ALFAGTV6.COM

[Mats]

Boy, Dennis, you sure are a tough customer! I think the Catcams 1030206 is an excellent profile for a Godzilla engine. Just make sure your engine builder can accommodate 6.5mm lift at TDC, which isn't easy at all when going for high CR. You'll need some very clever piston design. With a 126-130cfm head (very difficult) and good large headers, you'll get lot more than 200hp at ~7.5-8krpm. Now 24kgm....I don't know about that!
Jim K.

Why the fcuk can't I find that one by browsing? Only find it when I write in the number in the search box.
lift is 6mm är TDC btw.

[Maurizio]

So for my own piece of mind, to see if I understand it right.
To make power and still have a decent torque curve.
You want a cam that rises fast to max lift and stays there for a max amount of time, and not too much overlap?

Going further on that:
I noticed that the flow gain above 11mm valve lift for TS head is marginal.
So if flow gain above 11 mm is marginal, a regrind of original cams with steeper ramps would be the budget solution.
And if you don't make it too wild, even the vvt will still work, which will give a nice idle as a bonus

Just for the hell of it, F1 engines have 0.2mm v/p clearance.

Just make the valves pneumatic controlled and put the valve with small pretension on top of the piston when opening, you can safely get v/p clearance 0
Jim, its time to start making our own heads.

[Dennis]

That was my evil laugh, Jim. Was meant at the "lot more than 200 hp" remark .

I didn't realise you meant an other cam then I suggested. Now the 1030206 is WILD 8mm of clearance.... I don't know if it can be done on my engine. Sice we're on a roll here, can someone explain to me what happens to your performance if the cam is too wild? It will be less, but how exactly?

The catcam distributor, Emerald ECU supplier and eventually my dyno guy, suggested 1030533. This is the same inlet cam I suggested before, but with a milder exhaust cam. I'm still a bit in the dark, but there is light at the end!

[Jim K]

Mats, who says you have to time them where they suggest? We got a pair of them here and I graphed them out (book p137). At 104*LC, TDC lift is as you say 6mm and 6.5mm at 100* (although I'd time them at 108* where TDC lift is 5.4mm and then go to the dyno to play) Main thing is you don't know where to time until after the dyno! So, doesn't it make sense to have the available v/p room to experiment?
Correct Maurizio, you don't need more than 10.5-11mm valve lift with the 44mm valve (std TS engine has 12mm cam lift!!) but in a proper race head with 46-47mm valves, I'll bet you will see flow gains at 12+ mm.
As far as cam design goes, its not very smart to depart from a true cosine curve when high revs are involved and especially with heavy valves. If you take a look at actual high rpm valve dynamics with non-cosine lobes you will quickly change your mind! Enormous spring pressures are needed to follow non-harmonic motion ramps such as those having prolonged high-lift dwell. Alfa was able to get away with it in the 3.2 engine because the valves are light. Using such cams partially makes up for their technically stupid but financially correct decision to use the existing 24v 3liter heads for the bigger engine. Putting in 37mm valves (yes, they do fit!) would necessitate bigger seats and this all would be far more expensive than 4 new bumpsticks!
Design our own heads? We're too late for that, mine is already 54years old and the material inside is drying out...Ok MD, you have the floor all to yerself now!! Dish it out!
Had to edit this, just read Dennis' post. I tell you what: find one of your guys there who builds them 240hp engines and ask them how much they want to build you one!! Hell, I wouldn't know how to count that high with an 8v TS! BUT, you would only pay after seeing them horses on the dyno!!! That's the arrangement I would make! Pay a down payment covering parts and let them take it from there. I really do think this is a reasonable proposition. If you can get that kind of power, who cares if you built it yourself? You can always take it apart later and spy on the magic you paid for!
Jim K.

[Mats]

Oh, my poor wallet...

[Maurizio]

Oh, my poor wallet...

Common problem here, I guess.

non-cosine lobes

I know from motion control, using a ramp profile called (free translated) "oblique sine line" will get the minimal amount of jerk. Now I only have to make a nice profile which fits into a standard TS profile. What is the disadvantage of a smaller base circle and compensate by cutting the valve seat 0.5-1 mm to get the valve 0.5 mm more up, to keep mass low. Instead of using very thick valve shims.
(Obvious will loose some flow)

[Micke]

You said it! Don't do it. The results I've seen from cutting down the valve seat are all bad.

Being an injuneer you can calculate the added mass on the shim and put it in proportion to the rest.

If you want to do something about mass, start with lighter valves.

[TS_turbo]

You said it! Don't do it. The results I've seen from cutting down the valve seat are all bad.

Being an injuneer you can calculate the added mass on the shim and put it in proportion to the rest.

If you want to do something about mass, start with lighter valves.

