69 Big Block pumps and pulleys fitment

[Grahame M.]

Hi All,

G'Day from Aus. Its been a while since i last posted something on the forum but have continued to enjoy the great information shared by everyone.

I've been doing some updating in the engine bay and wanted to check a couple of things around pulley's, Water pump and Power Steering pump.

Ive attached some photo's to show the current set up with the radiator and shroud out, as this will be the last thing i refit. The water pump. pulley and idler are only test fitted for the moment just to get a feel everything will work. My questions are:

1. Whilst the bottom mounting bolt and spacer are not fitted does the new idler pulley look to be in the correct place? It seems to be very close to the power steering pump pulley, within millimetres

2. I believe the water pump pulley is the correct on for my car (July 69 L68) but when i pulled it apart it had a spacer fitted (see attached pic). is this because an aftermarket water pump was fitted? I have a refurbished correct date replacement pump i purchased form the states.

3 Does the power Steering pump look to be fitted correctly as the cap is very close to the bolt (see attached pic)?

4 I also have a correct dated replacement alternator but when i removed the aftermarket unit (Chrome) there where several washers used to space out the main mounting bolt bracket as you can see in the attached pic. Is this because the aftermarket unit is a different size? Should i remove the washers for the correct replacement part?

Sorry for all the questions but there are a few things that i'm unsure of before i refit everything. many thanks in advance for your help.

Cheers
Grahame

[Richard K.]

Re: 69 Big Block pumps and pulleys fitment

Hi Grahame,
I've recently dealt with these brackets on three different engines. To start with the group of washers has to go. The front mounted brace mounts to the water pumps driver side top bolt. It is a special bolt with a stud and nut used to secure the brace. I believe most vendors sell the correct mounting bolts. I'm sure when you install the correct size belts a lot of your clearance concerns will be addressed. I have seen the shims for water pump used before.

[Joe L.]

Re: 69 Big Block pumps and pulleys fitment

Hi All,

G'Day from Aus. Its been a while since i last posted something on the forum but have continued to enjoy the great information shared by everyone.

I've been doing some updating in the engine bay and wanted to check a couple of things around pulley's, Water pump and Power Steering pump.

Ive attached some photo's to show the current set up with the radiator and shroud out, as this will be the last thing i refit. The water pump. pulley and idler are only test fitted for the moment just to get a feel everything will work. My questions are:

1. Whilst the bottom mounting bolt and spacer are not fitted does the new idler pulley look to be in the correct place? It seems to be very close to the power steering pump pulley, within millimetres

2. I believe the water pump pulley is the correct on for my car (July 69 L68) but when i pulled it apart it had a spacer fitted (see attached pic). is this because an aftermarket water pump was fitted? I have a refurbished correct date replacement pump i purchased form the states.

3 Does the power Steering pump look to be fitted correctly as the cap is very close to the bolt (see attached pic)?

4 I also have a correct dated replacement alternator but when i removed the aftermarket unit (Chrome) there where several washers used to space out the main mounting bolt bracket as you can see in the attached pic. Is this because the aftermarket unit is a different size? Should i remove the washers for the correct replacement part?

Sorry for all the questions but there are a few things that i'm unsure of before i refit everything. many thanks in advance for your help.

Cheers
Grahame

Grahame------

1) Does this car have A/C? If not, no idler pulley was used. If so, from the little I can see, the idler pulley looks to be correctly mounted. However, an excellent diagram of the mounting can be found in the 1969 AIM. If you don't have this publication, you should obtain one from the NCRS store. Even with the cost of shipping to Australia, you need to have this reference;

2) The GM #3889372 waterpump pulley you picture is correct for your application. It was originally used with TWO GM #3740523 spacers. The pulley will run fairly close to the waterpump body;

3) The power steering pump cap does appear to be close to the bolt. However, when the proper length belt is installed I think you will find that the pump will be rotated a bit more to the driver side providing more clearance. It will still be fairly close, though.

4) I think the washers are installed because the brace is improperly mounted. Attached are photos of a correct installation. This will also be found diagrammed in the AIM.

