[DeTomaso] Budget 351C Rebuild for Lori Drew
audionut at hushmail.com
audionut at hushmail.com
Tue Aug 11 14:43:42 EDT 2015
Wow. Great detailed info, Daniel. This is right along the lines of
what I plan on doing with my C when the day comes. Thanks for
posting!
Sent using Hushmail
On August 11, 2015 at 9:44 AM, "Daniel C Jones" wrote:Rather than
hammering the list with all the pictures, I posted the pictures
(and text) to the 351C forum here:
http://www.the351cforum.com/viewtopic.php?f=4&t=656
and just the text with links to the pictures below.
Dan Jones
Dave McLain recently rebuilt and dynoed a 351C for Lori Drew's
Pantera.
Lori's Pantera is a 1971 model with 95K miles on the odometer but the
engine was leaking and burning oil and detonated badly under
acceleration.
At a PCNC tech session, a valve cover was removed and the engine
started
briefly to discover one of the rocker arms was barely moving, a clear
sign
a lobe had worn off the cam. Dave had previously built a 408C for
Mike
Drew's Pantera that Mike was very happy with so the decision was made
to
pull the engine, crate it up and ship it to Dave for a rebuild. Mike
reused the crate and steel engine cradle that Dave had made to ship
Mike's
408C. Along with the engine, Mike had collected a bunch of parts over
the
years that he packed in the crate. All totaled, the shipping crate
weighed
nearly 850 lbs.
Mike and Lori's instructions were to perform a basic rebuild, re-using
as
many parts as possible to keep the cost down. A generous Pantera
Owners
Club member donated a set of lightly used (approximately 1000 miles)
Ross
pistons on a set of stock connecting rods that were fitted with ARP
rod
bolts. The pistons are part number 80556 which are a forged flat top
with
1.668" pin height, large single valve relief and 1/16", 1/16", 3/16"
ring
grooves.
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Ross_Piston_polished_rods_zpsvy3nm6r4.jpg
Assuming a block deck height of 9.213" and 0.050" piston to head
clearance
(block plus compressed head gasket) and closed chamber heads, the
static
compression ratio should be approximately 10.4:1. In addition to the
pistons, we'd be re-using some low mileage parts that were on the
engine:
Ford Motorsports double roller timing chain set
Aviaid gated and baffled Pantera oil pan
Edelbrock Performer 351C-4V aluminum dual plane intake manifold
Holley 650 double pumper carburetor
Ford distributor with Pertronix ignition module
Robert Shaw thermostat
Crane plug wires
The roller timing set is one that Mike and I picked out at Summit
Racing in
Reno, NV several years ago. We had them bring out a bunch of timing
sets
and opened the boxes to check the chains. The Ford Motorsport set
used the
good Renold chain from France while many of the other boxes contained
the
poor quality Rolon chain from India. The 650 DP carb was one that
Mike had
first put on his Pantera in 1989 and later moved over to his GT350
clone
Mustang. Mike had it worked over by John Christian at Roush. While
we
might have been tempted to toss the used thermostat in the can, the
high
quality Robert Shaw unit was nearly new and unfortunately the Robert
Shaw
units are no longer available new. The right thermostat is crucial in
a
351C as it needs to have a shoulder that matches the restrictor ring
in the
block so that the bypass port works as intended:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/OHOnews21of38_zpsrl5zhn8v.jpg
The Cleveland thermostat is not shared with other Fords. Using a
Windsor
thermostat (which the parts counter monkeys will often try to give
you)
will lead to over-heating because coolant will bypass the radiator.
The
same thing happens if you remove the thermostat. Mike specifically
requested we use a Fel Pro 35041T thermostat gasket, instead of the
typical
paper gasket, as the Fel Pro can be re-used. FWIW, the paper ones
seal
well with a light coating of Permatex Form-a-Gasket but need to
scraped off
when replacing the thermostat.
After the engine was pulled, it was noticed the block did not have a
serial
number stamped on the back, as DeTomaso normally did, and it was a
four-bolt-main block. Except for the Boss 351, closed chamber headed
Clevelands generally left the factory mounted on 2 bolt main blocks
which
means the block (or possibly the entire engine) was replaced somewhere
in
the vehicle's past. Disassembly and inspection revealed what appeared
to
be a stock short block in good rebuildable condition. As expected,
the cam
had a flat lobe. Dave plotted the cam and the specs (196/204 degrees
@
0.050", 117 degrees lobe separation angle, installed on a 114 degrees
intake centerline) suggest it was a stock 1970 to early 1971 part.
