914 Water pump, Yes a SBC Options

[Phoenix-MN]

I'm not sure I follow the idea of a smaller hot water line and a bigger cold water line. Most things expand with heat and contract when cold except for water that freezes that I work with. I do have three fieros and they use at least 1.250 or 1.50 id lines to get to the front radiator. I noticed the small lines on some v8 conversions but I never planned on running any smaller than 1.250 id on my suby conversion. I think I've read where mercedes or some mfg uses a electric water pump controlled by a electric thermostat. This kinda reminds me of the guys that use to badmouth the airride stuff when we discuss the electric water pump. I know mezerie probably makes a good pump but the small lines may put to much restriction on the pumps.

I'm afraid the 33% may be too much change and the pressure will get really high at 6 or 7k. I never had any success changing the pulleys on sbc pumps.

You can gets lots of ideas here and there are probably lots of people that have fought cooling problems on hot rods. I would check on what the gt40, pantera, or the others do or any other how high performance mid engine cars work on their cooling.

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I also had a Fiero for nearly 10 years and plumbed my 914 V6 just like a Fiero (ncluding using the filler neck on the intake manifold). I used 1.25" to the radiator and 1.5" return lines. I dont have many street miles on it yet but everything works well so far.

[GS Guy]

Pretty sure the "Renegade way" is to use a 1" line from engine to radiator and 1-1/4" line from radiator back to the water pump. It was stated the smaller "hot" line was to speed up flow, reducing the return time. It also creates slightly more internal pressure inside the engine, I presume to help reduce chances of hot spots in the heads and promote heat transfer. Larger return line to the pump to give a nice lower pressure steady feed back into the pump and combined with the pump housing inlet shape - minimize cavitation. They claim this works exceptionally well (with their radiator of course!) in the hot 100F+ Nevada heat with the AC on....

I can imagine the 1" line would increase pressure against the water pump, but can't imagine any pressure increases causing that kind of pump damage? I would gather full warm-up would be the order of the day before any significant revving - else too much pressure is built up - maybe blowing off hoses?

Jeff

[drive-ability]

I'm not sure of anything that's the reason for testing different ideas. I run my engine between idle and 4500 rpm 99% of the time and don't run a thermostat, the rev limiter is set at 5k so when I get off a AS* I'll install the new pulley and let you know how things turn out.. (IMG:style_emoticons/default/smash.gif)

[computers4kids]

don't run a thermostat:

When I spoke to you at Slits place (Rustmeat) a couple years ago, I remember you saying that you didn't run a theromstat. I forget...why? I have a thermostat with three air bleed holes drilled in the housing per Renegade instructions. What would be the pros and cons of running a thermostat?

[drive-ability]

don't run a thermostat:

When I spoke to you at Slits place (Rustmeat) a couple years ago, I remember you saying that you didn't run a theromstat. I forget...why? I have a thermostat with three air bleed holes drilled in the housing per Renegade instructions. What would be the pros and cons of running a thermostat?

I ran a thermostat as most V8 guys do with out any water pump bypass. Chevrolet stock setups have a water pump bypass to keep pressure from building up before the thermostat opens. About 2 years ago I revved the engine cold and my water pump impellers bent. From that point on I haven't run one. I'm sure its better for the engine to run one, its best to keep an engine at a tight coolant temp range, but for now I'm not.
I do understand about the holes drilled in the thermostat and that does work fine.

I have started working on using the holes in the heads where you can plum water to a tee to act as a bypass, just haven't done the work.. Once I do that I will run a thermostat. If its working for you by all means run one.. (IMG:style_emoticons/default/aktion035.gif)

[charliew]

The quicker a motor gets up to 200f the better it will burn off deposits and moisture in the oil and the clearances will work the way they are engineeded to work. The pistons need to expand, the oil needs to thin, and the castiron needs to stabilize to allow all the clearances to be where they willnot be on their tight side. 10w oil is very thick when it is cold.

Some people think the suby has a factory oil cooler but it's really a oil warmer.

[drive-ability]

I thought I would share to the V8 guys what I ended up doing. I used the standard pulley, shelved the smaller one for now. I ordered a pump via ebay that has a cast impeller which states it moves 30% more water.
When I got the pump I found it wouldn't fit in the Renegade housing, so I spent a few hours porting the housing to accommodate the pump. I took time to grind out only what was needed for a tight fit. There was some shaping involved to accommodate the larger oval shaped impeller. I got it to spin free without the gasket installed, then boiled and froze the unit to make sure its not going to hit during expansion or contraction. I used clay as well to guide the porting process.

I've had the pump in operation for 2 days and the overall cooling system is working much better than the 8 paddle stamped steel unit. I installed a pressure gauge because at 3k I could feel the coolant hose expand a bit. The pressures are moving between 5 and 14 psi, that works for me. There's no dough this pump moves more water and thus cools better.
I am going to set up the smaller pulley in a week or so and see how the system responds to the different ratio.

[computers4kids]

Thanks for keeping us informed on your progress. Do you have any pics of the porting, the part # for the cast pump and a source?

How did you add a pressure gauge...I would be very interested in what pressure my systems runs since it is your 'typical renegade setup.'