long vs. short water pump
Melting Slicks
Joined: May 2006
Posts: 2,590
Likes: 403
From: Nashville TN
St. Jude Donor '09
I beleive there are 3 sizes -- short, long and corvette which is between a short and long. Are you replacing one you already have? If so, measure the distance from the mounting surface to the end of the shaft where the pulleys mount. Also, measure the diameter of the shaft; they are different too. I ordered the corvette pump, right? It's a Corvette!!! I forgot that my motor is not original, so then I measured and bought the correct one (short). If you end up with the wrong size, you're pulleys will not line up with your accessories. Fortunately, I had enough forthought to compare the new to the old one before I installed and noticed the difference. Just wish I had measured BEFORE I ordered.
Melting Slicks
Joined: Oct 2002
Posts: 2,316
Likes: 111
From: St Louis MO
Corvettes used the "short" water pump up to about 1970, then went to a slightly longer "short" water pump by about .140 inches (block to fan flange); this pump also used a larger shaft at 3/4 inch instead of the previous 5/8 inch.
Pro
Joined: Oct 2004
Posts: 573
Likes: 0
From: Stafford VA
If a guy wanted to replace the stock water pump and pulleys on a 1970 BB, would a short water pump and the matching short aftermarket pulleys work fine? I know they will line up on the motor, just not sure if there is anything about the C3 chassis that makes it interesting. Thanks!
4th Gear
Joined: Feb 2010
Posts: 4
Likes: 0
From: Charleston SC
Help on 77 Water andPower Steering Pumps
Newbie here, but a long time Corvette owner (77 since 1988, 86 Z51 for about 10 years which I wish I still had, and a 1969 427 resto project for about a year).
I need help on my 1977 L48:
Thank you in advance!
Anyway - I'm in the process of getting everything back up to snuff, and look forward to talking more with everyone here!
I need help on my 1977 L48:
- Water Pump - I have read the extensive forums here on short v. long v. Corvette v. 5/8"shaft v. 3/4"shaft, but am still not sure what I need. I went to NAPA, and they have 2 basic options: 1 with 1/2-1/2"outlets and one with 1/2-3/4""outlets. Whats the deal? Both numbers are different from a stock 350 Camaro water pump for the same year. I read a reply saying I have a Long pump if I can get my finger between the pump and the timing cover, otherwise its a Short (or Corvette). I checked this, and find that my water pump actually touches the timing cover. My timing cover is not stock, and may be deeper to accommodate the double roller Crane timing chain I put in 16 years ago (about 5,000 mies ago). Any ideas??????
- Power Steering Pump - I rebuilt the engine 16 years ago (5k miles ago), and put in bigger Comp Cam, double roller timing chain, 1.6:1 Roller Rockers, Edelbrock performer aluminum intake, new push rods, springs, stainless valves, and 58cc 10.5:1 1969(?) Chevy iron heads. When I put the alternator back on, I can no longer remove the cap from the power steering pump, as it hits the alternator bracket. I can raise it and pour fluid in, but cannot remove. Any ideas?
Thank you in advance!
Anyway - I'm in the process of getting everything back up to snuff, and look forward to talking more with everyone here!
Last edited by SC77; Feb 18, 2010 at 06:16 PM.
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
This question come frequently and I'm sometimes amazed at the self induced confusion that comes with it. Forget the 'short' vs. 'long' stuff that means nothing to the kid at NAPA. C3 Corvettes have specific water pump requirements that vary according to engine size and year of car. In specific, the shaft size is larger on later pumps, the casting configuration and number changed at least three times but most importantly the total height of the pump from backface to fan clutch mounting face is different than any other car IIRC.
There is only one correct pump for each application, and that's what should come up on the parts guy's screen. Every time I've bought one, it's been spot on. My local guy even found me one with a correct casting date on it.
If you've modified your engine with different pulleys, then all bets are off.
WRT your steering pump cap, the drive belt is the wrong length, a very common problem. The correct belt will position the pump so that the cap can be manoeuvred off.
There is only one correct pump for each application, and that's what should come up on the parts guy's screen. Every time I've bought one, it's been spot on. My local guy even found me one with a correct casting date on it.
If you've modified your engine with different pulleys, then all bets are off.
WRT your steering pump cap, the drive belt is the wrong length, a very common problem. The correct belt will position the pump so that the cap can be manoeuvred off.
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4th Gear
Joined: Feb 2010
Posts: 4
Likes: 0
From: Charleston SC
The problem is the NAPA guy's screen shows 5 options (and I looked it up on their web site as well):
As for the Power steering pump belt, I can't go longer, or the pump pulley will hit the frame, and a shorter belt will leave the cap buried further under the alternator.
It's been 16 years since the rebuild, so I have no recollection of what it looked like before, but I know I could remove the cap.
- 1/2"-1/2" outlets
- 1/2"-3/4" outlets
- Severe Duty
- New Delco
- Aluminum (and I looked this up, but its for C4 vettes)
As for the Power steering pump belt, I can't go longer, or the pump pulley will hit the frame, and a shorter belt will leave the cap buried further under the alternator.
It's been 16 years since the rebuild, so I have no recollection of what it looked like before, but I know I could remove the cap.
