Well the more I check the more information comes up. Beru had the patent rights to this twin coil regulating system under patent for many years. Other companies were aware of it but beru refused to licence the technology to others.

If they used it in our common beru glow plugs I think not. It almost looks like they may have just sat on the technology until the patent rights expired. It is a wonder mercedes tollerated it though unless they had a vested interest in the companies. They had to have known.

This I suspect as the bosh and beru glow plugs seemed from what I have heard are just about equal during that period. Also why increase internal costs if the end users are unaware?

Wellman glow plugs in the twin coil setup are available in our old series setup .9 volt plugs as well. Since you would have to replace them in a complete set I see no advantage at all in using them. You could not mix with bosh series glow plugs for example.

The twelve volt bosh conversion plugs because of the improvement in efficiency would probably cancel out any gain the series wellmans had. There is no way at present I can be sure though.

This is the 12volt pencil plug in a larger base to fit the older engines. This issue and availability is not clear at all when it comes to the older Wellman type plugs. Unfortunatly they reffered to them as the .9volt plugs without mentioning anything else. So wellman apparently does not manufacture the conversions unfortunatly.

Anyways this is somewhat premature until we get some valid tests and feedback coming back. Wellman states there product lasts longer in service but talk is cheap.

I was suprised by the actual amount of glow plug manufacturing firms existing once I checked. Also a lot of names I suspect the majority of site users like myself have not heard of.

I will now try to lever a test set of mercedes plugs out of wellman. They sell us mercedes owners on site none that I am aware of. Maybe just at a comprimise price..Let you know.

I very much doubt my viewpoint will change. If any glow plug can be proven to have a real advantage at the same price. Plus we can establish it is reliable in service most site members I believe would buy them. Saving your electrical system wear and tear. If able to start a colder engine than the current glow plugs we use will do it easily.

I had been starting to actually wonder why some indirect diesel engines where starting when our mercedes engines will not. Thought it was a lower compression issue. Now not as sure. We might be able to do better.

Time will tell. It is thirty years since our glow plugs where issued. I think ours are still the same from beru and bosh. Thirty years and same plugs? Glow plugs have evolved several times in that time frame for other manufacturers.