[DeTomaso] what have i got?

[Daniel C Jones]

> i believe i have what is known as a solid lifter engine, correct?

Yes. More specifically, a solid flat tappet engine (as opposed to a
roller lifter design)

> in what way does that differ from a hydraulic lift engine?

The camshaft spins in the block. Lifters ride on the cam lobes
and impart motion to the push rods which push on the rocker arm
which, in turns, pushes down on the valve to open it. As parts
(camshaft, lifters, valves and valve seats) in this system wear,
something needs to be done to keep a gap from growing. Hydraulic
lifters pump oil through the lifter to move the pushrod cup so
it takes up the slack. With a solid lifter cams are designed
differently (with clearance ramps) and run with a certain gap
(measured between the valve and rocker tips with a feeler gauge
with the lifter on the base circle, not the lobe, of the cam).
As that gap, known as the lash, grows you have to go in and re-adjust
the gap back to the specified value. The lash will be listed
on the cam card and there are different values, depending upon
whether the lash is set cold or hot to account for thermal
expansion.

> what is valve lash and why does that seem to be so burdensome
> with a solid lifter engine? - is there anything special one
> needs to do to maintain a solid lifter engine v. a hydraulic
> lift?

You need to periodically remove the valve covers and check or
re-set the lash. The lash must be set when their lifter is on the
base circle of the cam. At this position the valve is closed and
there is no lift taking place. The SAE method (a.k.a. the EOIC
method for Exhaust Open, Intake Closed) is to:

1. Warm the engine. Once you know the difference between hot and
cold lash, you can set the lash cold.

2. Follow the firing order. You can pick any cylinder but I usually
start with number one and have a copy of the firing order and
cylinder numbering in front of me.

3. Crank the motor over by hand (socket on the balancer bolt), set
the intake lash just as the exhaust valve begins to open.

4. Watching the same cylinder, crank the engine over some more and
then set the exhaust lash just before the intake valve closes.

In more detail,

1. Remove the valve covers and pick the cylinder you are going to adjust.
If your cam is already broken in, do this with the engine fully warmed up
(takes thermal expansion into account). If installing a new cam, use the
cold specs before firing the engine, then re-lash after cam break0in with
the engine hot.

2. Hand turn the engine in its normal direction of rotation while watching
the exhaust valve on that particular cylinder. When the exhaust valve begins
to open, stop and adjust that cylinder's intake valve. When the exhaust is
just beginning to open, the intake lifter will be on the base circle of the
lobe, ready to be adjusted.

3. With a solid cam, use a feeler gauge to set the correct valve lash.
Place it between the tip of the valve stem and rocker arm. Back off the
lock nut, turn the adjuster until you arrive at the proper setting then
lock the adjuster in place.

4. After the intake valve has been adjusted, continue to rotate the engine,
watching that same intake valve. The intake valve will go to full lift and
then begin to close. When the intake is almost closed, stop and adjust the
exhaust valve on that particular cylinder. When the intake valve almost
closed, the exhaust lifter is on the base circle of the cam. Follow the
procedure in step 3 to set the lash or pre-load.

5. Both valves on this cylinder are now adjusted, so check the firing
order and move to next cylinder and repeat the procedure.

The SAE method is more accurate than the 90 degree method described in the
Ford manual and the more overlap the cam has or the less piston-to-valve
clearance you have, the more important this method is.

> why do people alwasy question whether a solid lifter engine is "streetable"?
> why wouldn't it be?

Streetable may refer to the RPM band the cam operates in or on how aggressive
the lobe is. If the cam is designed to operate in the 4500 to 8000 RPM band,
it won't work well on the street where you operate outside that RPM band most
of the time. Also, the more aggressive a lobe is, the faster it wears and the
harder it is on the rest of the bits in the valve train. Furthermore, a solid
roller cam has needle bearings which may or may not be pressure fed at idle and
can get hammered by the lash. Some cam companies recommend solid roller lifters
be inspected every oil change which means removing the intake manifold.

> with respect to these heads, are folks familiar with them? - i believe they
> are from australia - what positive attributes do they have?

The are not from Australia. They are Chinese copies of the CHI heads from
Australia and Pro Comp has been deceptive in their advertising in the past,
quoting flow bench numbers that were not accurate (used CHI's numbers, not
their own). I've flow benched and dyno tested them on the 351C dyno engine.
On that relatively mild engine, the Pro Comps were down 30 HP to stock iron
4V Cleveland heads and were down 50 HP to the CHI 3V heads they copied.
Pro Comp screwed up the intake short side radius and the flow bench showed
the exhaust out flowing the intake (it should be the other way around).
The part number you list appears to be a CNC-ported version so perhaps they
have improved things but I'd still be suspicious of the quality of components
used.

> anything special about the design (flat top) or build?

Flat top is usually used to refer to pistons, not heads. You probably
mean closed or open chamber. The heads are nominally closed chamber but
the chamber volume listed for that part number is 74 cc's which is closer
to an open chamber volume though I suspect that means the chambers were
unshrouded.

> what do people think of this build generally? - is it a high quality build?

