Engine pre-heaters

[guilleracing]

Here is what I have discovered with 12V heaters.

A 12V 200 watt heater takes about 30 mins to warm oil from 10 degrees to 50 degrees. This draws about 8 amps. In practical terms this takes the chill off and allows the oil to reach the engine in a slightly warmer than ambient temperature. The down side is the cooling effect of the engine block etc.

On the oil comment.
I have in the past used the Motul product V300. This was in a 2008 GSXR 1000 bike engine in an ADR Sport 2. The oil does get round the engine and warms up quickly. I did note that when it was over 100 degrees there was very little oil pressure on tick over. (5 PSI) However when the engine was over 3000 rpm, 90 PSI on the gauge.

Good oil in my humble opinion, the engine ran many miles without issue and was still perfect when I sold the car.

Greg.

[tristancliffe]

"........Dry sump systems are much worse because there is seldom a relief valve on the scavenge circuit. Slipping clutches are sometimes employed to mitigate this....."

I had hoped to keep clear of this... however

(a) i'm not sure i follow the quote above as surely the scavenge circuit consists of one bit sucking (ooooooh what fun) and another bit just squirting (aaaarrrrgh) the oil through largish pipework into the tank. Can't really see how under any circumstances there could be a significant build up of pressure in a scavenge circuit.....hence no need for relief valve..and i'd be interested in the examples of the slipping clutches you talk of 'cos i've never encountered any.

(b) Also, the issue of appropriate oils in production derived engines perhaps also needs to take into consideration the tastes of hydraulic tappets which can be fussy about what they are fed & perhaps might pump up if they find it too indigestible.

a) Lots of engines have burst oil filters and coolers on cold start ups when either an oil with too great a viscosity is used, or the ambient temperature is too low. The scavenge pump is still trying to pump (nearly as effectively as the pressure pump, but usually with less pump volume), and the thin bits (filters/radiator cores) can't always cope. The DFV has a clutch on the oil pump drive shaft. I'm sure there are hundreds of others. It's rather more severe than 'just squirting' although it may be you just wanted the fun of using innuendos on the internet!

b) Another part of the endless compromise...

Greg - the 12V heater sounds like it does the job wanted of it! I may have to knock something up at some point. Low oil pressure on a hot idle isn't a problem, as long as the oil is flowing, and as long as it picks up with revs.

[samier]

Very good article.

Martin mentions about cold start, thicker oils being harsh during start up. In our colder climate, surely a 0w or a 5w oil would be better than say a 10w or a 15w oil?

Regarding the hot weight, ie 30, 40, 50 something like a 40 should offer adequate protection at 100 degrees? I know modern engines usually run a 30 weight such as Duratecs etc, I am guessing this is due to narrower bearing anf ring tollerances?

Our climate isn't considered cold, especially during the racing season.

Modern oils retain their ability to lubricate and generate hydrodynamic films well into the 130° range.

Thinner oils are used to promote economy - this would obviously also promote power if that's what you're after (and in racing, it is), but at the expense of lubrication. Then modern cars are given silly service intervals that aren't actually good for them... it's a wonder that they last as long as they do.

And do try not to use the term weight with oils. Sure, they all weigh something (mass under the influence of gravity), but the term weight when discussing viscosity is a horrid Americanism made popular by stupid people.

In your view what do you think is the optimum grade?

[samier]

edited...

[samier]

Here is what I have discovered with 12V heaters.

A 12V 200 watt heater takes about 30 mins to warm oil from 10 degrees to 50 degrees. This draws about 8 amps. In practical terms this takes the chill off and allows the oil to reach the engine in a slightly warmer than ambient temperature. The down side is the cooling effect of the engine block etc.

On the oil comment.
I have in the past used the Motul product V300. This was in a 2008 GSXR 1000 bike engine in an ADR Sport 2. The oil does get round the engine and warms up quickly. I did note that when it was over 100 degrees there was very little oil pressure on tick over. (5 PSI) However when the engine was over 3000 rpm, 90 PSI on the gauge.

Good oil in my humble opinion, the engine ran many miles without issue and was still perfect when I sold the car.

Greg.

What grade of of did you use?

How about adding a kettle element with a plug socket on the outside as suggested by Tom? I am sure it would heat the oil up in no time.



Should drop into the oil tank?



Or something like this can be perm fitted.

How about chilling the fuel at the same time

http://cgi.ebay.co.uk/12-VOLT-WATER-HEA ... 0296624112

[tristancliffe]

There isn't an optimum grade. It's all about satisfying your own compromises. How much power? How long between rebuilds? What risk of failure? We used to run a 5W40 in the Reynard and the early days of the Dallara. We now run a 10W60. The power loss is fairly negligible. We don't have hydraulic tappets or variable valve timing (often controlled hydraulically).

F1 cools the fuel for various reasons not important to Mono. At the end of a race, their fuel is at about 80 degrees!!!!!!

And the grade of oil will have pretty much no effect on the rate of heating (electrically) as the Specific Heat is pretty much the same regardless...

[Russ]

a) Lots of engines have burst oil filters and coolers on cold start ups when either an oil with too great a viscosity is used, or the ambient temperature is too low. The scavenge pump is still trying to pump (nearly as effectively as the pressure pump, but usually with less pump volume), and the thin bits (filters/radiator cores) can't always cope. The DFV has a clutch on the oil pump drive shaft. I'm sure there are hundreds of others. It's rather more severe than 'just squirting'

But the filter and cooler are on the pressure side of the system, they have nothing to do with the scavenge.
The scavange side definately gets an easier life!

I suspect that the DFV has a clutch in the system for shock / vibration / resonance reasons, aren't the ancillaries of a DFV all gear driven?

[guilleracing]

Continuing on the thread of warming the engine......

I have tried running the engine up to temperature without any form of external heater.

I have a ff2000 legal DAMICO built pinto engine in a FF2000 Van Diemen. The engine builder recommends a Millers 20/60 oil for the engine. This is not available locally and I have very few choices of oil available. I have used a Mobil 10/40 instead.

With an ambient air temperature of 5 degrees c, I ran the car for twenty minutes. The engine speed was 1200 rpm. The car has twin alloy water radiators and no thermostat. There is no oil cooler. There was no wind to affect the result and once there was a steady idle, I refitted the engine cover to keep the heat in.

After twenty minutes the engine temperature was 39 degrees c. The oil temperature was slightly lower at 38 degrees c. These were recorded with a digital thermometer.

I have read that you get the best general protection from oil about 80 degrees c.

I stopped running the engine in deference to my neighbours after twenty minutes but this does illustrate the amount of time involved in getting temperature into and engine from cold.

Whilst I appreciate that road car based engines will not suffer unduely from being started from cold, I do think there is some value in getting some heat in first. I have bought one of the 12 volt water heaters from the seller on ebay. My only caution about having it fitted full time to an oil tank would be that It appears to be slightly delicate and probably wouldnt like temperatures above 100c or the vibrations likely to be encountered when racing. It does however heat water very effectively.

Greg.