914 with V8 Conversion Running Hot
 

Good morning,

I have a 74 914 with the v8 conversion, with Renegade Hybrids kit. The issue is on hot days, it will get to 200 or 220. It does have a pretty high performance V8, should be in the range of 330 hp from a 305. A hot cam and a bigger Edelbrock carb.

Timing has been done and had to replace the water pump. Wondering if I should have gone with a hi flow one or if I need to look at an electric water pump or a pusher water pump in the front. Radiator is 4 core aluminum. It doesn't seem to get that hot.

The radiator does have duct work. I can upload pics if that helps.

That's not THAT hot. Most GM engines operate at 210*. We have issues with my wife's SBC S-10 getting hot, but its got the 400 block that is more prone to overheating. My cure is the 6.0L with LS3 heads sitting the in the shop.

Getting a more powerful fan may be the answer for you. There are additives like "water wetter" you can add. Do you have a 160* thermostat in there already?

Can you measure radiator inlet and outlet temps with a thermocouple or at least an IR thermometer to see what effect it’s having?

Having built a 912 with a V8 there are a few things you can do.
1) burp the engine. Elevate whichever end of the car you have the coolant cap, remove the radiator cap and elevate that end of the car by 1 foot.
2) For summer driving run straight water, no antifreeze. Water has a higher specific heat capacity than antifreeze.
3) Go with a 160 F thermostat.
4) How good is your ductwork, all air needs to be pushed through the radiator.
5) Do you have an overflow tank, make sure it’s at the correct level.
6) Most conversions use a Dodge Viper water pump.
7) Don’t waste your money on an electric pump.
8) Check the belt on your water pump, is it tight?
9) Do you have a single fan or dual fan? Dual is best.

A few more things I’ll add. As Mr Merk points out, that’s not that hot and as Phelix says look at all the components with an IR thermometer. Although I am very much a fan of air cooled engines there are a few other things you can do to make a cooler running engine. Wrap your exhaust manifolds. Doing this reduces heat radiating in the engine bay. Wraping the exhaust causes the exhaust gases to flow slightly faster through the exhaust system and can give you a very small amount of hp. Another thing I experimented with was a more open exhaust system. Reducing back pressure particularly with a hotter cam can slightly reduce engine running temps. With a v8 914 as was with my 912 creating the perfect exhaust system is challenging.

Thank you everyone.

It still has the 180 F thermostat in it.

I had to replace the water pump this winter and went with the Gates 440 water pump. Wondering if I should have gone with high flow one. Any thoughts on that??

Will get stats on the temp at the thermostat, upper radiator, lower radiator with the IR thermometer this weekend.

As for the fans, they are a set of dual fans from a first gen Chrysler 300. They seem to work well at moving air. But I'm open to suggestions.

Quick question for Jess P, on your 912, how large was your front opening in front of the radiator?

I had purchased the entire kit from renegade hybrids. The kit included a Ron Davis racing radiator, with dual fan setup. As you know a 912 is essentially a 911 body and as such air had to flow in from the bottom of an RS style bumper with an opening on 26 inches by 10 inches. The radiator being angled back 45 degrees. My water pump was from a Dodge Viper. I had to install a small custom fuel tank. You have a better advantage regarding airflow with a 914 in that you can get a more adequate airflow considering the front of your car and the type of front bumper you use.

Thank you, Jess,

quick update. Installed the 160 thermostat this weekend. Seems to have corrected the problem.

Update on temps, with the IR thermometer. At the thermostat 159, going into the radiator, 142-145. Coming out of the radiator, 128-132. Testing several times after running for 20-40 min.