This is a cross post from the 996TT forum. Any of you guys have used Todd McKenzie in Oxnard CA for cylinder and valve train work? I think he is the one that does a lot of Porsche head work for Proto and others and is very respected in the Porsche community. I spoke with him today and he seemed like an extremely nice and knowledgeable guy. We are currently doing a 3.8 race motor rebuild (roughly 650whp), and for my application he recommended going +1mm on both the intake and exhaust valve along with porting both intake/exhaust, his upgraded valve springs, guides and seals. Locks and retainers would be reused. He said that 7500rpm would be absolutely no issues with this set up. I have sort of narrowed it down between Todd and Extreme cylinder heads in Florida that does CNC head porting on the Rottler P69 and has a lot of Porsche experience also. I believe Todd does hand porting. Thoughts, comments?

 

Curious.. what is going rate for Porsche head work? Did you break it out by material, valve job and porting?

The hand port guys can do just as good of a job as the CNC guys (Core shift means CNC guys cant be as aggressive on some heads)

 

Rottler p69 is a nice machine for floor programming. One thing they don't offer is virtual flow testing on port and surface finish aid. Most of this would have to be tested on a PC based system.

CNC machining is not even comparable to a man and his dremel.

 

yea.. I would hand finish either way

 

he's done my heads .. OEM was flowing @ .5" 217 cfm end result was north of 330

 

Thanks for the data. Seems like he's the real deal. I know you said McKinzie but I'm assuming we are talking about the same guy on Oxnard CA just outside of LA. How many miles do you have on his set up?
I looked at your thread and you said you dropped a valve. Was that on the stock heads / valve train?

 

I have seen with my own eyes the flow results of a similar heads work using bigger Ferrea valves, heads were flowing like 330ish too, but dont know how this will impact the mid torque, my guess is not the best idea as this is suitable more for high hp top ends, I might consider some time just stock size valves (maybe lighter) and reinforced springs and everything the builder will need, maybe lower top flow but better midrange, I would approach the heads work for this kind of setup from the safety and increasing reline limit only instead of thinking to maximize the hp... just my thoughts

 

about 1500 miles.. on his setup... I dropped a valve OEM heads / valve train .. and id think i am the culprit as i over revved the engine ...

Yes he is in oxnard ca.. i am in los angeles so I drove out to him about an hour .. very nice and knowledgeable. we had a little discussion over keepers ... switched over to single grove keepers which lock vs the triple groove OEMs which actually allow the valve to spin within the keepers. (I have my opinions on this one...as 9k+ revving gt3s are on triple grooves and have no issues).My valves are I think 3/2 mm over oem and I have stiffer springs as well.. he says 8k should be no prob.. I still like to stick to 72-7400

 

My heads are shipping to McKenzie tomorrow. After an exhaustive search, seems like he's the guy. He's doing +1/+1 for my application. Should have them back in 3 weeks or so...

 

Looking forward to the results. This should be fun!

 

whats a +1/+1?

 

increase in the size of the intake and exhaust valves

 

I'm guessing that will need bigger cams then to take advantage of the increase in valve size?

 

Not exactly but running a longer/higher lift cam will flow more. So will Rpms.

 

Stock cams. Todd favors increasing both intake and exhaust valve size by 1mm for my race application. Stock is 37/32, he's going to 38/33. (stock 996GT3 sizes are 41/35.5 in comparison). By slightly increasing the valve sizes, McKenzie says the turbos will spool quicker which will more than make up for any small loss of low end torque. We are doing a 3.8 which will further help with low end torque and throttle response. We dynoed the engine just prior to tear down and with the current turbos it pulls strong all the way to its current 7200 redline with max power reached just prior to it. With my current set up there is no fall off in power up high and Todd feels we see excellent results all the way to 7500 or so where we plan to cap it. His valve train is good for well past 9k. The guy has been doing this for a long time with excellent references. He knows his stuff.. After my engine builder spoke with him on the phone at length regarding our engine goals and requirements, he basically told me that "yeah, this is your guy." Guess we'll see...