Cam Overlap

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Feb 16, 2005 | 09:10 PM

jz06man

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Cam Overlap

What is the best overlap a cam can have and still pass emissions in places like California, i know their are other factors, but this is the main factor.

What is a good/average overlap for a smooth running cam/idle and one for an agressive cam/idle with loop.

Feb 16, 2005 | 11:42 PM

BADFNZ

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From: Dyess AFB, TX

I'd say you want 0 or negative overlap. My TR224 on a 112 has an overlap of 1.2*@.050.

Feb 16, 2005 | 11:56 PM

jrp

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From: Valencia, Ca

yup 0 or negative, the tr224 has -4* overlap @ .050

Feb 16, 2005 | 11:56 PM

jz06man

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I believe that 224 has a 0 overlap.
224+224/4=112-LSA 112=0X2=0

Feb 16, 2005 | 11:57 PM

jz06man

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JRP, 0 will pass emissions ???

Feb 17, 2005 | 03:36 PM

BADFNZ

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From: Dyess AFB, TX

According to my cam sheet and my calculations, mine has 1.2*@.050. My LSA is also 111.5.

Feb 17, 2005 | 04:25 PM

jz06man

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ok, now it makes sense- 1.2 overlap is correct for this 111.5. a 224/224 with a 112 is 0 overlap.
Still I'm not sure it 0 is still ok for california emissions.. Does anyone know ?