BJ 2.0Lt head porting

[chipa]

I'm looking at getting my head ported (along with other things) and I was wondering if anyone knew if the 1.8Lt head is the same design. i.e. ports/valves/chamber size. This is so that I can source a spare head to give to an engine builder to play with on the flow bench.

[boostedbatman]

Have you ever considered 'Extrude Honing' seems to be a lot more precise and failsafe.There is an awesome article about it in Hot Fours Magazine this month and let me tell you I wont be heading down any other path
Extrude Honing

[chipa]

From the look of it the main benefits would be stabilisation of the air flow which wouldn't result in a major shift of the total air flow. AFAIK porting would actually maximise the flow through your head by mildly changing the ports by removing material and deburring. 'Extrude Honing' seems to be essentially beburring and polishing the ports. Correct me if I'm wrong but I'd expect a bigger change from porting.

[twilightprotege]

1.8 should be the same.

but what are the other things you have in mind? a head port wont do much without certain mods

[chipa]

Well the headers are towards the top of the list, after that custom cam grinds, the new improved andy/gav intake manifold may be in the picture as well. After these basic NA mods are done a new piggyback computer will be needed. Thats as far as I've got so far. Its the weekend so my brain is getting far past switching on. At the moment I'm just looking at what may be possible or worthwhile to pursue while going for a bit more NA power.

[Cosmo Dude]

There are two schools of thought with porting,
Port and Polish
This theory claims that the polished surface helps air move more quickly and easily through to the engine.
Port alone
This theory claims that air is going to slow no mater what the surface so you may as well leave the surface die ground and put the polishing money into something more practacle.

Best to talk to the people who will be doing the job, they will know what they need to do but be prepaired with what you plan to do with your engine including cam info etc....

[BigMal]

Extrude Hone is an abrasive paste works great as you keep on pumping it
through till it flows a certain cfm. It also cleans the whole path as opposed
to porting which is limited to how far you can reach in. The upside of porting
though is you can work on a specific area eg enlarging the ports or grinding
off a hump that extrude hone may not concentrate on. Ideal would be a
combination of both eg port matching & extrude hone but not sure if anyone
does that.

Regards

Mal

[boostedbatman]

Most Abrasive Flow Engineers that perform the Extrude Hone will be able to do the porting as there are always sections on thin walled parts that the Extrude may be too risky if it removes too much metal so therefore the Engineers are also skilled porters for these sections. If you told them what you wanted I am sure they would be all to happy to help you out with additional porting. Everything in life has a price, if you give them what they want they will give you what you want.

[twilightprotege]

there is a place in sydney that does extrude honing, but it's not cheap. a good port job will be better. in terms of p&p, smooth the flow, but dont polish it. polishing will yield a too smooth of a run and the air and fuel wont mix as well.

anyway, since you're going full exhaust, cams, IM and ecu, p&p will do nicely.

[BigBoyLemonade]

Im getting my heads on the eunos polished and a mild port on the exhaust valve. I would just get it ported by a professional/engineer. They will use a flow bench and will know when to stop porting or to keep going.

To be honest im not sure what effect it will have on my motor but it should make it nice and smooth, even though its one of the smoothest v6's ever. The intake ports are perfect according to Greg my engine rebuilder http://www.proengines.com.au - free plug! The exhaust port has this funny lump that restricts a lot of air and looks like its part of the original cast.

This extrude method sounds a little dangerous and not good value for money...

thats my 2 cents

[twilightprotege]

dont forget too chipa, leave the intake valves the same size, but get the exhaust side a mm or 2 bigger (they are 5mm smaller stock)

anothing about extrude honing, it works hardest on the narrowest part of the runner it's working on....which isnt always a good thing (aka valve seats)

[chipa]

Originally Posted by twilightprotege

dont forget too chipa, leave the intake valves the same size, but get the exhaust side a mm or 2 bigger (they are 5mm smaller stock)

anothing about extrude honing, it works hardest on the narrowest part of the runner it's working on....which isnt always a good thing (aka valve seats)

Thanks, that was going to be my next question (changing valve sizes).

[twilightprotege]

yeah leave the intake the same, but make the exhaust side bigger.