[Fot] Re TR4 camshafts

John Styduhar johnstydo at gmail.com
Thu Oct 26 17:22:28 MDT 2017 

Art, you are speaking about an asymmetrical cam.  When degreeing an
asymmetrical lobe cam you must use the opening and closing figures at .050"
tappet lift *off the base circle of the cam not from the point of maximum
lift*. The problem with using the intake centerline method is that it has
you finding the theoretical centerline of the intake, and or exhaust lobe.
That system will work on a symmetrical lobe cam but when you try and do it
with an asymmetrical cam when you try to find the centerline of the lobe
there is an automatic error that may be as little as 2 degrees or as much
as 6 degrees depending on the actual lobe design. Also the centerline
method does not really indicate if your camshaft was properly produced, as
no confirmation of the duration occurs. Since the opening and closing at
.050" lift method is not affected by the lobe design, it is more accurate
to degree using the opening and closing at .050" tappet lift method. This
method will also verify your actual duration figures.
The above recommendations were gathered from several cam grinder sites.

On Thu, Oct 26, 2017 at 6:25 PM, <riverside at southslope.net> wrote:

> The lobe is that part of the cam that is not base circle.
> some cams open the valve more rapidly than they close it.  This
> shifts the max lift point to the front side a little.
> Mr. Elgin instructed me to go to the degree marks corresponding
> to .050 before and after the point of maximum lift and split that
> in half; the resulting reading would be the true lobe center.
> I had a devil of a time the first one of his cams I degreed.
>
> art de armond
>
>
> *From:* John Styduhar <johnstydo at gmail.com>
> *Sent:* Thursday, October 26, 2017 4:21 PM
> *To:* riverside at southslope.net
> *Cc:* patrickmannion1 at netzero.com ; Duncan Charlton
> <duncan.charlton54 at gmail.com> ; Triumph 'Friends of Triumph
> <fot at autox.team.net>
> *Subject:* Re: [Fot] Re TR4 camshafts
>
> The definition of cam lobe center line *is* the point of maximum lift.  ​
>
>
> On Thu, Oct 26, 2017 at 12:19 PM, riverside--- via Fot <fot at autox.team.net
> > wrote:
>
>> to further complicate,   the lobe center may not be at the
>> point of maximum lift.
>>
>> art de armond
>>
>> *From:* patrickmannion1--- via Fot <fot at autox.team.net>
>> *Sent:* Wednesday, October 25, 2017 10:25 PM
>> *To:* duncan.charlton54 at gmail.com
>> *Cc:* fot at autox.team.net
>> *Subject:* Re: [Fot] Re TR4 camshafts
>>
>> Hi Duncan, John and all,
>> I sent the proper information to Newmans in June and again this week but
>> haven't had any response.I was wrong when I posted the lift figure, on
>> Monday. When I didn't get a response from Newman in June with accurate
>> timing events I through my notes in a box and misread them the other night,
>> the lift was actually .015" less than specified in lift at cam which would
>> be .022" less lift at the valve.
>> The total lift, rise figure at TDC, and the figure at which max rise
>> should occur did not match what their website specified. The two sentence
>> response from them was like a politician saying "trust me", it only stated
>>
>> "The best way to set the camshaft is that you have maximum valve lift on the
>> inlet 110° after top dead centre" with no other information to second verify events
>>
>> In the past when we've ever had a figure on a timing card that didn't
>> match our cam grinder would get back and be able to say, check timing
>> events at this lift and verify by checking lobe centers and he would give
>> you ways to verify that all was correct. His cams always worked great.
>> I have three different types of cams, I'm going to plot and graph them
>> later in the week but will just use a camshaft from now on from a source I
>> trust.
>> thanks for you responses
>> Pat Mannion, Santa Cruz
>>
>> ---------- Original Message ----------
>> From: Duncan Charlton <duncan.charlton54 at gmail.com>
>> To: Triumph 'Friends of Triumph <fot at autox.team.net>
>> Cc: patrickmannion1 at netzero.com
>> Subject: Re: [Fot] Re TR4 camshafts
>> Date: Tue, 24 Oct 2017 06:50:56 -0500
>>
>> Hi Patrick,
>>
>> You didn’t say whether you determined how many degrees of advance/retard
>> you’re putting in by setting max lift at 110˚ ATDC.  Confirming that figure
>> ought to give you some confidence that what they’re telling you is in the
>> ballpark.  2 to 4 degrees advance seems appropriate for a street engine.
>>
>> Since you've been in the business for a while (I’ve heard your name in
>> Morgan circles for many years) I assume you already have the tools and
>> knowledge to do this, so I won’t go into a long-winded description of the
>> process, but for those reading this who haven’t done this before:  put a
>> degree wheel on the crank, zero it at true TDC and measure lift at the cam
>> or at the valve using a dial indicator, starting a few degrees before max
>> lift and ending a few degrees after max lift to be sure you’ve found mean
>> maximum lift.  Do this for both intake and exhaust and calculate the
>> midpoint between those two mean maximum lift points.  That gives you the
>> cam's “zero” point.  Decide whether to advance or retard a few degrees from
>> zero.  Advancing moves torque lower down on the rpm scale (but also
>> decreases intake valve to piston clearance).  I find I have to plot this on
>> paper so I can make sense of it and to make sure I don’t move the the wrong
>> direction in altering the valve timing.
>>
>> Newman overstated lift by 34%.  Wow.
>>
>> Duncan
>>
>>
>> On Oct 23, 2017, at 2:48 PM, John Styduhar via Fot <fot at autox.team.net>
>> wrote:
>>
>> ​Follow the instructions for setting the cam and you will be fine.  An
>> adjustable cam sprocket will make the job easier.
>>
>> On Mon, Oct 23, 2017 at 11:54 AM, riverside--- via Fot <
>> fot at autox.team.net> wrote:
>>
>>> Yikes!   I  have always had great success with Dema's cams.
>>> I hope his shop survived the fires.
>>>
>>> art de armond
>>>
>>> -----Original Message----- From: patrickmannion1--- via Fot
>>> Sent: Saturday, October 21, 2017 5:11 PM
>>> To: fot at autox.team.net
>>> Subject: [Fot] Re TR4 camshafts
>>>
>>> Hello all,
>>> I have always nearly always built Triumph TR4 engines with cams from
>>> Dema Elgin Superlobes in Santa Rosa. Occasionally I had installed other
>>> cams supplied by customers that had a valid timing card supplied. I decided
>>> with the English pound being low vs the Dollar I would try the PH1 Cam from
>>> Newman Cams in England. I had heard good things about their PH1 cam as
>>> being a great street cam.
>>>
>>> When installing the cam. Information on there website stated peak cam
>>> lift was .295" (it is only .220") resulting in a lift at the valve being
>>> .120" less than stated. Starting off with" incorrect lift figure all valve
>>> event figures on the website are wrong. After several emails I got a two
>>> sentence email saying ,set Intake for max lift at 110 degrees ATDC and the
>>> cam will work,
>>>
>>> After doing lots of engine modifications I would like a more scientific
>>> answer than the cam will work. Has anyone used this cam or a Newman cam
>>> before, or found that the information supplied by Newman was incorrect. I
>>> hate to eat the cost of the camshafts I bought or incur the cost of sending
>>> them back to England, but I would have no confidence in using a camshaft
>>> without having a correct timing card for the camshaft. -
>>> thanks
>>> Pat Mannion
>>> Santa Cruz California
>>> ____________________________________________________________
>>> Megyn Kelly's IQ Has NBC Embarrassed
>>> modernwomannews.com
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