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wmunchovie's Avatar
 
Join Date: Nov 2007
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valve recommendations?

Hello All,

I am looking for recommendations for intake, exhaust valves, seats, guides and possibly springs; I have a set of 3.3L twin plug heads and I want to go back with something dependable but not too exotic. This is a street 930 going to the deli a couple of times per month but I need for the seats to stay glued in

Thanks for the feedback!

Munchovie.
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Old 12-10-2007, 08:03 PM
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I would go with some Ferrara valves- people seem to have good luck with them- maybe 1mm up on the intake side?
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86' 930/GT-40R Sold
94' Rustang GT daily (long gone)
2008 C6/Z51 Corvette
Old 12-11-2007, 06:38 AM
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Wo ist die Rennstrecke?
 
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What's wrong with OEM for your application?
Old 12-11-2007, 02:58 PM
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Quote:
Originally Posted by DonE View Post
What's wrong with OEM for your application?
Not ruling out OEM at all, rather just trying to get everyone's experience with different valve related components; the last time I used OEM I wound up with pitting of the exhaust valves, and some splitting of intake valves with hairline cracks Im not too sure what is causing these maladies so I want to try and do my research so they are avoided during my current rebuild.

So my friends: step up and tell me the valves you like and why ( even links if you have them handy )

Thanks!
Munchovie.
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Old 12-11-2007, 03:15 PM
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OK

I use stock valves. The seats and guides were installed by JB Racing and I didn't ask them for anything different other than what they suggested for my 80% street / 20% DE.

As for valve springs, I use JB Racing springs - the GTII EVO cam and the stock 930 springs would bind.
Old 12-11-2007, 04:35 PM
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i am thinking the factory valves are SS ?

i know that the ferrea valves are , and if the OEM ones aren't then you can see some benefits from the difference of alloys alone as SS valves will withstand heat better ... also a 1mm oversized valve will benefit in low cam lift situations (more air coming in) , thus giving you a better low end torque.

the real benefits are in the valve seat and porting out the stock intake/exhaust ports .

if you get aftermarket valves and a good 5-angle valve grind you can see some benefits on the overall powerband, i believe the stock valve seat is a 3-angle . porting will gain alot more top-end but you might loose some low-end/mid-range torque if you really hog them out . the more agressive the valve grind the more flow you will see but it will also wear the valve seat out faster and vice-versa.

on other watercooled engines , i have seen a big gain out of grinding the valve guides flush with the head , granted that the engine is watercooled it had a margin of safety, on an aircooled engine this may not be very wise , uless its a race engine that will be torn down. consistently .

end rant..
Old 12-11-2007, 05:10 PM
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also i might add that stiffer valve springs are imperative . using an aggressive cam grind means that at high rpms you will get valve float . also on high boost situations you may see the same results . both are bad if you want to make the most power.

and if remember correctly the intake valve is much bigger than the exhaust valve . on turbo cars you want to get most exhaust gas out since it is what drives the turbo so i would suggest to go over sized on the exhaust valve if you can only do one . both valves are very close tho and you may not be able to go oversize at all.
Old 12-11-2007, 05:25 PM
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Munchovie- after watching your video I am defenatly all for you using STIFF valve springs- I got the Porsche motorsport springs in my car.
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2008 C6/Z51 Corvette
Old 12-12-2007, 06:06 AM
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Quote:
Originally Posted by 930gt-40r View Post
Munchovie- after watching your video I am defenatly all for you using STIFF valve springs- I got the Porsche motorsport springs in my car.
Well, I must admit that maybe I was just a tad mean to the tach that day But you are right, I think with the flat top pistons and beefier cam that I don't want my intakes doing an automatic piston relief job....

Stiffer valve springs it is then...

munchovie.
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Old 12-12-2007, 01:39 PM
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