Cyl head porting

[saildrive2001]

I want to smooth the intake & exhaust ports in the head & wondered whether it is advisable to use a Dremel tool with a 120 grit sanding drum. I am wondering if the grit might get inbedded in the aluminium & cause a problem by getting into the cylinders. What would you suggest to use if this is not advisable.

[niallf]

There's some notes on Porting tools about 2/3rds the way down this very informative K-Series (Lotus Elise) engine page. May be useful.

http://members.aol.com/dvandrews/kengine.htm#headtools

Niall

[saildrive2001]

Thanks for the info Niall, a very interesting & informative article. The spiral wound drums are what I was going to use. I*'m just going to do some general cleanup of the ports, not confident of doing too much reworking. The car is only for road use & not racing.

[memini55]

Keith,
Something I have used on the last couple of head rebuilds with great results is a two stone brake hone. You can get a couple of different grits of stones and I used a squirt of WD40. This worked really well on the long intake side and keeps things very uniform. This is a super easy way to get rid of the casting trail or ridge which most heads have.
Good Luck
Mark

[memini55]

Keith,
Something I have used on the last couple of head rebuilds with great results is a two stone brake hone. You can get a couple of different grits of stones and I used a squirt of WD40. This worked really well on the long intake side and keeps things very uniform. This is a super easy way to get rid of the casting trail or ridge which most heads have.
Good Luck
Mark

[jono]

I was going to draw you to the same article and porting advice therein. Dave Andrews of DVA rebuilt the K series on my seven and is a top bloke - what he doesn't know about porting heads and engines generally isn't worth knowing

[steveww]

Pay attention to the area immediately around the valve seat. Think about the flow at small valve lifts. This area is just as important as the radii in the ports.

A Dremel is good for tight areas but will take an age to do anything on the main runs. A spira band in a regular drill is what is required here, for removing more material go for a tungsten carbide burr. Remember to get one for aluminium (larger grooves) and use a bit of light oil (3 in One) to stop it clogging. Use some old valves turned down to protect the seats while you are working in this area. Use an old head gasket to protect the head face as well.

See http://www.steveww.org/index.php?id=76 for more of my tips.

[saildrive2001]

Thanks for the advice & ref. to the articles. Can any of you send a sketch or sketches of where to remove metal, as they say a photo (or sketch) is worth a thousand words. I am not sure about what to look for in the valve guide area. I should add that my head is a Stromberg unit which has of course siamesed inlet ports which are a little more complicated than the Weber ones.

[Bill]

Keith

I did my Elan head porting over 40 years ago - it was a long tough process then.

I have just finished a TR3 head (cast iron) I used several air tool die grinders, various stones in a drill and finished it all off with a dremell tool - flexible extention from 120 grit down to polish, The ports are now a mirror

DO use a manifold gasket as a pattern 'tho (even if you have to make one for the intake side) and match the manifolds to the head ports outline. This will INSURE that there are NO obstructive ridges at the interface of the ports to the manifolds.

Worked for me!

Keep your stick on the ice!! Take your time - get a few more hosepower and assist smoother running.

Bill - 26/0538

[steveww]

Don't use a die grinder on an aluminium head unless you are an expert A regular drill with a burr will remove material more than fast enough. You don't use grind stones either as these clog up really quickly.

Fortunately when I did the Stromberg head on my car I had the guidance of Dave Andrews to point me in the right direction. Getting a copy of the Vizard book on the A Series is well worth it. Although not directly related to the Lotus twinc the principals laid out in there are good for any engine.

For the Stromberg do not be tempted to make the divide between the two inlet ports sharp. Think what happens when only one cylinder is drawing air. Also the floor of the inlet port is rather important, think about what the carb is doing particularly the air valve when not at max rpm.