Cylinder Head Removal

[Mark Halligan]

Doug,

I just followed the instructions that came with the porting kit from Standard Abrasives, these say that the inlets should be roughish and the exhausts polished, I hope thats right cos it's the way I have done it now!

Can you post a pic of your exhaust ports when you get the head off. it will be interesting to see what has been done to them too.

Cheers,

Mark.

[marty]

Yes it definatly been fiddled with, the brass looking thing is the valve guide this would normaly have been removed before porting so as not to damage it.
doesent look like it was done profesionaly
You will see better when you get the head of and valves out if thave done enough to matter you can polish exhaust ports but you get a better gain by making shoure manifolds and gaskets line up perfect.
When you refitt new gaskets make shour they dont hang over the edges (into the ports)

my speling is terible

[Doug_RS2]

Cheers guys - all advice is getting taken onboard.

More pics to follow - hopefully get that head off and in bits tomorrow night.

[desmo888]

Originally posted by Doug_RS2


If you look at the brass coloured thing (is that the valve stem guide?), it has the markings/scoring on it as well - as if a wire brush has just been thrown down each port.

Doug,
That would be a rotary file that did that work. I would have those guides replaced while the head is off. They are probably okay but it is a lot easier to do it now.
The roughness is okay but I would go in there with some fine sanding drums to clean up some of those rough edges like on the splitter. Those are high stress points which should be smoothed out.

[Mihnea]

Doug, that port really looks like some monkey lad has thrown a rotary metallic brush through it saying "it'll flow better!" but without having a real clue as to how one is supposed to do it. I'm far from being an expert in head porting jobs but the way Mark did his seems to be the right way for me.


Keep us posted!

Cheers,

Mihnea

[A6 AVANT]

Doug, The "brass coloured thing" is your valve guide and to me it looks like someone has taken a die grinder to it and butchered it! I know the different theories on inlet ports but take a comparison between what yours look like and Mr Halligan's after he has "played" with it. If it was me I would go for a smooth clean finish. If your head is going away to be done I would get new guides and see if they can polish the ports a bit. It doesn't look too bad.
This is only my opinion and every one else may have different one's, but hey that what this forum is for.
Good luck on the rebuild

[Doug_RS2]

Yes - I agree it looks ***** - I think I will get the inlet polished up - I won't get any material taken off in case a substantial amount has already been taken off. I'll get new valve guides as well - Are thes something a head specialist is likely to have or do I have to get Audi ones?

Well, i managed to get teh head off tonight - another 3.5 hours work, so about 9.5 hours for me to do it. Bloody heavy thing to lift off yourself!

Mark - the exhaust ports are black and I couldnt get a good picture - basically they, look standard to me - quite rough but I'm not sure if it's becasue of all teh carbon deposits - it really is thick black stuff on it.

[Doug_RS2]

The worrying thing about my head is in the pic - the one that looks damaged is cylinder 3, the one that had the spark plug fly out. The damage doesn't look new, as it is discloured like the rest of the head. Do I just live with that, or get it ground out and smoothed?

I thnik I might be asking Mark for some polishing tips!

[Doug_RS2]

Forogt to say - I nearly got it all stripped down but couldn't get the cam sprocket off - should have done that on the car! But i'm going to grip the cam chain in the vice and undo it - I'm replacing the chain (and cm) anyway!

Do head companies usually want the head stripped of the valves or do I leave everything in after I remove the 2 cams?

[marty]

Where i used to work we would do as much or little as the customer wanted just charge for the time. They kept in stock a lot of guides and would macine to suit.

[A6 AVANT]

Doug, When I did Beeties head (3b) about 2 months ago, I stripped the head of everything apart from the cams,chain,valves etc. The company we use in Leicester are very good and stripped the valves out,ground the head, pressure tested it,replaced worn guides,re-cut the seats,and rebuilt the head with new chain etc so when we got it back all I had to do was fit the manifolds etc. I can see you have some broken exhaust manifold studs and cannot stress enough that they all need to be replaced as they will all be weak! Also whilst head is off make sure all your water ways are clear as the small ones on Beeties were corroded and blocked! From your pics of your head yours do appear ok.
HTH
regards,
Chris

[A6 AVANT]

Sorry, forgot about the damage to your head, if the car ran fine before it blew a plug I would ask the head company to clean it up and it should be fine. Might be worth checking the tightness of your spark plugs from time to time as I have known plugs to work loose and with the pressures you guys are running at it wouldn't take much to blow someone elses! Just a thought guys!

[marty]

I dont Know enough about tuning turbo cars to coment properly but if it was a motobike head the damage to the comustion chamber would have to be repaired as this would be a cause of detonation.(possibly why it blew the plug out)
Problem is you would have to measure the volume after repair and match the rest of chambers to it. As i say i dont realy Know how imortant this is an these cars.

[Mark Halligan]

Doug,

I wouldn’t polish the inlets, just tidy them up with a flap wheel to tidy/smooth them up a bit. The instructions with the Porting kit I used said that the inlets should have a “slightly rough finish” a 120 grit flap wheel will do this and shouldn’t remove too much material at the same time.
The Standard Abrasive’s kit instructions do say that the exhaust ports would benefit from some polishing though, I think that the theory is that it avoids all that carbon that builds up on a rough surface and impedes flow.

Doug is the piston marked as well on that cylinder or just the head?

Here’s a pic of the Standard exhaust port, before polishing, after cleaning up with a bead blast.


Mark.

P.S. Oops forgot to say this pic is with the guides pressed out.

[Doug_RS2]

The pistons are in good shape there are a few pit marks were the inlet valves would be. Cylinder 3 is not any different from the others - and certainly isn't damaged like the head.

If I get the damage smoothed out, does that mean they need to match the other 4 cylinders for volume? Is this the thing you were tlaking about Mark - put a sheet of perspex over each one and fill with a liquid to match them?

Mark - have you got a source of the head polishing kit - I though I had a link for that sort of kit somnewhere but can't find it.

Thanks all.

Greg - the head gasket is not as thick as 3mm - not even 2 mm.