Measured Cam Duration & Lift Data

Most interesting Phillip. There were a couple of spec I didn't allready have, so Thanks! Do you by any chance have the events on them, as in open and closeing degrees? I find that the 3x8 series, with the almost 2 to 1 rod stroke ratio causing more "hang time" on TDC and BDC, and the attendant rapid acceleration rates of the pistons as the move away from the end to be a critical factor in reversion.
Take the intake closing for example. The P-6 according to my records closes at a wild 62 degrees ABDC, which is far from the norm. Only the f-50 (at 54 degrees ABDC) and the 348 (at 53 degrees) come close. The rest are in the 40's so the motor does not try to stuff the intake charge back into the runner. I have always been a bit baffled by running a P-6 on the street, but it does get done. IMO 54 degrees seems to be the right "limit" on how long you can take advantage of the intakes inertia, before the piston rising overcomes that presure and starts to push back. But at 62 degrees, hell you are closer to mid stroke than BDC, and peak piston speed is always at 90 degrees. it must take some serious RPM to make that work, but when it does, WOW!

 

Great data, especially on the 348 as I just dropped the car off for hotter cams myself will probably be using lift of i:368 and 235@050 e:lift 307 220 @ 050.

To add to this post as a reference, here are some event timings @ 020:

308 2v carb Euro
i: 30/50
e: 36/28

308 2v carb US
i: 34/46
e: 36/38

308 i 2v Euro
i: 16/48
e:54/10

308 i 2v US
i: 16/48
e: 50/14

308qv Euro
i: 16/48
e: 54/10

308 qv US
i: 16/48
e: 40/14

328:
i: 16/48
e: 54/10

348:
i:14/53
e:53/10

I have some of the 12 cyl data if anyone interested.
Great data in the thread.

 

Quoting figures as opening and closing degrees, gives large windows for variation due to EXACT clearances, and human/mechanical error on TWO points of referance.

I've still not seen a Ferrari camshaft that wasn't symmetrical on it's opening and closing ramps, so converting all the data into points of max open is far more accurate, as clearance is not relevant, and only one point of referance is used..

eg Most Inlets are about 110 ATDC max open, Most Exhausts are about 110 BTDC or (70 ABDC)

 

Great point.
Yes, the quoted figures are how many references gives the data, but the calculated 'lobe centers' which are the 'max open' as I understand it are far better. Then the intake and exhaust cams are also set to a lobe center angle in relation to one another helping to negate as much event timing error as possible, and this angle also determines engine characteristics. While I do not have a lot of experience, I've always been told that Ferraris run remarkably narrow lobe center angles.

 

Phillip, I can hardly believe it would run at all. Must be a tow start type I would think, as the low speed compression couldnt be much. Amazing.
next point:
"Quoting figures as opening and closing degrees, gives large windows for variation due to EXACT clearances, and human/mechanical error on TWO points of referance.
I've still not seen a Ferrari camshaft that wasn't symmetrical on it's opening and closing ramps, so converting all the data into points of max open is far more accurate, as clearance is not relevant, and only one point of referance is used.."
With the greatest of respect to your many years and knowledge I would not agreee completely. Lets face it, we are asked in the manual to line up two marks, one on the cap and the other on the cam. With the am diameter less than one inch, just how accurate is that? Does it help to file a groove in the thumbnail for better lineup? It is without a doubt one of the most primitive there is. Hell, error is built into that method, no matter how carefull you are. I have found in dialing cams in that often the factory pointer on the flywheel end needs one side filed to get it to line up with the real TDC.
What we are doing, or attempting to do is a comparitive study. Cams can be dialed in with the opening and closing events wherever we want to with the right equipment, in order to move the power bands in desired direction. With the design that they have being certainly more adjustable than the greatest percentage of MFG's I believe they intend that it can be done accurately.. IMO the marks are a safe settup, and are a quick way to get them close, no more. It is the easiest (cheapest for the beancounters) way to do it. Yet they spend the time to drill multiple holes in the pulleys so that it can be done accurately. No Factory is going to use the dial indicator, degree wheel method of assembly, as it is far to time consuming. it will however , if done correctly tell the lifts at what degree, lobe centerlines, et al, and that is the key to making the motor more efficient. Stock carb usa cams are a good example of working with what you have, in that they can be moved considerably, depending on the desired outcome. Going the more exact route is not for everybody. But then neither is First Place!
On the side.. If you think pressed on lobes are strange (I had never heard of it), try the M73 BMW V-12. The lobes are pressed on Powdered Metal, on a hollow shaft to boot and that is not for oiling as ours are. worthless to me, as they cannot be welded to build up.
Kermit

 

I don't quite get your point Kermit.

