How to machine match 172 manifold

[Mase]

Hello all - I am after information to aid in my project to machine match a 172 Mk II manifold. Being in Australia the price to purhase in from the UK units already done is seriously cost prohibative (well over $100 Aust per HP) to most people thus I am aiming at doing my own as a project. I have discussed this with some who have done their own successfully with a dremel and some skill but they don't have any comprehensive pics or final dimensions / pics or being from a non-english speaking country we have an english barrier.

So if anyone can provide some useful info / pics etc that would be much appreciated. I realise some people on this forum will have a vested interest in keeping the 'black art' of flow modified RSC manifolds somewhat secret via retention of info however spare a thought for your aussie counterparts and the unfortunate exchange rates and distances involved.

Feel free to access my e-mail and mail me direct

So fingers crossed and hope to hear from someone,

Cheers - Mase

 

[matty172cup]

hey mase i did know some dimensions for the inlets but they are all slightly different to each casting if you dremal them out place gasket over top and bottom half of inlet the scribe a line on the inside of gasket and that is the area to be ground out simples just takes a bit of time tho lol

Matty

 

[Mase]

Thanks Matty - I just found this thread http://www.cliosport.net/forum/showthread.php?t=399653&highlight=how+to+machine+match+manifold which gives me a reasonable idea however I don't think I'ld rush it in a few hrs in the morning Pitty the images are so poor.

So as you say you use the gasket to scribe on the mating surfaces of the plenum section and the lower runner section the max extents of material removal.

It also appears you do a similiar process with the lower manifold to the head trusting that the gasket is not 'oversized' too much to the head ports..correct?

I am working a manifold that is off another car so will be swapping into my car when done.

 

[matty172cup]

yep thats correct but if the gaskets where slightly bigger it wouldnt be to critical dude

Matty

 

[Mase]

Thanks Matty - it's all nice and clear now. Any other comments from forum members? I am a tad worries od removing too much material in the head to manifold join but I could be conservativer and keep the cutting to under the scriberd mark on this join.

What about cleaning up the inside of the runners? Is this a good idea and any suggestions on a tool to achieve this?

Also - I note that where the injector ports are there is a very slight bulge on the material that runs like a 'ridge' perpendicular to the head port. Maybe this is there for a reason?

 

[Mase]

This about answers the total query. http://www.cliosport.net/forum/showthread.php?t=205076

Interesting the 20 thou step down to the head.

What's the scoop here?

 

[sideways danny]

Dont take the port right out to the gasket, the hole in the gasket is bigger than the port in the head

 

[johnnybravo]

sorry to sound thick, but are we talking about eht exhaust manifold here, or the inlet manifold?

 

[Mase]

Dont take the port right out to the gasket, the hole in the gasket is bigger than the port in the head

Inlet.

Yep..looking over the details in other threads this has become apparent.

Thanks