Inlet manifold materials.

[quadcam boat]

I am planning an inlet manifold which I hope to make shortly. Its a intercooled supercharger setup. Is mild steel suitable for inlet manifolds. Chev V8's used to have cast iron inlet manifolds. The only thing I am concerned with is will the manifold rust on the inside? I was thinking of anodising it after it was finished to get around this. Anodising is the gold coloured coating you see on bolts and brackets around your engine bay. That what I call it anyway. I read in an old Zoom mag that it is cheep to do, you just have to send it away. You can get other colours other than gold with differing properties of corrosion protection I think.
Other than that I would concider Aluminium or a composite material such as fiberglass or carbon fibre/ kevlar.

I have a MIG welder, but it is not set up for aluminium. I have never used a MIG on aluminium but done some basic TIG welding at a tafe course. That is what puts me off the logical choice of aluminium.

I also tossed up the idea of using a composite material. Am reading a book about it at the moment, but am starting to go cold on the idea. Does anyone know if fiberglass would stand up to the heat from being bolted onto the heads?
This is a picure of what I have in mind.

 

[Zuffen]

Andrew,

As you plan on hanging the blower off your intercooler/manifold it will have to be pretty strong to take the loads. Fibreglass will never do it and carbon fibre is not easy to work with.

A supercharger on full song can draw close to 100hp to drive it!

Even in alloy it would have to be substantial to take the stresses of the blower coming on and off boost and the resultant torque reaction.

Steel looks the easiest for you as it is not hard to work, welds well and is strong. It won't look as pretty as alloy but you can build it. Would you make it so the intercooler core was removable?

Whilst I like the idea I still think hanging the intercooler under the blower is campact and production units are available. This route entails moving the starter but I don't see that as being too difficult, particularly on a boat.

Almost any form of corrosion protection would work, but you need to be sure whatever you use can't flake off an pass thru the engine.

 

[quadcam boat]

Can't move the starter as there is no room under the motor. The blower will still be on top of the starter. The intercooler core will be removable, maybe use one like this picture or 2 placed either side of the blower in the plenium

 

[LEXUSV8NZ]

IS it just me or does that look like a bloody tiny cooler core?
How restrictive would that be?

Logan

 

[Zuffen]

Andrew,

Logan is right it is a little tiny unit.

I would look at two of them munted on their sides, or at an angle, on each side of the plenum. That way the air would pass up and thru the core and down it's respective sides manifold.

 

[quadcam boat]

Yeah, thats what I meant by using 2 either side of the blower. Interestingly, that photo is a allens supercharger( www.allenengine.com )and they use that core with all their superchargers up to 5.4 litre V8's. I would use a bigger core if I use a single setup.
Logan it is small, but remember its an air to water core and the water passes through the inside of it and the supercharger air on the outside. Actually, when you look at the size of his hand, it is tiny isn't it!

 

[LEXUSV8NZ]

I realise that and i was comparing it to the size of his hand

Logan

 

[autocol]

I was thinking of anodising it after it was finished to get around this.

anodising is a process performed on aluminium. it involves dropping an alum component in a solution-bath (dyed the colour of your choice) with an electric current run through the bath with the component as the anode (hence - anodising). it's actually accelerated oxidation in reality and if you tried to anodise steel you'll end up with rust!! so i'd suggest not trying that! also, only certain grades of aluminium anodise well, and as i understand it alum-alloys that weld well, don't anodise well, as a general rule, which means you might give them your finished part and ask for gold anodising, and get dogshit brown back.

there's no reason not to make the intake out of steel though, as the temp's are never going to harm the material (and aluminium would be LONG gone if it did!), and the cast iron intakes would be just as prone to corrosion as a fabricated steel unit (look in the water passages of any second-hand holden or chev manifold). the plating you're referring to for use with steel is probably zinc or nickel plating. you can ask for a finish called "gold passivate" when you zinc plate which gives that yellowy-gold finish, which usually looks good on small components but generally speaking looks pretty crappy on anything of any decent size, like a manifold.

which-ever plating you decide to go for, the shinier and smoother the part goes in - the shinier and smoother the part comes out.

if you want to ask anything, i send a lot of parts to plating and may be able to point you in the right direction.

col.

 

[turboandrew]

how about ceramic coating a steel manifold? You have your choice of colors and it would look great.

 

[Toranamat69]

Autocol, good summary of coatings above. I certainly agree regarding checking the grade of alloy before anodising. When doing my wheel centres, the first set were 2011 alloy which has high lead content and when anodised, the lead leaches to the surface and you get grey spotty appearance and it is a dull finish in general. Made another set in 6061 and they look superb.
I have a chart of how well different grades anodise which is handy.

The passivated zinc coating is most often used to coat high tensile stuff as you do not need to heat beyond the annealing temp of the material as you do for hot dip galv. doesn't usually get an even colour on large stuff.

 

[quadcam boat]

Thanks for the info - now I know the correct term for the stuff. Only the lower section will the steel and most of it won't be visable. I was probably going to powder coat or paint the outside of it if looks come into the equation. The passivated coating is to prevent the inside of the runners rusting.
Col,
If I had the sealing surfaces milled flat prior the passivating, would the surface still be good enough to seal, or should I have it milled afterward?
Also who do you use and how much does it cost?
An aircraft mechanic I know gets his fasteners Cad plated, is this similar again?

 

[quadcam boat]

Turboandrew,
been doing some reading on that ceramic stuff, and sounds good. I have never seen it, would it flake off at all inside the inlet manifold?
Would be ideal if it is not too dear, prevent corrosion, reduce heat soak and look good!

 

[Toranamat69]

I would go with HPC Ceramic Hyper coat inside and outside if making this from steel (alloy is the nice option if you can). Gives it that alloy finish which you can polish up even brighter, is very corrosion resistant and you don't risk it coming loose and going down the guts of the engine as may happen with paint or powdercoat. I use the HPC a fair bit and I have hit things with a hammer and bent brackets over at 90 degrees and back a few times and the bracket will snap before the coating comes off.
It is applied using a plasma arc process I believe (they are very sectretive about it all)

I have had many things coated which bolt up to machined flanges and they are perfectly flat when they come back as the HPC coating is only a few thou thick and goes on fairly evenly when they apply it well. I would recommend the HPC in Melbourne over the brissy one as they are better quality and quicker turnaround.

Not sure about Cad plating, I thought this referred to Cadmium plating but I could be wrong.

 

[quadcam boat]

what sort of dollars to coat the lower section of the inlet manifold in the top picture- not the supercharger or plenium on the top.
Also, now much prep work before you send it to them. If I sandblasted it to remove any rust and coated it in oil, would that come out well, or does sandblasting 'dull' the finish? Or do they do that for you?
Is HPC the only mob who do it?

 

[Zuffen]

A mate uses HPC on lots of parts.

He has piston crowns coated to increase their resistance to heat.

He has rusty old Ferrari exhaust systems coated and it increases their life many times over.

For what you get it is quite reasonably priced.

You don't need to worry about surface rust but tidying uo welds will make it look lots better.

 

[Toranamat69]

I'd be surprised if those cost you more than $100 plus postage to get those done but give them a call.

HPC High Performance Coatings Pty Ltd
6 Watson Rd Leongatha 3953 (03) 5662 4338
Fax (03) 5662 4719
Internet www.hpcoatings.com.au
Email [email protected]