The
heads were verified to be of the desirable closed chamber variety but
did
not have the original (and failure prone) Ford valves. The intakes
checked
out and were the right 2.19" diameter for the seats but had 0.100"
longer
stems. The exhausts were 1.65" diameter. However, all the valves had
the
OEM multi-groove loose-fit keeper design and were replaced with new
single
groove stainless valves from SI in the standard Cleveland length and
stock
2.19"/1.71" diameters. Hardened seats were installed and the left had
side
cylinder head had 4 bolts broken off that Dave had to extract. The
stock
pedestal mount rocker arms were inspected and found to be in good
condition
but are of the lugged variety:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_stock_rockers_showing_oil_zpshtqc6y6n.jpg[/IMG]
There are two types of stock 351C rocker arms (lugged and unlugged):
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/OHOnews16of38_zpsdsyg293s.jpg[/IMG]
The ones with a lug on top have a clearance problem with cams of
0.550" or
greater lift. The pushrod tube can contact the lower position of the
rocker arm when the valve is fully open. Dave compared the two styles
of
rockers side-by-side and there is a noticeable difference back under
the
pushrod seat where the angle up from the bottom of the pivot is less
steep
on the lugged style and would get closer to the pushrod. He noted it
would
really be a problem if a 3/8" diameter pushrod was used. I offered up
a
Crane rocker arm guideplate conversion kit and 1.7:1 Crane roller
rockers
but it was ultimately decided to keep the lugged rockers and just
limit the
lift of the cam. In keeping with the budget rebuild theme, a
hydraulic
flat tappet cam was chosen with emphasis was on low and mid-range
performance with a 6000 RPM red line, assuming 91 octane fuel. Mike
had
run a Comp 280H Magnum flat tappet cam in his Pantera's previous 351C
(open
chamber 4V heads with domed pistons and Blue Thunder dual plane) and
found
it pretty lazy below 3000 RPM so wanted something that worked better
down
low. The Comp 280H has 60 degrees of overlap with specs of:
Comp 280H Magnum 280/280 degrees seat duration (230/230 @ 0.050"),
0.530"/0.530" lift, 110 LSA
So we'd likely be looking at something around 54 degrees of overlap.
Specific instructions from Mike were:
"The goal is to maximize torque in the low- and mid-range, with a 5500
RPM
power
peak and 6000 shift point. This engine will never see more than 6000
rpm
so
there's no need to build it with a cam that is dead down low, and
would
continue
to build power at 6500-7000 rpm. For simplicity and cost sake, this
means
a
traditional non-roller hydraulic cam."
I had some time to kill on a flight to Finland, so I modeled the
engine in
Dynomation and ran a bunch of off-the-shelf hydraulic flat tappet
camshafts
through, along with a few mild hydraulic rollers. Some of the cams
evaluated were:
Isky 264 Megacam..264/264..(214/214)..0.525"/0.525"..108 LSA
2000-5800
RPM
Isky 270 Megacam..270/270..(221/221)..0.542"/0.542"..108 LSA
2000-6200
RPM
Lunati 10320311...275/275..(225/225)..0.550"/0.550"..108 LSA
1800-5800
RPM (old p/n 07111)
Erson E220421.....296/296..(228/228)..0.545"/0.545"..108 LSA
3000-6000
RPM
Bullet 138268.....268/268..(218/218)..0.528"/0.528"..110 LSA Good
idle,
good street and off-road performance.
Lunati 10320302...276/276..(221/221)..0.524"/0.524"..110 LSA
idle-5600
(identical to Ultradyne below)
Ultradyne.........276/276..(221/221)..0.524"/0.524"..110 LSA
Performance and economy for 4WD's, pickups, and Panteras.
Elgin E-1801P.....284/284..(222/222)..0.539"/0.539"..110 LSA
Crower 15173......280/287..(219/225)..0.530"/0.524"..110 LSA
2300-6300,
3800 RPM peak torque, 5700 RPM peak power
Crower 15174......289/295..(227/233)..0.555"/0.547"..110 LSA
2400-6400,
3900 RPM peak torque, 5900 RPM peak power
Erson E220222.....284/296..(220/228)..0.545"/0.545"..110 LSA
2500-5500,
strong mid-range
Comp Cams 270H....270/270..(224/224)..0.519"/0.519"..110 LSA
Comp Cams 280H....280/280..(230/230)..0.530"/0.530"..110 LSA
Bullet Custom 1...275/275..(223/223)..0.567"/0.567"..109 LSA
Bullet
HF275/328 CRA lobes (Ford lifter diameter)
Bullet Custom 2...275/277..(223/228)..0.567"/0.580"..111 LSA
Bullet
HF275/328 and HF277/335 CRA lobes
Reed TM276H-11....276/276..(223/223)..0.543"/0.543"..111 LSA
Many of the profiles were eliminated with the decision to stick with
the
lugged rocker arms due to the maximum lift considerations. I also
evaluated all combinations of the following Reed Torque Master lobes:
Seat...0.050" Lift (w/1.73:1 rocker ratio)
252....205....0.497"
264....214....0.519"
272....218....0.531"
276....223....0.543"
280....227....0.548"
Dave likes the Torque Master lobes. They are quiet, reliable and run
well. Since the engine won't be spun past the HP peak very often,
there's
no need for the usual extra exhaust duration so a single pattern cam
was
picked. Also, on a 351C with 2.19" canted valves, I might widen the
LSA to
111 degrees to reduce reversion but, with the minimal overlap, that's
not
an issue so we stayed with a 109 degrees LSA. The cam was sourced
through
Steve Demos (formerly of Reed Cams) and with the smallish 650 CFM
carb,
small port dual plane intake manifold and shorty Pantera headers is
quite
mild:
Demos 272H-109 272/272 (218/218) 0.531"/0.531" 109 LSA 108 ICL
Valve springs are PBM/Erson 3100 set at 1.810" intake and 1.860"
exhaust
for loads of 110 lbs seated, 270 lbs open intake and 93 lbs seated,
250 lbs
open exhaust. There were no signs of valvetrain instability on the
dyno up
to the 5800 RPM maximum that was run on the dyno.
