Listers,
All this talk about Ford vs BOP/R V8s has gotten me to thinking. I've got
about 15 minutes before all this thinking puts me to sleep, so I thought I'd
try to summarize my thoughts before I nod off.
The Ford engine in my TR6 weighs 436 pounds. That's 12 pounds more than I
posted recently, because the heavy duty clutch I just received last week
weighed 12 pounds more then the light duty Ford clutch that I previously
weighed. That 436 pound weight includes: engine, aluminum heads, valve
covers, 27 pound flywheel, clutch, intake manifold, carburetor, air cleaner,
distributor, alternator, water pump, fan belt, pulleys, lightweight Ford
MotorSport (FMS) starter, and headers. When I received my crate engine
long/block assembly, I removed the packing material, weighed it, and
subtracted that from the freight invoice weight. When I compared that weight
to the what I calculated the engine should weigh in that configuration, my
figures agreed to the pound with the freight invoice, so I believe my engine
weight above is reasonably accurate.
According to David Hardcastle, in his book "Tuning Rover V8 Engines," Buick
originally listed the weight of the 215ci aluminum block V8 as 218 pounds,
while Oldsmobile listed a weight of 350 pounds for basically the same engine.
Most sources list the weight of BOP/R engine as 318 to 325 pounds. This means
the Ford weighs from 118 to 111 pounds more then the BOP/R engine.
Hmm, this is curious. Comparing the two engines, and assuming a BOP/R weight
of 320 pounds, there is a difference of 116 pounds:
Block (- 30 pounds):
The bare BOP/R block is 1/2" shorter, 1 1/2" taller, and 1/8" narrower then
the Ford. With heads installed, the BOP/R engine is 1 1/2" wider than the
Ford with heads installed. The Ford dimensions came from measurements made on
a spare engine in my garage, while the BOP/R dimensions came from the factory
blueprints that Dan Lagrue was so kind to display at the Cleveland V8 meet
two weekends ago. The bottom of the BOP/R block extends below the crank
centerline, while the Ford block ends even with the crank centerline.
The Ford iron block weighs 127 pounds, while the aluminum version of the same
block from Ford weighs 97 pounds (per the FMS catalog), for a weight savings
of 30 pounds. Comparing the two blocks, the BOP/R will have more material
than the Ford, so I would assume the BOP/R block would weigh close to the
Ford. Anyone know the weight for sure? This accounts for 30 pounds of the
difference.
Front engine dress components (0 pounds):
Both engines have the distributor and oil pump in the front, and are
basically of the same layout. I would assume, then, that the water pump,
distributor, timing cover, timing chain, pulleys, etc, would be very near
equal for both engines, especially if you are using aftermarket components.
The Weiand water pump I'm using weighs 7 pounds, as compared to 14 for the
stock iron pump of the early Ford engines.
Crank (- 10 pounds):
David Hardcastle, in the above referenced book, states that the BOP/R crank
weighs 79 pounds. The Ford crank weighs 40 pounds. I find it hard to believe
that the BOP/R crank would weigh 39 pounds more than the Ford, so I assume
Hardcastle was fed erroneous data. However, since the cranks are about the
same size, I would expect the weight to be similar as well. With a shorter
stroke, the BOP/R crank might weigh a bit less, so I'll assume it weighs 30
pounds, so that will account for another 10 pounds of weight difference.
Heads (0 pounds):
Both engines use aluminum heads, of comparable dimensions, so no weight
difference here.
Cam/valve train (0 pounds):
The cams are virtually the same length, so the weights should be virtually
the same as well. Same with the valve train.
Piston/Connecting rods (- 8 pounds):
Each piston/conrod/wrist pin/bearings, etc weighs 3 pounds in a Ford. Given
the smaller bore and stroke of the BOP/R engine, a weight of 2 pounds per
would be reasonable, although I really believe the difference would be less.
This accounts for 8 pounds of difference.
Flywheel/clutch (0 pounds):
The standard Ford flywheel weighs 40 pounds - the FMS flywheel weighs 27. A
10 1/2" performance clutch weighs 22 pounds, compared to 10 -15 for lighter
weight clutches. These items are a matter of choice for either engine, so no
weight differences there.
Starter (0 pounds):
The stock BOP/R and Ford starters weigh around 16 pounds. Lightweight
starters are available for either engine. My FMS starter weighs 11 pounds.
Intake/carburetors (0 pounds):
Using aluminum aftermarket intake manifolds, the weights should be near the
same. Both engines typically use the same carburetors - Holley, Carter, or
Edelbrock, so they will weigh exactly the same.
Alternator (0 pounds):
Most folks use a GM alternator, which is also usable (and preferable) on the
Ford. If desired, the stock Lucas alternator could be used on either engine
as well, so no weight difference here either.
Costs:
I paid $3,141 for a complete, brand new, 320 HP Ford crate motor, long block,
with GT40 aluminum heads and a B303 high performance roller cam. To make the
motor complete, I had to add the same items as most would have to add to the
BOP/R engine to get it into the desired state of tune - Intake & exhaust,
starter, alternator, distributor, and clutch. Junkyard engines are cheaper,
currently around $1,000 - $1,200 for a late model Ford with fuel injection,
and professionally built BOP/R engines can run higher, depending on the state
of tune. I would dare say that a BOP/R engine, tuned/modified to produce over
300 HP would cost major coin. Of course, 300+ HP is not really a requirement,
but...................why not?
Summary:
Weight:
Based on the above, I can account for 38 - 48 of the 116 pound difference in
weight between the two engines. I know that a few ounces here, and a few
ounces there can add up, but it takes a lot of ounces to make up for the
missing 68 pounds! Are the BOP/R engines as light as we think they are?
Where am I missing the pounds? Input and corrections cheerfully and
gratefully welcomed!
Supposedly, the Rover engine weighed 40 pounds less than the stock 4-banger
MGB engine, so even if the Ford does weigh 116 pounds more then the BOP/R, it
would still only weigh 76 pounds more than stock.
Size:
The difference in size between the blocks is pretty much insignificant. The
wider dimension with the heads installed (1 1/2") of the BOP/R is easily
accommodated in an MGB. The installation of headers might be more difficult
for the BOP/R than with the Ford in some makes of cars (TR6, for example),
because of the extra width.
Costs:
Way too many variables here to make any kind of meaningful comparisons.
Nevertheless, on a dollar/HP basis, the Ford is the winner, I believe, at
least as the HP begins to reach the 300 level. At lower power levels, say
around 150 - 200, the BOP/R might be cheaper, especially if you have to buy
aluminum heads to keep the Ford weight down (the aluminum heads reduce the
weight by 50 pounds). Currently, fully assembled aluminum heads for the Ford
cost in the $900 - $1,100 price range, bare heads for around $400 - $500.
There should be no trouble finding a solid, rebuildable, Ford block for under
$500 dollars (I bought one from a '67 Fairlane for $100 - all Ford V8s after
'66 use the current bellhousing bolt pattern), bringing the total to under
$1,600.
Well, it's time for my nap.....zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
Dan Masters
Alcoa, Tennessee
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