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Registered:
May 2002
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 2TGEU - MAXIUM lift on custom cams...
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Sun, 07 September 2003 23:37
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Hi all,
What is the maxium lift you can have on your cams before they hit the pistons on a standard motor? And how much difference will the compression have on the lift?
The idea is to put big, fat cams without lifting the head to machine the pistons to suit the cams.
cheers
Frank
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Location:
Adelaide
Registered:
June 2003
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Re: 2TGEU - MAXIUM lift on custom cams...
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Mon, 08 September 2003 01:33
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have a look in the toysport articles under 2tg, 3tg, 18rg tech notes. That should tell you what duration is possible for standard pistons.
I have seen one set of custom cams for a 2tg, they were around the 300 degree mark with a 10.1 lift.
The lift was not much more than stock really. (10mm if I remember rightly)
The more duration you have, the less lift you can afford to have in a stock engine.
Anyone please feel welcome to correct me if I'm wrong.
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Location:
South Australia
Registered:
July 2002
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Re: 2TGEU - MAXIUM lift on custom cams...
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Tue, 09 September 2003 02:59
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The only thing I can say is that (I've heard) the best power is achieved when the cams have lift near to 1/4 the diameter of the port size. I can't remember the port size on a standard 2T-G, but it's not so large that you would put high enough lift cams to hit the pistons -> although, that depends on duration.
I suppose that doesn't really answer your question... sorry 
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Location:
Perth
Registered:
May 2003
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Re: 2TGEU - MAXIUM lift on custom cams...
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Tue, 09 September 2003 03:06
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Sounds right Steve M.
Just a few more points to consider:
Maximum lift will also be determined by spring bind.
Becareful if regrinding the standard cams below the original base circles as it changes the angles at which the cam lobes first strike the buckets - in turn possibly damaging the buckets.
To get really precise the cams and valve springs should be matched to avoid resonances occuring at too lower a frequency - i.e. valve bounce occuring in the operating rev range of the motor.
Hope this is helpful.
Tyron.
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Registered:
May 2002
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Re: 2TGEU - MAXIUM lift on custom cams...
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Tue, 09 September 2003 06:07
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Thanks guys, i'll take this on board when i locate another set of cams ir get some machined to suit the rebuild (the cams i had lined up were sold even though i had the deposit), but at least now i can rebuild a motor and get cams to suit instead of building a motor to suit the cams.
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