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_rockers_springs_zps8kzaiusa.jpg
All the older dual plane intake manifolds we've had on the flow bench
have
had good and bad runners and have benefited from plenum entry work.
Dave
did some minor work on the plenum and port exits and welded the
exhaust
crossover shut:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_plenum_zpsbtdzu2ot.jpg
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_runner_roof_zpsfmub3uot.jpg
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_runner_zpskf3l6dn0.jpg
On the dyno, the engine was tested with the restrictive Euro GTS
headers
and ANSA mufflers but will get the stainless steel Wilkinson Euro GTS
replacements that performed much better in previous testing. This
shot
shows the entire Euro GTS Pantera exhaust with the mufflers rotated to
clear the dyno:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_headers_mufflers_zpshcxahdp9.jpg
and a shot from the front showing just the headers:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_351C_on_dyno_zpsukbzjwso.jpg
The Pantera Euro GTS Ansa muffler bodies are quite small with long
tips:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_mufflers_zpsex7zrshf.jpg
and the GTS headers are oddly sized with large 2" outer diameter but
short
(16 to 22 inches typically) primaries along with a short tri-y style
collector having a small 2 1/4" ID outlet:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_headers_zpsipaecpjs.jpg
In testing, the headers do pretty well on peak power but give up quite
a
bit of peak torque (25+ ft-lbs) when compared with more conventional
long
tube headers. The mufflers are quite restrictive, costing on the
order of
50 HP on 500+ HP engines.
When Dave first fired the engine, it didn't sound so hot so he pulled
the
donor plug wires off and replaced them which made the engine sound
much
better. Turns out several of the wires were bad. The cam was broken
in,
rings seated and some pulls made to optimize the timing and jetting.
With
the closed chamber heads, best timing was 14 degrees initial and 36
degrees
total. Dave ordered a 4 hole 1 inch tall spacer that he modified into
a
design with two oval shaped holes to match the oval holes on the dual
plane
Performer intake.
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_phenolic_spacer_zpsfafucadx.jpg
The spacer helped torque by about 5 lbs-ft but peak HP was unchanged.
The
best pull was with the GTS headers but without the ANSA mufflers:
378 HP @ 5700 RPM
396 ft-lbs @ 4100 RPM
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Drew%20351C%20No%20Mufflers_zpsjzywch24.jpg
With ANSA mufflers and a 1" spacer, it made:
355 HP @ 5800 RPM
388 ft-lbs @ 3900 RPM
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Drew%20351%20C%20With%201%20Inch%20Spacer_zps0g1rzpnj.jpg
The ANSA Euro GTS mufflers cost 23 HP and 8 ft-lbs on this combo. The
non-GTS ANSA mufflers are even more restrictive while the Wilkinson
exhaust
should be closer to the open header pull. The engine ended up peaking
at
5700 RPM with nearly 400 ft-lbs of torque so I'd say we pretty much
nailed
Mike's request. With their overly large ports, its easy to kill the
bottom
end on a 351C-4V with the wrong combo (too much cam, not enough
compression, wrong intake and/or headers) but this build demonstrates
that
with nothing more than a well thought selection of parts and careful
assembly, a 351C-4V can make quite respectable torque in a daily
driver RPM
range.
If you were to remove the lift restriction imposed by the lugged
rocker
arms and run more aggressive hydraulic flat tappet lobes, there should
be
more power to be had, even with the same modest cam overlap. I ran a
cam
of the same 54 degrees overlap but using more aggressive cam lobes:
Bullet 275/277 (223/228) 0.567"/0.580" 111 LSA
through Dynomation and, with no other changes, the simulation predicts
an
additional 13 HP peaking 200 RPM higher. The lobes might be a bit
noisy,
though. If you were to build a similar engine for a Mustang or
Cougar,
previous testing of 1 3/4" long tube Mustang headers have added 25 to
30
ft-lbs of peak torque and the MPG Stinger exhaust stuffers were also
worth
some peak torque. If the intake doesn't have to fit under a stock
Pantera
engine screen, I'd wager there's another 20 to 25 HP to be had with an
Edelbrock Performer RPM Air Gap high rise dual plane and, perhaps, a
carb
with 50 more CFM. For comparisons sake, here are some A/B
measurements I
made of the various dual planes available for the 351C. The
measurements
represent the drop from a straight edge laid across the carb pad to
the
closest point where the end rail bends inward (each end).
