Well here is something I knocked up over New Year

[img]
http://locosbuilders.co.uk/upload/5Image000.jpg[/img]


manifold 1

I was aiming to keep the inlet lengths as near the same as possible the result is a rather long manifold. The carbs are off a CBR600 so should be OK for my 1600 Pinto.

The plan is to go for max torque rather than max BHP more handy for a road car I think. Any suggestions welcome.

Caber

OK folks I give up how am I supposed to link an image from the photo archive?
[Edited on 1/4/2008 by caber]

[Edited on 1/4/2008 by caber]

[Edited on 1/5/2008 by caber] at bloody last!

[Edited on 1/5/2008 by caber]

What, this?



manifold 1

Yes

Why didn't that work for me?

Caber

seems good to me!

gonna start knocking one out (or should that be up?) soon

was it difficult? where did you get the bends from? did you have to do much work on the tubes to shape them or ovalise them? what was the thickness of the tubes and the plate for the flange? how did you cut the flange? what did you make it from?

etc etc

quote:

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Originally posted by caber
My first manifold

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quote:

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Originally posted by caber
Yes

Why didn't that work for me?

Caber

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Recepie for manifold:

Take old bit of scrap steel plate, mark outline from pinto manifold use angle grinder with thin cutting disk to cut out shape until it statrs smokeing, get another angle grinder to finish the job. Replace cutting wheel with flap disk to finish edges to outline of original manifold.

Measure and mark ports ideally using gasket, drill centres 6mm with sharp drill on drill press then use starrett or other good quality 40mm hole saw to cut ports. Drill water port out to 13mm.

Realise I don't have any suitable tube except copper ask questions on locostbuilders about TIG brazing follow suggestion to get exhaust tube from motor factors. Pick up scrap exhaust S bend.

Try and apply geometry to working out angles and cut first two pieces of tube, offer up and realise some thing is wrong with geometry! Change angles to fit by eye and cut two more pieces of tube by eye.

Tack up tubes to manifold plate admire result for 2 seconds as they are no way in line! Break two off grind a bit more and tack back on again.

Take S curve cut into 4 pieces clean all corrosion back to metal and be happy there is plenty metal left! Cut angles to look like they will work and offer up to stubs. Grind until satisfied with angles and tack on to stub pipes.

Trim ends of curves to same length, offer up carbs and realise outer pipes are too close together. swear for minutes.

using angle grinder slitting disk cut into outer pipes then bend out and weld shut, now it all fits!

Weld all up and dress welds. offer up carbs and find they don't fit. swear for 10 mins.

Put manifold engine side on bench and realise it is no longer flat! Stick in vice and lean on it until it is straight again!

Figure out I should have welded a stub for the water, find a bit of tube and weld in cursing as it would have been much easier to weld this in first!

Realise it is too cold to paint and bring it all home!

Caber

BenB OK I cut and paste what you put into my IMG tags still no picture!

ARGH Caber

oooh, just had a look at the RWD exhaust manifold off my engine, the pipes happen to be the same diameter as the carbs, so i can cut the pipes just above the bends that send the tubes under the engine, use those tubes/bends for the intake manifold, and weld some new pipes to the exhaust to run to the back of the car! nice

That certainly sounds like a locost solution!

Caber

lol, it does, but for the sake of a few inches of new tube...

i'd have to take the 60mile round trip to glasgow one saturday morning for the metal for the flange anyway... its the bending the of tube i'm thinking of though. that will be the most difficult part

unless i re space the carbs, but that sounds like more hassle!

[Edited on 5/1/08 by blakep82]

also , nip into your local plumbing /gas/pipe stockist to look at some weldable steel bends , they work just as well for in lets as exhausts , sch 10 pipe gives about a 40mm inside diameter .

altho exhaust tubing is more workable an comes in many more sizes .

^ ah, good call!

what thickness of plate should i use for the intake flange?

HI have a look in my photos under zx9 carbs & maniford it WILL help you
Jacko

well, is it?

dont know but i have had it on my carbs for 2 years and seem it be ok

i'll go get some tomorrow then! gonna start work on my manifold very soon. what thickness of plate should i use for the flange?

Mine is about 9mm as i said a bit of scrap I had lying around, it actually start life as a rail in a butcher's shop about a 100 years ago!

Caber

gonna go and see my engineering dude tomorrow if he's in (he works whenever he wants), see if he's got any. 10mm steel. just whipped the gasket off tonight, carbs aren't too badly spaced for the inlets on the engine, the middle 2 are only about 3mm out each, the outer two are quite a way out, but the bends in the exhaust tube i don't need should sort that

i spent a while on this and figured out that angling the tube to the manifold plate and die grinding a curve is probably less resistance than adding another curve to the tube. Th only real bends are those that straighten the tube up to match the carb ports however the length of my leaders are nearly 100mm so it may cause problems at the bonnet side, the shorter the leaders the more bends and more differences between lengths.

Caner

oooh, thats a fair point. i may have to get the engine to sit in the front of the car before i do it. there's some chassis tubes very close to where the carbs go, and the pedal box. might need quite short runners...

is the angle of the carbs critical?

The float bowls should be pretty level though mine aren't dead flat. These carbs aren't always dead level in bike installs, I have also sen a Bogg bros manifold with the trumpets pointing vertical though they may have changed floats in bowls for that.

Caber

mine are zzr1100 carbs, but i don't know how to tell when the floats are level

Float levels are adjustable, so the angle is not critical, especially when you have turned them ninety degrees to where they should be. On the bike they have to cope with a lot of angle changes, as the bike accelerates, brakes, even wheelies in the same plane as the floats are working, in the car the acceleration and braking does not affect the float levels as they are now in the same plane as the float movement, and the cornering forces will be less than standing as bike on it's back wheel while accelerating. As long as the jets are covered in fuel and it's not spewing out of the breathers then its fine, there's generally about 15mm of area that's near enough, just aim for the higher end.

hi, i got a set of cbr600 bike carbs last week, i was wondering did the flange need to be machined down after welding?

by the way nice manifold Caber i think i will do mine the same.

stuart

Hi my manifold is made from 5mm steel and i had no problems with it .
I bolted the plate to some steel channel before welding
there is some photos of the jig i used in my archives
Jacko