Trident oil cooler?

There was a similar post to this on (I think the heavy twins section) where somebody enquired to the running tempersture of a Dominator. I posted that my Commando runs much hotter than my singles. After a really long ride on a single the oil tank is hardly more than a bit warm. Whereas my Commando oil tank is usually to hot to touch after a short time. The engine runs perfectly so I do not suspect that it is mixture or timing fault causing it.

So yes I think an oil cooler would be a good addition to a Commando or big twin, although I dont think I will fit one. I prefer to keep the bike looking standard(ish), and chang my oil very often.

Hi Alec,

Have a look at http://home.clara.net/captain.norton/cnn4sec23.html

He has some numbers on temperature etc.

I would be suprised if the hot oil actually caused the plastic to melt, was the pipe resting on the head ?

One thing to consider is that an engine likes to have warm oil, if it takes a long time to warm up due to the cooler in circuit this may cause more damage than ocasionally overhot oil (depending on where in the world you live of course).

Regards

Tony

I suspect I am going to sound like a Luddite but there are many 1000s of Commandos that have been running satisfactorily in much warmer parts of the world and people have not found it neccessary to fit an oil cooler, so why should we think it is needed now?

One of the problems with Tridents is that the oil does not get hot enough when the weather is mild and I used to blank off almost all the cooler in order to get the oil warm.

I would leave well alone. If the oil tank gets so hot you can't touch it then be grateful that the condensation within the engine has probably been burned off. Just make sure you use a good modern synthetic oil and all will be well (at the risk of starting another dreaded oil thread!)

David

If it has got that hot to melt that pipe, then I suggest that something else may be an underlying cause. I now run full synthetic in my commando and have done so for years. It runs a LOT cooler and the brand I use has a specifiaction exceeding Mobil 1 - the last time I checked, and it costs £20 for 4 litres! and it is available everywhere - why use monograde.

Even on our racebikes- an original 1970 Production Racer and a self-built Commando Racer- we run without oil cooler, have done so for many seasons, often in hot weather, never had a problem.

If you fit an oil cooler it does more harm than good unless you find a thermostat to cut it out whilst the oil is too cold.

When oil coolers are fitted they often seem to be mounted in front of the head. When i see that it always makes me wonder whether the disruption of air flow over the head makes the whole exercise a step backwards even before considering general oil temperatures.

Previously joe_seifert wrote:

Even on our racebikes- an original 1970 Production Racer and a self-built Commando Racer- we run without oil cooler, have done so for many seasons, often in hot weather, never had a problem.

If you fit an oil cooler it does more harm than good unless you find a thermostat to cut it out whilst the oil is too cold.

You say that your rings lost their temper. Cast iron rings will not be tempered. Sounds to me that along with the worn valve guides the whole engine was shagged out. Whilst there is a trend to fit bronze valve guides, cast iron guides have free carbon which lubricates itself to a certain extent. Was the rocker feed pipe original, from a reliable source etc? I replaced mine with nylon pipe supplied by a local hydraulic supplier. Much cheaper than replacing the whole lot. (but if you have any doubt, fit the proper item) The fitting involves dipping the tube in boiling water and slipping it over the banjos. That's 100 degrees C and the tubing didn't melt. I'd be suprised if your engine oil was over 100C

Cast iron guides aren't necessarily better than modern alloys of bronze. Coefficient of friction is a result of friction between two materials. So consideration is required to valve stem material when choosing valve guide material. As an example, a bronze/steel pairing has a lower friction coefficient than cast iron/steel and bronze also has a greater heat transference than cast iron so the valves run cooler.

This explains why manufacturers such as KibbleWhite supply DLC (diamond like carbon) coated valves which run in a modern alloy bronze guide material.

Simon.

I personally use bronze valve guides in all my Commando engines- road and track- with the original Andover Norton valves (chromed stems, Stellite tips).

Andover Norton now offer those valve guides- made for us to our spec- as an alternative to the original cast iron ones. See http://www.andover-norton.co.uk/SI%20Valve%20Train.htm