Recent discussions of how the stock crank damper can shift with age got me thinking. Mine is original (72 Pre-L) and with 132,000 miles on it .. maybe I should consider a new damper. So I have a couple of questions: 1) recommendations (my engine is essentially stock BTW) with reasons. And 2) can it be installed with the engine in the car .. any installation tricks? Thanks.
Original Post
Your Pantera's 351C is equipped with an inexpensive unbonded damper made of cast iron. The damper was intended for 280 horsepower and 6200 rpm at the best.

The fact that the damper needs replacement is not the sign of a defect, just a sign of old age. Nor is this a problem peculiar to the 351C, it happens to all “aging” engines equipped with unbonded crankshaft dampers. An unbonded damper is held together simply by the “stiction” of the rubber sleeve installed between the hub and the outer ring. After 20 years the rubber sleeve shall have hardened enough and lost enough “stiction” that the ring can shift its position on the hub. The ring can both rotate on the hub and move fore and aft. A ring that walks-off the hub in the aft direction will eventually begin hitting stationary parts and fail (i.e. fly apart, some folks would describe that as “exploding”). Some dampers are balanced via the ring (this is true of the Q code engines), so if the ring rotates on the hub it throws-off the crankshaft’s balance. A ring that has rotated on the hub will also throw-off ignition timing based on the scale on the ring. And there’s one last issue, the hardening of the rubber sleeve also prevents the damper from properly dampening the crankshaft as it was designed to do.

I recommend replacement of the “aging” OEM damper with a Power Bond p.n. PB1082SS race damper (which is fully bonded). The fully bonded damper is only $215 USD at Summit Racing. This damper is made of steel, not cast iron. It is the least expensive fully bonded damper I am aware of. Its made in Australia, not China. Its a better quality damper than the one installed on the Boss 351 engine … because its made of steel rather than iron.

I used to recommend the Romac dampers, I had one on my engine. Turns out they weren't bonded at all, but you had to read the small print to find that out. I hadn't read the small print until an Australian bloke pointed this out to me.

Its do-able in the car. Loosen the belts, and remove the crank pulley. Break the crank snout bolt loose while preventing the crank from turning. Then use a puller to remove the damper.

While you're there install a SACC overdrive coolant pump pulley too.
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Robbie, like a number of other engine, chassis and body parts, the steel pulleys on a 351-C for a Pantera are specific to the car. Generic 351-C pulleys will not be the same nor run at the stock ratio.

If you want to change the ratios for some reason, you will need aftermarket parts or find someone with a 6" (minimum) lathe, as they are not hard to fabricate. I've made a few sets, especially for engine-swap Panteras. Note that some commercial aluminum pulleys are cast, then lathe-turned for appearance and have cracked in use on a few cars. Others are made of aluminum plate and can be heat-treated to be much stronger. Cast and plate parts look identical after lathe turning, so buy from someone you trust.
quote:

Originally posted by Robbie:

... why the overdrive water pump pulley ...



The Pantera cooling system has two flaws, (1) insufficient coolant flow (especially at low rpm) and (2) air collection in the radiator. The overdrive pulley spins the coolant pump faster, increases coolant flow, goes a long way towards alleviating the first problem.

The Pantera cooling system presents the coolant pump with way more head than what it was designed to cope with. The pump operates way outside of its design parameters. I suspect there is little to no coolant flow at idle. The pulley spins the pump fast enough at idle to get the coolant pump higher into its "pump speed verses flow curve", to a point where coolant actually begins to flow. Folks report 5°F to 10°F drops in temperature.
On the overdrive pump pulley, there seems to be a pretty big difference between the SAAC and the IPSCO pulley diameters. Although I'm not a high RPM guy .. can there be a problem by over-reving the stock pump? Which of the two pulleys are recommended?
AFAIK, When first sold by SAAC, they sold the IPSCO water pump pulley. They changed suppliers at a later date.

SAAC website currently does NOT list the water pump pulley??

The SAAC pulley I won at a Fun Rally is 4.90" in diameter.

IPSCO still lists theirs - $85 - no description of diameter.

Stock cast iron pulley was 5.5" in diameter.

Larry
no problem over-revving the stock pump.

The coolant pumps in air conditioned Fords and Mercurys powered by the 351C were over-driven by approximately 10% . The SACC pulley over drives the pump by 11% to 12% depending upon how you do the math.

A quote from the DeTomaso Macchine da Corsa book, page 102, from an interview with former group 4 Pantera driver Marcel Schaub: “Bertocchi also installed a smaller pulley on the water pump, which helped increase the pump speed and lowered the water temperature. I raced chassis 2873 for ten years from 1974 to 1984. I won three Italian and one European championship.”

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