V6 Camshafts
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Thread: V6 Camshafts

  1. #1
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    Default V6 Camshafts

    Does anyone know any of the valve lift figure for any of the Peugeot/Renault/Volvo standard V6 cams? Im getting rough ideas of around 5-6mm, which on a 44mm inlet valve, only equates to about half the flow its area could allow. I know cams with more duration are available for more power, but has anyone experimented or knows the problems or limits of increased valve lift on this engine (other than hitting the pistons...)
    Thanks

    Dave

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  2. #2
    Budding Architect ???? pugrambo's Avatar
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    i can give you volvo figures

    these are lifts at the cam

    type 1 LH lift 0.202" 5.144mm
    type 1 RH lift 0.199" 5.059mm
    type 2 lift 0.236" 6.004mm
    type 3 lift 0.234" 5.960mm

    i have the 604 ones here somewhere but i will have to go searching so i will get back to you later on that

    type 1 came in all B27A and B27F engines and B27E from 75-78
    type 2 came in B27E 79/80 B28A '80 and B28F '80
    type 3 was all engines from '81
    3 x '78 604 SL

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    1 x '99 406SV 5spd wagon, time to burn more fuel

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  3. #3
    Fellow Frogger! OddFireV6's Avatar
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    Just under 10mm is possible as far as valve train goes but to go over this you need to use Porsche adjusters that have the pivoted contact face otherwise the tappet to valve stem interface suffers from fatigue. Also you will find that the valve spring washer fouls on the valve stem seal and so you would need to use simple umbrella type stem seals that take up less space.


    IF you do have 44mm inlets, this is big? you only need about D/4 or 11mm to get the maximum efficiency from this valve size.

    The B280 cams, in some countries has a lift of 9.5mm but has no spline for a distributor, If you have had serious headwork done get some custom cams made by someone who knows how to do them. Many sets have been made in Aus which are only useful as paperweights.
    OddfireV6
    504 V6 24V, 203

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    Thanks for that. I have cams available which have 8.2mm lift for the V6, its just when I looked at the FerryDev page the other day, they were only mentioning a lift of around 6mm, which got me wondering about what the limits were...

    When I was saying 44mm, that was the valve area, not the size of the inlet port. The turbo V6 has 44mm inlet valves, with 40mm smallest inlet dia, while the later Z7X PRV has 46.5mm with 46mm smallest inlet dia! I was trying to work out what was the biggest restriction, the ports, or the air flow via the low lift of the valves?
    Last edited by David Gentleman; 13th December 2004 at 09:52 PM.

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    Quote Originally Posted by OddFireV6
    Just under 10mm is possible as far as valve train goes but to go over this you need to use Porsche adjusters that have the pivoted contact face otherwise the tappet to valve stem interface suffers from fatigue. Also you will find that the valve spring washer fouls on the valve stem seal and so you would need to use simple umbrella type stem seals that take up less space.
    I dont think there is much of a problem on the Renaults as a couple of cam manufacturers I deal with have quoted 10-11 lift, on 270-305 degree cams, with no additional or change of parts required. The valve train must be different, does anybody know?
    Last edited by David Gentleman; 14th December 2004 at 08:05 AM.

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    The MRV6 manual for the Renault PRVs doesnt mention valve lift, but it mention about the valve springs. 47mm free length, 40mm at 24.8daN and 30mm at 60daN (coils touching at 28mm). This indicates to me 10mm valve lift, does anyone agree, or can shed light on this?

  7. #7
    1000+ Posts alan moore's Avatar
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    Possibly the installed height is 40mm, but this is not quoted, only that the spring will have a certain tension at set heights. Check the actual installed height on your engine, or perhaps on the spare heads that you have.

    Often when wanting to run a fairly high lift cam, the spring seats and guide bosses have to be machined a little further into the head to allow a longer spring to be fitted. Don't know about the PRV V6. Anything over 10.5 mm at the valve is up there on a road engine. What rocker ratio do they have? 1.5 to 1?
    '56 Renault 750 (16TS Power)
    '62 Renault Dauphine Gordini
    '89 Renault Alpine GTA V6 Turbo
    '08 Renault Megane sedan

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    Hi Alan,

    Ive got rid of the spare heads I had, other wise I could have just measured them. Im doing a 2.8 turbo conversion, and the cams I supply have 10.5mm lift on a long duration, I know they work without any problems, but I never measured the original lift of the standard cams to see how much gain 10.5 mm was. When I pull the new enigine apart I can measure them then, it was just getting things clear in my head now.

    I think this is the installed height because the manual also lists lenghts for the 2.7 V6, at different loads, presuming a lower lift cam, therefore less load.

    I would have thought if it was just to show a certain length at load, they would have used the same loads, not different ones for different V6 engines?

  9. #9
    1000+ Posts alan moore's Avatar
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    I admit 40mm for the spring and another 2.5 or so for the retainer would be about right as an installed height. For the tensions, I admit to working in pounds as do not know the conversion from the Renault figures.
    '56 Renault 750 (16TS Power)
    '62 Renault Dauphine Gordini
    '89 Renault Alpine GTA V6 Turbo
    '08 Renault Megane sedan

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