Panhard Engine Musings

The Panhard engine is intrinsically well designed, but the two things that could be improved with hindsight after having ceased production for nearly 50 years, is oil filtration & oil cooling. These two factors are fundamental in making a Panhard engine last longer, and the reason why they were vulnerable to failures in their production years.

Filtration is required because roller bearings have much less tolerance to particulates & contamination than the more widely used shell bearings, and fortunately tor Panhard owners there are various alternatives out there. Mr Guny and myself have developed suction variants, and later Mr Lauffenburger developed his pressure fed system. The latter is a comprehensive upgrade, and includes a new oil pump, the option to fit oil coolers and various other sensors.

It really doesn’t matter which one is used, as long as you employ some type of filtration. Historically, Panhard did fit a positive pressure filter off the RJH banjo feeds of the cylinders, but it was a partial system, because once the RJH system got up to pressure the main oil flow was through the camshaft gallery bypassing this arrangement.

Why did Mr Guny & myself both go down the suction route? I’d like to think we both recognised the oil flow of the Panhard engine is so low (compared to modern engines), that the pressure drop across a paper filter is negligible, and not a problem for the oil pump. This can be quite hard for people to understand, especially when surrounded by modern engines and all the technobabble that they are exposed to, but the simple fact is the Panhard engine is a low flow device, really elegantly designed, and it’s only when you start to use the engine harder in modern traffic conditions that the system gets stretched, and mainly because the oil gets too hot.

Again, there is a school of thought which says you should use OEM oils in your car even 50 years later, well that is nonsense. Do you think oil technology has stood still in that time, so don’t expect your engine to suffer the old stuff either. In todays driving conditions, on a summers day going down the motorway, you will exceed the oil temperature limits of straight mineral oil frequently, however around town stuck in traffic with little airflow only occasionally.

What does this tell you? Simply, the engine cannot dissipate the heat in the oil. So how to do something about this? Heat dissipated is proportional to the flow rate, the surface area available, and also the quantity, because a small kettle boils faster than a big one. The complicated way (and not dissing anyone) is fit an oil cooler (more surface area), and a bigger oil pump and tackle the flow side of the equation, but the really smart option is to increase the oil capacity.

How you do this is down to the individual, one resourceful chap aka yves31 submitted these photos on the forumpanhard.free.fr. If you look closely, he has removed a thin portion off the base of his existing engine, taken another engine, and removed the sump with a higher cut line, and TIG welded the two together. All of this adds 21mm to the depth, and gives 1.3 litres of extra capacity. It is an excellent idea, but probably not easily achieved by typical owners, needs a donor crankcase, some skilful welding and requires a total stripdown of the engine. The last point is only valid if you have an engine in good condition.



The next way, is to take a leaf out of the competition engines of the 1950’s and fit a double sump or double carter. The beauty of this system is it is easily fitted, has more surface area, yet still adds about 1.1 litres of extra oil, and can be purchased for around €140, without the oil pump adapters. This is the system that I fitted to Ron Tyrrell’s car, along with a modified oil filter kit, that placed the filter inside the crankcase, and not externally, like my other versions, which meant the extra depth of the sump (44mm) was about the same as the screw on oil filter conversion.


In tests, the oil temperature of his car dropped significantly around town, rarely went above 80ºC in drives around the rural roads. In motorway work this summer on the way to the Citröen Rally at Harrogate where 130ºC had been seen in the sump previously, the temperature never went above 115ºC, and once the ignition timing and fuelling had been dialled in, the car was travelling faster and only recording 105ºC in the sump. Another observation was, as the car was being used the oil temperature rose more slowly than before, and also recovered, whereas I seem to remember in a fateful journey to Worcester one year in the same car (without the sump addition) as the day got warmer, the temperatures kept getting hotter, until a valve seat let go.

This reinforces the best way to cool the engine is with more oil capacity, however fitting an oil cooler has other benefits in that it can be used as a heating matrix for demisting & added warmth without the oily whiffs off the air fed heating system at present.

One of the problems some Panhard owners have with filtration is the ground clearance issue, which is really is a non issue on Dyna X, PL17 & 24 models, because the exhausts hang down further either side of the sump plate, where typically an aftermarket filter is located. If adding a double sump or anything else it would be best to fit an internal filter, with the flatter sump plate, and although filter changes are not as quick, if ground clearance is an issue to the owner, an internal filter would be the best option.

Over the next few months I will be making a revised internal filter kit for the double sump variant, based on the Ron Tyrrell prototype, as Brian’s engine needs one and so does a friend in Belgium, but I am just rejigging the CAD files, as this latest double sump, has a smaller hole on the underside than previously. Ideally, I’d like to make one new sump plate fit both versions, but even though it would compromise the ground clearance by only 13mm, it’s probably better to make two different versions to negate criticism.

Panhard Oil Light Piston

I have been asked to make an oil light piston for a friend in Belgium, and as promised here it is. This is only used when you modify the crankcase oil circuits, and although it is of similar dimensions to the OEM part, there is a built in oil pressure relief valve that only dumps oil through the side drilling to the timing gears when the camshaft gallery has a minimum of 30 psi or 2 bar pressure.

The diameter of the side drilling can be increased, but at the moment, there appears to be sufficient lubrication to the timing gears.


The circlip is not fitted in the following pic, and I haven’t rounded the corners at the tip. The evidence so far is it isn’t needed, but you can do this if you want.