Measurements are
in inches:
Intake A B
Edelbrock F-351 Performer 4V 3 3/4 4 3/8
Edelbrock Performer RPM Air Gap 2V 4 1/2 5 5/8
Ford aluminum 4V 3 1/4 4 3/8
Scott Cook 3 3/4 5
Blue Thunder/Shelby/Holman Moody 4 7/16 5 3/8
Note that both the Scott Cook and Blue Thunder dual planes are the
canted
pad versions but both are available with flat carb pads for Panteras
that
mount the engine level. Note that, being an air gap design, the
Performer
RPM would be slower to warm up.
I'm quite interested in hearing what Lori's Pantera does for fuel
economy.
If I'd thought of it at the time, Lori's engine would have been
perfect to
test my ported spread bore Offenhauser Dual Port intake manifold with
Carter ThermoQuad. The vacuum advance unit on the Ford distributor
was
blown so Dave replaced it with a single diaphragm style that is
adjustable
and measured how much each turn of the adjustment changes the total:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_351C_vacuum_advance_zpsldclegoc.jpg
Dave connected it to the ported vacuum source so it is not active at
idle
and one turn on the adjustment equals 5 degrees change in the amount
of
timing it can add to the engine under light load conditions. There's
one
turn of adjustment "into" the pod so it gives the engine five degrees
more
when its at part throttle above idle. In the Pantera, with the center
bulkhead cover removed, there is access to the front of the engine so
Mike
and Lori can adjust it from there for best cruise fuel economy.
Here's a
link to a video of Dave messing with the carburetor/idle settings and
the
vacuum advance:
https://onedrive.live.com/redir?resid=a9d064308c1f92bf!87848&authkey=!AGb4h-XRCGW9F1Y&ithint=video%2cmp4
Overall, the engine parts list looks like:
Holley model 4777 650 CFM double pumper carburetor with added
electric
choke
Edelbrock Performer 351C-4V aluminum intake manifold (with port and
plenum
work by Dave McLain)
Closed chamber 4V Cleveland heads
Valve job, hard exhaust seats and resurfaced, machined for Viton
seals
intake and exhaust
SI stainless valves in stock 2.19"/1.71" sizes
PBM/Erson 502S retainers
PBM/Erson 3100 valve springs set at 1.810" intake and 1.860" exhaust
for
loads of
110 lbs seated, 270 lbs open intake
93 lbs seated, 250 lbs open exhaust
Ford Motorsport aluminum valve covers with baffles that are welded in
place to keep oil off of PCV and breather
351C block bored to 4.020 bore size (with 3.5" stroke = 355 cubic
inches
displacement)
Ross flat top forged pistons
Ross forged flat top pistons, part number 80556, single large valve
relief, 1.668" pin height
Mahle 1/16", 1/16" 3/16" standard tension ring set
Ford 351C connecting rods, polished, shot peened, ARP bolts
King rod and main bearings, 0.002", 0.0028" clearances
Ford 351C crank, polished, rotating assembly balanced
New Power Bond damper
Stock timing pointer corrected
Engine Tech gasket set
Ford Motorsport timing set
Aviaid gated and baffled Pantera road race oil pan and matching
pickup
Stock volume/pressure Melling M84A oil pump
New Melling oil pump drive shaft
Joe Gibbs BR oil(8quarts)
Hastings LF 115 filter
Custom grind flat tappet hydraulic cam from Demos Cams using Reed
272H
Torque Master lobes:
272/272 seat duration, (218/218 degrees @ 0.050"), 0.531"/0.531",
109
LSA installed on 107 degrees ICL
Stock Ford 351C non-adjustable rockers (with oil deflectors) and
pushrods
Distributor is stock Ford with a Pertronix Ignitor kit and adjustable
vacuum advance
Autolite 25 spark plugs gapped at 0.045"
Edelbrock aluminum water pump
Here's a shot of the assembled long block:
http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_longblock_zpsnee2hv8f.jpg
Lori was pleased the that the total cost of the engine build,
including
intake and head work and a full day of dyno tuning came in at less
than
$3000.
Dan Jones
-------------- next part --------------
Wow. Great detailed info, Daniel. This is right along the lines of
what I plan on doing with my C when the day comes.
Thanks for posting!
Sent using Hushmail
On August 11, 2015 at 9:44 AM, "Daniel C Jones"
<daniel.c.jones2 at gmail.com> wrote:
Rather than hammering the list with all the pictures, I posted the
pictures
(and text) to the 351C forum here:
[1]http://www.the351cforum.com/viewtopic.php?f=4&t=656
and just the text with links to the pictures below.
Dan Jones
Dave McLain recently rebuilt and dynoed a 351C for Lori Drew's
Pantera.
Lori's Pantera is a 1971 model with 95K miles on the odometer but
the
engine was leaking and burning oil and detonated badly under
acceleration.
