cobalt

what is the length of a water pump for a 1972 olds 455 engine with ac? thanks

Octania

per 1975 printed PN Manual

PN 556283
71-74 V8 C.A.C. or Y72
also used on
75 260, 455 eng. C.A.C. or Y72
75 all A, B 350 Eng C.A.C., Y72

I am *guessing* that this is
#4 casting 412265
Water Pump, ID= 4, L= 6.1

the exceedingly common one.

cobalt

so if i get the long water pump i should be ok for ac then..thanks

Mr Shifty Sidney

71/72 Cutlass with A/C should have a water pump that is aprox 6" tall.

Don W

RocketDevo

Hello, the length of the water pump shaft should be 5.572" inches. As far as the casting number for original water pumps, it is 407586. The number 8 looks like a 3 thought. Another way of identifying this pump is a large number "3" near the outlet. Hope this helps.

BlackGold

Make sure you get a pump with the proper size inlet. 1970 and earlier used a larger inlet than 1971 and later.

Of course, the "right" size inlet for YOUR car depends not necessarily on the year of the car as on which radiator is in it. The radiator outlet changed size in 1971 as well. If a previous owner swapped in a different year radiator and pump, then you may have to follow suit.

Sorry, I don't know the exact dimensions of the different inlets and outlets off the top of my head. I'm sure a search on this website will find it for you.

Mr Shifty Sidney

For 71/72 Olds used 3 water pump lengths. 5", 5.5", and 6" (technically they are 5.072, 5.572, and 5.947 per the 71 Service Manual). They are easily identified by a single number (1,2,or 3) cast into the pump housing.

1 = 5"
2 = 5.5"
3 = 6"

The 6" pump was used on 71/72 Cutlass with A/C.

Don W

Mr Shifty Sidney

This picture shows the three pumps compared. Each pump is labled with a red number to show the difference.

Don W

Mr Shifty Sidney

#3 pump showing 6" height.

Don W

Mr Shifty Sidney

Top view of a #3 pump showing id number and casting number.

Don W

Mr Shifty Sidney

As Brian noted some water pumps have different size inlets. I think the 71/72s are 1.5" and the 70's are 2". Changing pumps from year to year can create problems with length, radiator hoses (again as Brian noted) and also pulleys. I always try to go back to original if possible to elimanate headaches.

Don W

Octania

WORDS TO LIVE BY

#3 and #4 are both 6.1" as I call them pumps

ck the inlet diameter at 1.75 vs 2.0"

cobalt

the problem here is this engine im using was taken out of a car at some piont then later used in a boat..in which process they took off the water pump..so i have nothing to go by but little info gleened from the block...i know its a 1972 oldsmobile 455 from lancing mich..so im gonna have to roll the dice and get a 1972 ac pump and hope for the best

Mr Shifty Sidney

That will work, just keep in mind you will have to match up the pump application with the same pulley application. For example non A/C pulleys may not work with a water pump for A/C.


Don W

RocketDevo

The "KM" pulley is what you need; for non AC cars when using the longer shaft water pumps.

cobalt

here is where im at...i got the 6 inch ac water pump..questions as you can see the pulleys dont line up... first question is being my car has power steering will have ac eventually and of course it has the altenator..should this have 3 grooves on the fan and cam pulleys? second whats the best way from this piont to line up the pulleys? it seems if they made a 5.25 inch water pump it would bring it in just right being they are off by 3/4 and i have a 6 inch pump right now..but from all my reading they dont..next i could try to find a 3.25 tall fan pulley as mines only 2.5 and that would bring it back and line up..but nobody lists that on ebay..and last of all should i get another cam shaft pulley... HELP....oh another thing what is the difference between a ac and non ac pump? besides length? and why is it longer? and could you run a non ac pump on a ac car? thanks

RocketDevo

To answer to your first question, the crank and water pump should both have 3 grooves for AC applications. As far as making things line up, you need to sync everything. What I mean by this is, you need to have all AC components. This includes the water pump and pulleys for said setup. The W cars without AC used a heavy duty water pump. They were able to get around having the longer shaft water pump by using the "KM" pulley with its offset. I believe The Parts Place reproduces the "KM" pulley. Keep in mind the "KM" pulley is a 2 groove, so if ultimately you will have AC you will need to have the correct 3 groove pulley. It is a good question, what is the difference between a AC and non AC water pump besides shaft length. The GM/Oldsmobile engineers would be best to answer that question, as there does not seem to be a real difference as far as design and flow. However a 1970 original water pump has a larger outlet AC or non AC than 1971 or later does. The real difference is because of the shaft length. The heavy duty water pumps were part of the heavy duty cooling package which included a fan shroud. The reason for the increase shaft length was to have the fan sit in the shroud for optimum air flow. If the fan was to far in or out from the shroud it would greatly decrease the amount of air it would pull through the radiator.
Finally as I mention earlier you can run an AC or non AC water pump on a vehicle as long as the matching pulleys are used. Hope this helps.

