as "Magnificent!" by an old Lancia hand.

My work was described as "Brutal!" by the undertaker who eventually bought the car!!!!



ROFLOL :o) :o)

It's OK Neil, Rob will get me to do it for him....LOL

Would love to have seen the Lancia after the Andrews treatment....
tim woolcott

It was a bit of a baptism by fire for Tim, but he stood up well despite the car fighting back... well done that man.

A Dremel isn't really powerful enough to remove the weld clag since it is stainless and *very* hard, you will need a die-grinder with a 6mm or 1/4 inch collet and a seriously agressive carbide burr, protective glasses and a dollop of patience. You don't really need to go into the headers themselves, just remove/smooth the weld build up at the manifold flange, do the same to the weld build up at the flange where it connects to the downpipes.

The Lancia is a peach of a head to start with but just has a few machining anomolies to sort out round the valve seats and short turns and in the exhaust ports.

Dave
Dave Andrews



I am considering buying (very cheap) a old K series 214 one of the 103 bhp multipoint versions from around 93 as a practice vehicle to "tinker" with.

Decent Lancia's are getting a bit thin on the ground and I have no interest in welding in new sills, arches suspension turrets... etc

Dave's work on the Lancia was exemplary, showed how it should be done, and has started all those wheels in my head whirring again.
Forget all those bolt on gimmicks I want all my cars gasflowed


Neil

Neil, can you drop me an email.....

Tim
tim woolcott

Neil - watch out for the head you are about to buy: check out Dave's web site for the differences between early low-port heads and later versions (the ones you want)
Rob Bell

Thanks Rob

I am aware of this but I do beleive that the car above has the right one... Oeer will check with DA though!

Neil

This thread was discussed between 11/10/2003 and 14/10/2003

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now