Author Topic: BBC 3856284 short water pump impeller comparison  (Read 581 times)

Mike S

  • Hero Member
  • *****
  • Posts: 2128
    • View Profile
BBC 3856284 short water pump impeller comparison
« on: April 15, 2018, 01:46:56 AM »
 I had to rebuild the 3856284 water pump on the L35 due to some coolant seeping out of the weep hole from a faulty seal.
I decided to post pics of what an original impeller looks like compared to the metal ones in the rebuild kits for those who have an interest or just curious. I reused the original impeller. The factory P/N is 3921939.

Mike
« Last Edit: April 15, 2018, 03:04:10 AM by Mike S »
67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored

bcmiller

  • CRG Member
  • *****
  • Posts: 2430
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #1 on: April 15, 2018, 02:18:31 AM »
Mike did you rebuild it yourself?
Bryon / 1968 Camaro SS 396 coupe - now 468 cubic inch BBC/M21
67 RS/SS 396 coupe L35/M40 - 4 generation family project
Looking for 68 Camaro with body # NOR 181016

Mike S

  • Hero Member
  • *****
  • Posts: 2128
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #2 on: April 15, 2018, 02:38:57 AM »
Hi Bryon,

  Yes. I did the work in my basement with some deep sockets and a Harbor Freight 20 ton press.

Mike
67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored

JKZ27

  • Hero Member
  • *****
  • Posts: 513
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #3 on: April 15, 2018, 12:59:06 PM »
Mike, where did you get the rebuild kit?
John
69 RS/SS Cortez Silver, L48 MC1
68 RS Ash/Ivy Gold 327EFI M20

Mike S

  • Hero Member
  • *****
  • Posts: 2128
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #4 on: April 15, 2018, 02:06:28 PM »
Hi John,

 I used one from Zip Corvette I bought a few years back and even though their website states it doesn't interchange with original parts, I found that not to be accurate as I was able to reuse my original impeller. The ID of the original impeller was the same as their steel impeller. When you think of it, the shaft has to be the same size in order for the belt pulley and fan space to properly fit snug on the shaft.
   I have to rebuild another 67 water pump and this time I'm going to get the kit locally from LI Corvettes.  https://licorvette.com/water_pumps_and_water_pump_rebui.htm
  They have the '65 396 and '66-'67 427 kits. I am told the kits are the same with the exception for the rear plate retaining hardware. The earlier 396 used screws and the 427 used recessed head hardware. The LI kits don't have the steel impeller so you'll have to reuse yours.
  If you have a press handy then you can easily rebuild yours. I used this article as reference and though it mentions setting the hub height to 5 5/8" (for a SB),you'll have to set it to 5 3/4" if you have a BB. Also, some kits have a 2-piece bearing seal and others have a 1-piece seal. The kit I bought had a 1-piece seal and the video link below shows how to install that.
https://www.powernationtv.com/two-minute-tech/2min-434/how-to-rebuild-a-water-pump

Mike
67 LOS SS/RS L35 Hardtop - Original w/UOIT
67 NOR SS/RS L35 Convertible - Restored

bcmiller

  • CRG Member
  • *****
  • Posts: 2430
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #5 on: April 15, 2018, 05:14:54 PM »
Thanks for sharing that Mike. On you next one, maybe take some pics during the process. I need to do this on a 67 water pump that I have.
Bryon / 1968 Camaro SS 396 coupe - now 468 cubic inch BBC/M21
67 RS/SS 396 coupe L35/M40 - 4 generation family project
Looking for 68 Camaro with body # NOR 181016

JKZ27

  • Hero Member
  • *****
  • Posts: 513
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #6 on: April 16, 2018, 01:57:32 PM »
Yes! Thank you for the details, Mike! I have to rebuild the one for my 69 350.
John
69 RS/SS Cortez Silver, L48 MC1
68 RS Ash/Ivy Gold 327EFI M20

hihorse

  • Member
  • ***
  • Posts: 190
    • View Profile
Re: BBC 3856284 short water pump impeller comparison
« Reply #7 on: May 07, 2018, 09:10:15 PM »
Did rect port cars receive the high output impeller?