Mr Shifty Sidney

Here is a diagram from the 1971 assembly manual. I think 72 uses the same pulleys. For your 6" water pump you will need one of the bottom two combinations of pulleys. The top two combinations use the 5" and 5.5" water pumps. The code is stamped into the pulley. For example a 455 with A/C will use a KC crankshaft pulley. Other years may or may not work. As Devo has said, the key is to get a complete set of pulleys for the same application as the water pump.

Just to be clear, the KM pulley is not used with the 6" water pump. It is used with the 5.5" water pump.

Don W

cobalt

thanks for the info...im getting a pair of matching 3 groove pulleys and i have done a diagram and asked what the width of the belt groove area was.. he said it was 2 7/8 so if i match it up to these mockups of his pulleys i think the 5.625 water pump will match the best..now to find the part number for it....should be fun... :/

Octania

That is no way to measure pulleys. What matters? And is easy to measure and record/ compare?


number of grooves obviously

Diameter

OVERALL WIDTH - easiest to measure.

distance from mounting surface to some feature of interest. Easy for crank, not for WP...

more later, gotta go.

HERE is WP 101 again, I have a database designed to help figure out WP/pulley issues...

.++++++++++++++++++++++++++++++++++++++

Outside of Oddities such as the Missing Nipple issue, the "wrong side" inlet 1964-only 330-only unit, and that oddball V6 Diesel serpentine belt drive unit that rotates the other way... there are two main features of the Olds V8 water pump that matter as far as FITMENT, never mind correct function...
1) LENGTH overall from gasket surface to pullet mounting surface. Affects pulley position and therefore alignment. Place a straightedge across the hub surface where the pulley would be, and measure to the gasket surface. The flavors are [give or take a little]:
5.1" - early [pre-70??] no-AC
5.6" - Early AC and later No-AC
6.1" - Later w/AC and then pretty much ALL V8's after oh 1975 or so
2) Inlet nipple diameter - where the radiator hose fits on.
Other differences such as the type of impeller and the diameter of the housing volute ID and of the impeller... might matter to function under extreme conditions, but can likely be worked around.
I have a free Excel database with most of the known castings listed, how to ID them, maybe what they came on so you know what to tell the parts guy, crucial dimensions, what pulleys they use, etc. Free upon request. Nearly worth it too.
Consulting that, without listing every individual casting ID, I see IN GENERAL:
5.1 long x 2" inlet = the shortest earliest type.
5.1 x 1.8, typical large casting ID on the RH outlet boss is "1" or "2". Yes, 1.8 is shorthand for 1 & 3/4 inches. Oddball applications, mainly 71-72 w/o AC.
5.6 x 2.0 - HD Cooling 68-69, maybe the '70 W30 &c with HD Cooling. Includes the rare and now pricey "X" 404847 casting. Also the 400268 or similar miisread 400xxx numbers, typically with a large "O" on the RH outlet boss. And, no, it's not on YOUR right as you face the engine from the front, it's on the CAR'S RH side.
5.6 x 1.8" - seem to be for 70-72 SB/Non-HDC apps
6.1 x 1.8 - far and away the most common. Most midrange apps w/AC, and almost all of everything since oh 1975 or so. Includes the ubiquitous #4 casting 412265, #3-407536, O-404562, and some other less common and aftermarket variations.

cobalt

the guys said the pulleys are off a 71 cutlass 350 v8 with ac

sammy

How did you make out with this cobalt? I am having a similar issue.....thanks

cobalt

Sammy i finally went to ebay and bought a matching set of early cutlass 3 grove pulleys off of a car that way i know the went together im sure any early olds that had ac and it was 3 grove would of worked...then i bought a ac water pump from napa auto(and it is 6 inches tall from the block) and it all lined up..thats where i am right now as im setting the engine in the 56 olds right now