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Re: [Fot] Mystery cam

To: Duncan Charlton <duncan.charlton54@gmail.com>
Subject: Re: [Fot] Mystery cam
From: Bill Babcock <ponobill@gmail.com>
Date: Tue, 14 Jun 2016 14:18:32 -0700
Cc: Friends of Triumph <fot@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
References: <294DA329-A981-49E4-BE88-7A1E0B27DA73@ponostyle.com> <F42B6E64-04C4-4462-AECD-C69982F2DBF0@gmail.com>
Damn, Iâ??ve been staring at this too long. Of course youâ??re right. I bit the 
bullet and pulled off the rocker arms to do it right and now the numbers are 
even more confusing. 


> On Jun 14, 2016, at 1:08 PM, Duncan Charlton <duncan.charlton54@gmail.com> 
> wrote:
> 
> Hi Bill,
> 
> If I understand you right, you measured lift at the valve itself, in which 
> case it looks to me that you did the rocker arm equation backwards.  0.050â?? 
> lift at the cam should see a greater movement at the valve, not a lesser 
> degree.
> 
> I hope you ended up with a Tiltech cam â?? thatâ??s what I would choose if I 
> could get one today.
> 
> Duncan
> (Texas)
> 
>> On Jun 14, 2016, at 12:11 PM, Bill Babcock <ponobill@gmail.com> wrote:
>> 
>> Iâ??m building a new motor for Peyote from the bits of itâ??s previous 
>> engine. I discovered the front main bearing cap was cracked in half when I 
>> decided to freshen the motor. Iâ??ll work on replacing the cap laterâ??maybe 
>> get a billet one made, but in the meantime Iâ??ve run into a minor problem. 
>> I donâ??t know for sure what cam I have or how it should be set.  Tony 
>> Garmey says itâ??s a BFE cam, but I canâ??t find any specs for those and 
>> canâ??t get ahold of Ken. 
>> 
>> I ballparked where I think the cam might want to be and got this for 
>> measurements: 
>> 
>> Reading the Intake and exhaust valve movement from the spring retainers I 
>> use 0.033â?? as the open/close height which is .050/1.45 which as I recall 
>> is the ratio of the stock rockersâ??
>> Intake open .033 @ 36 BTC
>> Intaake close .033â?? @ 76 ABC
>> Exhaust open .033â?? @ 76 ABC
>> Exhaust close .033â?? @ 42 ATC
>> 
>> By my calculations that gives:
>> Intake duration 292.0 degrees
>> Exhaust duration 298 degrees
>> Intake lobe center 110.0 ATC
>> Exhaust lobe center 107 BTC
>> Overlap 78
>> Lobe separation angle 108.5
>> 
>> Pretty sure this isnâ??t exactly where it needs to be. I have a vernier 
>> sprocket so I can adjust the timing precisely. My questions are:
>> 
>> What cam is this?
>> Where should it be set?
>> How much advance?
>> _______________________________________________
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>> 
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>> 
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>> 
> 

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