Building up a mean F head

[fixeruperer]

pre HE v12 jag engine have the combustion chamber in the piston and a flat head, the inlet ports aims right on top of the valve and those things can rev hard when played with and only a 70 mm stroke.

[ed]

except for the fact that by the late 90's you would have a hard time getting the heads off due to complete corrosion of the head studs

[fixeruperer]

the 6's (pre 88) are bad for it but most 12's dont really give you a reason take the head off, some can be nasty others can be sweet.
i got a v12 engine at work im umming and arring to build, an e-type is the only thing i wanna put it in but cant afford the car dammit.

[abently]

im no expert...

but i think theres more to it than simply narrow is better.
ie oldcorollas suggestion?

its just very weird that for all these years ppl like cosworth, ford, toyota, honda, chev etc etc have all been wrong.

im not outright saying your wrong bill, im just not understanding as to why its better!
i shall do more reading...

The narrow angle/straighter port allows the use of small ID ports, which inherently helps low-rpm port velocity and being straighter also allows greater possible high-rpm port velocities. The old ports would choke around the SSR at much lower high-rpm port velocites so the only way around this was to make them larger then neccessary which gave bad low-rpm port veloctiy results but then worked fine at high-rpms.

If you look at the 2005 Honda patent of the High-velocity port (which I posted a while ago), that is about already 95% of what the optimal port will be in 20 years time. From here on in, there won't be much more you can do to an N/A Engine without loosing low-rpm drivability via different Camshafts and matching headers.

I certainly wouldn't recommend to anyone, to port the new Cylinder Heads which come out unless they've been obviously restricted from Factory for emission reasons.

If you look at the Calibra (Cosworth) heads you'll see the ports are already narrow, which Mitsubishi followed later on with the 2G / Evo 1-3 Heads and same with Toyota and the Beams Head. All the new Heads cast by independents for the old V8 Ford/GM Engines feature straight ports also.... so its not old news, its just most automotive enthusiasts haven't picked up on it.

There is a picture of the 2006 Cosworth V10 Head cut-away and it is almost identical to the picture Sam_Q used for F1 heads so you won't pick up anything new from it (except for camshaft design).

And for those that say, well F1 and bikes rev past 15,000rpm.... that also means nothing. Its the piston speed which sucks and pushes the air in/out of the Head and this is limited to ~ 27Mps (by the laws of physics), conincidentally almost the same piston speed in a road going V-Tec Honda @ 9000rpm. (~ 26Mps)

[jezza323]

also have a look at the ports of the R32 VW Golf V6....interesting ill see if i can find some pics

EDIT - not really how i remembered it being but yeah, still an interesting design for an engine

[Sam_Q]

jezza: post it if you can

anyway people I have some pics that may interest people:





cams in place showing scissor gear arangement





comparasin for a 20v flange vs the FE head, the two outer ports on the FE head curve inwards. There is access to add material and realign the ports if wanted, I wont bother.





exhaust of a 7afe vs a 20v





intake of a 7AFE vs a 20v, the 20v being modifed however in the height of the injector releif.





a dial gauge on the intake measuring real intake lift, unlike many claims I found my stock ae112 intake cam to have 8.6mm lobe lift and about 8.35mm actual lift

[Sam_Q]

pics updated, I had 2 that wernt showing up

[Tap]

nice read... i have to keep in mind alot of things now