At a PCNC tech session, a valve cover was removed and the engine
started
briefly to discover one of the rocker arms was barely moving, a
clear sign
a lobe had worn off the cam. Dave had previously built a 408C for
Mike
Drew's Pantera that Mike was very happy with so the decision was
made to
pull the engine, crate it up and ship it to Dave for a rebuild. Mike
reused the crate and steel engine cradle that Dave had made to ship
Mike's
408C. Along with the engine, Mike had collected a bunch of parts
over the
years that he packed in the crate. All totaled, the shipping crate
weighed
nearly 850 lbs.
Mike and Lori's instructions were to perform a basic rebuild,
re-using as
many parts as possible to keep the cost down. A generous Pantera
Owners
Club member donated a set of lightly used (approximately 1000 miles)
Ross
pistons on a set of stock connecting rods that were fitted with ARP
rod
bolts. The pistons are part number 80556 which are a forged flat top
with
1.668" pin height, large single valve relief and 1/16", 1/16", 3/16"
ring
grooves.
[2]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/Ross_Piston_polished_rods_zpsvy3nm6
r4.jpg
Assuming a block deck height of 9.213" and 0.050" piston to head
clearance
(block plus compressed head gasket) and closed chamber heads, the
static
compression ratio should be approximately 10.4:1. In addition to the
pistons, we'd be re-using some low mileage parts that were on the
engine:
Ford Motorsports double roller timing chain set
Aviaid gated and baffled Pantera oil pan
Edelbrock Performer 351C-4V aluminum dual plane intake manifold
Holley 650 double pumper carburetor
Ford distributor with Pertronix ignition module
Robert Shaw thermostat
Crane plug wires
The roller timing set is one that Mike and I picked out at Summit
Racing in
Reno, NV several years ago. We had them bring out a bunch of timing
sets
and opened the boxes to check the chains. The Ford Motorsport set
used the
good Renold chain from France while many of the other boxes
contained the
poor quality Rolon chain from India. The 650 DP carb was one that
Mike had
first put on his Pantera in 1989 and later moved over to his GT350
clone
Mustang. Mike had it worked over by John Christian at Roush. While
we
might have been tempted to toss the used thermostat in the can, the
high
quality Robert Shaw unit was nearly new and unfortunately the Robert
Shaw
units are no longer available new. The right thermostat is crucial
in a
351C as it needs to have a shoulder that matches the restrictor ring
in the
block so that the bypass port works as intended:
[3]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/OHOnews21of38_zpsrl5zhn8v.jpg
The Cleveland thermostat is not shared with other Fords. Using a
Windsor
thermostat (which the parts counter monkeys will often try to give
you)
will lead to over-heating because coolant will bypass the radiator.
The
same thing happens if you remove the thermostat. Mike specifically
requested we use a Fel Pro 35041T thermostat gasket, instead of the
typical
paper gasket, as the Fel Pro can be re-used. FWIW, the paper ones
seal
well with a light coating of Permatex Form-a-Gasket but need to
scraped off
when replacing the thermostat.
After the engine was pulled, it was noticed the block did not have a
serial
number stamped on the back, as DeTomaso normally did, and it was a
four-bolt-main block. Except for the Boss 351, closed chamber headed
Clevelands generally left the factory mounted on 2 bolt main blocks
which
means the block (or possibly the entire engine) was replaced
somewhere in
the vehicle's past. Disassembly and inspection revealed what
appeared to
be a stock short block in good rebuildable condition. As expected,
the cam
had a flat lobe. Dave plotted the cam and the specs (196/204 degrees
@
0.050", 117 degrees lobe separation angle, installed on a 114
degrees
intake centerline) suggest it was a stock 1970 to early 1971 part.
The
heads were verified to be of the desirable closed chamber variety
but did
not have the original (and failure prone) Ford valves. The intakes
checked
out and were the right 2.19" diameter for the seats but had 0.100"
longer
stems. The exhausts were 1.65" diameter. However, all the valves had
the
OEM multi-groove loose-fit keeper design and were replaced with new
single
groove stainless valves from SI in the standard Cleveland length and
stock
2.19"/1.71" diameters. Hardened seats were installed and the left
had side
cylinder head had 4 bolts broken off that Dave had to extract. The
stock
pedestal mount rocker arms were inspected and found to be in good
condition
but are of the lugged variety:
[4]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/Lori_Drew_stock_rockers_showing_oil
_zpshtqc6y6n.jpg[/IMG]
There are two types of stock 351C rocker arms (lugged and unlugged):
[5]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/OHOnews16of38_zpsdsyg293s.jpg[/IMG]
The ones with a lug on top have a clearance problem with cams of
0.550" or
greater lift. The pushrod tube can contact the lower position of the
rocker arm when the valve is fully open. Dave compared the two
styles of
rockers side-by-side and there is a noticeable difference back under
the
pushrod seat where the angle up from the bottom of the pivot is less
steep
on the lugged style and would get closer to the pushrod. He noted it
would
really be a problem if a 3/8" diameter pushrod was used. I offered
up a
Crane rocker arm guideplate conversion kit and 1.7:1 Crane roller
rockers
but it was ultimately decided to keep the lugged rockers and just
limit the
lift of the cam. In keeping with the budget rebuild theme, a
hydraulic
flat tappet cam was chosen with emphasis was on low and mid-range
performance with a 6000 RPM red line, assuming 91 octane fuel. Mike
had
run a Comp 280H Magnum flat tappet cam in his Pantera's previous
351C (open
chamber 4V heads with domed pistons and Blue Thunder dual plane) and
found
it pretty lazy below 3000 RPM so wanted something that worked better
down
low. The Comp 280H has 60 degrees of overlap with specs of:
Comp 280H Magnum 280/280 degrees seat duration (230/230 @ 0.050"),
0.530"/0.530" lift, 110 LSA
So we'd likely be looking at something around 54 degrees of overlap.
