Basic Head Work.

[CastleMGBV8]

Found this article on the Brish V8.org board which gives some good basic info on how to modify heads in the importanrt area behind the valves.

http://www.britishv8.org/Articles/Insta ... Valves.htm

Kevin.

[sidecar]

Found this article on the Brish V8.org board which gives some good basic info on how to modify heads in the importanrt area behind the valves.

http://www.britishv8.org/Articles/Insta ... Valves.htm

Kevin.

Hi Kev,


Good stuff, I wanted to post in this thread so I can find it again and read it at my leisure when the missus is down the gym!

Pete

[CastleMGBV8]

Pete,

Good idea I was surprised at how restrictive the Chevy heads are, they look a lot worse than the rover heads in the all important area behind the valve heads, and demonstrates why it is the most cost effective way of increasing power on an otherwise standard engine apart from a sensible increase in compression ratio to say 9.75/1 and your dizzy mods.

Kevin.

[sidecar]

Pete,

Good idea I was surprised at how restrictive the Chevy heads are, they look a lot worse than the rover heads in the all important area behind the valve heads, and demonstrates why it is the most cost effective way of increasing power on an otherwise standard engine apart from a sensible increase in compression ratio to say 9.75/1 and your dizzy mods.

Kevin.

Hi Kev,

I've just modded another dizzy, it was a right git to get the "star wheel" off, I had to make a puller in the end! Anyway one copper spring and one silver spring seemed too stiff on this dizzy for some reason. Max advance was only going in at around 3.5 krpm. Maybe the bob weights were lighter? I'm going to try two copper springs to try to get it all in around 2.5 krpm. You will need to check your dizzy when you run your new motor up.

Pete.

[CastleMGBV8]

Pete.

Thanks, when we get it running, about another week I'll check what advance I'm getting, as long as it's in the ball park and all in by 3000- 3250RPM it will do for the time being.

The plan is go Edis 8 in due course, I have fitted the trigger wheel and sensor bracket and have had bungs welded in to the collectors for the wide bands so can upgrade to distributorless ignition in due course.

I already have the hardware and injectors from a Gems/Hotwire EFI but will need an earlier 3.9/4.2 plenum as the gems one sits too high at the front.

Just more money!

Kevin

[bones]

ive opened my rover heads alot and just re-done the exhausts to let the gas out better, i would put a picture up ,but no camera rich

[Eliot]

Here's some photo's my late father did for my mates seight. The valve sizes remained standard, but he machined seats out and gained 1 or 2 mm just by reducing the seat width. He reckoned you only needed about 1.5mm of actual mating face to get a seal.
Manifold was ported lightly, trumpets shortened a little - other than that, all sizes remained standard. (Sadly I didn't take notes on all this stuff, so only have photo's to go on now - 30 years experience lost forever)

http://www.mez.co.uk/westfield/09110004.JPG
http://www.mez.co.uk/westfield/09110003.JPG

He then machined down the guides and ported the heads:
http://www.mez.co.uk/westfield/09110001.JPG

He never used stones for porting - just tungsten carbide burrs (not to be confused with the cheaper carbide only burrs)