Using the max open technique to dial them all in, I then check the cap/cam referance marks for accuracy... and I am yet to find one that wasn't within a line width of the referance mark.......

Curiously, the ONLY engine I've found to be a little off, was the 550 engine I built most recently... where one cap mark was almost out of line... but still close enough to confirm that the referance marks are fine for 90% of circumstances.

 

That's interesting. I would wonder if the belt (and sprokets?) are still available. The belt would almost have to be more durable than the stock. I wish I spoke enough Italian to ask them, as I am in a position now to retrofit such a belt. It might even have applicability to Nick/Mark/Steve's 3.3/4.0 prototype.

Anyone know anything specific or have a source on the Michelotto belts?

Speaking of timing belts, when I first joined FChat a couple of years ago there was an FChatter, Herbert Edward Gault frpm Gaffney, SC (since left), selling a belt upgrade kit to a thicker, heavier rounded tooth belt that came with belt and sprockets, much like the long life Honda system. The idea was a MUCH longer change interval (100K miles) and less distortion. He was not able to generate enough interest for a 4valve engine, and kits were only made for the 2 valve. I would love to hear from any FChatters that used this system and how things are going so far. I remember him to becoming disenchanted from some of the negative posts and leaving, which was our loss, of course. Here's the story, you can decide for yourself:
http://70.85.40.84/~ferrari/discus/messages/256120/2273.html

Actually, if I were to adapt anything from the 3.3/4.0 thing, it would be a belt system.

Will drop a quick new thread to see if I can find any of his users.

best
rt

best

 

a line width on the cam timing mark? Consider that the circumference of the cam equals 720 degrees of crankshaft rotation. If the cam in that area is 1.15 inches, I think thats what I measured, one degree of crankshaft rotation would equal a whopping .005 of an inch on the camshaft edge where the mark is. That IS certainly enough to see visually, and IF you have at least checked it once with a degree wheel to verify the marks, I can see no real reason to go through that trouble again unless you are trying to alter timing away from the marks.

When I measured mine, with P6 cams, using the marks as my setting point, I got the following numbers:
valve clearance nominal at .008 and .012...
I 46-62 with .372 lift 288 duration---E 60-54 with .345 lift 294 duration

Obviously that would be somewhat late on exhaust, I will have to correct that on final assembly. I show the LM being 51-58---64-44
I also took gross measurements directly off the lobe, and got 57-85---67-66, so perhaps the 72 degrees was a tight clearance? I am not sure why I have 5 degrees more duration on my exhaust than what is shown for the LM. My cams are all punched with a P6 and a correct part number in the shaft between the outer seal and the pulley hub. I will check it again on assembly and see if I was incorrect on a measurement or in writing it down.

 

Remember that opening/closing figures are a semi theoretical number based on a clearance of EXACTLY 020".

if you've got 018' or 022" during your test, then your numbers will not match the "spec"

Convert to max open point and clearance is irrelevant.

Also, as repeated many times before, actual timing has little to do with peak power and torque fugures, it has more effect on drivability and the rpm at which the peaks are achieved... within reason of course.

 

Could you please explain how to measure/calculate the points of max open?

I think I know what you're getting at, but want to be certain. Is it conceptually similar to obtaining a calculated TDC using a fixed length piston stop in the spark plug hole & degree wheel?
Ie: Take open & close meas'ts, then max open is half-way between them? This would certainly factor out any errors due to shim-cam clearance.

 

Phil,
I think there is a miscommunication here.
I prefer to go for of events as they measure out on the motor, with the cam being ideal (as quoted). However, if the cam is in reality a few degrees short on actual duration, going from centerline "splits" the error or shortage.
For example, if the motor is built with top end power in mind, with drivability of importance, I would prefer to open the intake no later than 54 degrees ABDC, which seems to be the max on factory cams and is pretty close to what is wanted in this aplication, as it gives the maximum amount of intake flow, but does not tend to cause reversion (streetability issue).
I prefer to time it to that event, as a matter of choice, and let the shortage effect on the ovelap end of the cycle.
On the exhaust event, I prefer to make the decision on the opening as a more important priority. We are in effect trading combustion pressure off to start the flow of exhaust gasses. Opening sooner, I loose combustion pressure, which is what it's all about, for more agressive flow start in the exhaust system. Depending on the application, particularly street motors, I may not have the exhaust system to take advantage of the agressive flow, and may want to open the valve later and get the power out of the cumbustion. Once again, let the overlap end of the cycle take up the slack, It's all trade offs.
Kermit

 

Yes Verell. It's simply a plot half way between events. eg, on Inlet.... Add up the book spec angles of BTDC, TDC to BDC (180), and ABDC to find the duration, divide by 2 to find half way, then subtract the BTDC event to find the Max open ATDC... usually about 110 +- 5 deg

Using event timings assumes too much for the real world in my opinion. As any wear on the opening and closing ramps (even slight), or a slightly off spec clearance when doing it, will affect the readings you get and may move the point of max open which is REALLY what the cam designers have in mind.