Specific instructions from Mike were:
"The goal is to maximize torque in the low- and mid-range, with a
5500 RPM
power
peak and 6000 shift point. This engine will never see more than 6000
rpm
so
there's no need to build it with a cam that is dead down low, and
would
continue
to build power at 6500-7000 rpm. For simplicity and cost sake, this
means
a
traditional non-roller hydraulic cam."
I had some time to kill on a flight to Finland, so I modeled the
engine in
Dynomation and ran a bunch of off-the-shelf hydraulic flat tappet
camshafts
through, along with a few mild hydraulic rollers. Some of the cams
evaluated were:
Isky 264 Megacam..264/264..(214/214)..0.525"/0.525"..108 LSA
2000-5800
RPM
Isky 270 Megacam..270/270..(221/221)..0.542"/0.542"..108 LSA
2000-6200
RPM
Lunati 10320311...275/275..(225/225)..0.550"/0.550"..108 LSA
1800-5800
RPM (old p/n 07111)
Erson E220421.....296/296..(228/228)..0.545"/0.545"..108 LSA
3000-6000
RPM
Bullet 138268.....268/268..(218/218)..0.528"/0.528"..110 LSA Good
idle,
good street and off-road performance.
Lunati 10320302...276/276..(221/221)..0.524"/0.524"..110 LSA
idle-5600
(identical to Ultradyne below)
Ultradyne.........276/276..(221/221)..0.524"/0.524"..110 LSA
Performance and economy for 4WD's, pickups, and Panteras.
Elgin E-1801P.....284/284..(222/222)..0.539"/0.539"..110 LSA
Crower 15173......280/287..(219/225)..0.530"/0.524"..110 LSA
2300-6300,
3800 RPM peak torque, 5700 RPM peak power
Crower 15174......289/295..(227/233)..0.555"/0.547"..110 LSA
2400-6400,
3900 RPM peak torque, 5900 RPM peak power
Erson E220222.....284/296..(220/228)..0.545"/0.545"..110 LSA
2500-5500,
strong mid-range
Comp Cams 270H....270/270..(224/224)..0.519"/0.519"..110 LSA
Comp Cams 280H....280/280..(230/230)..0.530"/0.530"..110 LSA
Bullet Custom 1...275/275..(223/223)..0.567"/0.567"..109 LSA Bullet
HF275/328 CRA lobes (Ford lifter diameter)
Bullet Custom 2...275/277..(223/228)..0.567"/0.580"..111 LSA Bullet
HF275/328 and HF277/335 CRA lobes
Reed TM276H-11....276/276..(223/223)..0.543"/0.543"..111 LSA
Many of the profiles were eliminated with the decision to stick with
the
lugged rocker arms due to the maximum lift considerations. I also
evaluated all combinations of the following Reed Torque Master
lobes:
Seat...0.050" Lift (w/1.73:1 rocker ratio)
252....205....0.497"
264....214....0.519"
272....218....0.531"
276....223....0.543"
280....227....0.548"
Dave likes the Torque Master lobes. They are quiet, reliable and run
well. Since the engine won't be spun past the HP peak very often,
there's
no need for the usual extra exhaust duration so a single pattern cam
was
picked. Also, on a 351C with 2.19" canted valves, I might widen the
LSA to
111 degrees to reduce reversion but, with the minimal overlap,
that's not
an issue so we stayed with a 109 degrees LSA. The cam was sourced
through
Steve Demos (formerly of Reed Cams) and with the smallish 650 CFM
carb,
small port dual plane intake manifold and shorty Pantera headers is
quite
mild:
Demos 272H-109 272/272 (218/218) 0.531"/0.531" 109 LSA 108 ICL
Valve springs are PBM/Erson 3100 set at 1.810" intake and 1.860"
exhaust
for loads of 110 lbs seated, 270 lbs open intake and 93 lbs seated,
250 lbs
open exhaust. There were no signs of valvetrain instability on the
dyno up
to the 5800 RPM maximum that was run on the dyno.
[6]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/Lori_Drew_rockers_springs_zps8kzaiu
sa.jpg
All the older dual plane intake manifolds we've had on the flow
bench have
had good and bad runners and have benefited from plenum entry work.
