Author Topic: cylinder head rockers  (Read 3545 times)

t.h.

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cylinder head rockers
« on: January 29, 2010, 06:54:14 »
does any one know what the rocker arm ratio is on a 130 engine please

ja17

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Re: cylinder head rockers
« Reply #1 on: January 29, 2010, 18:36:49 »
Hello t.h.

I am not sure what you mean by "rocker arm ratio" ? 
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

t.h.

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Re: cylinder head rockers
« Reply #2 on: January 29, 2010, 21:29:36 »
Hi The ratio is determined by where the camshaft is positioned in relation to the length of the rocker arm.
Example is if the cam is positioned directly above a vavle the valve would only open as much as the lift on
cam lobe is but as you move move the cam along the rocker arm towards the pivit post it increases the
amount the valve opens.
I have seen the figure somewhere but buggered if i can find it and i need it for the engine shop as the head is being
flowed modified if required and ported and polished

jeffc280sl

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Re: cylinder head rockers
« Reply #3 on: January 29, 2010, 22:23:05 »
Isn't the rocker ratio created by dividing valve lift by cam rise?

ja17

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Re: cylinder head rockers
« Reply #4 on: January 30, 2010, 02:10:22 »
Hello th,

Thanks,.......... interesting.  Let us know how much difference the modification and flow work does on the head.

Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

Benz Dr.

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Re: cylinder head rockers
« Reply #5 on: February 02, 2010, 05:14:35 »
I have the flow bench results for a 250SL head. They're much beter than you might think and are about the same as a typical small block chev. The guy who did it was very impressed and it was a dirty old head with crud all over the valves.

Rocker geomerty is critical on these engines. Get the rockers out of whack and you can ruin valve guides in to time at all. Less than a few miles if really bad.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn

1970  3.5 Coupe
1961  190SL
1985   300CD  Turbo Coupe
1981  300SD
2013  GMC  Sierra
1965  230SL
1967 250SL
1970 280SL
1988 560SEC