Re: [DML] New door struts - anyone interested?

Martin,

I’m no expert either but I was told by this manufacturer that higher pressure struts will never last as long as the low pressure ones. It does make sense to me.

You’re right saying that when oil surrounds the seal it will help keep the nitrogen in. That is why I recommended storing the struts removed, in vertical position with the piston/rod pointing down. Or at least leaving the doors open.

I’ve sent a list of questions to the manufacturer so I’ll let the experts answer those. We’ll see what they say.

Tom

From: Martin Gutkowski

Sent: Monday, April 14, 2014 3:05 PM

To: dmcnews@xxxxxxxxxxxxxxx

Subject: Re: [DML] New door struts - anyone interested?

Hi Tom, all other things being equal, the higher the pressure, the higher the leak rate, but you're suggesting that it's a given fact that higher force strut won't last as long as a lower force strut. I think that's an over-simplification with different seals, different tolerances, and all manner of changes being made depending on the strut in question. I'm no expert though.

Setting that aside for a second, the density and viscosity of the lubricating oil is many many times that of nitrogen and the leak rate will be reduced by a similar proportion if the oil surrounds the seal.

Martin

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From: "Tom" <dmctom@xxxxxxxxx>

Sender: dmcnews@xxxxxxxxxxxxxxx

Date: Mon, 14 Apr 2014 13:17:53 +0200

To: <dmcnews@xxxxxxxxxxxxxxx>

ReplyTo: dmcnews@xxxxxxxxxxxxxxx

Subject: Re: [DML] New door struts - anyone interested?

Martin,

You’re absolutely right. If you are to store your car and not drive it for a long time and you want your door struts to last as long as possible I would recommend removing them and storing them upright (piston/rod down) or at least leaving the door open. When you close the door and collapse the strut the internal pressure raises even more making it leak even faster.

The horizontal position of the strut is one reason why they don’t last very long but the major factor here is the internal pressure. At around 180 BAR or over 2600 PSI the nitrogen is trying really hard to get out. Most gas struts (hood, bonnet, hatch, etc.) use about 10% of that pressure and that is why they last a lot longer.

I would say that the internal pressure is actually 90% of the problem with the horizontal position being the remaining 10%.

Greetings from Poland!
Tom Niemczewski
Vin 6149 plus 2418, 3633, 5030, 16473, 17086
Google earth: 52°25'17.66"N, 21° 1'58.40"E
www.deloreana.com

From: Martin Gutkowski

Sent: Sunday, April 13, 2014 11:50 PM

To: dmcnews@xxxxxxxxxxxxxxx

Subject: Re: [DML] New door struts - anyone interested?

Whatever you do, store them with the rods pointing down so the oil pools on the seal. If you check the use of gas struts on any other car, you'll see that this is true in the position in which they live for the majority of time (and should inform the fit of bonnet and louver struts too!).

The fact that door struts sit flat when the doors are closed is the single reason why delorean door struts don't last very long.

Martin

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