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Guide to head porting
Irony - 9/6/10 at 11:05 AM

I am rebuilding a Rover V8. I have been reading my book 'How to powertune a Rover V8' and it mentions polishing/cleaning up the inlet and exhaust ports in the heads. I have my heads off now and they are in general good condition. A good clean to get some grott off and they will be okay I think. Whilst I have them off is it worth me doing some grinding polishing work on the ports?? I am a dab hand at using a dremel but I need some instruction as I am a newbie.

Is it worth me doing this? If so is there a half decent guide anywhere?

dan_g8 - 9/6/10 at 11:31 AM

hi, im not going to be any help with your question. but im planning on rebuilding my v8 soon, where did you get your book from ? i had a look on amazon and its over £150 !!!

ta dan

Jon Ison - 9/6/10 at 11:50 AM

Don't know the heads in question intimately but a few general tips.

Do not highly polish the ports.

Highly polished and all sharp edges removed from combustion chambers is the way to go.

Remove any casting flashing.

Smooth radius's are what to go for.

Air does not like tight turns.

The valves/stems/guides are a big restriction, any widening in this area will be a plus.

Ports can be to big !!

Match the port joints to the manifolds, when assembling make sure the gasket does not stick into the port to restrict flow.

Dan, I have vizards RV8 book at home, want it ?

Rod Ends - 9/6/10 at 12:03 PM

Porting School articles by David Vizard

Irony - 9/6/10 at 12:11 PM

quote:
Originally posted by dan_g8
hi, im not going to be any help with your question. but im planning on rebuilding my v8 soon, where did you get your book from ? i had a look on amazon and its over £150 !!!

ta dan


ebay i think. A good website is Mez. Can't remember the addy but just google Mez Rover V8

contaminated - 9/6/10 at 12:51 PM

I've got a PDF'd porting guide. Send me your email.

Dan

contaminated - 9/6/10 at 12:53 PM

quote:
Originally posted by Jon Ison


Do not highly polish the ports.



Interesting, I'd half agree with that. I'd highly polish the exhaust ports but leave the inlet ports rough to encourage air turbulance. Any views - I'm about to have a go myself.

mcerd1 - 9/6/10 at 01:19 PM

quote:
Originally posted by contaminated
I'd highly polish the exhaust ports but leave the inlet ports rough to encourage air turbulance. Any views - I'm about to have a go myself.


I've been told about not over polishing the inlet ports by several different engine builders that I'd trust

but I'm not sure if you'd gain anything noticable by polishing the exhaust ports to a mirror finish....
only one way to find out I suppose - it'd be interesting to see if you can measure any difference

BenB - 9/6/10 at 04:11 PM

Commonly held belief is that you want a slightly rough inlet to ensure turbulent flow to keep the air / fuel mixture mixed and to ensure a good boundary effect. Some people though say that the fuel / air mix moves too quickly for this to be an issue, however, dynos seem to suggest that a slightly rough inlet is a good thing.