Polishing my head
Turbo Mini Forums

Just thought i'd post up some pics of what i'm doing to my old stage 4 head, I should have taken a before picture, but hind site is a wonderfull thing.

Anyway, it was about 3 different colours and I took it right back to the metal and masked off the important bits and took all the valves out and proceded to paint it, loads of nice thick coats.

Just need to polish the inlets and outlets to make them shiny again and put it all back together with the new double springs and it'll be ready for ebay, lol.

What do you reckon?

Tony

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What happened to chamber no.2?

In the 13's at last!.. Just

The valve came off the stem at around 7000rpm and must have bounced around a bit before lodging itself firmly in the piston, i'm going to grind it smooth, luckily there is no damage to the valve seat.

Tony

At least have the valve seats recut, they look rubbish. Also, polishing the inlets is NOT a good idea. Exhaust ports OK, but even there a waste of time. Remove the exh valve guides and have that area properly ported instead.

I agree the seats look crap in the photo, but they are actually quite good, as for polishing I was only going to take off any surface rust and clean it up a bit to make it look more appealing on flea bay, I don't want to spend any money or un-needed time on it.

Tony

Ah fleaBay!

You've just lost yourself about £100 by painting it black! Everyone knows that the best way to make good money out of eBayers is to paint everything RED.

In the 13's at last!.. Just

Ha ha, very true, although black was all I had to hand :(

Tony

at least say it red in the listing and say the light makes it look black.

also tell everyone it comes with a free pleninuminimum but dont send them one.

Im surprised noone has commented about the title of this thread? Wheres Nic........?
SHane

i know ive been waiting for it to happen....

It was going to read refurbing my head, but thought this would attract more attention

But it is taking a while 8-)

Tony

EDIT: Also just noticed the name on the hand held hoover in the first pic, lol

Edited by mokle on 4th Jul, 2008.

the seats from this chamber (damaged one ) are too close the valve didn't drop of the stem, the other valve have pushed it , look at it closely three others are ok but number two is a big fish in the bocal

Hi Mokle, ive strated porting and polishin gmy head, im using carbide burr and grinding stones, what did you use to get a nice polished finish?

1972 998 TURBO SLEEPER

Wake up people, polishing is NOT good.
Quit this polishing nonsence.

When finished with the carbide burrs a stone finish is what you want.

I bought this head like this, all I have done is clean it up a bit for resale.

Tony

Cheers Vegard

1972 998 TURBO SLEEPER

Out of curiosity Vegard, why is polishing not good? I honestly don't know the answer to this and was thinking about it at work today.

I would have thought that a nice smooth surface would be better for air intake? Also, does this apply to only turbo'd minis or all engines?

Cheers

Tony

The finish wants to be smooth, as in no lumps & bumps, but doesn't want to be a highly polished finish. It wants to be a stone ground finish. This creates a slight turbulence in the mixture allowing the air & fuel to mix properly.
A highly polished finish will allow fuel to run down the port walls which won't be introduced back into the air.

WWW.TURBO-MINI.COM

That is because the smoth surface make the fuel condensate in the port wall. This means that the droplets of fuel will find their way into the comustion chambers. This leads to the combustion not being as efficient. In the exhaust ports this ofcourse doesn't matter at all. However, it's time consuming as doesn't add any difference there either apart from possibly increasing/decreasing the chances of carbon build up.

Thanks, that actually made sense to me, lol.

Tony

however polished combustion chambers and exhaust ports will reduce carbon build up because there is less of a key for it build up on..

THe jury is still out on that one, however, polished chambers do the same thing as polished inlets. No polish for me!