performance cam regrinding

Russ - Just curious if you mind sharing the cost that webcam quoted you for the grind. I am going to give them a call when I get back to minnesota next week to talk about what I want out of my car and see if I can get some specs as well.

Look forward to the desktop dyno numbers as well.

John

 

John
Have you thought about contacting Michelotto to see if they'll give you specs for the race cams or sell you a pair if they have any lying around?
I've not dealt with them but am told they've been helpful to others.
Philip

 

Russ you are the man! I am going to get in touch with Laurie next Monday to see what they can do for the 348. I have to imagine the cam profile is very similar to your's. Hopefully I can get a nice grind as well and get to my 95-100bhp goal as well. Man you have me so pumped now for next winter to get here so I can tear my engine apart!

I want to thank you so much for the time you put in and the information sharing. You have been great! I will post what I find from them on Monday as well and throughout the process. Hopefully the cams, along with the rest of the car and me getting to a lot more track days this summer with all combine for a ton of fun!

As far as Michelotto I have contacted them and their cam grind they said i would not be happy with at all on the road. Basically they assured me it was a track special not making any power till 5500-8500.

 

Be advised that 308 qv cam pulleys will not fit 328 cams so figure in a set of new (or used) cam pulleys if you change. Hub has a different diameter.

 

Russ - Yep I have a 914 v-8 but currently am still assembling her. It was a little project that I wanted to see if I could pull off with all the fabricating and floor up restore before tackling something bigger like an older Fcar, etc. Lets just say I got more than I bargained for out of that 71 chassis and learned how to do more metal working and welding than I expected. I replaced more body parts, and frame areas than I ever expected. However I cant wait to have it done and on the track....put a 289 in her so I didnt kill myself but it still makes 340hp in a car that weighs just over 2000 lbs with me in it. I am just hoping a slightly warmed over 901 tranny will hold up for a few years, but it should as I am not making ungodly torque out of the 289. Driven a couple with 350's running the 911 tranny that were just rockets...you think the Viper is a fast car these redefine the meaning.

Anyway now back to regularly scheduled Ferrari programming. Where did you get your camshaft blanks from. I am trying to find a set of 348's but have had a little bit of a struggle so far with some sponsors on the board being able to find them. I probably will call trutlands and gtcar parts here Monday but just wanted to hear from you where yours came from.

 

I will get in touch with Bill. Do you mind if I ask what you paid for your cam blanks?

Your car is amazing man...has to be something else to drive!

 

That grind is insanely agressive...I have to imagine thats for a 2V as the power band would be ungodly high in the RPM range and I would probably stall the damn bastard on the street non-stop! Anyway calling WebCam tomorrow and will post my grinds as soon as possible.

 

I find a good place to get ideas for where to go with the cam is the crane cams web sight and find a honda or toyota 4 cylinder 1.5-2.0 liter. They list the specs for the different grinds, what rpm it works in and what other stuff you need, like what compression, porting, open exhaust. It might help.

 

There have been some that have implied that using a hotter cam is way to approach the horsepower numbers of a 4-liter engine. Regrettable the camshaft is only one part of this equation. I would suggest that you consider the following:

1. The amount of duration is contingent upon the amount of displacement. The more displacement that an engine has the more duration it can tolerate. This means that the 4-liter engine have more duration than a 308 and still maintain idle quality.

2. The 4-liter engine isn’t a compromise between low-end torque and high rpm horsepower. Camming a 308 means that something is sacrificed…generally throttle response and low-end torque.

3. The lift figures that have been quoted in this thread are artificially low. There have been some that have contended that max lift for a 2-valve engine is about .400 lift. This is wrong. Max lift is in the neighborhood of .500 lift. The 4-liter engine has intake lift of .485. It is my opinion that some of you are leaving about .100 of lift or more on the workbench. Yes, it does require modification to the heads and new springs. I would strongly suggest that you contact Steve Demirjian to determine how your heads can be modified to obtain more lift.

4. If you want more flow, then change the valve size. Intake should be larger and exhaust should be smaller.

5. Heads should be ported. Stock 2-valve head flow is only 150 cfm at 28 inches of water. 200 cfm is possible, with better low lift flow and continuous flow all the way to max lift. Adding more lift to a stock port is a waste of time because flow max's out at .300 lift with stock ports.

6. Optimize cam timing requires more compression. The stock 308 compression is very low…8.5 to 1.

7. While you are messing with the heads do a high performance valve job. Replace the seals and guided. You won’t burn oil any more and most of the flow gains are within one inch the valve seat.

8. Please quote cam timing at .050 inches of lift. .020 is an advertising number an as such is not terribly valuable for the purposes of this thread. I noticed that Russ quoted Cam figures at .050 lift…thanks.

Sincerely,

Mark Lewis

 

I'm going to add some to Mark's reply

The torque you can make is mostly a function of displacemnt, assuming the basics are right to begin with. So changing the cam GENERALLY does not increase torque.

HP is really only limited by 2 things, head flow and red line assuming the other components match. A 2 liter engine at 16000 rpm will make as much hp as a 4 liter at 8000. but the 4 liter will have twice the torque.

The duration sets the rpm band the engine will operate at and when the head flow and compression all match, the widest torque curve in obtained. If the compression is low or the flow too high, torque will be lost in the bottom of the curve. If the head flow is too low, the top of the curve will be lost.

