Non-Underdriven C3 Aluminum Pulleys- Do they exist?
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
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From: Woodinville WA
Non-Underdriven C3 Aluminum Pulleys- Do they exist?
Does anyone know of ANY manufacturer making aluminum pullies for C3s that are NOT underdriven?
I believe the stock crank diameter on my 79 L82 was 6 5/8" or 6 11/16". The CVF Racing crank pulley for C3s is only 5.4"; their water pump pulley is 6.2".
That would drop the ratio between the crank and the water pump from 1.0685 to 0.871 which is a LOT for a car that's pretty infamous for running hot in traffic.
The March C3 pulleys are: crank pulley 5 1/2"; water pump pulley 6 1/4", which is a .88 crank to water pump ratio.
GOOD water pumps lose so little HP now that there's no reason to run them underdriven.
Stewart Components explicitly recommends a minimum of a 1:1 ratio for street cars and says that from their testing, more HP is lost to higher temps from underdrive ratios than is gained by running the water pump slower: “Stewart Components does NOT recommend the use of underdrive pulleys on any STREET application. Stewart high-flow water pumps only consume 2.26 horsepower at 4,000 RPM, so the actual savings in parasitic horsepower loss through the use of underdrive pulleys is minimal. In addition, a properly designed cooling system's flow and efficiency are designed to operate at a given speed. In years of testing, Stewart has consistently proven that the engine will lose more horsepower due to higher operating temperatures than any possible gain from underdrive pulleys.”
There was a CF thread on this subject back in 2002 but all the other pulley vendors mentioned back in that thread that offered a more stock-sized aluminum pulley are no longer in business now...
What does it take to run a regular small aluminum crank pulley on a C3? (I already have to space stuff out to make room for my crank trigger wheel, so I'm ok with altering spacing outward...)
There ARE some high flow water pumps that flow more on a C3 and might help make this situation better (Both the FlowKooler and the PRW water pumps), but they both go into cavitation at higher RPMs... For a C3 with a 5,000 RPM HP peak, one of these pumps with the March or CVF racing alum pulleys might be a good combination. I'd rather have pump that's going to flow well and not cavitate until an engine speed of 6,000 RPM, though...
Adam
I believe the stock crank diameter on my 79 L82 was 6 5/8" or 6 11/16". The CVF Racing crank pulley for C3s is only 5.4"; their water pump pulley is 6.2".
That would drop the ratio between the crank and the water pump from 1.0685 to 0.871 which is a LOT for a car that's pretty infamous for running hot in traffic.
The March C3 pulleys are: crank pulley 5 1/2"; water pump pulley 6 1/4", which is a .88 crank to water pump ratio.
GOOD water pumps lose so little HP now that there's no reason to run them underdriven.
Stewart Components explicitly recommends a minimum of a 1:1 ratio for street cars and says that from their testing, more HP is lost to higher temps from underdrive ratios than is gained by running the water pump slower: “Stewart Components does NOT recommend the use of underdrive pulleys on any STREET application. Stewart high-flow water pumps only consume 2.26 horsepower at 4,000 RPM, so the actual savings in parasitic horsepower loss through the use of underdrive pulleys is minimal. In addition, a properly designed cooling system's flow and efficiency are designed to operate at a given speed. In years of testing, Stewart has consistently proven that the engine will lose more horsepower due to higher operating temperatures than any possible gain from underdrive pulleys.”
There was a CF thread on this subject back in 2002 but all the other pulley vendors mentioned back in that thread that offered a more stock-sized aluminum pulley are no longer in business now...
What does it take to run a regular small aluminum crank pulley on a C3? (I already have to space stuff out to make room for my crank trigger wheel, so I'm ok with altering spacing outward...)
There ARE some high flow water pumps that flow more on a C3 and might help make this situation better (Both the FlowKooler and the PRW water pumps), but they both go into cavitation at higher RPMs... For a C3 with a 5,000 RPM HP peak, one of these pumps with the March or CVF racing alum pulleys might be a good combination. I'd rather have pump that's going to flow well and not cavitate until an engine speed of 6,000 RPM, though...
