6.2 CUCV water pump on a 6.5

Here's a new one for you. As many of you know, I have a new P400 6.5 long block on the way to install into my M1028. Because I want to maintain the original 12/24 volt CUCV alternator system, I plan to move my original CUCV alternators, brackets, and PS pump over to the new 6.5 from the 6.2. For the past several weeks I have been accumulating parts for this swap, and had decided to abandon my original 34-year-old factory 6.2 water pump for a new high-flow pump to help cool the extra horses the P400 would be producing. Because I plan to re-use my original V-belt system on the new 6.5, I needed a clockwise (CW) rotation pump, as the serpentine belt system requires a CCW rotation pump. After exploring all the "high-flow" pumps available, I settled on a new high-flow CW water pump from FlowKooler to accomodate the 6.2 V-belt design https://www.flowkoolerwaterpumps.com/ . Yesterday I called FlowKooler and spoke with a fellow named Lee and explained to him what I planned to do. He then told me that the CW rotation 6.2 pump will not work on a 6.5 engine because the bolt pattern is different. I questioned this, so I pulled up images of both pumps, and although the castings are different (they have to be for the dirrerent water flow), the bolt pattern looks the same to me.

Anybody else heard of this?

Thanks.

Done some more investigating and a lot of reading on this today and concluded that I will need to use a 6.2 water pump backing plate in order to bolt up the 6.2 CW rotation water pump. Now all I need to do is confirm that the 6.2 backing plate will bolt up to the 6.5 timing cover housing. Anybody done this?

Thanks.

I would look up the gaskets and see of they're the same.

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Yes you are correct. There is two different backing plates. One for the CW pump and one for the CCW pump. You can use your original 6.2 backing plate with no problems. It will bolt to any 6.2 or 6.5 timing chain cover. You can even use the bolts. They are also the same. I have done this multiple times. My 1028 has a civi 6.5 that I used my CUCV 6.2 parts on. My 6.5 GEP engine in my M998 is the same way. I have a 6.2 Vbelt with a 60 amp alt on it. With the engines removed this is a quick 15 min change out.

Thanks Ken for that great piece of knowledge. I need to buy a 6.2 V-belt backing plate, because I want to leave my original 6.2 engine intact to enhance its resale value. So if anybody has an original 6.2 V-belt backing plate laying around, pm me and I will see if I can scrape up the dough.

Try KASCAR at www.real4wd.com They are a Humvee parts supplier. Their part number is 12562637. They want $55.30. For a new one.

Geez, it figures. I just took 5 6.2 water pumps to the scrap yard and one had a backer plate on it, I didn't need it and am trying to clean up stuff soooo.....

Sharecropper said:

Thanks Ken for that great piece of knowledge. I need to buy a 6.2 V-belt backing plate, because I want to leave my original 6.2 engine intact to enhance its resale value. So if anybody has an original 6.2 V-belt backing plate laying around, pm me and I will see if I can scrape up the dough.

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I have a brand new GM backing plate if your still looking for one.

Tinstar said:

I have a brand new GM backing plate if your still looking for one.

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Is your backing plate for a CW 6.2 pump or CCW 6.5 pump? Do you have the GM part number?

Thanks.

sharecropper said:

is your backing plate for a cw 6.2 pump or ccw 6.5 pump? Do you have the gm part number?thanks.

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cw 6.2

Tinstar said:

View attachment 734754View attachment 734755
cw 6.2

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No Mr. Tinstar, that plate is for the 6.5 CCW serpentine water pump. I happen to have that same 12562637 plate here in my inventory and it is exactly like your photo. The correct water pump backing plate for the V-belt 6.2 CW rotation is part #14024208. Here are the pages from the 9-2320-289-34P CUCV TM. If you look closely at the gasket in the image, you will see that the water flow is opposite from your plate.

gringeltaube said:

Mr. Sharecropper: Mr. Tinstar is indeed correct; what appears in his first picture is for the 6.2L & 6.5L N/A (detuned) V-belt driven, CW- rotating water pump.
I think that is what you are looking for...?

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I have in my hands the exact same plate as his first photo. Part #12562637. That plate is for the CCW serpentine pump.

I need the 14024208 plate for the V-belt CW pump. If you will look at the gasket image #7, Figure 31, you will see that the water flow is opposite from Tinstar's image.

GM purposely drilled the plates differently so the pumps could not be mixed up.

You are right, and that is why I deleted my previous post... Sorry about the confusion.

Sharecropper said:

No Mr. Tinstar, that plate is for the 6.5 CCW serpentine water pump. I happen to have that same 12562637 plate here in my inventory and it is exactly like your photo. The correct water pump backing plate for the V-belt 6.2 CW rotation is part #14024208. Here are the pages from the 9-2320-289-34P CUCV TM. If you look closely at the gasket in the image, you will see that the water flow is opposite from your plate.

Click to expand...

I stand corrected.
Thanks for the info