Valves

I didn't check but if those Ferrea valves are titanium, you are looking for truble IMHO. Ti on the street is not a good idea- first, the stems need to be chrome-plated or they sieze in the guides, the tips need either lash-caps or stellite weld as pounding from the rockers causes flaking on bare Ti, and finally, in the exhausts, the seat areas spall at high temperaturers. Racers use them successfully by tearing the heads down every rasce or 500 miles, which ever comes first. The cheap Ti valves you see on E-bay & others are usually worn-out racengine take-offs. If the Ferreas are SS, no problem- they make good stuff if a bit pricey. I personally run Manley ss valves, the exhausts with cut-down stem dias in the port areas, for a little more exhaust flow.
Aussie 2V heads can run 4-V valves with a pocket-port job, done by someone who knows what they're doing with Ford engines.

Thanks for the reply. In an earlier post Dan Jones wrote "A lot of people blindly install 4V valves in Aussie 2V heads but I don't recommend it. You want the valve size to match the port size. The larger 4V valves also hurt the transition at the short side radius." Comments? He also mentioned "unshrouding" and "bowl porting". Can you enlighten me as to what these are? I'm not terribly familiar with head machining. Is the performance change worth the extra expense? (I know everything is relative....)

[This message has been edited by Husker (edited 07-31-2003).]

quote:

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Originally posted by MARLIN JACK:
.... After all I'am NOT going racing at LeMans!

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Off Topic:
Cozman's GT5 was the Pace Car at the 1982 LeMans (I think he said 1982, but it could be '80 - '83 LeMans) and it's White GT5. I'd like to get a VHS of this race and present it to him in appreciation of the help he's provided me. So, can anyone advise me how or where I can obtain a film of the 1980-83 LeMans race? Maybe even e-mail me or record it if you see it re-run on ESPN-2 or the Speed Channel? I'd appreciate it and would make a reasonable payment, even if you saw it and didn't even catch the entire race on VHS. I'll ask him what year LeMans and update this post. But if you see a White GT5, no elephant ears or rear spoiler going around LeMans as Pace Car on TV, then please insert a VHS tape and hit the Record Button on your VCR. He'll really get a kick out of it, and deserves a nice little momento, given what he's been through with his baby. IMHO.

Bowl or pocket-porting concentrates on the volume directly below the valve seat rather than the whole port. Since we know the bottom of the exhaust port from the turn outward is pretty much useless area (ala 4-V exhausts), there really no sense in opening this up on your 2V heads. The turn from vertical to horizontal is also worked to a larger radius, but this is dangerous with Cleveland heads- see the photos I published in the April POCA news of various cut-away heads and how thin this area really is. All porting should properly be done by an expert with a flow bench to incrementally check the effect, but nearly anyone can do a little pocket-porting without too much fear of screw-ups. Incidentally, Dan may be correct- 'bigger' often doesn't translate to' more power', even if the worked port flows more air. Theres a new (to me anyway) technique being used by porters that involved squirting Dykem metal-dye into the flow-bench airstream, then analyzing the resulting dye patterns in the ports and combustion chamber. Good write-up w/photos in the latest Circle Track magazine.

> Jack, Marlin. Thanks for the input. I guess I should have been more
> specific with my question. In an earlier post, Dan Jones wrote " A
> lot of people blindly install 4V valves (2.19" and 1.71") in Aussie
> 2V heads but I don't recommend it. You want the valve size to match
> the port size. The larger 4V valves also hurt the transition at the
> short side radius. Comments?

Compared to the intake, the exhaust port on the 2V heads is relatively
strong. Getting the intake port to flow 225 CFM and the exhaust 180
CFM is relatively easy. 250 CFM on the intake takes considerable
work. Without more intake flow, increasing the exhaust flow past
doesn't the 75% mark doesn't make more power but it may increase fuel
economy. Also 2V head flow tends to level out at 0.500" to 0.550" lift.
I recommend a 2.1" intake valve, a 1.65" exhaust valve (both with a
back-cut) and a good multi-angle valve job. If you do not bowl port
then stick with a stock 2.04" diameter intake valve.

> In the same post, he mentioned "bowl porting" and "unshrouding".

Bowl porting is as Jack describes and provides the best porting bang
for the buck. Valves are said to be shrouded if there is material
around them that inhibits flow. Removing material in the combustion
chamber to improve flow is "unshrouding". Aussie 2V heads have
a particularly tight combustion chamber and benefit from unshrouding.
For more information, I suggest you pick up David Vizard's book on
350 Chevy cylinder heads. It's the best cylinder head porting book
in print.

> Is the boost in performance worth the expense?

Cost varies by region and by head porter. I suggest you look into
head porters in your locale that cater to the circle track crowd.
You should be able to find one who has experience porting 2V heads
and can back it up on a flow bench. Whether or not it is worth it
is highly dependent upon the rest of the engine combination and the
fatness of your wallet.

> I didn't check but if those Ferrea valves are titanium, you are
> looking for trouble IMHO.

The ones I suggested are not titanium.

> Ti on the street is not a good idea- first, the stems need to be
> chrome-plated or they sieze in the guides,

Most are moly-impregated these days.

> the tips need either lash-caps or stellite weld as pounding from
> the rockers causes flaking on bare Ti, and finally, in the exhausts,
> the seat areas spall at high temperaturers.

Agreed. To run titanium successfully you need a compatible guide
and seat material, as well as hardened tips and coated stems.

> If the Ferreas are SS, no problem- they make good stuff if a bit pricey.

Ferrea makes several different valves for 2V and 4V heads. The entry
level 5000 series street valves are quite cheap, around $150 for a set
of 16. I run the competion series valves which are suitable for spring
pressures associated with solid roller cams but these cost more like
$350 to $400 a set. In between is the 6000 series.

> Incidentally, Dan may be correct- 'bigger' often doesn't translate to'
> more power', even if the worked port flows more air.

4V valves may increase flow over stock but it's typicaly not the
valves but the rest of the port work that did the trick. Based upon
the flow bench data I've reviewed, the sizes I recommend above work
best for the typical high performance street engine.

BTW, I've had several different heads on the flow bench recently.
When I get the chance I'll post the results.

> Theres a new (to me anyway) technique being used by porters that involved
> squirting Dykem metal-dye into the flow-bench airstream, then analyzing
> the resulting dye patterns in the ports and combustion chamber.

Sounds like a flow visualization method to me. We use smoke in our
wind tunnels for flow visualization. Helps to visualize where the
flow transitions from laminar to turbulent, velocity differentials,
and areas of flow separation. There are also water tunnels that
accomplish the same thing.

Dan Jones