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308 p6 cams

Discussion in '308/328' started by st@ven, Dec 7, 2009.

  1. st@ven

    st@ven F1 Rookie
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    as i'm building a racer and i've been told that the p6 cam aren't very street-usable i wonder if maybe some has a set and is willing to part with it.

    please pm me if so
     
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  3. duck.co.za

    duck.co.za Formula Junior

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    I have a set that I can part with I'll send you a PM
     
  4. mk e

    mk e F1 World Champ

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    Do your class rules require a factory cam? Webers and P6 cams aren't a very good way to make hp compared to other options but it's all they had in 1975.
     
  5. st@ven

    st@ven F1 Rookie
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    no, it's full freedom. Please advise on this if you know a better way but i thought that p6 cams were a major improvement ,esspecially since i now have the '79 type cam with very minor lift
     
  6. Newman

    Newman F1 World Champ
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    A modern grind will out-perform any old performance cam thats decades old in design. Better off selecting a custom grind that suits your application and having your cams used as cores to make them. I was quoted $1300 to do four cams from WEB, have any grind I wanted if I provided the cams as cores. I think P6 cams are more a nostalgic thing.
     
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  8. speedy

    speedy Formula Junior

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  9. Ferraripilot

    Ferraripilot F1 World Champ
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    nope, Norwood is all out of those. has been for some time. they just don't update their website.
     
  10. mk e

    mk e F1 World Champ

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    The place to start is what do you want and what are you willing to spend?

    Are the carbs staying and staying 40mm or will it be 44mm or EFI?
    Are the heads getting ported and if so do you know the specs?
    Are the pistons being custom made so valve relief pocket are no problem?
    Redline?
    Compression ratio?


    Everything has to match to have a good final combination…which is part of why P6 cams don’t work real well when you drop them into a street engine.
     
  11. st@ven

    st@ven F1 Rookie
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    that's ndeed a very sound question. The answer might be stupid: i do not know yet.
    for most part it will depend on budget indeed.


    I like to build an engne which ca grow wth me. Startng with a std 2V. I like to sort of gragually upgrade to eventually a turbo setup. with eventually i mean that i do like to build it in a few steps. (for budget-sake)

    first step was to upgrade the cilinderheads. First thing i (already)did was replacing all valves by high flow stainless ones. as i have the '79 cam the next step seems logical to look for an upgrade on cams. Please tel me if you think this is indeed the best next step or that you would advise otherwise. Wouldthe p6 cam be wise n combination with the endstep? (turbo)
     
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  13. mk e

    mk e F1 World Champ

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    I understand working on a budget all too well……

    Did you do any porting on the head while they were off? The intake flow is about 20% below where you really want it to be, the exhaust side is fine. This is pretty important to making hp.

    On the same line, webers are pretty restrictive and not a real great option for boost so 2 strikes against keeping the carbs.

    After those 2 are sorted you should be at about 280-300hp and it’s when it’s time to talk about cams. I don’t think P6 cams are a good option for a boosted motor because they have too much valve overlap that you won’t need or want anyway once the head flow is fixed. Once the flow is fixed you’ll want is a cam with about 235 (stockish, early US or euro carb cams are not that bad) to maybe, maybe 250 degrees at .050” lift and .380+ lift I think. P6 cams are 270 degrees at .050” lift I believe and that is way too much IMO.

    Once you do the cams you should be up around 320-350 hp and it you want more it’s time for boost. 8 psi will bump you to 450ish. Add an intercooler and go to 15psi and you’ll be at 550-600ish. This is the way I would do it anyway, it’s certainly not the only way.

    Another option is to go straight to boost now without spending another cent of anything else. The cams you have will be just fine and at 8 psi you will be at 300 hp. When you want more you can add an intercooler and go to 15 psi and you will be at around 400 I’d think. This path makes a lot of sense too, it won’t net as much hp as the fist option but it will cost ½ as much.
     