Plus, the event may be the same on two different spec cams, but the ramp angles and lift could be savagley different, so to tune based on events alone is potentially misleading.

 

Thanks Phil & Matt,
This was very helpful. I understand where both of you are coming from.
The max open measurement certainly sounds like the way to go for general servicing (eg: daily drivers/street cars). It's been the way that I came up with to cross-check the cam/cam cap timing marks for errors, but never knew the technique's name.

BTW, A long time ago, someone showed me how to detect valve opening/closing by pressurizing a cylinder to 10-15psi & listening for hissing/whistling to start/stop. Have either of you used this as an alternative to putting a dial indicator on a valve & looking for it to move/stop moving? Any comments?

Presumably you could pressurize the cylinder thru a small orfice, and detect the pressure change when a valve opened or closed.

Obviously not useful when valve openings overlap tho.

Any comments?

 

Did your hotter 348 cams please you?

 

The short story is no.

What we found out was that the cams and the head were fairly well matched, ir, the head WAS ALREADY at it's flow limit with the cam. We've also figured out that porting the head with the came cam would have been a better way to go. If I have to make a recommendation on the 3.2/qv head, the money may be better spent toward porting as your head flow is already maxed.

So, we are looking at porting the head. Apparantly, the 348 head design is different, much improved (oval vs fig 8) and CAN handle more flow from a hotter cam. Strangely enough, the current discussion on head porting with sims is going on in the turbo / supercharging thread of Mark's. His sim seems much more accurate than mine based on what results I got. Having said that, it also shows that porting the head may increase the 3.2 hp WITH OEM CAMS upto 335 or more. So with my higher lift cams, it sounds promising.

We'll know in a couple of weeks as Mark has his qv heads done (identical to the 3.2) where we are numberwise from the flow bench.

We'll see.

best
rt

 

I missed this thread the first time around, a lot of good information.

This is probably a good place to ask the quation I came to on on the othe thread:

Does anybody know how much lift can be put into a QV head? The math says that once the port is fixed so it flows what will go through the valve seat ID, the valve wants almost .400" lift before it’s not the flow restriction....but that seems like an awful lot of lift to me.

I’m going to talk to Vic (my head guy), maybe the right way to port this head is to go by the valve curtain area instead of the seat ID area and keep the velocity higher though the port….I’m probably off track here though.

Last, I find its much easier to set the cams up using centerline as ferrarifixer says. No need to shim to zero lash, no chance of a measurement error. The only think that needs to be right is the degree wheel on the crank.

I’ll also say that when I first looked at the timing marks on the cam, I shook my head an reached for the degree wheel and indicator. I played around a bit and found that if the cam was out of the factory spec (+/- 2 degrees if I recall), the factory marks were clearly out of position. I was surprise how go the factory marks worked.

 

Its funny how you start out thinking in one direction, and as you move along you question your decisions or your direction.

Ive done tons of engine work in my life, but have never before tried to port match an engine. I never before actually checked and double checked measurements to calculate compression ratio, or ever before ordered pistons that were higher compression than stock. Yet here I sit with this Ferrari and I have done all these things. All I thought I ever wanted was just a nice GTB. But as mine came to me with P6 cams, I just had to work the motor up into them. But I am at present rather lost wondering if I am doing the correct thing. I now have pistons that will net me 10.4:1 compression and are coming slightly above the deck surface where before they were .055" below. I trust Wiseco, but boy, what if were off?

At any rate, I have known the benefits of porting most of my life. I also know the downsides. While a lot of this discussion focuses on the 4 valve motors, it seems it also equates to the two valve. And in that light, it seems both have much larger exhaust ports. I dont recall now, but it seems my exhaust ports are like 6mm larger than the intakes, and offset 4mm from the header flange. It was said that this was done to create turbulence for the air injection nozzles.

Are you guys now of the opinion that the exhaust needs to be smaller than the intake? Does it need to stay equal size all the way out? I would like if someone could show (or clearly describe) a crosssectional view of what they feel would be optimal. Also, just so we are all on the same page, when you are refering to camshaft centerline, you are talking lobe center, or center of highest lift, correct? And the consensus is we want approximately 100 crankshaft degrees of lobe center seperation? In this vien, at what approximate locations of crankshaft degrees would you want the centers located?