Adam
Le Mans Master
Joined: May 2007
Posts: 5,029
Likes: 1,120
From: North tonawanda NY
Does anyone know of ANY manufacturer making aluminum pullies for C3s that are NOT underdriven?
I believe the stock crank diameter on my 79 L82 was 6 5/8" or 6 11/16". The CVF Racing crank pulley for C3s is only 5.4"; their water pump pulley is 6.2".
That would drop the ratio between the crank and the water pump from 1.0685 to 0.871 which is a LOT for a car that's pretty infamous for running hot in traffic.
The March C3 pulleys are: crank pulley 5 1/2"; water pump pulley 6 1/4", which is a .88 crank to water pump ratio.
GOOD water pumps lose so little HP now that there's no reason to run them underdriven.
Stewart Components explicitly recommends a minimum of a 1:1 ratio for street cars and says that from their testing, more HP is lost to higher temps from underdrive ratios than is gained by running the water pump slower: “Stewart Components does NOT recommend the use of underdrive pulleys on any STREET application. Stewart high-flow water pumps only consume 2.26 horsepower at 4,000 RPM, so the actual savings in parasitic horsepower loss through the use of underdrive pulleys is minimal. In addition, a properly designed cooling system's flow and efficiency are designed to operate at a given speed. In years of testing, Stewart has consistently proven that the engine will lose more horsepower due to higher operating temperatures than any possible gain from underdrive pulleys.”
There was a CF thread on this subject back in 2002 but all the other pulley vendors mentioned back in that thread that offered a more stock-sized aluminum pulley are no longer in business now...
What does it take to run a regular small aluminum crank pulley on a C3? (I already have to space stuff out to make room for my crank trigger wheel, so I'm ok with altering spacing outward...)
There ARE some high flow water pumps that flow more on a C3 and might help make this situation better (Both the FlowKooler and the PRW water pumps), but they both go into cavitation at higher RPMs... For a C3 with a 5,000 RPM HP peak, one of these pumps with the March or CVF racing alum pulleys might be a good combination. I'd rather have pump that's going to flow well and not cavitate until an engine speed of 6,000 RPM, though...
Adam
I believe the stock crank diameter on my 79 L82 was 6 5/8" or 6 11/16". The CVF Racing crank pulley for C3s is only 5.4"; their water pump pulley is 6.2".
That would drop the ratio between the crank and the water pump from 1.0685 to 0.871 which is a LOT for a car that's pretty infamous for running hot in traffic.
The March C3 pulleys are: crank pulley 5 1/2"; water pump pulley 6 1/4", which is a .88 crank to water pump ratio.
GOOD water pumps lose so little HP now that there's no reason to run them underdriven.
Stewart Components explicitly recommends a minimum of a 1:1 ratio for street cars and says that from their testing, more HP is lost to higher temps from underdrive ratios than is gained by running the water pump slower: “Stewart Components does NOT recommend the use of underdrive pulleys on any STREET application. Stewart high-flow water pumps only consume 2.26 horsepower at 4,000 RPM, so the actual savings in parasitic horsepower loss through the use of underdrive pulleys is minimal. In addition, a properly designed cooling system's flow and efficiency are designed to operate at a given speed. In years of testing, Stewart has consistently proven that the engine will lose more horsepower due to higher operating temperatures than any possible gain from underdrive pulleys.”
There was a CF thread on this subject back in 2002 but all the other pulley vendors mentioned back in that thread that offered a more stock-sized aluminum pulley are no longer in business now...
What does it take to run a regular small aluminum crank pulley on a C3? (I already have to space stuff out to make room for my crank trigger wheel, so I'm ok with altering spacing outward...)
There ARE some high flow water pumps that flow more on a C3 and might help make this situation better (Both the FlowKooler and the PRW water pumps), but they both go into cavitation at higher RPMs... For a C3 with a 5,000 RPM HP peak, one of these pumps with the March or CVF racing alum pulleys might be a good combination. I'd rather have pump that's going to flow well and not cavitate until an engine speed of 6,000 RPM, though...
