Manifold.

[amgrave]

Anyone know if it's possible to separate the exhaust and inlet manifold without damage to either or would I have to get a second set and destroy one half of each to achieve two separate pieces.

[liammonty]

Assuming you have access to a standard armoury of tools like me (angle grinder, hacksaw etc), you will need to sacrifice one of them to save the other, as it were. Unless you're better at cutting around corners than I am, that is! I've done it twice, but only wanted to retain the exhaust manifold, so it didn't matter.

[amgrave]

Ah, so it's not just a straight cut through then. Now why did I think it might be easy with a steady hand

[bmcecosse]

You can try - but the norm as others have said is to make sure you keep the exhaust intact. An unheated alloy inlet is a much better bet anyway. Why do you want to separate ? (I can guess the answer - but do tell....)

[amgrave]

Your guess is correct bmc.

[bmcecosse]

So you need this http://www.ebay.co.uk/itm/Classic-Mini- ... 35ed524648

[amgrave]

Thanks for the link BMC you have guessed correct. For now I just want to have an unheated manifold as an engine is better off with that anyway. As I am now retired I intend over a period of time to have a play with the car to improve things in general no major changes but a few more horses and maybe a 3.9 diff. I am also tight so will be looking to spend as little as possible while doing it

[bmcecosse]

I understand - but an alloy manifold is better flowing - and if the price is right....it will only go up in value anyway. Used to get them for a Fiver!

[amgrave]

Used to get them for a fiver, I will watch the price of the one listed but I have a feeling it ain't going to be cheep

[bmcecosse]

With 'cutting', the two parts will still be v close together and I suspect there will still be quite a bit of heat transfer. Cold air in is worth approx 2 bhp.... Larger 1.5" carb is worth another 2 bhp on it's own , but of course allows other modifications (head / cam / exhaust) to develop nicely.

[don58van]

With 'cutting', the two parts will still be v close together and I suspect there will still be quite a bit of heat transfer.

I think Roy has a good point here.

Has anyone succeeded in cutting joined intake and exhaust apart on two manifolds then put one of each back on the engine?

I tried cutting the two bits apart without leaving a hole in either part. I worked extremely carefully and slowly with a variety of tools, including an angle grinder with 1mm disk, die-grinder, mini-grinding tool, hacksaw and hand files. I concluded that it isn't possible to save both parts.

So, I have come to the conclusion that if two manifolds are cut apart leaving a safe amount of metal on the intake and exhaust parts where they are separated, they will probably foul each other when mounted on the head. If they are carefully fettled to make them fit, they will probably transfer pretty much the same amount of heat as a joined one.

Don

[amgrave]

I think you both have a point there about them still being too close together. I was thinking along the lines off parting them and re-facing the inlet flanges to lift the inlet up clearer of the exhaust however it sounds like a better bet to source a ally inlet instead saving a lot of work then source and fit a hif 44 on the ally which I think is what they are made for. Thanks for your input all.

[bmcecosse]

HIF44 is too big for a 1098....HIF38 is ideal.

[amgrave]

Noted bmc and changed for hif38, thanks for that.