Saabretooth
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Re: 3.0 24V - your suggestions

Post by Saabretooth »

Nice..... well thought out there JK.
AlanV6
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Re: 3.0 24V - your suggestions

Post by AlanV6 »

Jim did you ever tested AHMotorsport regrinded cams for 24valve? I have them for over 3 years now on stock hydraulic lifters. They should be around 9.8 lift and 290° duration, timing is at 107° for all 4 cams.
Engine feels strong and revs nice.
Jim K
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Re: 3.0 24V - your suggestions

Post by Jim K »

Alan, I have only measured C&B and gta1 cams, besides the std 3liter and 3.2 cams. 290* is very excessive duration in my opinion (just for comparison, the M3 has 260*...)
I am interested in the best possible idle quality and performance up to 7800rpm at the most. My latest design is a departure from common profiles, aiming for the most area under the curve. THIS is what makes power and not duration or lift. The difficulty is to combine this feature with acceptable acceleration and lowest possible jerk (= undesirable lobe/follower impact).
The interim lobe (Sabretooth and Zamani have them) has 10mm lift and the latest one 10.3mm. Lift limitation is linked to the follower displacement because of the regrind action decreasing the lobe base circle.
I am trying to come up with the necessary funds to make a set of these cams and map them in my 3liter along with the new headers.
Jim K.
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Re: 3.0 24V - your suggestions

Post by kevin »

Some info I got off race guys in SA for best all round oombo including street was 272 degrees . Not more than that . But as mentioned before this all happens at 6000 ft above sea level .
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Re: 3.0 24V - your suggestions

Post by 75evo »

JK,

Just curious, do you have access to F355 or F360 cam lobes? Only problem I see is, since they have 3 intake valves, the lift may not be so high. The 360 has a variator so it's not too much of a surprise that the torque spread in that thing is amazing.

One thing I'd like the 3.2 to have is lots of revs. That's what the V6 is for. If I wanted brute power I'd just get a 2.0L turbo. Just thinking of the 3.2 at 7800 rpm .... :D

BTW JK you did mention about an old italian engineer who showed you a cam where the lobes would "grow" in a nord or something. Forgot when you said it, a while back I guess. Gosh this forum is older than my kids :(
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Re: 3.0 24V - your suggestions

Post by Jim K »

No, it was a greek engineer, the father of my grinder. He started the business many years ago, when Alfa was paying him to race-develop their 1600 and later 2liter and GTAm engines for the greek championship, 1964-73. He had one of the two engine dynos in the country back then and did contract work for Alfa and Ford. He has several patents on automotive technology and the variable lift and duration cam was one of them. I was totally amazed when he showed me how it works. Same thing with the gearless LSD!! There were people from the US Army technical staff here negotiating to buy it but the deal fell through with orders from higher up (Detroit maybe?) :roll:
Oh, if your 3.2 is built right, you WILL get lots of revs but having most power from 3500-7200 I think is enough. After all, you're not building a pro racer so why look for the highest revs -they usually don't last too long that way! :wall:
Jim K.
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Re: 3.0 24V - your suggestions

Post by 75evo »

The engine will be balanced this month with a lightened flywheel. I will be running over F355 challenges on the track :lol: ...because I can't brake in time :)

oil cooler will be run from a separate electric pump.
Power steering will be electric, bought a Citroen SAXO VTS pump
Thinking of going with a stewart electric water pump.
So the engine will only have to drive a big alternator.
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Re: 3.0 24V - your suggestions

Post by Jim K »

Ok, there's a 3-day Alfa trackmeet coming up on April 4-6. I'm going to take both 75's, the 24v and the 1.8T. However, I am so curious about the possible gains with my new 24v cam profile that I just have to try it... These are financially difficult times but a junkie is a junkie... I called the grinder today and asked him to have the master lobe cnc cut by Wednesday and I'll take my cams there by Friday. I hope to have them back by the 20th so I'll put them in by the 22nd. Then, if the thing runs :roll: I'll set up a date for dyno/mapping last week of the month. I'll have the new cams and the big headers on, so I hope to see good numbers... to make up for a total cost of ~700€!!
Here is a comparative graph of 3 cams: gta, my interim 10mm profile and the 10.3 one. Notice the considerably increased 'area under the curve' which, like I said, is what counts.
Jim K.

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75evo
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Re: 3.0 24V - your suggestions

Post by 75evo »

WOW! The lift is considerably more right off the heel, even to my cams!!!

BTW did Sabretooth modify oiling to the lifters?

I'm curious, is it possible to have variable lift if the oil pressure to the lifter is controlled? Sort of like multi-air.

Although from what I know, once the oil is in the lifter, the lifter stays inflated so can't really be controlled. That's why when swapping cams I was told to deflate all the lifters rather than just popping the new cams in. I must say my knowledge of 24Vs is very limited.
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Re: 3.0 24V - your suggestions

Post by Saabretooth »

I actually didn't redo the oiling of the lifters.

Is there a step by step instruction? Seems like I have to open up the engine again?
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Re: 3.0 24V - your suggestions

Post by Jim K »

If there are no followers making noise (ticking) it seems you have no problem! Typically, its a good idea to widen downward the 'belt' in the follower surface by ~2mm.
Jim K.
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Re: 3.0 24V - your suggestions

Post by kevin »

Or you can cut a groove vertically .
Their are pics of the hydraulic lifters in this thread and how to remove .
viewtopic.php?f=5&t=2643
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Re: 3.0 24V - your suggestions

Post by Jim K »

Yes, the vertical groove is done on the bore, elongating the oil feed hole upwards, not the follower.
Jim K.
Saabretooth
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Re: 3.0 24V - your suggestions

Post by Saabretooth »

Thanks. No clicking noise from the engine.
Its possible that the oil I use has got a good flow rate, or its really hot here.
Average water temp is 90C and 85C when cruising.
Could be 100C when pushing the car harder.

There's an electrical sparking noise though from the coils. I had the coils recently replaced and its still making those noises.
I'm guessing that I have to regap the plugs to work with the higher compression.
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Re: 3.0 24V - your suggestions

Post by Jim K »

100*C?? :shock: Its when you push it that you don't want to see any more than 82-85*. I don't know about fwd's but is it possible the rad is small/blocked or the thermostat has insufficient flow?
Jim K.
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