Decided to see if I could do something with the exhaust ports. Just a bit of very mild porting, as I've no real experience.
As can be seen from the photo this is a typical port, all four are very similar. The black outline is were the exhaust manifold gasket actually mates to the head, so anywhere from the outside edge of the line can be removed. I think that's a reasonable amount of material overall. And more can be removed further inside heading towards the valve seats. I'll go easy there as I've no idea how much can be removed.
Started doing some porting. I've opened up the exhaust ports to the manifold by approx 12% in diameter and back into the ports just before the port divider which is approx 10mm. As for the rest of the ports to the valve guides I'm only sanding rather than grinding leaving the ports polished with all the casing marks removed.
I've decided not to port the inlet side, to my untrained eye it looks good with a nice machined surface to promote atomization of air & fuel and there's not much meat to remove were the ports meets the inlet manifold. Also, I reckon if there's any real gains to be had it's on the exhaust side as the S/C does the work to get air in but on the exhaust side any possible back pressure should be reduced as much as possible.
Now, I may not make any significant gains from porting the exhaust side but my view is it won't do any harm and can only aid expelling the exhaust gases, plus it costs nothing to do really except time which is fine, and the bonus is, I'm out of sight of Mrs Woofwoof!
Initial porting.
Decided while I was at it to lightly port all of the exhausts rather than just sanding polishing. I took it easy as I just don't know how much can be removed without doing damage. But I go rid of the casting lines and improved the valve bowls and got rid of a few sharp edges plus overall the ports are larger with diameter increase of 1-1.5mm Ideally, to do maximize the porting an old head chopped up showing the cross section would've been ideal.
Just sanding & polishing left to do which will again help flow.
I know the photos are curse word, it's difficult to get real clarity with a camera phone and average lighting.
At long last my straight edge arrived on a second attempt. I originally ordered an ''engineers straight edge'' as it was called but it never arrived which turned out a bit of blessing. After another online search I came across steel Gauge Plate or Ground Flat Stock as it's also known. This has a tolerance as good as the ''engineers'' steel straight edge (thickness: +0.05mm/-0.00mm per meter) and better still it arrived within a few days and as a bonus was 1/3rd the price of the first straight edge I ordered from a non premium brand.
Checked the head just incase at several points, all good
6 x 40 x 500mm
As can be seen from the photo this is a typical port, all four are very similar. The black outline is were the exhaust manifold gasket actually mates to the head, so anywhere from the outside edge of the line can be removed. I think that's a reasonable amount of material overall. And more can be removed further inside heading towards the valve seats. I'll go easy there as I've no idea how much can be removed.
Started doing some porting. I've opened up the exhaust ports to the manifold by approx 12% in diameter and back into the ports just before the port divider which is approx 10mm. As for the rest of the ports to the valve guides I'm only sanding rather than grinding leaving the ports polished with all the casing marks removed.
I've decided not to port the inlet side, to my untrained eye it looks good with a nice machined surface to promote atomization of air & fuel and there's not much meat to remove were the ports meets the inlet manifold. Also, I reckon if there's any real gains to be had it's on the exhaust side as the S/C does the work to get air in but on the exhaust side any possible back pressure should be reduced as much as possible.
Now, I may not make any significant gains from porting the exhaust side but my view is it won't do any harm and can only aid expelling the exhaust gases, plus it costs nothing to do really except time which is fine, and the bonus is, I'm out of sight of Mrs Woofwoof!
Initial porting.
Decided while I was at it to lightly port all of the exhausts rather than just sanding polishing. I took it easy as I just don't know how much can be removed without doing damage. But I go rid of the casting lines and improved the valve bowls and got rid of a few sharp edges plus overall the ports are larger with diameter increase of 1-1.5mm Ideally, to do maximize the porting an old head chopped up showing the cross section would've been ideal.
Just sanding & polishing left to do which will again help flow.
I know the photos are curse word, it's difficult to get real clarity with a camera phone and average lighting.
At long last my straight edge arrived on a second attempt. I originally ordered an ''engineers straight edge'' as it was called but it never arrived which turned out a bit of blessing. After another online search I came across steel Gauge Plate or Ground Flat Stock as it's also known. This has a tolerance as good as the ''engineers'' steel straight edge (thickness: +0.05mm/-0.00mm per meter) and better still it arrived within a few days and as a bonus was 1/3rd the price of the first straight edge I ordered from a non premium brand.
Checked the head just incase at several points, all good
6 x 40 x 500mm