Dave
did some minor work on the plenum and port exits and welded the
exhaust
crossover shut:
[7]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_plenum_zpsbtdzu
2ot.jpg
[8]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_runner_roof_zps
fmub3uot.jpg
[9]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Clev
eland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_runner_zpskf3l6
dn0.jpg
On the dyno, the engine was tested with the restrictive Euro GTS
headers
and ANSA mufflers but will get the stainless steel Wilkinson Euro
GTS
replacements that performed much better in previous testing. This
shot
shows the entire Euro GTS Pantera exhaust with the mufflers rotated
to
clear the dyno:
[10]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_headers_mufflers_zps
hcxahdp9.jpg
and a shot from the front showing just the headers:
[11]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_351C_on_dyno_zpsukbzjwso
.jpg
The Pantera Euro GTS Ansa muffler bodies are quite small with long
tips:
[12]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_mufflers_zpsex7zrshf
.jpg
and the GTS headers are oddly sized with large 2" outer diameter but
short
(16 to 22 inches typically) primaries along with a short tri-y style
collector having a small 2 1/4" ID outlet:
[13]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_headers_zpsipaecpjs.
jpg
In testing, the headers do pretty well on peak power but give up
quite a
bit of peak torque (25+ ft-lbs) when compared with more conventional
long
tube headers. The mufflers are quite restrictive, costing on the
order of
50 HP on 500+ HP engines.
When Dave first fired the engine, it didn't sound so hot so he
pulled the
donor plug wires off and replaced them which made the engine sound
much
better. Turns out several of the wires were bad. The cam was broken
in,
rings seated and some pulls made to optimize the timing and jetting.
With
the closed chamber heads, best timing was 14 degrees initial and 36
degrees
total. Dave ordered a 4 hole 1 inch tall spacer that he modified
into a
design with two oval shaped holes to match the oval holes on the
dual plane
Performer intake.
[14]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_phenolic_spacer_zpsfafuc
adx.jpg
The spacer helped torque by about 5 lbs-ft but peak HP was
unchanged. The
best pull was with the GTS headers but without the ANSA mufflers:
378 HP @ 5700 RPM
396 ft-lbs @ 4100 RPM
[15]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Drew%20351C%20No%20Mufflers_zpsjzy
wch24.jpg
With ANSA mufflers and a 1" spacer, it made:
355 HP @ 5800 RPM
388 ft-lbs @ 3900 RPM
[16]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Drew%20351%20C%20With%201%20Inch%2
0Spacer_zps0g1rzpnj.jpg
The ANSA Euro GTS mufflers cost 23 HP and 8 ft-lbs on this combo.
The
non-GTS ANSA mufflers are even more restrictive while the Wilkinson
exhaust
should be closer to the open header pull. The engine ended up
peaking at
5700 RPM with nearly 400 ft-lbs of torque so I'd say we pretty much
nailed
Mike's request. With their overly large ports, its easy to kill the
bottom
end on a 351C-4V with the wrong combo (too much cam, not enough
compression, wrong intake and/or headers) but this build
demonstrates that
with nothing more than a well thought selection of parts and careful
assembly, a 351C-4V can make quite respectable torque in a daily
driver RPM
range.
If you were to remove the lift restriction imposed by the lugged
rocker
arms and run more aggressive hydraulic flat tappet lobes, there
should be
more power to be had, even with the same modest cam overlap. I ran a
cam
of the same 54 degrees overlap but using more aggressive cam lobes:
Bullet 275/277 (223/228) 0.567"/0.580" 111 LSA
through Dynomation and, with no other changes, the simulation
predicts an
additional 13 HP peaking 200 RPM higher. The lobes might be a bit
noisy,
though. If you were to build a similar engine for a Mustang or
Cougar,
previous testing of 1 3/4" long tube Mustang headers have added 25
to 30
ft-lbs of peak torque and the MPG Stinger exhaust stuffers were also
worth
some peak torque. If the intake doesn't have to fit under a stock
Pantera
engine screen, I'd wager there's another 20 to 25 HP to be had with
an
Edelbrock Performer RPM Air Gap high rise dual plane and, perhaps, a
carb
with 50 more CFM. For comparisons sake, here are some A/B
measurements I
made of the various dual planes available for the 351C. The
measurements
represent the drop from a straight edge laid across the carb pad to
the
closest point where the end rail bends inward (each end).
Measurements are
in inches:
Intake A B
Edelbrock F-351 Performer 4V 3 3/4 4 3/8
Edelbrock Performer RPM Air Gap 2V 4 1/2 5 5/8
Ford aluminum 4V 3 1/4 4 3/8
Scott Cook 3 3/4 5
Blue Thunder/Shelby/Holman Moody 4 7/16 5 3/8
Note that both the Scott Cook and Blue Thunder dual planes are the
canted
pad versions but both are available with flat carb pads for Panteras
that
mount the engine level. Note that, being an air gap design, the
Performer
RPM would be slower to warm up.
I'm quite interested in hearing what Lori's Pantera does for fuel
economy.
