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inlet manifold construction
cd.thomson - 22/9/09 at 05:28 PM

Hi guys, I feel embarrassed posting another of these threads after people have been so helpful in the past already..

My garden shed fabricator has backed out of making my inlet manifold as it is "too complicated", I still have the flange so I was thinking of going to a proper fabrication company in Burton/Derby but for that I will need to take plans. Better still, as recommended by blake, I could prepare the tubing myself and get them to weld it together.

The first hurdle arises because the ports on the XE flange are oval and the carbs I've just bought are round. What fabrication wizardry will have to be performed to get a pipe with one round end and an oval end?

I'm hoping to do something similar to this:



[Edited on 22/9/09 by cd.thomson]


cd.thomson - 22/9/09 at 05:39 PM

also, just to add, I know theres a few people on here involved in various kit car related fabrication jobs. If you think you can produce something then or know someone who can I'd happily employ you to do it .


adrianreeve - 22/9/09 at 05:40 PM

Put the tube in a vice and gently squeeze! Do it a little at a time, and the tube goes a lovely oval shape. I did it this way with mine and they came out brilliantly.

Here's a link to another thread: Not the best pics but hopefully you get the idea.

http://www.haynes.co.uk/forums/showthread.php?t=1843

HTH

Cheers

Adrian

[Edited on 22/9/09 by adrianreeve]


flak monkey - 22/9/09 at 06:00 PM

Yep, gently squeeze in a vice. Simple as that.

Then, once you have it somewhere close, tack it onto the plate and then use a punch to knock the tube into its final shape.

Its possible to make some complex shapes with some practice.

Inlet manifold 4
Inlet manifold 4


David


cd.thomson - 22/9/09 at 06:06 PM

cheers adrian and david,

i cant see those pictures unfortunately, the problem i imagine happening is that the oval will be larger than the port itself despite being the same shape. This will create a substantial lip at the inlet end of the manifold which will catch fuel and all sorts (i think?).

tell me if im visualising it all wrong!

[Edited on 22/9/09 by cd.thomson]


adrianreeve - 22/9/09 at 06:20 PM

It obviously depends on the application, but for the zetec engine, 45mm tube was perfect for the round end at the throttle bodies, and when squeezed, matched the oval port shape exactly (and it really was exactly!)

Cheers

Adrian


omega0684 - 22/9/09 at 06:34 PM

those pipes look rather loooooooong


cd.thomson - 22/9/09 at 06:48 PM

6 inch total runner length to keep the max torque down at a sensible level I think


andrew-theasby - 22/9/09 at 07:10 PM

ive just made one this week for my xe. I used 48mm x 4mm wall tube to suit t/b's. I cut 4x 30mm long pieces then turned a v into then for the mounting rubbers. then using a hole saw, cut 4 48mm holes in a piece of wood on same centres as t/b's. I mounted this to another piece of wood at the right angle and distance i wantedd from the head. The flange was then clamped on to this centrally and the 4 short tubes put in pkace flush with the top. Then i cut 4 more lengths of tube to filt the gap. trial and error proved i had to cut a v in these first then weld them back up so ene endnd was smaller dia. then i squashed them to an oval and mitred them as necessary with slitter and a lot of grinding, then tacked it aall up then fully welded it. Took it out of the jig, shot blasted it, smoothed the inside with liquid metal and painted it. Its a lot of work, and if you dont feel upto it, id definitely try bogg broos for a price first otherwise youll waste a lot of time and still end up buying one. HTH, ill poost up soome pics when i get home on saturday ifyou like.


will121 - 22/9/09 at 07:40 PM

have a look at this basic guide ive done for zetec manifold fabrication, principal is the same. it does make the manifold easier to make if you re-space the carbs but not essential. easiest way i found to make bends is to cut a wedge out rather than cut off totally.
guide to making a manifold




cd.thomson - 22/9/09 at 07:42 PM

id love some pictures Andrew. I was quoted close to £400 for carbs and a manifold from bogg yesterday which is eye watering for a second hand part fitted to some metal tubing.


andrew-theasby - 22/9/09 at 09:14 PM

Didnt realise theycharged thatmuch, was expecting morelikee 150 for a manifold. U2U me ifi dont post them up on saturday. Ps sorry bout th ttyping my keyboards playing up andn cant be bothred to edit eeverything


andrew-theasby - 25/9/09 at 11:27 PM

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andrew-theasby - 25/9/09 at 11:27 PM

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andrew-theasby - 25/9/09 at 11:28 PM

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mr T - 26/9/09 at 01:37 PM

Got mine from Bogs worth the money