Adam
Le Mans Master
Joined: Oct 2000
Posts: 7,831
Likes: 5
From: Austin TX
I have Zoops pulleys on my big block that overdrive the pump 7%.
I took a look on ebay and there are NOS small block pulleys for sale.
If you could find out the right part numbers maybe you could find some...
I took a look on ebay and there are NOS small block pulleys for sale.
If you could find out the right part numbers maybe you could find some...
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
Adam
Le Mans Master
Joined: May 2007
Posts: 5,029
Likes: 1,120
From: North tonawanda NY
That makes sense... I was talking about original c3 power steering.
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
The 1971-1982 small block C3s need very special pulleys; regular “short” small block pulleys don’t work; that’s the problem. (The block surface to pulley surface distance is different, so is the groove spacing between the grooves on the pulleys and the water pump requires a bigger bore.)
There are plenty of Chinese 6.6” 3 groove aluminum crank pulleys that work for normal short small blocks, but it seems to be only CVF racing and March that makes aluminum pulleys for C3s, so you’re stuck with either 0.87 or 0.88:1 unless you randomly find someone selling an old Zoops pulley or you run a stock steel crank pulley and aluminum on the other pulleys.
Adam
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
I would ask the guys at March as they might make them for another application. They make a lot of parts for many different applications. I converted my engine over to the single Serpentine belt many years ago using their parts. My only complaint is that their Powder coating was not up to snuff when they made my parts. I had sheets of the powder coating come off the brackets.
You are absolutely right about the Steeroids Rack and Pinion Power Steering System. I was originally told to go to a newer style power steering pump which has a different setup than the factory PS pumps. They guys at Turn One were able to help me get things working right by getting the right pump pieces to get the flow rate where the PS system wanted it. I kept trying different sized pulleys when the folks at Turn One supplied me with a fitting that went into the pump to solve the flow rate problems. I am using a remote reservoir and several times the volume of power steering fluid in an effort to keep the rack and pinion cooler so it will last longer.
You are absolutely right about the Steeroids Rack and Pinion Power Steering System. I was originally told to go to a newer style power steering pump which has a different setup than the factory PS pumps. They guys at Turn One were able to help me get things working right by getting the right pump pieces to get the flow rate where the PS system wanted it. I kept trying different sized pulleys when the folks at Turn One supplied me with a fitting that went into the pump to solve the flow rate problems. I am using a remote reservoir and several times the volume of power steering fluid in an effort to keep the rack and pinion cooler so it will last longer.
Le Mans Master
Joined: May 2007
Posts: 5,029
Likes: 1,120
From: North tonawanda NY
Zoops was a company that was mentioned in the thread back in 2002 but they don’t exist any more.
The 1971-1982 small block C3s need very special pulleys; regular “short” small block pulleys don’t work; that’s the problem. (The block surface to pulley surface distance is different, so is the groove spacing between the grooves on the pulleys and the water pump requires a bigger bore.)
There are plenty of Chinese 6.6” 3 groove aluminum crank pulleys that work for normal short small blocks, but it seems to be only CVF racing and March that makes aluminum pulleys for C3s, so you’re stuck with either 0.87 or 0.88:1 unless you randomly find someone selling an old Zoops pulley or you run a stock steel crank pulley and aluminum on the other pulleys.
Adam
The 1971-1982 small block C3s need very special pulleys; regular “short” small block pulleys don’t work; that’s the problem. (The block surface to pulley surface distance is different, so is the groove spacing between the grooves on the pulleys and the water pump requires a bigger bore.)
There are plenty of Chinese 6.6” 3 groove aluminum crank pulleys that work for normal short small blocks, but it seems to be only CVF racing and March that makes aluminum pulleys for C3s, so you’re stuck with either 0.87 or 0.88:1 unless you randomly find someone selling an old Zoops pulley or you run a stock steel crank pulley and aluminum on the other pulleys.
