[Fot] Do(o)med or flat lifters?
Gregmogdoc at surfnetusa.com
Gregmogdoc at surfnetusa.com
Thu Aug 30 12:20:31 MDT 2018
I bought my 1964 Morgan +4 new in 1965. When I first
took the engine apart to modify it for more power at
around 16,000 miles, there were two lifters in the
engine that were not rotating! They had "butterfly"
wear patterns on the bottom of the lifters caused by
the lifter oscillating back and forth. So this is a
fault in the original production of the engine.
Over the years, whenever I have taken apart what I
believe to have been "virgin" engines, I have ALWAYS
come across 2 or 3 lifters in each engine that have
not been rotating. When they don't rotate, they
eventually pit and fail, then damage the camshaft.
The original cam lobes were flat, not tapered, and
relied on the offset of the tappet bores in the block
from the center of the cam lobes to induce rotation.
It was not enough! All or our cams are ground with a
taper to the lobes that matches the offset of the
lifter bores in the block to the cam lobes. This
means that 4 lobes have a taper in one direction and
4 lobes are tapered in the other direction. The
tappets are ground with a crown to match. Since we
have been doing that, all the lifters rotate
consistently, and if the lifters are hard enough, we
do not have excessive wear problems unless poor
quality oil is used or the break in procedures and
not correctly followed.
Greg Solow
The Engine Room
Sports Car Specialists
Santa Cruz, CA 95060
831 429-1800
------- Original Message -------
>From : fubog1 via Fot[mailto:fot at autox.team.net]
Sent : 8/29/2018 4:08:02 AM
To : tr4racing at googlemail.com;
pegandbobm at aol.com; rkrantz77 at comcast.net;
fot at autox.team.net
Cc :
Subject : RE: Re: [Fot] Do(o)med or flat lifters?
#1 cause of failure- dirt 40+%.
#2 cause of failure- assembly error 40+% (note
assemblers responsibility to ensure parts are to spec)
This is part of the problem with rebuilt failures, it
isn't all "defective parts".
HTH
Glen
problems came in when people used aftermarket parts
or tuning parts.
-----Original Message-----
From: Chris Marx via Fot <fot at autox.team.net>
To: tr4racing <tr4racing at googlemail.com>; pegandbobm
<pegandbobm at aol.com>; rkrantz77
<rkrantz77 at comcast.net>; fot <fot at autox.team.net>;
Fubog1 <Fubog1 at aol.com>
Sent: Wed, Aug 29, 2018 5:37 am
Subject: Re: [Fot] Do(o)med or flat lifters?
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Let me add:
Standard means….from factory
Tuning means…..from so called “experts”
I don’t know how much experts they are but one thing
is obvious.
In the past, Triumph seems not to have much trouble
with camshafts…..problems came in when people used
aftermarket parts or tuning parts.
This is always suspicious to me.
Cheers
Chris
Von: tr4racing at googlemail.com <tr4racing at googlemail.com>
Gesendet: Mittwoch, 25. Juli 2018 07:54
An: pegandbobm at aol.com; rkrantz77 at comcast.net;
fot at autox.team.net; Fubog1 at aol.com;
tr4racing at googlemail.com
Betreff: AW: [Fot] Do(o)med or flat lifters?
I had a look around German forums and it seems to be
a difference between tuning and standard engines.
Standard – flat
Tuning – domed.
Von: pegandbobm at aol.com <pegandbobm at aol.com>
Gesendet: Montag, 23. Juli 2018 22:17
An: rkrantz77 at comcast.net; fot at autox.team.net;
Fubog1 at aol.com; tr4racing at googlemail.com
Betreff: Re: [Fot] Do(o)med or flat lifters?
Not an expert but I WILL GUARANTEE the lifters in my
air cooled German made VW Formula Vee engine have a
slight radius/angle. I check this before each
rebuild to ensure they have not flatten. Pre-Trump
I think Germany was still considered part of Europe>
Bob
-----Original Message-----
From: Ron KRANTZ via Fot <fot at autox.team.net>
To: Christian Marx via Fot <fot at autox.team.net>;
Fubog1 at aol. com <Fubog1 at aol.com>; Christian Marx
<tr4racing at googlemail.com>
Sent: Mon, Jul 23, 2018 1:46 pm
Subject: Re: [Fot] Do(o)med or flat lifters?