  14. Artvonne

    Artvonne F1 Veteran

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    I respect many peoples opinions here, but the P6 bashing by people who have never seen them in an engine with high compression is a bit disingenuous. I own set of them, and as far as I am aware am one of only two or three people on Fchat to claim any experience with them. To hear it from the bleachers, one would think these awful cams will make the engine idle at 1500 rpm shaking like a banshee with absolutely no power at all below 5000 rpm and totally undriveable. Yet my motor with 9.7 pistons and otherwise completely stock, idled smoothly at 800 rpm and was quite streetable WITH TWO DEAD CYLINDERS. It wasn't as smooth and didn't have as much low end power as my engine with stock cams, but it wasn't an animal by any means either. At least not until it went above 4000 :) Imagine how much smoother and more powerful it would be with all 8 cylinders pulling! They do seriously pull in the upper revs, and the sound is unreal.

    Also be aware that some grinds in a 308 have been known to flip out shims and gall lobes. The P6 is a race proven cam which ran successfully at LeMans and other tracks without any trouble, and it is not a known shim flipper. High lift short duration cams do not work well in these 2V engines unless you run shim under bucket, and you may still gall lobes. So the best grind from only a performance perspective may not always be the most reliable grind at keeping your engine together long term, and experimenting can oftentimes get quite expensive. Again, no offense to anyone, but the only other opinion I would seek is from Norwood. They have a long history of hands on experience with that particular cam in the 2V 308 motor, and will tell it to you straight. If there is a better grind that works well without tearing up a motor they will know about it. Just to keep it all in perspective, the P6 is a drop in and go cam without any guesswork or experimenting.

    Outside of that I totally agree that supercharging is the best route to much higher HP. Throw a CIS injection system on and blow the stock motor, it will be very fast, TRULY reliable, and not too expensive.
     
  15. blainewest

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    I have a question...it was my understanding that p6 cams were stock in the early cars both US and Euro versions. My car is a series one '75 gt4. If mine has p6 cams I can tell you that even with high compression pistons (10.something to 1) the car idles very smoothly even at 600 or so rpm. Engine spins like a top. No issues whatsoever.

    Now can anyone tell me if my car has p6 cams?
     
  16. Racing-Baker

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    i'm no engineer/enginetuner what-so-ever and i'm picking up things here (on the chat) and there. like Steven i'm also planning to put it some cams.
    my question; i've heard about high-lift camfollowers... can these be used with stock cams to acchieve more hp? like a highlift cam? it would certenly be cheaper i guess.

    i know turbocharging a carb 308 is not the way to go but i've seen a blown 308carb here, is this as easy as it looks? i'm guessing there is not a plug-and-play kit? i have no expierence in blown cars :( what has to be done??!!
     
  17. mk e

    mk e F1 World Champ

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    p6 cams were never stock so you most likely do not have them.
     
  18. mk e

    mk e F1 World Champ

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    Sorry, no.

    Turbocharge or supercharge with carbs is about the same in terms of issues to deal with. I think someone has been selling turbo kit on ebay???? There are a couple blower options that would get a blower mounted to the engione but you would need to do the plumubing part yourself.
     
  19. Newman

    Newman F1 World Champ
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    It comes down to personal preference. In my opinion a 308 is slow off the line, even the best drysump version in stock trim is a slug. Since driving 3 times the limit gets me in trouble up here, I look for torque and the rush that goes along with that rather than winding the snot out of my car to get a thrill. P6 cams will only hurt performance in a realistic street application and with todays technology there are better grinds to suit any needs, the numbers dont lie so going for a ride in one isnt necessary. Its like saying a purpleshaft in a 340 is still the best cam you can get, not anymore.
     
  20. mk e

    mk e F1 World Champ

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    I agree on the personal preference comment. A P6 cam is not a “bad” cam and it will add about 10% to the top end. Anyone who drives above 4000 more of the time will probably be very happy with the result they get dropping is a P6. It’s proven, it’s bolt-in, no argument. I had a 2V motorcycle with nearly identical bore/stroke to a 308 with a cam with 270 degree at .050 just like a P6 with carbs (slide type though). I never went below 3000and I was happy with it.