Adam
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Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
I would ask the guys at March as they might make them for another application. They make a lot of parts for many different applications. I converted my engine over to the single Serpentine belt many years ago using their parts. My only complaint is that their Powder coating was not up to snuff when they made my parts. I had sheets of the powder coating come off the brackets.
You are absolutely right about the Steeroids Rack and Pinion Power Steering System. I was originally told to go to a newer style power steering pump which has a different setup than the factory PS pumps. They guys at Turn One were able to help me get things working right by getting the right pump pieces to get the flow rate where the PS system wanted it. I kept trying different sized pulleys when the folks at Turn One supplied me with a fitting that went into the pump to solve the flow rate problems. I am using a remote reservoir and several times the volume of power steering fluid in an effort to keep the rack and pinion cooler so it will last longer.
You are absolutely right about the Steeroids Rack and Pinion Power Steering System. I was originally told to go to a newer style power steering pump which has a different setup than the factory PS pumps. They guys at Turn One were able to help me get things working right by getting the right pump pieces to get the flow rate where the PS system wanted it. I kept trying different sized pulleys when the folks at Turn One supplied me with a fitting that went into the pump to solve the flow rate problems. I am using a remote reservoir and several times the volume of power steering fluid in an effort to keep the rack and pinion cooler so it will last longer.
I have a crank trigger wheel between my damper and my crank pulley already so I've already had to space my accessories and pulleys so I have no problem spacing them, so I was hoping that I could use a regular short pulley and just space it differently, but they clarified that the Corvette pullies have different amount of space between the grooves vs. a regular short pulley, so just spacing a short pulley to work when it's mixed in with other Corvette pulleys won't work well. (You'll keep throwing belts anytime you hit a decent rpm and probably wear them out pre-maturely.)
As far as I can tell the options are to run a stock steel C3 pulley with the rest aluminum pulleys, or just use a water pump that's designed for lower RPMs so the flow is still acceptable at low RPM. I've already swapped to a CS144 alternator so my charging at low RPM is good and I'll just have to deal with the water pump and AC running lower.
A shame that no one make a normalish sized alum crank pulley for C3s, but they're super weird pulleys and a very small niche market, so I get it...
Adam
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
I'm hoping a couple 1/8" thick washers make getting the AC compressor lined up easy-peasy.
Adam
Thread Starter
Melting Slicks
Joined: Jun 2016
Posts: 2,979
Likes: 332
From: Woodinville WA
You are absolutely right about the Steeroids Rack and Pinion Power Steering System. I was originally told to go to a newer style power steering pump which has a different setup than the factory PS pumps. They guys at Turn One were able to help me get things working right by getting the right pump pieces to get the flow rate where the PS system wanted it. I kept trying different sized pulleys when the folks at Turn One supplied me with a fitting that went into the pump to solve the flow rate problems. I am using a remote reservoir and several times the volume of power steering fluid in an effort to keep the rack and pinion cooler so it will last longer.
Steeroids recommends 1,000-1,200 PSI. The stock OEM pumps were all 950 PSI. Steeroids says not to exceed 2 gallons per minute and then said "well as long as you don't exceed 2.5 gallons per minute". (Which is hilarious because the stock 74-82 pumps were 2.9 gal / minute from the factory!)
I bought CVF's super expensive chromed pump, because it is the 1975-1982 style "Canned ham" reservoir, with the SASE hose barbs of the 75-79, but then the woodruf keyway and nut systems of the early C3 pumps so it can be used with CVF's aluminum power steering pulley.
I can't remember the flow rate any more, but I checked with CVF and it was 2.5 gallons per min or less. I know some folks have run custom lines that go from the pump through a cooler and then back to their rack, but I'm going straight to the rack with the 75-79 style Steeroids hoses.
https://www.cvfracing.com/saginaw-p-...-keyway-shaft/
If it feels too "darty", I know I can pickup the little restrictors that drop the pressure.
Adam