Turbo Head Coated
Turbo Mini Forums

I got my head back from the performance coater on Friday! Yay!

I've posted a lot of pics here: http://www.drjing.com/Mini/BLOG/PolyDyned.htm

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1967 Cooper 's' Turbo build @ www.drjing.com

I'm not wanting to sound negative here, but:

If I were you, I'd use some time/money on having the head ported instead of coating hte internal passsages in the head. If you've removed the valve bosses etc. and reshaped the head, more exhaust would more easily have escaped. This also mean less area for the heat to dissapate to.

What you've done is very smart, but you should have modified the head first.

Hi, Vegard. I did modify the head a bit (note that the combustion chambers are not standard size!). If you look at my blog, you'll find a few head mod posts I made. I opened up the wrist areas in the chambers, as this seems to be the biggest restrictive area. I also did some smoothing in the ports. I don't know how far I can go without destroying the head, so I was pretty conservative with my mods... Getting good heads over here is a much more expensive proposition than it is over there, and I prefer to be cautious...

mini1071s, yup, I'll be doing the pistons, too. They'll get the reflective coating on top, and slick coating on the skirts. Also, the bearings are getting a slick coating, and the header and downpipe will get ceramic and header wrap..

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1967 Cooper 's' Turbo build @ www.drjing.com

I can see that you've modified the chambers, but that's not the most important place. If you look at this picture:

http://www.drjing.com/Mini/Images/PolyDyned/IMG_6597.JPG

You haven't removed any material where it's important. I'm not trying to attack you, rather inform you :)

mini1071s, their web site is www.polydyn.com. To do the pistons with the reflective and slick coatings, it costs $33/piston (site still does not have a pricing list). I don't know how much the oil-shedding coating would be for the bottoms, but I'm installing a windage tray, so don't expect I'll need that done...

Vegard, like I said, I did light mods. I didn't remove the bosses on the intake because I didn't think they'd make that much of a difference (when compared to the other restrictions in the head). Again, I did light modifications, nothing too extreme. You don't state it, but I assume that the head mods you are implying are per Vizard? Or is there some other reference you are using?

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1967 Cooper 's' Turbo build @ www.drjing.com

Comment, not sure if its valid or not but is the internals of the head coated with water repellent?
Just wondering if this aids or hinders heat transfer from the head to the cooling system

Yes, the inside is coated with the repellent. I was concerned that this would act as a thermal barrier, but was assured that it would actually help in heat transfer. If temps shoot up over 200F, I'll know that there's a problem. Then I'll just have to pull over and pee in the radiator (the coating doesn't like urine)... :)

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1967 Cooper 's' Turbo build @ www.drjing.com

good call although pee is usually warm

as long as its been considered then thats all that matters. should certainly help if it stops corrosion and is just as effective at transfering heat if not more so.

I think Vegards right though, surely leaving the guide bosses "stock" will restrict flow somewhat. This is the most restrictive area of the ports, not only does the gas have to make it's way round a tight bend, but it also has the valve guide and boss to pass around. This is usually the first area to be modified as mods in other areas have little or no effect if this area is untouched ?
Again not trying to be negative, just my 2p worth. lol

WWW.TURBO-MINI.COM

I didn't think the intake needed that much work since this is an MG, and the intake is HUGE! I did remove corners and open up the short side on intake and exhaust. Guess I live and learn, eh?

But I would like to see real data on that. I think that Vizard recommends it (have to go back and re-read that section), but just because everyone else is doing it isn't enough justification in my mind. Do you guys really see an improvement from this?

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1967 Cooper 's' Turbo build @ www.drjing.com

mini1071, sorry, I forgot to respond to your condolences!

It is a tragic situation. Thankfully, I'm not that close to the area (several hundred miles, I believe). And sadly, the situation devolved to the basest human instincts. It's getting under control, and help has been pouring in from around the country. Houston is a major relief hub for refugees from New Orleans, and I'm hearing that many plan to relocate here. The vast majority of the refugees are grateful for the help, but there is always some scum in the pot, and some are taking advantage of the situation here. Curfew has been put in place to try to prevent criminal activity. Sad, sad, sad...

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1967 Cooper 's' Turbo build @ www.drjing.com

Dr Jing is this the head that I sent all the way out there to you?

Dan

Indeed it is, Dan! Looks a bit different than when you sent it, eh?

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1967 Cooper 's' Turbo build @ www.drjing.com

Oh, and I'm still looking for advice. I've gotten "constructive criticism", so far, but no guidance... I've looked at Vizard, again, last night, and see some potential areas for modifications, but making more than a little change can translate easily into a scrapped head...

I might go ahead and take down the intake bosses, as I can still do that at least... But it being an MG Metro head, I'm not sure how much difference this will really make.

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1967 Cooper 's' Turbo build @ www.drjing.com

Dr,

If you imagined you were to press out the guides, and then swept a nice radius onto the 'long' side of the elbow, you won't cut into the water jacket. There looks to be a lot more 'area' in there than a stock head anyway, and you are ramming the air in with the aid of a turbocharger, so you have to ask what the real world gains will be - the valve is still the limiting factor in the majority (all?) of the cycle - except maybe at full lift...
Basically, if this was a nat-asp head, you'de see a huge difference - being a turbo, it won't be so great.

Thanks, Dave. So, you're saying I'm fine as-is?

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1967 Cooper 's' Turbo build @ www.drjing.com

What i'm saying is - it could be better - but what will you lose? three, maybe four hp right at the top end of the rev/power range?
Is it worth the effort?

Another analogy - I always do my own heads; I figure I can get to at least 90% of the flow of a ?600 race head for 1/10th of the cost. That makes sense to me - especially in forced induction format. Unlike nat-asp, the ports are far from the most critical thing for power / torque devivery / fun. There is waaaay more going on elsewhere.

Good to know. Thank you, Dave. I'll leave as-is, and maybe port my other head a bit more radically, for comparison. Then I can see what kind of difference it makes! :)

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1967 Cooper 's' Turbo build @ www.drjing.com

im with you on that one dave also there is a nice buzz when you do the work yourself rather than of the shelf item.

mind you im having a few probs with mine at the moment as i seem to be getting water in number 2 and cant find were its going. just thats its always wet and i lose water when cold so will be doing a parifin test and fit my old head back on for the time being, hopefully not a crack but may be a slight warp in the head.

fitted a new head gasket the other day but didnt last long befor etrouble started again.

so watch this space.

always looking for them bigger bunches of bannanas