If I'd thought of it at the time, Lori's engine would have been
perfect to
test my ported spread bore Offenhauser Dual Port intake manifold
with
Carter ThermoQuad. The vacuum advance unit on the Ford distributor
was
blown so Dave replaced it with a single diaphragm style that is
adjustable
and measured how much each turn of the adjustment changes the total:
[17]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_351C_vacuum_advance_zpsl
dclegoc.jpg
Dave connected it to the ported vacuum source so it is not active at
idle
and one turn on the adjustment equals 5 degrees change in the amount
of
timing it can add to the engine under light load conditions. There's
one
turn of adjustment "into" the pod so it gives the engine five
degrees more
when its at part throttle above idle. In the Pantera, with the
center
bulkhead cover removed, there is access to the front of the engine
so Mike
and Lori can adjust it from there for best cruise fuel economy.
Here's a
link to a video of Dave messing with the carburetor/idle settings
and the
vacuum advance:
[18]https://onedrive.live.com/redir?resid=a9d064308c1f92bf!87848&aut
hkey=!AGb4h-XRCGW9F1Y&ithint=video%2cmp4
Overall, the engine parts list looks like:
Holley model 4777 650 CFM double pumper carburetor with added
electric
choke
Edelbrock Performer 351C-4V aluminum intake manifold (with port and
plenum
work by Dave McLain)
Closed chamber 4V Cleveland heads
Valve job, hard exhaust seats and resurfaced, machined for Viton
seals
intake and exhaust
SI stainless valves in stock 2.19"/1.71" sizes
PBM/Erson 502S retainers
PBM/Erson 3100 valve springs set at 1.810" intake and 1.860" exhaust
for
loads of
110 lbs seated, 270 lbs open intake
93 lbs seated, 250 lbs open exhaust
Ford Motorsport aluminum valve covers with baffles that are welded
in
place to keep oil off of PCV and breather
351C block bored to 4.020 bore size (with 3.5" stroke = 355 cubic
inches
displacement)
Ross flat top forged pistons
Ross forged flat top pistons, part number 80556, single large valve
relief, 1.668" pin height
Mahle 1/16", 1/16" 3/16" standard tension ring set
Ford 351C connecting rods, polished, shot peened, ARP bolts
King rod and main bearings, 0.002", 0.0028" clearances
Ford 351C crank, polished, rotating assembly balanced
New Power Bond damper
Stock timing pointer corrected
Engine Tech gasket set
Ford Motorsport timing set
Aviaid gated and baffled Pantera road race oil pan and matching
pickup
Stock volume/pressure Melling M84A oil pump
New Melling oil pump drive shaft
Joe Gibbs BR oil(8quarts)
Hastings LF 115 filter
Custom grind flat tappet hydraulic cam from Demos Cams using Reed
272H
Torque Master lobes:
272/272 seat duration, (218/218 degrees @ 0.050"), 0.531"/0.531",
109
LSA installed on 107 degrees ICL
Stock Ford 351C non-adjustable rockers (with oil deflectors) and
pushrods
Distributor is stock Ford with a Pertronix Ignitor kit and
adjustable
vacuum advance
Autolite 25 spark plugs gapped at 0.045"
Edelbrock aluminum water pump
Here's a shot of the assembled long block:
[19]http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cle
veland%20Stuff/Lori%20Drew%20351C/Lori_Drew_longblock_zpsnee2hv8f.jp
g
Lori was pleased the that the total cost of the engine build,
including
intake and head work and a full day of dyno tuning came in at less
than
$3000.
Dan Jones
References
1. http://www.the351cforum.com/viewtopic.php?f=4&t=656
2. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Ross_Piston_polished_rods_zpsvy3nm6r4.jpg
3. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/OHOnews21of38_zpsrl5zhn8v.jpg
4. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_stock_rockers_showing_oil_zpshtqc6y6n.jpg[/IMG]
5. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/OHOnews16of38_zpsdsyg293s.jpg[/IMG]
6. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_rockers_springs_zps8kzaiusa.jpg
7. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_plenum_zpsbtdzu2ot.jpg
8. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_runner_roof_zpsfmub3uot.jpg
9. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_Performer_runner_zpskf3l6dn0.jpg
10. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_headers_mufflers_zpshcxahdp9.jpg
11. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_351C_on_dyno_zpsukbzjwso.jpg
12. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_mufflers_zpsex7zrshf.jpg
13. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_GTS_headers_zpsipaecpjs.jpg
14. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_phenolic_spacer_zpsfafucadx.jpg
15. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Drew%20351C%20No%20Mufflers_zpsjzywch24.jpg
16. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Drew%20351%20C%20With%201%20Inch%20Spacer_zps0g1rzpnj.jpg
17. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_351C_vacuum_advance_zpsldclegoc.jpg
18. https://onedrive.live.com/redir?resid=a9d064308c1f92bf!87848&authkey=!AGb4h-XRCGW9F1Y&ithint=video%2cmp4
19. http://i1127.photobucket.com/albums/l621/danielcjones2/351%20Cleveland%20Stuff/Lori%20Drew%20351C/Lori_Drew_longblock_zpsnee2hv8f.jpg
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