I agree too. only advantage for deep valve seats are increased v/p clearance TS stock valve is very heavy ... even compared to 46mm 8v merc one

[Jim K]

All my designs are based on an exponential or hyperbolic lower part, merging into a true cosine (or sine depending how you look at it). When the master lobes are then checked on the Cam-Doctor setup, there is almost zero jerk and acc. is as smooth as can be. As they say..."works for me"!
You can't be sure that sinking the valve in the head will decrease flow. As a matter of fact, doing so in the 3liter heads increased flow! You must of course blend the seat/chamber properly. However, this is best verified on the flowbench.
Smaller base circle for a given profile will decrease follower side-loading which is always good, plus it will save you having to make big notches for lobe rotation clearance. Smaller base circles also require very good cam-grinding equipment. A bigger lobe size/follower diameter combination for a given lift, is preferred for accuracy.
Speaking of cams, here's a money saving tip for Nord (not TS) motors: get the cams from the carbed 75 engines from junkyards. They have huge meaty lobes which can be reground to almost any Godzilla profile, so you don't have to buy brand new cams!
There I go editing again, just read the last two posts. If you look for the best valve shape for higher flow, chances are you'll end up with a much lighter valve! Whatever you do don't cut down the valve margin (thickness of the dish, ~1.5-2mm) to lose weight, you will also lose flow! A knife-edged valve flows much less.
Jim K.

[Mats]

What about a dish on the cumbustion chamber side of the valve? Besides losing some CR the weight gain should be nice.

[Jim K]

That's ok and won't hurt flow, but doing it to the exhaust valve may or may not hurt intake flow!! Incoming mixture flows around the intake valve following the chamber contours. If the dip in the ex. valve face is substantial, flow may be adversely affected by forming little vortices in the valve dip area. Its amazing what you see on a flowbench! Small bore hemi chambers usually need ex. valves with bowls in them, large shallow hemis don't.
Jim K.

[TS_turbo]

hm 1mm deep seats with allready shity small side radius of nord/ts ports and beter flow ... dont think so speaking of superperformance NA engines may be Jim K. will tell us about greek NA cosworth engine ...
"Recently i finish a race car with cosworth NA engine. I will tell u about this project so as to see in action the theories that i told u to my previus posts.
The engine is ford cosworth NA 2ltr 16v the stock form (90.8mm x 77mm).
The customer wants the maximum power of this engine no matter the cost.
The car is race car so we must stay until 1999cc engine displacement to stay in the regulations.
So the only way as i told u before is to make it revs very very high. I design the engine configuration and what parts would i use. After when finish the theory that i thought i start gothering the parts and some of them i make it special order.
The result of the project is: 412hp at 11700rpms and 28.1kgr of torque at 9750rpms and revlimit is 12600rpms.
Its world record of an engine below 2000cc NA.

Some specs: 92mm piston with 72mm stroke, custom length aluminum rods, supertech special order pistons,
custom design 4340 billet crank, nicasil sleeves, yellow titanium valves, custom berilium seats, custom billet cams, compression ratio 17,5:1, Haltech e8 managment system. 60mm throtlle bodies, and 90mm exsaust pipe.

I manage to use the wave sound efect perfect. So i had 1.3bar extra pressure at the intake port and 2.4bar at the exsaust port.

Spyros "

[Micke]

I like it. Is he running diesel or methanol with 17.5 compression?
28.1 m/s pistons speed
15.5 bar mean combustion pressure at max hp and 17.3 bar at max torque.
Not only world record for <2.0 but beats all ETCC, F3 and F1 engines too.

[Jim K]

A little detective work, a few key phone calls and here are some answers:
the engine was built using a very clumsily ported head, with multiple welds to repair breakthrough to the water jacket as a result of trying to come up with giant ports. Final flow was 156cfm (not bad for a 16v Cosworth head) but velocity would suffer due to large port sizes. I don't know about the rest of the engine but here's some more: they went to the same optimistic dyno (that gave me 235 instead of 205hp for the old engine) and got an indicated 300hp. The car went to a hillclimb and BOOOOM, expensive engine parts everywhere and thats the end of it.
I don't know the driver or the builder of the engine.
I don't like to get in the middle of gossip BS but the story as reported (absurd claims included)should be an Oscar nominee.
Jim K.

[TS_turbo]

...Speaking of cams, here's a money saving tip for Nord (not TS) motors: get the cams from the carbed 75 engines from junkyards. They have huge meaty lobes which can be reground to almost any Godzilla profile, so you don't have to buy brand new cams!...

Jim 75 carb cams are 10548's ... may be you mean alfeta motronic and 75 motronic nords .. they have 300 degree 11 lift 30mm base circle intake cams (10548's have 27mm base circle)