Last edited by SC77; Feb 18, 2010 at 01:59 PM.
4th Gear
Joined: Feb 2010
Posts: 4
Likes: 0
From: Charleston SC
Pulled the old one off - it sits about 1/32" off of the timing cover, so it should be OK.
Someone mentioned "spacers" here - but I don't recall ever seeing any spacers on my water pump. If they were about 1/4" thick,they could be a good addition.
Called and ordered a new NAPA Tru-Flow TFW-43104P Water Pump ("P" indicates High Performance, extra $25, and 3 days delivery).
I'll plug the heater bypass port (4th/bottom hole on the right side mounting flange. Its not cold in SC, so I'll let the engine get the cooling rather than my feet getting the warmth.
Heres' the Corvette section of Tru-Flow's (carried by NAPA) Water Pump Chart for everyone's reference:
Heres the TFW-43104P Water Pump ...
Someone mentioned "spacers" here - but I don't recall ever seeing any spacers on my water pump. If they were about 1/4" thick,they could be a good addition.
Called and ordered a new NAPA Tru-Flow TFW-43104P Water Pump ("P" indicates High Performance, extra $25, and 3 days delivery).
I'll plug the heater bypass port (4th/bottom hole on the right side mounting flange. Its not cold in SC, so I'll let the engine get the cooling rather than my feet getting the warmth.
Heres' the Corvette section of Tru-Flow's (carried by NAPA) Water Pump Chart for everyone's reference:
Heres the TFW-43104P Water Pump ...
Last edited by SC77; Feb 18, 2010 at 06:08 PM.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
This is the dimension for the Corvette water pump
Corvette to 70---Block to hub----5.625"----3/4" shaft
Trucks up to 72 also
Corvette 71-82---Block to hub----5.795"----3/4" shaft
SC77
If you are going to block the bypass, then you must drill a least 3 1/8" holes in the tstat, so as not to develop dangerous steam pockets in the engine before the tstat opens.
Your pump will almost touch the timing cover, and depending on the bolts used on the back of the pump, you may have to grind some of the bolt heads thinner.
The correct pump has the 3/4" NPT port on top and the 1/2" NPT port on passenger side, but all sorts of variations of hose nipple adapters are available anyway.
I always use double rollers too.
Corvette to 70---Block to hub----5.625"----3/4" shaft
Trucks up to 72 also
Corvette 71-82---Block to hub----5.795"----3/4" shaft
SC77
If you are going to block the bypass, then you must drill a least 3 1/8" holes in the tstat, so as not to develop dangerous steam pockets in the engine before the tstat opens.
Your pump will almost touch the timing cover, and depending on the bolts used on the back of the pump, you may have to grind some of the bolt heads thinner.
The correct pump has the 3/4" NPT port on top and the 1/2" NPT port on passenger side, but all sorts of variations of hose nipple adapters are available anyway.
I always use double rollers too.
4th Gear
Joined: Feb 2010
Posts: 4
Likes: 0
From: Charleston SC
Noonie -
Thanks for the reply.
I'll check my dims to see if my old (and new) pump is 5.795" ...
Yes - the 1/8 holes in the Tstat are critical for those who do this warm-climate mod.
I hope the new water pump has steel blades like my old one did . I had modified the vanes with a circular stainless steel plate that increase cooling flow.
I dug around and found my old "Small Block Chevy Performance" book, which states that there wer indeed 3 waterpumps use don Chevy small blocks:
I'm not sure what current Vettes use.
Now I know a lot more than I ever wanted to about Corvette and Chevy water pumps ;-)
RJ
Thanks for the reply.
I'll check my dims to see if my old (and new) pump is 5.795" ...
Yes - the 1/8 holes in the Tstat are critical for those who do this warm-climate mod.
I hope the new water pump has steel blades like my old one did . I had modified the vanes with a circular stainless steel plate that increase cooling flow.
I dug around and found my old "Small Block Chevy Performance" book, which states that there wer indeed 3 waterpumps use don Chevy small blocks:
- ALL small block Chevy V8s built prior to 1969, as well as 1969 and 1970 Corvettes, used a "SHORT" water pump thats 5.545" from hub face to block with 5/8" shaft,
- 1972-1982 "CORVETTE" Water Pumps measured 5.795" with a 3/4"shaft,
- 1969 and later passenger car and truck small blocks used a "LONG" pump, measuring 6.900" with 5/8" shaft,
- 1984 and later C4 Vettes used Aluminum (counter rotated) water pumps which were the same length (5.795").
I'm not sure what current Vettes use.
Now I know a lot more than I ever wanted to about Corvette and Chevy water pumps ;-)
RJ
Last edited by SC77; Feb 18, 2010 at 07:34 PM.
Melting Slicks
Joined: May 2002
Posts: 2,716
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
best I can tell;
the sizes mentioned are the different configurations for the hose connections.
rockauto lists about 12 or so pumps for the 77 vette
chevy only made two height pumps short and long
the corvette pump has a larger shaft and bearings (3/4")
the sizes mentioned are the different configurations for the hose connections.
rockauto lists about 12 or so pumps for the 77 vette
chevy only made two height pumps short and long
the corvette pump has a larger shaft and bearings (3/4")
Instructor
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Le Mans Master
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
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