[Fot] Mystery cam

[Larry Young]

Bill, I believe you had a 298D cam that was in an engine from uncle 
jack, but you told me you were not going to run it.  That was a few 
years ago. Someone on the list will probably want it if you don't.  I'll 
send you the cam card.  It should be run with 0 to 4 degrees advance and 
a valve lash of 0.015.

Steve Long sent me the specs of all the Erson cams, so the numbers on my 
website should be accurate.  Steve will grind whatever lobe separation 
you want, so you can't use lobe separation to identify his cams. The 
Erson 23 should have similar lift, but a lot more duration than my 298D cam.

Cam timing is confusing because the scales on the degree wheels run one 
way then another. I often subtract when I should add, because of the 
scale direction.  I'd prefer a scale that runs from 0 to 360.  I have a 
couple of Excel spreadsheets you can download from my website that might 
help with some of this.  The one for timing is confusing because of the 
conversions of all the degree wheel readings.

Larry

www.TildenTechnologies.com


On 6/14/2016 12:46 PM, Bill Babcock wrote:
> Searching around on the web, it kind of looks like a TilTech 298Dx, but I don’t recall buying a cam from Larry and Tony Garmey doesn’t think so either. I could just set it up as if it were, but it would be good to know.
>
>
>> On Jun 14, 2016, at 10:40 AM, Bill Babcock <ponobill at gmail.com> wrote:
>>
>> Oh, and the lift is .372
>>
>>
>>> On Jun 14, 2016, at 10:11 AM, Bill Babcock <ponobill at gmail.com> wrote:
>>>
>>> I’m building a new motor for Peyote from the bits of it’s previous engine. I discovered the front main bearing cap was cracked in half when I decided to freshen the motor. I’ll work on replacing the cap later—maybe get a billet one made, but in the meantime I’ve run into a minor problem. I don’t know for sure what cam I have or how it should be set.  Tony Garmey says it’s a BFE cam, but I can’t find any specs for those and can’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 0.033” as the open/close height which is .050/1.45 which as I recall is the ratio of the stock rockers”
>>> Intake open .033 @ 36 BTC
>>> Intaake close .033” @ 76 ABC
>>> Exhaust open .033” @ 76 ABC
>>> Exhaust close .033” @ 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 isn’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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