Please attach photos of your restored alternator.

[Joe L.]

Re: 69 Big Block pumps and pulleys fitment

Hi Grahame,
I've recently dealt with these brackets on three different engines. To start with the group of washers has to go. The front mounted brace mounts to the water pumps driver side top bolt. It is a special bolt with a stud and nut used to secure the brace. I believe most vendors sell the correct mounting bolts. I'm sure when you install the correct size belts a lot of your clearance concerns will be addressed. I have seen the shims for water pump used before.

Richard------


I note that you have an aluminum waterpump installed. This is a good thing. However, I just wanted to make sure you know that no PRODUCTION Corvette big block was originally manufactured with an aluminum waterpump including L-88 or ZL-1.

[Richard K.]

Re: 69 Big Block pumps and pulleys fitment

Joe,
I just wanted to get a quick comment off to Grahame about his incorrectly mounted front support. The only car I had handy was my 1970 LS-7 to use for an example. I do use Genuine GM # 3975928 pumps.

[Grahame M.]

Re: 69 Big Block pumps and pulleys fitment

Thanks Richard, the pic is great and put it into perspective. I'll check your pic against my set up to see what i need to buy.
Cheers
Grahame

[Grahame M.]

Re: 69 Big Block pumps and pulleys fitment

Hi Joe,

Sorry, i should have said the car has Air (factory) which ads to the complexity. I have the AIM and have seen the diagram but have to admit i probably didn't look at it carefully enough. Now i have pics of the correct setup i'll have another look and set it up properly.

I'll get some images off to you on the alternator, its a date correct one from Ken Bruno Motorsports (i think that's the name). I've also got a date correct clutch and fan as well as fitting a new Dewitt's direct fit aluminium radiator.

So, do i assume the spacer behind the water pump needs to go when using the correct dated replacement? I'll attached a copy of this one as well. I'm away with work tonight but will send when i'm home tomorrow.

Cheers
Grahame

[Joe L.]

Re: 69 Big Block pumps and pulleys fitment

Hi Joe,

Sorry, i should have said the car has Air (factory) which ads to the complexity. I have the AIM and have seen the diagram but have to admit i probably didn't look at it carefully enough. Now i have pics of the correct setup i'll have another look and set it up properly.

I'll get some images off to you on the alternator, its a date correct one from Ken Bruno Motorsports (i think that's the name). I've also got a date correct clutch and fan as well as fitting a new Dewitt's direct fit aluminium radiator.

So, do i assume the spacer behind the water pump needs to go when using the correct dated replacement? I'll attached a copy of this one as well. I'm away with work tonight but will send when i'm home tomorrow.

Cheers
Grahame

Grahame------

As far as the spacers go, they are used IF the water pump hub is at the correct position on the shaft and the original GM #3889372 pulley is used. The correct hub spacing is 5-3/4" (measured from the block mating surface to the face of the hub). I believe the replacement pulley, GM #3995644, has "built-in" reinforcement and does not require the spacers.

The DeWitts Direct Fit is a great way to go. It appears very similar to the original radiator but the one for your application has a cooling capacity greater than any radiator EVER originally installed in a Corvette from 1953 to the present.

With the alternator, please include photos of the front and rear as well as the stamping.

[Grahame M.]

Re: 69 Big Block pumps and pulleys fitment

Hi Joe,

I hope these are ok.

Cheers
Grahame

[Grahame M.]

Re: 69 Big Block pumps and pulleys fitment

Hi Joe,

i forgot to ask you which page in the AIM is the best description for the correct configuration. I found one on page 425 under N40 option, its a little difficult to follow. I also have this stud that i was unsure where it went but it makes sense now that it goes in the top mount for the water pump that mounts the "s" bracket in your pic, is this correct?

Are there any other parts I'm missing that you can see? Sorry one last question, do you know the best part number for a water pump belt where no AIR is fitted?

Cheers
Grahame

[Joe L.]

Re: 69 Big Block pumps and pulleys fitment

Hi Joe,

I hope these are ok.

