[george kujanski]

Ted.....my opinion is on a 8 bolt pump, the divider plate, the one with the large hole should "divide" the cavity into two spaces, half of the flow going to each bank. The other plate (the"internal housing", from the manual) is the one where the clearance from the int. housing to the vanes should be minimum.

George

[TedRamAirII]

Originally Posted by george kujanski

Ted.....my opinion is on a 8 bolt pump, the divider plate, the one with the large hole should "divide" the cavity into two spaces, half of the flow going to each bank. The other plate (the"internal housing", from the manual) is the one where the clearance from the int. housing to the vanes should be minimum.

George

Do you think it would be better to just raise the impeller to minimize the gap. How far is "too far"? I made a puller to raise the impeller and I think that may be the best way to go so that the plate matches the contour of the blades. Does the gap at the back of the impeller matter much? If this doesnt work out I would purchase another impeller from the Flying Dutchman. Thanks for all the help. ; )

[silverbullet07]

I just picked this one up. The impeller looks pretty good and is about even with the shaft.

[TedRamAirII]

Originally Posted by silverbullet07

I just picked this one up. The impeller looks pretty good and is about even with the shaft.

I guess thats a reman, from the looks of the pitted housing, but what brand? that does look like a good impeller. I think the one I have pis of is a old AC Delco reman I bought years ago. I may buy one just to get a good looking impeller and swap it into a good housing. ; )

[silverbullet07]

Not sure the brand. Here is the front.

[george kujanski]

The way i see it, there are 2 variables in the design of the 8 bolt pump, the position of the impeller on the shaft and the impeller vane height. if the impeller vane height is OEM, then if the position on the shaft is correct to minimize the clearance of the vane to the internal housing, it will be at OEM specs.

In my opinion, the pressure at the impeller and behind it should be the same, regardless of the distance behind it (distance between the pump housing and the back of the impeller). More critical is the clearance from the vane edges to the internal housing, if that's too large, there will be recirculation around the impeller, reducing the suction from the radiator, and robbing flow form the cylinder banks.

Hence, position on the shaft to minimize clearance to the internal housing is the way to go, in my opinion.

George

[TedRamAirII]

Originally Posted by george kujanski

The way i see it, there are 2 variables in the design of the 8 bolt pump, the position of the impeller on the shaft and the impeller vane height. if the impeller vane height is OEM, then if the position on the shaft is correct to minimize the clearance of the vane to the internal housing, it will be at OEM specs.

In my opinion, the pressure at the impeller and behind it should be the same, regardless of the distance behind it (distance between the pump housing and the back of the impeller). More critical is the clearance from the vane edges to the internal housing, if that's too large, there will be recirculation around the impeller, reducing the suction from the radiator, and robbing flow form the cylinder banks.

Hence, position on the shaft to minimize clearance to the internal housing is the way to go, in my opinion.

George

Thanks George. I have raised the impeller to about .025" clearance to the plate. I put the gasket on, then the 2 plates and made the measurement. The gasket really needs to be added into the measurement because that backs it out quite a bit (.035). So now I just need to clean up the front on the engine, paint it up and see what happens. ; )

[TedRamAirII]

As I am mocking up the fit of the plates. On the right side where the plate matches up to the hole in the timing cover going into the block. The end of the "hole" is not nice and square. At the plate and the end of the hole there is somewhat of a gap there. I think I need to minimize that gap. I have not seen any post here adressing that. I took a section of small vaccuum hose, split it with a razor blade and attched it to the edge of the plate hole and made it so it seals that gap. I think if I didnt do that, there would be no point to all the progress we have made so far, minimizing the plate/impeller clearances. What say you? ; )

[george kujanski]

Sounds like a nice idea.

On the later 11 bolt pump, Pontiac did away with the divider plate and instead used a closing plate that mated with two tubes in the timing cover to direct the flow. The mating surface of the tubes have a rubber seal to seal to the closing plate nicely. A better design, in my view.

george

[TedRamAirII]

Yes, I believe the 11 bolt pump is a superior design, maybe thats why they changed it. I will know more next week after I get this Bird running. Thanks for all of your help, Ted. ; )

[67Twistytee]

Guys

I'm having the now notorious heat creep on my '67 GTO. I drained the system and removed the pump and it's a stamped impeller. I ordered a Cardone from Rockauto and it showed up with the same stamped impeller. Napa says they can get me one from their warehouse (their in-house reman brand) and the stock photo looks like it's original cast impeller. Has anyone here used the Napa unit successfully? Did it come cast as original? Also looks like Autozone has a Valucraft reman that I can order. Same stock photo but I guess you never know what you're going to get.

[silverbullet07]

Also you can find several on ebay with the cast impeller if you need one.

[Old Goat 67]

Originally Posted by 67Twistytee

Guys

I'm having the now notorious heat creep on my '67 GTO. I drained the system and removed the pump and it's a stamped impeller. I ordered a Cardone from Rockauto and it showed up with the same stamped impeller. Napa says they can get me one from their warehouse (their in-house reman brand) and the stock photo looks like it's original cast impeller. Has anyone here used the Napa unit successfully? Did it come cast as original? Also looks like Autozone has a Valucraft reman that I can order. Same stock photo but I guess you never know what you're going to get.

Try to get one as close as this. NOS 67 water pump.

http://forums.maxperformanceinc.com/...d.php?t=752911

If not, ship it to this guy.
http://www.fdrbp.com/

This is what it looks like when you get it back. $90

[67Twistytee]

Thanks! Any secret to where you got the OEM unit? Does the Dutchman repair these with any core? I unfortunately no longer have the original core with cast impeller and the one on it was replaced in 2001.

[Hooch]

I got one from NAPA on Tuesday for $38.00 and it has the cast impeller same as the original one did. I had to bend the plate closer but it looks ok to me. You can also get one from summit that has more flow your call.
http://m.summitracing.com/parts/mil-16281

[Old Goat 67]

Originally Posted by 67Twistytee

Thanks! Any secret to where you got the OEM unit? Does the Dutchman repair these with any core? I unfortunately no longer have the original core with cast impeller and the one on it was replaced in 2001.

Call the Dutchman, you'll be pleasantly surprised! He'll use your core most likely, but he is well versed on the Pontiac pumps, knows what the trick is to put a CORRECT impeller on it AND make sure the plates fit properly!
You'll be way better off waiting a week or so and you won't have to waste gas looking.

Oh, I have been searching for an NOS one in the box for about 12 years.

Charles

[67Twistytee]

Thanks Charles. I was hoping to get it done before a road trip I had planned next weekend. I'll see what the Napa one looks like in the am and if it's the same story I'll mail the one I have to the Dutchman.

On a related topic, I know these had a 190 T stat originally. The one in now is a 180 but needs replaced. Any benefit (or harm) going to a 160? I've read through many of the prior posts and didn't see a consensus. The summers are nasty and humid here and I wouldn't mind it opening earlier if it helps move water through the block.

[Old Goat 67]

160° too cool, 180° best overall. 195° was factory for good heater output.

Charles

[67Twistytee]

Thanks again. It looks like they used sealer along with the paper gaskets last time. Is this necessary or am I good with just the gasket?

[Old Goat 67]

Well, I always use a THIN coating of sealer to fill scratches.