The reason for a slight angel on the lifter is to
keep it from digging into the ramp on the cam lobe
due to an aggressive acceleration design. Typical
American (cannot say what European mfg. does) lifters
have approximately a 60 inch radius. I even have an
additional edge radius put on the lifters. The cam
lobes have a slight taper side to side for rotating
the lifter. Lift on a cam is limited by base circle
radius which in turn is limited by cam bearing
diameter. Then you get into duration and how fast
you can get the valve open. All the Triumph "flat"
tappets I have ever seen have a slight radius. The
rules say you must retain the same type (flat,
roller, mushroom) lifter as stock. My question is
"how flat is flat". Rule does not say the lifter has
to rotate. If a lifter has a 0.75 inch radius across
the lifter diameter and no taper on the cam lobe,you
can keep the lifter from rotating and accelerate the
cam opening very fast. Think about that.
On July 23, 2018 at 8:46 AM Christian Marx via Fot
<fot at autox.team.net> wrote:
This may be true for American engines.
All European engines have no angel in the Cam shaft.
And all the tappets, lifters, rollers, are flat. Dead
flat. No light with an edge on it.
So maybe this is just an American thing?
Cheers Chris
fubog1 < fubog1 at aol.com> schrieb am Mo., 23. Juli
2018, 15:40:
This is well covered in many engine-building books &
I've discussed it at length with several camshaft
engineers over the years.
It's my understanding that the lobe should have a
very slight angle ground in, and the "flat" tappet
really isn't, it's very slightly convex.
This will give it rotation, if it doesn't rotate it
will wear.
There could also be spring pressure or lubrication
issues?
In any case I would discuss it with the tappet
supplier before doing anything, at the least make
sure that they are sufficiently hard to begin with
and can be reground.
Glen
-----Original Message-----
From: Christian Marx via Fot < fot at autox.team.net>
To: fot at autox. team. net < fot at autox.team.net>
Sent: Mon, Jul 23, 2018 6:04 am
Subject: [Fot] Do(o)med or flat lifters?
In the past we had this discussion.
I've bought some high quality lifters from USA, made
from tool steel I suppose. 400$ they've cost..... and
started to fail. On 3 of them, the very center does
show e few pittings. Also visible that only a small
part of the Cam is used.. The cam is okay
The machine shop will grind the lifters dead flat, as
they should be, they say.
Cheers
Chris
Am 18.07.2018 02:12 schrieb "fubog1 via Fot" <
fot at autox.team.net>:
Yes, lacking access to a Cam Doc, you can use a set
of V or bearing blocks, a degree wheel, dial
indicator, and a bit of time, checked at 5 cam
degrees, works fine.
I'm still old school though, I plot them out on graph
paper!
That will give you the lobe profile but most folks
don't have the full specs on the cam, usually just
advertised lift and duration.
Since the tip of the lobe usually starts to go away
first, a simple lift measurement will reveal the
worst, best done with a dial indicator cuz some
(cheap) cams are ground on different base circles.
Generally, ramp wear is unusual if the tip is still
OK, although there can be exceptions.
Glen.
-----Original Message-----
From: timmmurphh < timmmurphh at gmail.com>
To: 'fubog1' < fubog1 at aol.com>; rbtr3a < rbtr3a at cox.net>
Sent: Tue, Jul 17, 2018 12:38 pm
Subject: RE: [Fot] Cams
By degreeing the cam using increments of 10
crankshaft degrees (5 camshaft degrees) and then
plotting the results in Excel, it is possible to get
a very accurate picture of the profile of the cam.
I’ve attached a spreadsheet showing an intake and
exhaust lobe comparison two years apart of our
Kastner G3 cam for reference.
Tim Murphy
#317 TR4
From: Fot <fot- bounces at autox.team.net> On Behalf Of
fubog1 via Fot
Sent: Monday, July 16, 2018 6:31 AM
To: rbtr3a at cox.net; fot at autox.team.net
Subject: Re: [Fot] Cams
Generally any obvious wear or pitting would make it
unserviceable, but the wear isn't always so obvious.
You can measure the lift and compare to spec, that
will show any worn lobes, but the best way is to find
someone who has a "cam doctor". It's a machine that
sets it up and measures the complete profile.
Usually if there is anything apparent that suggests
that there may be problems, there are...
Glen
-----Original Message-----
From: rbtr3a--- via Fot <fot at autox.team.net>
To: fot <fot at autox.team.net>
Sent: Sun, Jul 15, 2018 6:47 pm
Subject: [Fot] Cams
How do I determine if a cam is good or bad. If there
are any marks on it does that make it bad. I do know
that two of the lifters has pitting on the surface.
Ronnie
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