Cheers
Grahame

Grahame------


The alternator and waterpump appear very good and correct. The 1969 alternator rear case configuration is unique to 1969. The drive end case is unique to 1969 and all or part of 1970. I'm not so sure of the black alternator fan. Some may have been black. However, I can say, for sure, that my original 1969 alternator fan was zinc plated, not black. Photo attached of it. I KNOW it to be original since I'm the original owner of the car.

PRODUCTION big block waterpumps may or may not have had the dual bolt pattern configuration hub (8 holes). But, that's pretty much moot since the hub cannot be seen when installed on the car.

[Joe L.]

Re: 69 Big Block pumps and pulleys fitment

Hi Joe,

i forgot to ask you which page in the AIM is the best description for the correct configuration. I found one on page 425 under N40 option, its a little difficult to follow. I also have this stud that i was unsure where it went but it makes sense now that it goes in the top mount for the water pump that mounts the "s" bracket in your pic, is this correct?

Are there any other parts I'm missing that you can see? Sorry one last question, do you know the best part number for a water pump belt where no AIR is fitted?

Cheers
Grahame

Grahame-------

The configuration I was referring to involves the installation of the idler pulley. It can be found in UPC C60, sheet C2. This shows very clearly the idler pulley installation. The power steering bracketry installation is shown in UPC N40, sheet A7. As you mention, it's not very clear but it's the best there is. The stud you picture is, indeed, installed as you mention.

No 1969 Corvette was ever built without AIR. Thus, no belt for such an application was ever specified. However, for a situation in which the AIR has been removed, the 1970 configuration belt should work (1970 big block was not equipped with AIR). That belt was GM #3969948 which was later replaced by GM #3999272 which is also now GM discontinued. Both belts were 15/32 X 46-1/4".

I do not notice that any other parts are missing but I can't be 100% sure of this.

[Grahame M.]

Re: 69 Big Block pumps and pulleys fitment

Hi everyone,

i finally received my alternator bracket from paragon and went to fit it today but alas it still appears too short (please see pics), could it be that the reinforced bracket is also incorrect and too long?

I also went to install the water pump flange studs (please see pics) and the thread that is correct for the flange seems to leave very little stud length for the clutch flange to attach, is this correct. All holes (8 of them) have the same thread but do i just tighten them until they bottom out which would have some of the stud protruding on the engine facing side. clutch and fan are date correct refurbished unit.

Many thanks for your help.
Grahame

[Grahame M.]

Re: 69 Big Block pumps and pulleys fitment

Hi,

I'm pretty sure I've rectified the Alternator support strap by changing part numbers to a longer strap from Paragon, 2116.

I still have a question on the studs as they only go in one way and appear to go through the flange and poke out the other side. Is this correct and are these the correct studs (P/N 2127K-4) for my application (late 69 L68), as there doesn't appear to be much left for the clutch fan, nuts and washers to attach too?

Cheers
Grahame

[Joe L.]

Re: 69 Big Block pumps and pulleys fitment

Hi,

I'm pretty sure I've rectified the Alternator support strap by changing part numbers to a longer strap from Paragon, 2116.

I still have a question on the studs as they only go in one way and appear to go through the flange and poke out the other side. Is this correct and are these the correct studs (P/N 2127K-4) for my application (late 69 L68), as there doesn't appear to be much left for the clutch fan, nuts and washers to attach too?

Cheers
Grahame

Grahame-----

The studs appear correct to me. They do install the way you describe. What I have done is to not run the studs in until they bottom at the shank section between the threads. It's a little tricky because when you thereafter turn down the nuts it tends to also rotate the studs and turn them in deeper. However, the thread locking compound will help prevent this. You can also add additional thread locking compound and let it set up overnight. This will further prevent rotation of the studs when you turn down the nuts.

Actually, I think that GM really used an incorrect stud configuration for this application. The fine thread section should have been shorter and the coarse thread section longer. You can also obtain studs as I describe and use them instead. No one will ever know the difference.