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In these heads, valve lift is limited by spring coil bind and retainer/guide seal contact to a max of ~10,3-10.5mm. you can regrind the existing cam (without welding new lobe material) to obtain 10.4mm lift, but you would overextend the hydraulic follower by the amount you would reduce the base circle. For 10.4mm lift, the grinder said he'd have to shave ~1.6-1.8mm from base and he thought it would be borderline, meaning it may not work. I didn't like this possibility so I stayed with a 100% safe 10mm. Next time, I will have to look for Maserati valve adjusting shims (7mm?) which I think can be placed on top of the valves, under the follower; but this is only a thought now. How far out do you think the follower can be raised out of the bore and still be reliable? I don't have any info on this. Has anyone experimented with under-ground hydraulic cams?
Jim K.

My AHM regrind are grinded at base circle, max lift is now 10,1mm. After 5000kms no wear is showing on lobes or hydraulic lifters. i can only recommend AHM!
Duration should be around 290° and i have them set so that max lift is at 107°

Argrhhhh the problems with balancing, in my country noone is able to balance the crank, i have to go to Italy or UK...

When I used my cut cams I stripped the hydraulic lifters and got all oil out so they could collapse easily if compressed . I put them back in head with standard cam and measured gap when I pressed them down with thumb . I then did this with my cut cams and added a 1 mm shim to get the same gap . Only reason I did this as I heard stories from guys who never did this who raced . But then again you should believe everything you hear at the track .

That's clever Kevin! So, my idea about Maserati shims has already been verified!
Jim K.

On my other 24v engine I had the valves lengthened by by 1 mm as this technique is now bullet proof . I did this to reduce extra weight flying around above valve as this was a smaller much higher revving 3.0 24v . When I compare prices what I paid in SA to do this to uk it frightening and it was done by the top BMW Motorsport team who do work for all cars as the owner did race Alfas about 30 years ago . ( vanderlinde)

I'd feel pretty comfortable with 1.5mm shims over the valve. As it is now, it'll go to 7800 with std parts. With proper (a little uprated) springs there wouldn't be any problem at all. Besides, I think 7500rpm for the 3.2 should be fine for any use, if the intention is to also drive it on the street -a point I personally insist on.
Jim K.

Hey Jim, how about the hydraulic lifters? what's the max rpm they can stand? I remember having to limit the 33 16v rpm's due to the lifters not coping, 7600 rpm's was max, could have gotten more power as the curve was still climbing at that rpm....

My dyno man could hear some noise with the headphones at ~7800 so that's where we stopped. To me it doesn't matter though, as I don't exceed 7600 and with the 3.2 I will consider 7500 max. Anything higher than that borders on racing use in which case it would make sense to go mechanical.
Jim K.

I see what you mean, I was thinking more in the lines of revving the engine up for more power as it seems the ports are over dimentioned for the std 3 liter displacement instead of going the big bore route, at least for a bit of cost saving maybe, but as I see, the 24v has the same problem as the 33, over 7500 you need mechanical tappets...
I have to say that I like the sound of a high revving V6 though...

High revving power is usually not a problem with these engines. Having a full curve everywhere is the target. That would make a fast car. To achieve that, we have to adjust intake and exhaust sizing. In the simulator program I have, I am more concerned with 'average torque' and 'average hp', rather than max values.
Jim K.

I agree with you completely, doing that without variable cam timing is also another challenge, I guess the best approach, in case you need to rebuild the engine is the big bore approach and then cams, to make use of those big ports.
So what engine size do you think the ports are made for given their size?

Hard to say, but bigger than a 3liter! It would be nice to input different bores in the simulator and see where the heads become 'inadequate', but I'd have to be really curious to fiddle with it. Maybe one of these days when I feel bored! Right now I'm really into the 1.8T and will be for a few weeks, until I get the best I can out of it and verify reliability (waiting for some hot weather!!)
Jim K.

Cool! i'm interested on seeing the results on your 1.8 turbo, I have a Twin Spark engine for the race Giulietta laying around that needs a rebuild, and i've been toying with the idea to rebuild the engine for a turbo application, looking for broadband of torque and power more than peak, so turbo selection is going to be key, waiting on your results Jim!

Check the other thread: viewtopic.php?f=5&t=3612&p=46033#p46033
Jim K.

Flexhoned the cilinders, crosshatch is nice like stock!