    The 10% gain on top though comes at the cost of less power below 4000 and about 15%-20% less power at 2000. Most people spend most of their time below 4000 where the P6 cam is making less than stock hp so most people will not be all that happy with a P6 cam. Personally I would lean toward porting and stock early carb cams for a street car and it would make more hp than either a stock or P6 equipped car at any rpm. My next step would be to add some lift and make more hp across the board again…..but that is just preference, h8ll I HATE webers too so that tells you what my opinion is worth.
     
  21. Ferraripilot

    Ferraripilot F1 World Champ
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    Webcams has some great grinds that offer very near P6 performance (within 5-10bhp) but with greater low rpm performance. Paul has some good experience with these so I am inclined to listen to him, but there are a couple other fellows I see posting on here who currently have P6 cams on the street and are ready to throw their hands up in the air because of them. I think the only way one is really going to know if they like it or not is if they try it for themselves with the expectation that they may not like the end result (stay positive though!). People have different driving styles and like different things. The jury is still out for me as I havent tried it, but I want to!
     
  22. Artvonne

    Artvonne F1 Veteran

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    I wouldnt say I have good experience, barely any actually. But I have also asked about them from people who ran them in the past, and have experience with other carbed engines with wild cams.

    When someone says they are throwing up their hands in frustration, I first ask myself if we know all the parameters. There are very, very few people around that know how a carburetor works, much less how to balance and tune multiples of them. No one knew much about how to set points 40 years ago, much less today, and even fewer yet have any idea what "curving" a distributor and degreeing an engine means. Any one of these issues will screw up an engine so bad it may not even run. But most times its a little of each, and like the death of a thousand cuts they can ruin a perfectly good engines driveability and performance.

    But make some drastic alteration's to cam timing and compression, and any mechanic will have their hands full tuning it properly, because now it has to be "custom" tuned. And then, when all is said and done, a man has to know "how-to" drive a carbed engine with a big cam. If you dont know how to do that, you may as well accept a more stock engine because you'll be forever cursing it.
     
  23. Newman

    Newman F1 World Champ
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    Explain that please. I use the gas pedal, change gears when needed etc....If you mean put up with headaches and monkey business and its shortcomings then I guess I dont know how to drive a car with carbs and radical cams even though I had hemis and sixpack cars before the ferraris. They seemed to run ok.
     
  24. Ferraripilot

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    I have driven a couple somewhat radical cam'd carb cars. From those experience I learned you absolutely cannot stomp on the gas a low rpm without the thing hiccupping all over the place. These are early Porsche's with some serious ignition systems on them as well, but anything below 3k rpm you have to mind the expeditiousness of your foot so to keep one's cervical spine intact. I suspect this is due to a combination of poorly atomized fuel from the carbs and the lack of good vacuum at lower rpm.
     
  25. AZDoug

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    I don't know anything about P6 cams, but factory street hemis and the factory 340/6 and 440/6 didn't have radical cams. A little lopey, but not radical. At least the way they came from the factory.

    They did prefer lower gears,as in more turns per driveshaft/turn of rear wheel, to keep clutch feathering down on take off, and they were happiest over 2000-2200 RPM, as compared to a factory high lift hydraulic cam, which would run fine over 1500 RPM.

    The factory off road cams, which were available, but not on street package cars, were not what I would consider realistically everyday streetable, due to really needing to run from 3500 RPM up because of long duration and a bunch of overlap, unless you were a masochist and didn't mind sputtering and bunches of clutch work in traffic.

    Doug
     
  26. Newman

    Newman F1 World Champ
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    Mine were far from stock and I never had part throttle issues, couldnt pass a gas station though. Those were the days....
     
  27. AZDoug

    AZDoug Formula 3

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    There is that, make up for tons of overlap and poor fuel atomization with extra rich low speed jetting and monster accelerator pump cams and jets. 5-8 MPG or so around town...

    A 1200 RPM idle helped

    Doug
     
  28. Tokyo Drftr

    Tokyo Drftr Formula 3

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    gezzzzz, i couldn't even get that out of my mopars.......but i was running 4:30 in the cuda and 5:13 in the Challenger.....
     

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