Georgia Fiero Club Forum

All Things Fiero => Tech Tips, Tech Questions => Topic started by: TopNotch on February 20, 2016, 03:41:57 pm

Title: 3.4 Water Pump (???)
Post by: TopNotch on February 20, 2016, 03:41:57 pm
The Fiero I'm fixing up for one of the grandkids is turning out to be more and more of a Hodge-podge. It has a 3.4 in it, and I finally have it running very nicely. But it overheats. So I took off the water pump, and discovered that it is the kind designed to turn counter-clockwise. Is that what Cameros had on them?
Anyhow, now I  have to replace the water pump housing in order to put on the proper pump. Any tricks to doing that? I can steal the one off the engine in my garage, so at least I have one.
Title: Re: 3.4 Water Pump (???)
Post by: Fierofool on February 20, 2016, 04:33:16 pm
Hope you clamped the timing cover down before removing the pump.  This PFF thread may be of some help to you.

http://www.fiero.nl/forum/Forum2/HTML/132534.html
Title: Re: 3.4 Water Pump (???)
Post by: TopNotch on February 20, 2016, 08:36:16 pm
Well, since the timing cover is also the pump housing, and since I'll have to remove it and replace it with one made for a clockwise pump, no, I didn't clamp it.
Title: Re: 3.4 Water Pump (???)
Post by: Fierofool on February 20, 2016, 09:52:58 pm
There are several threads right now on PFF about water pumps.  They name a very good sealer for the cover and pump gaskets.  Some recommend clamping the corner until the pump is reinstalled.
Title: Re: 3.4 Water Pump (???)
Post by: TopNotch on February 21, 2016, 09:51:03 pm
I realize I might have sounded a little snippy in my last message, and for that I apologize.
And I have moved this topic, because it's getting a bit technical.
For those of you wondering what's the difference between clockwise and counter-clockwise water pumps, here's a picture:

The one on the top is a standard Fiero V6 water pump, which turns clockwise, as seen from the pulley side.
The one on the bottom is the one removed from the car I am working on. As you can see, the water passages are completely different. Also, the top pump has a more efficient fully enclosed impeller.
It's now wonder the car overheated!
I'm going to have to replace both the pump and the pump mount/timing cover.
Title: Re: 3.4 Water Pump (???)
Post by: Fierofool on February 21, 2016, 10:29:50 pm
Didn't take it as snippy at all.  Did you find the water pump or timing cover thread I mentioned?
Title: Re: 3.4 Water Pump (???)
Post by: Fierofool on February 21, 2016, 10:50:07 pm
Permatex Aviation Form A Gasket.
Title: Re: 3.4 Water Pump (???)
Post by: Raydar on February 22, 2016, 12:16:55 am
The bottom pump looks like it has a stamped sheet metal impeller. The Fiero pump is (unfortunately) available with a similar impeller.
But, as you already stated, the cast metal impeller is the one to get.
There are also pumps with plastic impellers. Don't... Just don't. After they get hot, they tend to slip on the shaft.
Title: Re: 3.4 Water Pump (???)
Post by: GTRS Fiero on January 24, 2020, 08:50:27 pm
What is the difference between a stamped impeller and a cast impeller?

Michael
Title: Re: 3.4 Water Pump (???)
Post by: The Art Doctor on January 25, 2020, 08:33:45 am
Stamped are made from sheet metal and look like an alternator pulley's cooling fan.  Cast are just that, sand cast liquid iron, much thicker and heavier.
Title: Re: 3.4 Water Pump (???)
Post by: GTRS Fiero on January 25, 2020, 08:40:35 am
Is cast somehow better?  Surely heavier is not better.  Cast has rough edges and imperfections.
Title: Re: 3.4 Water Pump (???)
Post by: Raydar on January 25, 2020, 09:49:08 am
It has more to do with the shape of the vanes. There is only so much you can do with a stamping. A casting can be much more precise.
The stamped steel would probably work acceptably, but the cast one would likely be more efficient - i.e. would move more water with each revolution.
Or maybe not. Just a SWAG.
Title: Re: 3.4 Water Pump (???)
Post by: GTRS Fiero on January 25, 2020, 09:56:35 am
I tried testing, but both setups made a mess.  I couldn't figure out how to measure flow.  Maybe it would have worked better, if they were mounted on the block, and I had measured at the thermostat housing.
Title: Re: 3.4 Water Pump (???)
Post by: Fierofool on January 25, 2020, 10:58:54 am
Castings can have areas almost entirely surrounded by the casting.  Picture trying to stamp a vented brake rotor.
Title: Re: 3.4 Water Pump (???)
Post by: scottb on January 25, 2020, 05:15:06 pm
Actually, heavier is better, there is more kinetic energy that is transferred to the fluid being moved...... At least that was what I recall from Machinist Mates school but that was a few days ago.