Hi all!

In the German Jaguar forum I have stumbled over an interesting information regarding “dry starting” of engines after extended periods of not being used. This in order to allow for oil pressure to build up properly and allow oil to be distributed in the engine before the engine actually fires up.

Here an interesting web article in English on how this officially works in Aston Martins: https://aston1936.com/2018/12/14/how...on-martin-db9/

According to the information on the German forum, this works also in our XKs, i.e. fully depressing the throttle and the brake pedal when starting will result in cranking of the engine but not firing up.

Anybody here has tried this and can confirm?

Also, what do you think, is it really considered helpful for the engine if dry started as described above?

To me in theory it does sound as if it would help an engine that hasn’t been used for some time. In particular it could also in theory be helpful for the chains and tensioners in the 5.0l XK, which in some models may be a weak spot.
Any opinions to this?

br
ter

 

A similar technique (flooring the throttle pedal only) was a regular quick way of resolving "bore wash" in the 4.0 litre Jaguar V8's. It prevents the fuel pump(s) operating. I haven't read mentions of it in regards to the 4.2 or 5.0 litre engines either as a procedure or a requirement.

Graham

 

While doing this may help slightly in the decrease of bearing and surface wear in an engine, I don't think that you'd ever find it makes any real statistical difference. My reasoning is multifactorial. First, even cranking the engine is subjecting the bearing and surfaces to accelerated wear until there's better oil pressure, so you're wearing on a known fragile electrical system to try to fractionally decrease wear on a more robust oiling system. Second, there have been millions (if not billions) of engines that have never had anything like this done to them, yet have gone millions of miles without issues. There are numerous vehicles that have been driven a million miles and are still on the original engine. They get started without any regard to oil pressure. Certainly they do not typically sit for extended periods, so the oil retention may be better than if one sits for several weeks/months; but they've still been started every time without residual oil pressure without hurting their engine longevity.
I would do this on an engine that's been apart to ensure that every oil passage does have oil, if at all possible. Years ago, the distributer shaft driven oil pumps were spun with the distributer out just for this reason, building oil pressure before starting the engine.

 

Positively sesquipedalian!

 

I hope that works on the 4.2, I would like to get the oil pressure up before firing up. :-) Mine is of the road but I think I'll try it next year. :-)

 

off the road ? I'm gathering as a result of weather conditions ?

 

Yes!

 

I tried it tonight on my '10 5 litre XKR and it does indeed work.

 

In the good old days (70 years ago!) there was an add on system called RedX that injected upper cylinder lube into manifold at start up. They claimed no cyl.wear for 50K miles!
Now days, I use a shot of Marvel Mystery Oil in the gas tank; not sure if it helps because I suspect it's nothing but automatic tranny fluid!
The reason Diesels last so long is because the fuel has lube in it, unlike gasoline which washes the cylinders clean.

Interesting topic, we need a Chevron guy to chime in...........................about additives etc.

Adrian, founder member JDC of NWA.

 

I can see someone trying it out on the 4.2?

And if it doesn't work, you've just started a cold engine on WOT !!!

Maybe test it out on a warm engine first LOL

 

Yes that works on the 4.2.....interesting. Press both pedals simultaneously while pressing the start button, starter runs until you release the gas and it instantly starts.