The Keith Black pistons used are their new Icon line of forgings. They are
inexpensive but appear to be decent quality. KB's hypereutectic pistons got
a reputation for being brittle and many people confuse the two lines of pistons.

> TCI Rattler

There are three basic types of harmonic dampers:

1. Elastomer
2. Lanchester
3. Visous Fluid

OEM automobile applications use elastomer-style dampers. Construction
consists of an outer inertia ring with rubber insulator that is bonded
or pressed onto an inner crank hub. The ring on the rubber is tuned to
a particular frequency. Essentially, an additional mass is elastically
bonded to the primary mass. Since the natural frequency of the additional
mass is constant, it is only effective when the crankshaft frequency is
within the range of the damper mass tuned frequency. It modifies the
the peak by introducing two new resonant peaks (one and and one below
the original) of lesser magnitude. When you know the frequency, this
method works very well. However, when altering an engine (particularly
when stroking an engine), the natural frequency may change. NASCAR and
Trans Am teams use SFI-spec elastomer type balancers but they also have
access to specialized equipment to measure torsional frequencies and
deflections that allow them to tune the dampers to their applications.
Some designs are bi-modal having inner and outer elastomer rings, each
tuned to a different frequency. The outer ring of elastomer dampers
can slip (causing timing marks to change) or even come off the hub.
Many sanctioning bodies mandate the use of SFI specification 18-1
approved dampers for racing. Elastomer dampers work by converting
differential movement of the ring relative to the hub to heat in the
rubber. Rubber hardens with age and temperature so the tuned frequency
can change over time and use. Harder rubber increases the tuned frequency.
One 'net source tested an intact but old balancer and found a 26% frequency
increase. On that particular crank and damper combination, a 10% increase
was found to permit greater than 1/2 degree amplitudes which is believed
to be large enough to crack a crank over time.

Viscous fluid dampers consist of an inertia ring that floats in high viscosity
silicone fluid. The ring and fluid are encased by an outer housing and inner
hub. Damping is acheived by shearing the thin film of fluid surrounding the
inertia ring. As the crank nears it's natural frequency, the crank is subject
to a torsional oscillation. The inertia of the hub lags the oscillation which
creates a differential shearing motion in the viscous fluid. This absorbs
the vibration energy which is dissipated as heat. Viscous fluid dampers are
not tuned to a particular frequency but work whenever there is torsional
vibration present (i.e. they don't tune out any particular frequency but rather
clip the peaks off the harmonics). They are effective at damping torsional
vibrations in a crankshaft but they work best in engines that see relatively
modest angular accelerations. They are well suited to engines that see heavy
loads at constant or slowly varying RPM and are commonly used in diesel truck,
marine and locomotive applications. However, on a road race engine that sees
constantly changing RPM (with high rates of change), the viscous damper lags
behind the RPM change which heats up the silicone fluid. You can thing of a
ring in viscous fluid as a damper like a shock absorber and it will overheat
if used continuously. Also, the silicone fluid will, after constant heat
absorption during its service life, reduce in viscosity value. Some industrial
dampers have sampling plugs fitted into the housing that allow fluid to be
extracted for analysis. Metaldyne recommends overhaul when the fluid has
reduced 50% in viscosity value. At that stage, the damping efficiency will
be 80% of the original.

The Lanchester damper is a pendulum style invented by aviation pioneer
Frederick W. Lanchester 100 years or so ago. It works at all RPM as the
centrifugal force field changes the natural frequency of the pendulum as
rpm increases (the natural frequency of the centrifugal pendulum absorber
is directly proportional to the angular velocity of the primary structure).
In theory, the Lanchester damper should be a good match for a stroker engine
but the published results I've seen were not particularly impressive.
The TCI Rattler is a pendulum style damper. TCI did an SAE paper on their
Rattler damper but the results didn't look any better than a conventional
damper.

All the serious race teams I'm aware of use elastomer balancers but some
of the teams have the resources to have them tuned to their specific engines.

> SA Gear 9 position tru-roller with Torrington bearing

SA Gear makes the sprockets. I prefer other sprockets but more important
is the chain manufacturer. If your chain says Rolon, it is junk.

oes the crank have a snout spacer
installed to take up the difference between the 351W style
snout of the Eagle crank and the 351C snout?

> Bore (.40 over/385c.i.) and hone block

Some get nervous at 0.040" pver unless they've sonic tested the block first.

> Dyno (500HP/472lb torque)

Do you have the dyno sheets or was this an estimate from the builder?

> Edelbrock air gap intake manifold (dual plane)

The Air Gap has 2V ports but Pro Comps are a copy of the CHI 3V heads.
Is there a spacer to handle the port transition? CHI used to do that
before dual and single plane intakes were available to match the 3V
port location. Eyeballing the CNC port version of the Pro Comp heads,
it's not clear to me what intake manifold they were designed for.

> Moroso oil pan

Is this in a Pantera? The Moroso 351C pan I'm familiar with is not
gated nor baffled for road race. A Pantera with good tires can generate
enough lateral g's to uncover the oil pick up in a pan without any
baffling.

> does this seem like a "streetable" engine or one that is designed primarily
> for racing?

You need to find the cam card and post the information here before we can tell.
You also need it for the lash information.

Dan Jones