[pontiacphil]

Help! Still fighting my overheating problem. I've got about a zillion posts on this problem at the "cooling and overheating" site. Jerry, at Rodney Red said my water pump pulley should be smaller than the crank pulley, at the most, the same size. Just pulled the radiator and getting ready to install the Cardone water pump (tweaked) and the new Flex-A-Lite #1818 Flex fan. I measured the pulleys and my crank pulley is 7.25 inch and my water pump pulley is 8 inch. My 67' is a 400, no air, PS, PB, Auto. What size water pump pulley should I be using and where can I locate one? Would any of the auto part stores have what I need? Need help ASAP. If anyone can provide the info. I need I would sincerely appreciate it. Thanx!

[johnta1]

Are you still using the original timing cover/water pump?

You could get the entire setup off of a junkyard 67 engine.

The best bet would be to convert to a later cover and pump with the corresponding pulleys.

OPH has a few posts on doing this. He might respond to this also.

[Tom Vaught]

While the PY Cooling forum is excellent, I would recommend that you purchase the Pontiac cooling book that is out there.

I have it! It is excellent. Trouble is I looked for it last night and can't find it (:>(

Maybe someone else can give you a better title of the book. Something like 'How to cool your Pontiac'

It goes into great detail on all of the issues with pulley ratios, pump designs, thermostats, radiators, etc.

Tom V.

[pontiacphil]

I'm trying to get my motor back together today. Is there a smaller water pump pulley than the 8 inch I currently have? Where could I purchase such a pulley if one exists? Did Pontiac make different sized pulleys or they all the same size? Are there any aftermarket pulleys available that would help my overheating problem? Thanx.

[6D6GOAT]

i posted this in the heating/cooling forum... post numbers 5 and 7 specifically http://forums.maxperformanceinc.com/...d.php?t=482440

[6D6GOAT]

http://cgi.ebay.com/ebaymotors/PONTI...QQcmdZViewItem

[johnta1]

I would say you still have the 8 bolt water pump.

480509 is a pulley that is 7-7/16" diameter, but the grooves probably won't line up.
There are some billet aluminum pulleys ($$$) but probably won't line up either with the early pum/timing cover.

[gtoformula]

pontiacphil,

I'm sort of on the same path as you are. I've got a '68 engine in my 1970 GTO that has the older style 8-bolt water pump. The current w/p pulley is 8" in diameter ... not sure what the crank pulley diameters is, but I'd bet that it is smaller than 8". I picked up a 7 1/8" pulley off eBay that has the same 2" spacing as the 8" pulley. I haven't yet installed it, but I'm hoping for some improvement. I went to our annual summer picnic yesterday here in the Dallas area. The outside temp was 103 degrees and I was on the freeway at 2PM. It would run just short of 200 degrees on a 70MPH roll using a 180 degree thermostat, but would head a bit north of 205 degrees at short traffic lights. I've done the water pump divider adjustment and am using a stock fan with a Hayden clutch fan. The fan sits in the stock shroud at the correct position.
I'm hoping that this pulley will keep the engine a bit cooler.
The part number is 9786909 ("X 1" listed just after the part number). I had another pulley that was under 7" in diameter, but that one came off the newer style w/p and had about 2 1/2" depth.

[6D6GOAT]

they probably wont, he will need to put a 1/2 inch spacer inbetween the pulley and pump but i the grooves look to be the same distance apart [V'V] [V'V]

[GTOLou]

I am pretty sure that 8" is the size for the NON-AC water pump pulley. Pontiac also made a 7 1/4" pulley for AC applications. The GTO restoration book has part numbers on all pulleys.

You don't need any spacers for this pulley and would prolly be a better choice than the T/A pulley to start with.

These come up on ebay pretty frequent.

[6D6GOAT]

Originally Posted by GTOLou

I am pretty sure that 8" is the size for the NON-AC water pump pulley. Pontiac also made a 7 1/4" pulley for AC applications. The GTO restoration book has part numbers on all pulleys.

You don't need any spacers for this pulley and would prolly be a better choice than the T/A pulley to start with.

if the 7 1/4 help it run cool a little bit better then the 6 1/2 should help just that much more. i say go with the T/A smaller diameter, bite the bullet and address the 1/2 inch spacer problem and be done with it.

PS Phil, i didnt catch what fan you are running.

[Big Injun]

How old is the engine? If it is a new rebuild, was it baked or acid dipped to get ALL of the rust and corrosion out?

It does not matter what pulleys/pump you have it you have "poor circulation" within the block. Everyone spends too much time with the pulleys/pump when in fact on an old engine the block is full of corrosion/rust and does not pass enough water.

[pontiacphil]

Total rebuild with machine shop work done by a very reputable builder. Block was hot tanked, dipped, magnafluxed and all new parts were the upper end of quality. In other words, very little expense was spared with this rebuild. I posted to another thread on this site about my attempt to see if I had corrected my overheating problem yesterday. However, couldn't let it run long enough because I had an underhood fire when the battery/starter cables caught on fire. Looks like the new Ram Air HO exhaust manifolds are too close to the wires and I now have to rewire/reroute my starter wires. Ain't life interesting!

[Region Warrior]

That is the correct pulley size(factory) for 67's w/o a/c.
You could try to find an early a/c pulley system, but 68 & up would be easier.
Will need 68-79 tmg cover.

Apr. size's are;

w/o ac:
crk 7-7/16 ", w/p 8"

w ac:
crk 8", w/p 6-3/8"

There were some different sizes 69-72, but all close to these measurements.

The larger crank plly w/smaller w/p plly will spin the water pump faster.
Must change as a set. Cant mix and match because they over lap(hit).

I have used small crank/large water pump plly's since 79 without problems.
Like them better because the belts dont slip as much as the large crk/small w/p plly setup.

I would get a 19" flex or a 19" factory clutch fan 1st.
Make sure it's close to 50/50 in/out of shrould.

[Region Warrior]

Oh, and will have to use later style balancer, which is better anyway.
Parts stores wont be any help on pulleys.

Look for 73-79 big cars in wrecking yards.
Grab the whole setup. Brackets, pulleys, bolts, tmg cover...everything.
If you cant find any, i have a 68 and later setup.