G'day,
Thanks for the remarks about the head.
After racing and developing heads over the years I have never seen a motor run poorly from too smooth a port.
I have heard lots of arguments about smooth/textured ports for decades.
Lots of stories by "experts" maybe covering up a fundamental flaw in an engine, with a bit of BS
The argument about too "shiny" ports, particularly intakes, was that fuel particles would drop out of (suspension) the dynamic emulsion in the ports, hit the wall of the port and splatter, forming a wet layer on the port wall, of the refrerred to as "film adhesion".
So if we go back to the engines being built in the 70's for argument sake, (where a lot of the urban motor myths come from), and take example of where this kind problem reared it's head.
The Ford 302 Boss motor.....302 Windsor with 4V Cleveland heads on it.....5 litres of motor with intake ports you could put your fist in.
Chuck in a huge flat tappet cam, a couple of 660 centre squirter Holleys on one of those horrid old Edelbrock dual 4 barrel high rise manifolds with the massive plenum, and that nice shiny port job.......well that motor didn't boogey until about 7000 rpm.
It suffered from insufficient "gas speed" through the ports which led to fuel particle drop out, (because of poorly atomised fuel particels from too big a carb or injector nozzle (eg. pool balls instead of grains of salt sized fuel articles) wet intake port walls and a tendency for the "tuners" to see wet spark plugs, jet the thing back heaps and end up with the motor generally running like a dog.
The problem is worse with methanol.
Blokes with sprint cars on 360 Chevs with 2.25" injector throttle bodies.
Back in those days injection was a bit raw and wet plugs foold a lot of tuners into backing off fuel the blowing a motor.
Similalry, the blokes who had the 1000 CFM Dominator sitting on a single plane manifold on a highly tuned 350 Chevy. Same deal.
The tuners would say "everything in the engine is top quality and well tuned. The problem must be those shiny ports."
Not really, just a bad choice of component combination.
Another excuse I used to hear about poor engine performance was that "the ring ends had lined up and the motor is losing compression".
Rubbish, ring ends might line up once in a blue moon for a milli second, because rings rotate at about 1 revolution per 1000 RPM in 4 cycle engines.
If you ever get the chance, go have a look at (ultimate performance) the heads on a Forumla 1 engine. All the ports are like a mirror.
If you ask you the engineer if the ports are too shiny, he would slap you on the shoulder, laugh and say 'you know a bit about engines do you?"
thinking you were having a joke with him/her.
My opinion is only one man's opinion, one of many opinions, but I can say it's my observation from over 40 years of specifically engine work, that a nicely finished port is never a problem. But, I might be wrong.
My main detractors over the years, always accused me of being too fussy and they used to hate it when we won and I would stand there and say "Who's a fussy boy then, who's a fussy boy?"
Alrighty then...........yep I reckon the Power Commander V with the auto tune is the go. Not too many dynos around Darwin.
To the guy with the cams, could you tell me where I can get them and the cost please ( if that is approriate here).
Really enjoying this forum and talking to you blokes.
Feels like I have been pulled out of the old shed and dusted off and made useful again.
Thanks all and have a good one.
Topic: Perforrmance Camshafts for the C5 (Read 12168 times)