The V8 Owners Forum -

Hi, all! Is there anyone here who runs on 4.6 with 14CUX hotwire installed in RRC with standard cooling system? I've swapped my 4.2 with 4.6 and since that I've got operating temp a little bit higher than it was before. In the same outside conditions it runs about 95 C degrees with brand new standard radiator installed. Aslo I tried 74C termostat but no changes. I'm not sure is it normal or not and what kind of upgrades should I tried to get it cooler. Any thoughts would be appreciated.

By definition, a 4.6 will produce more heat than the 4.2, so maybe you need to look at a bigger capacity radiator. If there is a core available with more rows or a purpose made one if it comes to that.
I assume your pump is in good order?

In my experience, RV8s do tend to run hotter than the thermostat says if idling on a hot day or in slow moving traffic. The gauge on my SD1 has 100C as the mid way point, so not unreasonable that it should read that on occasion. When cruising with plenty airflow through the rad, it reads about the thermostat temp, 88C. If you did want it cooler at very slow speeds, you'd need to fit a big electric fan.

How are you reading these temps? did you change the fuel map with the upgrade it may be just running leaner if the answer is no

I'm reading the temp by Rovergauge and my 14CUX is managed by Tornado chip

I replaced the 3.5 in my 101 with a 4.6 and used the thermostat out of the 3.5 and the 4.6 ran at the same temp measured on the dash as the 3.5.

I get slightly more consistent readings from the CTS on MegasSquirt than from the dash gauge with sensor beside the thermostat.

I fitted an Engine Guardian that monitors the temp of the actual engine block and you can set alarms for overheating. These are cheap,readily available on ebay and easy to fit and wire up. Replaced the mechanical fan with twin Ford V8 thermos the speed of which is ramped up and down to maintain a set running temperature by using a Delta Current controller. This has a dial on the dash, you turn it to select what temp you want the engine to run at and the DC controller does the rest resulting in a very even running temp and no sudden on/off of the fans that happens with more conventional systems. A lot of muscle car owners fit them in the US. I have the same set up on my 4.6 SD1 and Disco.

If you read my posts over many months finishing a few months ago, I summarise ...

My car has a small but deep (75mm core) rad - see my avitar - and was overheating. Ignoring that problem now totally fixed, my water temp runs at a steady 75 (74 thermostat) on open A roads and up to 85 on a blast. In sitting traffic will go to 97 before fan cools it down to 87 when fan stops. Therefore I would expect you to get similar readings. (yes, 75 is probably too cold so I will change thermostat.)

As said above, you need accurate temp reading as gauges are usually (way) out.