So if you have a set of heads ported to flow say 200 @ 28" H2O, you can make about 400 hp from the engine. A 4 liter 2v will do it at 7000 and need about 260 degrees of duration, it will be very streetable. A 3 liter will do it at about 9500 and need about 280 degrees of duration, that is a race only engine IMO. But it will work and if fitted with EFI could be street driven without a lot problem, but will beat up the valve train, figure no more the 30k-50k miles before the heads need to be freshened.

A good street engine is usually about moderation and wide torque curves, but there are those that actually like high rpm monsters. Personaly I've realy come to like wide torque curves that come in early, it's just so much less bother to drive.

 

There is an automotive axiom that states valve lift equal torque. Torque is a function of displacement and volumetric efficiency. Lift affects the ability to completely fill each cylinder with ambience air pressure.

The challenge that the 308-engine builder faces is that stock configuration does not provide much in the way of either lift or flow. What I have indirectly proposed is a solution for both of these limitations. Regrettably, this requires modifications to the head and not a simple replacement of the camshafts. Yes, it will be more work and more money.

This would not result in a 4-liter motor, but rather a better 308. You would end up with a wider and flatter torque curve and around 300 usable hp. Electronic fuel injection, a more aggressive ignition curve and more compression would also help. That which has been learned from the 4-liter would be directly applicable to making a better running 308.

Sincerely,

Mark Lewis

 

Yes, anybody who wants power from a 2v should get the heads to flow first if your numbers are right.

I have a modified harley xr750 race engine, it's a 2 cylinder with 375cc per cylinder, 2 valve, basically the same bore and stroke as a 308. It makes about 35 ft-lb@6500 torque and 55 hp@8400 per cylinder. That would make a 308 with 420 hp and it is definately possible to build. The 2 holdups are flow and valve lift. The cam in my engine in .570 lift and 270 duration @.050" lift. The intakes flow 148cfm@12" water, thats about 230@28" I think, and that is with the carbs in place. It idles well at 1000 rpm and pulls smoothly through the power band, if fact I ran this engine on the street for a few years.

Heads that flow 200, should be good for about 350hp on a 3 liter....maybe a bit less because the cam doesn't have quite the lift, but adding another 5-10 degrees duration might help make up for that.

Cams alone will only get you to about 260 or so, big difference.

....or put on a blower, that will make the heads flow like there's no tomorrow

 

A question:

Is maxium lift on a stock 308 limited by the stock valve springs? It is my understanding that the stock springs will bind at a cetain lift (well below 400). My lift will be in excess of 400 but the valve train was completely redesigned by Ferrea racing components and exotic cylinder heads inc. (machine shop) using I belive their modified "Honda" springs among many other items.

I am no expert in this matter so I am not looking to argue just hear others points of view on this issue.

Paul

 

Without going into a great deal of detail, the 4-liter heads are using special springs which will not bind at high lifts and other modification to the heads are employed to obtain .485 lift on the intake side.

Paul it sounds like you are on a similar path as the 4-liter project as far as achieving more cam lift. The heads do need to be ported. The size of the intake valve should be increase while the exhaust valve is decreased. More low lift flow is available. The ports can be improved to flow all the way to max lift without major changes to port volume. The shape of the intake valve has also been optimized, as well as multiple valve and valve seat angles have been experimented with to maximize flow.

Good luck with your project,

Mark Lewis

 

The 1st guy (hack) who attempted to port my heads ported right into the water jackets so with new heads in hand I took them to a real machinst who ported them and built them to Ferrea racing components specs with all new Ferrea valves, guides, seals, springs and retainers none of which have anything to do with Ferrari, the cams were built my web cams. This is a 4 valve 308 so valve size is not the same issue as with the 2 valve head.

What I still would like to know is at what point to stock springs start to bind?

Paul

 

Paul

I talked to Steve today and he noticed your question about how much lift before coil bind occurs. He will mock up a stock spring and get you an accurate figure. The stock flow numbers that he has quoted for a 308 are the real deal.

As for your heads, that is really sad…not to mention expensive! We do all our R&D on a junk head to avoid the very problem that you experienced. Finished port designs are then digitized so that they can economically be reproduced.

Our 4-liter port profile is done in conjunction with larger intake valves and smaller exhaust valves. The porting, valves, seats and guides could easily be used on a stock 308. Our cam spec would have to be checked for piston to valve clearance. We are running custom pistons with the appropriate size valve relief cut in the tops of the pistons.

The 4 valve head will be next up. I’m sorry that doesn’t help you now with your project.

Sincerely,

Mark Lewis

 

Russ,
Do you know what presssure those flow numbers were taken at?...they are pretty low number, so I'm guessing not much vacuum. Also do you know if that is with an intake manifold, velocity stack or bare head fitted?

It sure looks like what I need to do is just track down a set of stock 3.2 cams for my QV. I'm pretty happy with my power curve the way it is, but 12% more lift (and area under the flow curve) plus 4% more flow might be just what I need to get to the 200hp/liter I was hoping for

Also, if you are thinking valve springs, have a look at Crame Cams MG midget race springs. They pretty much dropped right in to my QV heads, added something like 50lb seat pressure (I need that for the high boost), a little higher spring rate and more lift before coil bind...but I'm not sure where I put my notes with the number on them.