I appologise if my questions seem to take this thread somewhat off track, or are of a wider scope, but first off this is one thread that has so far been totally free of bickering, and, it is my belief that all of these issues are related to one another. Head flow brickwalls, and no amount of cam will overcome it. Or cam lift and timing arent appropiate for a particular flow rate.

 

There are a lot of questions here...I'll take a stab at a few of them.

I used to use a head guy named Jerry Branch, and his line was “I don’t care if you’re Jesus Christ himself, you aren’t going to make hp without air”

As a starting point, the exhaust should flow about 80% of the intake. So if the ports are equally efficient, they should be 80% the area of the intake ports. From about the 40s up thought the 70s, the standard was BIG exhaust. In the 80s they started cutting it back and 92% was the magic number Today the number is 78-80%. Your exhaust ports are DEFINITELY too big and an insert is probably in order. The 308 race were using 208 heads because the exhaust ports were smaller. I don’t know what Nick and the gang did for the 4 liter project, but you might want to give him a call and ask how much. I’m sure my buddy Vic (who’s doing my QV heads) could work some magic on them too, if you want the contact info, shoot me a pm or email.

On the cams, I don’t want to speak for anyone else, but the point I’m talking about is ½ way between opening and closing. I just put a degree wheel on the crank and an indicator on the valve. I look for about .020” inch motion opening and note the crank degrees, then I go unit it’s .020 before closing and not the crank again. Split the difference and that is the lobe center. As a very general note of thumb, 110, 110, which gives a 110 lobe separation angle are a good place to start. The separation angle may drop to 105 in an NA engine and go to 114 in a boosted engine, but they’re all pretty close.

 

Mark, the heads I have checked ran into the seal @ .420"-.430" liftand the 2 valve heads ran pretty much the same.
In both cases, the heads flow seems to level out @ around .350" lift, and while it keeps climbing, they are running out of big gains. The notes I have show the stock 4 valve intake gained 1 cfm between .350" and .400", and no gains when opened to .450". The stock exhaust however seemed to keep increasing in flow with more lift.
Ported, both sides tended to keep climbing with valve opening, but again, it ws "maxing out port flow".
IMO, valve opening of much more than 10.25mm or .403 lift isn't worth the effort, especially when considering the valve guide work needed to move the seals in order to eliminate interferance.
One should also consider the longevity issue, as springs etc take a lot more abuse in larger lifts.
HTH

 

Thanks Kermit.

I'm not sure what I'm going to do yet.... I'm sure the exhaust port is way too big and will probably need an instert to get it right...and I'll probably need to re-work the headers somehow to match. The port is REALLY big and the fact that the flow keeps going up to .450" lift even though the valve shouldn't be a restriction after about .270 lift concerns me.

On the intake side I'm thinking the valves size will need to go...which probably means the lift needs to go up. I want to see 140 cfm at 10" H2O minimum. I tmay be possible with stock valves, but I think they will need to go up about 2mm.

 

Again, just so I am on the same page with you, and for anyone else who may be trying to understand what we are talking about. When you say 110, 110, are you talking placing the intake cam lobe center 110 degrees ATDC, and placing the exhaust lobe center at 110 degrees BTDC? I don't know if I am not seeing this correctly, but this seems closer to 220 degrees of lobe seperation.

Using P6 cam specs from the LM engine, intake is listed as open 51 BTDC, close 58 ABDC. If I split the difference, it would show the lobe center at approximately 93 degrees ATDC on the intake stroke. The exhaust is listed as open 66 BBDC, close 44 ATDC, with a lobe center at approx. 100 degrees BTDC on the exhaust stroke. So If I timed up this way, I would have an actual angle of 193 degrees. If I am understanding this correctly, your reference to 110, 110, was in keeping the centers 110 degrees either side of the TDC centerline?

 

Does anyone have the correct camshaft event timing for a 512BBI? Russ? Newman?
With the valve clearance readjusted to .020", using a degree wheel, and the flywheel "AA" intake open. and "CS" exhaust close, I'm speculating the following:

Intake opens at 12 degrees BTDC (referencing flywheel marker "AA")
Exaust closes at 10 degrees ATDC (referencing flywheel marker "CS")

I have the 365BB workshop manual with the 512/512BBI revisions but have doubts regarding the valve timing diagram as it appears to be more suitable for 365BB camshafts not a BBI.

Can anyone confirm both intake open/close Exhaust open/close for a BBI?

Thanks,
Dave