Have acquired a spare head for my 1600 Xflow, bought a dremel and grinding stones and flapwheels.
Going to give it a whirl to see if I can open the Exhaust ports enough to match the lolocost manifold and the inlet ports to match the inlet manifold
on the twin choke down draft Weber, and maybe open the manifold aswell.
Will keep you posted to let you know what happens.
(Is my Avatar christmassy enough)
No avatar complaints from me
me neither
Very tasteful (and acceptable in the office - just)
David
quote:
Originally posted by Kitlooney1000
Have acquired a spare head for my 1600 Xflow, bought a dremel and grinding stones and flapwheels.
Going to give it a whirl to see if I can open the Exhaust ports enough to match the lolocost manifold ...
Keeping the step in the exhaust is a good idea, but you could still do a bit of porting. Just try to follow the gasket port size but keeping an even 2-3mm lip inside it all the way around.
quote:
Originally posted by silex
Keeping the step in the exhaust is a good idea, but you could still do a bit of porting. Just try to follow the gasket port size but keeping an even 2-3mm lip inside it all the way around.
what's the technical reason behind leaving a step in the exhaust - wont it just fill up with burnt crap? or disrupt the airflow? i would have
thought (just from what feels sensible) that a smooth port would be better but obviously i am lacking knowledge here...
Don't start grinding before you know what you're aiming for. It might look nicer all polished and shiny but rough ports are better for fuel atomisation and if you go too big you'll make it worse than standard. It will all be wasted effort if you don't get it right. The valve seats and valve shape are the bits that need care.
It's worth getting hold of a copy of the Peter Wallage x-flow book
clicky
If you don't know a great deal about these engines then you'll find it a great help.
rgds,
David
Does this apply to all motors... BEC included? I was assuming (obviously wrongly) that polishing the 'blade engine ports would make the flow smoother too. Possibly releasing a few squidgens of bhp more.... no?
I think I understand... nothing is as lubricating as material of the same subastance in a fluid state. This obviously would minimise drag... as long
as the parent material isn't too rough - distorting the flow pattern.
It's a little like that manufacturing turbine blades and associated ports.
Its best to do both, Inlet ports should not be polished as this helps with the air swirl improving the mix with petrol. If the inlet flow is too
laminar the mix can starty to de-atomize and you get worse power.
Exhaust ports however can benifit from a good polish up. The gas flow will be more laminar and should flow faster, also there is a mirroring effect
that will help reduce heat transfer into the head and eject more of it into the exhaust.
Also, if you are going to give this a try, I would recommend making youself a very basic gasflow chamber using an old vaccum cleaner which is easy to
do and gives better results than guess work alone.
details and how to make a flow bench
http://www.veloce.co.uk/shop/products/productDetail.php?prod_id=V276&prod_group=Performance%20Tuning%20&%20Modification&