Hi all,

I've got a bit of a question for all you experienced engine tuners out there. I've got an R1 5PW cylinder head that's been ported, purportedly by a reputable tuner however having now spoken to said tuner it turns out it's not his work.

Said reputable tuner chooses to both port and polish his cylinder heads. The cylinder head I've got has been ported but not polished, it is instead finished with a sort of rough dipped finish.

I've spoken to a couple of different tuners, one who swears by polishing and one who says that the rough dipped finish provides a better surface for the fuel to atomize on.

Here's a couple of photos of my ports:




Does anybody have any opinions? Should I put the engine in, get it dyno'ed and see if I'm happy with the results or should I just get it re-worked?

Cheers!

Mirror finished ports create fuel droplets on the surface, a smooth sanded finish is better as this does not happen due to the very slight turbulence, well that's the theory.

I do not suppose it matters much if you are injecting into the head, I would not want to pay for a mirror finish anyway.

[Edited on 3/2/16 by mark chandler]

I bought a rebuilt R1 engine with identical looking ports.
Supposed to have been done by Peter Beale but in the end I think it might have been done by Ian Beale..
Engine blew first time out and upon taking it apart it was a bodge up.

Seller was an Italian bloke from the Cambridge area, Angellos rings a bell.

Given how uneven those port finishes look, I'd suggest getting it redone if you can afford it. They should all be smooth and flow evenly from curve to curve. It might just be the photos though, as I had a hell of a time trying to take decent photos of the heads I did for my V6.

I go with a smooth sanded/burred surface as the slight tumble helps keep the fuel evenly distributed in the inlet tract.

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Originally posted by DIY Si
Given how uneven those port finishes look, I'd suggest getting it redone if you can afford it. They should all be smooth and flow evenly from curve to curve. It might just be the photos though, as I had a hell of a time trying to take decent photos of the heads I did for my V6.

I go with a smooth sanded/burred surface as the slight tumble helps keep the fuel evenly distributed in the inlet tract.

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