New door struts - black and stainless - Anyone interested?

[Tomcio]

Tom, I didn't mention in my other posts, but I am in for a pair of your authentic German made Stabilus door struts.

Chris, you did mention it a while ago. Your name is on my pre-order list at number 18 and I will contact you as soon as the struts are ready.

All very interesting, perhaps I have fake ones then! I will have to go and get some part numbers from them, If I can remove the stickers!

Chris, it would be great if you could get the part numbers off of them. I can call Stabilus and confirm it since they have ALL the part numbers they ever produced. With the part number there should be a production date. When you look at the cylinder you should see all those warnings and under that should be a part number consisting of 6 digits, a force of 1200N and production date. In case of my old struts from one of my cars it looks like this:
867691 1200N 204/98
Part #, force, production date 1998

You may not want the struts specified the same as original if they now have "soft lift" operation. I would think a little more force would make them last longer since the soft lift prevents bounce.

It's also interesting John now has soft lift for all the struts. I don't see the need of soft lift on the others but again specifying more force would make them last longer.

Having stronger door struts might create more problems and will not really make them last longer. This is coming from the experts at Stabilus and other manufacturers I'm in touch with. Here's what I know:

More force will put more load on the strut mounts. The lower mount which is attached to the fiberglass body is very weak and actually it is too weak for the original force. The bracket bends, deforms and eventually comes off as the fiberglass around cracks. I will post pictures later on today... You should inspect your lower bracket to make sure it's not bending. Open the door and look at the lower door strut mount. It should be pointing straight towards the front of the car. If you see that it's starting to point outward the bracket is bent. I will be offering stainless steel reinforced brackets with the struts to fix this issue and prevent a disaster.

More force would not really extend the useful life of the struts by much. Higher pressure will cause higher leak rates and the struts will only last a little longer.

More force will mean more effort to close the door and more stress on the door structure and rear hinges.

The strut size used for the DeLorean doors (10mm piston rod, 22mm cylinder) has an absolute maximum force of 1200N with recommended maximum at 1100N. No sensible manufacturer will go above the 1200N max limit.

Original force of 1200N with properly adjusted torsion bar should provide between 10 and 15 LBS (about 5 - 7 kg) of force holding the door fully open. If you go higher this force will increase, if you go lower the door might sag in cold weather.

The 1200N is measured with the strut fully extended. As you push it in (collapse it) the force increases at a predetermined progression rate. At fully collapsed the force is higher. This progression is dependent on damping and the more damping you need the higher the max force will be. So, a nice soft lift is usually accomplished by adding more damping (it's where the struts slows down at the end of travel) and more friction on extension. The problem with that is more damping causes more progression and in the end the max force with the doors closed might be too much for the fiberglass body and the lower mount. If you raise the initial force you have to add more damping to prevent strong bounce and in turn this will increase the collapsed force. If you make a 1400N strut the resulting progression might cause the collapsed force to increase to well over 2000N and that will result in a loud crack and a snap. Adding more friction to slow down the extension causes more wear on the seals and the piston rod shortening the useful life of the strut. The higher the force the more friction is needed to slow it down.

As you can see making gas struts is not as simple as it might seem. I learned all this just recently as I started working on them. It's seems like a simple tube with gas inside but in reality it is a very complex piece of engineering. Making a good strut is a matter of finding the best mix of force, speed, damping, progression and not to forget critical dimensions.

[Tomcio]

Same here, mine could do with a replacement.

Martin,
Your name is on my list as well. You're at number 22.

Thanks.

[dustybarn]

Chris, it would be great if you could get the part numbers off of them. I can call Stabilus and confirm it since they have ALL the part numbers they ever produced. With the part number there should be a production date. When you look at the cylinder you should see all those warnings and under that should be a part number consisting of 6 digits, a force of 1200N and production date. In case of my old struts from one of my cars it looks like this:
867691 1200N 204/98
Part #, force, production date 1998

Hmm. the struts on my car are marked Stabilus too, but they might be quite old. I'll have to decode markings.

Please put me down for a set of Stabilus struts too.

[Tomcio]

Hmm. the struts on my car are marked Stabilus too, but they might be quite old. I'll have to decode markings.

Please put me down for a set of Stabilus struts too.

One of my cars came with struts from John. I'm going to take a closer look at them tonight.

OK, I've added your name to my pre-order list. Thanks.

[NightFlyer]

It's possible that my struts are three colored, but just oily and oxidized, causing them to appear all black. I'm definitely going to have to check them out (didn't get to look at them today, unfortunately).

Regardless, I haven't seen anything do a better job or last as long as struts with the Stabilus brand name on them, regardless of whether they were produced in Germany or Mexico. I do have (confirmed) the stock/OEM louver Stabilus struts, and they're good as new still (though I did have to replace the stock/OEM hood struts with Grady's struts from the early 2000s - which are also still working as new to this day).

The door struts currently on my car are the all black Mexican Stabilus.

Both work well and kept the doors open while cruising Woodward Blvd (speeds up to 35mph) this past weekend:

*Note that you can see the 4smd's of Tom's awesome LED door lights if you look closely enough at the photo

[refugeefromcalif]

Tom, I'm still interested in a Stainless pair. (Grained if possible).
The New ones that DMCF installed middle of last year, (When I had the Wings-A-Loft installed), are barely fully opening the doors in Hot weather.

George

[SIMid]

Hi Tom, not sure if I am still on your list?

Original Stabilus struts made in Germany (all black) - $120 for a set of two

[Tomcio]

The door struts currently on my car are the all black Mexican Stabilus.
Both work well and kept the doors open while cruising Woodward Blvd (speeds up to 35mph) this past weekend:

Those are the part number 867691. They are really good and even the ones I have are still strong enough to open the door fully. They don't have the strength to keep the door firmly up but they still work. It's amazing considering that the ones I have are 16 years old! Stabilus is the way to go...

*Note that you can see the 4smd's of Tom's awesome LED door lights if you look closely enough at the photo

Nice
It's great to see something that I've made here on my desk, living in a DeLorean half a world away and bringing joy to the owner. Really cool!

Tom, I'm still interested in a Stainless pair. (Grained if possible).
The New ones that DMCF installed middle of last year, (When I had the Wings-A-Loft installed), are barely fully opening the doors in Hot weather.

George, you're at number 5 and I will contact you directly as soon as the struts are ready. It's going to be a while before the stainless ones are available though, so I will email everyone when the first batch comes in. I will let you decide if you'd like to get regular ones or if you'd like to wait for the stainless ones.

I'm surprised that the struts have trouble fully opening the doors in hot water after just one year of use. Must have been a really high quality product...

Hi Tom, not sure if I am still on your list?

Yes, you're at number 3 for a set of all black struts.

I don't delete any names from the list. I just keep adding new names

I'm sorry that it's taking this long to get those struts to you. I'm doing my best but I'd rather see a delay than offer something I'm not 100% satisfied with. I promise you that once you receive the struts you'll see that it was worth the wait.

[Tomcio]

One of my cars came with struts from John. I'm going to take a closer look at them tonight.

As promised I have some pictures and interesting facts for you...

One of my cars in my collection came with Harvey door struts. The struts have no markings on them except for a sticker that looks like this:
2014-08-20 19.18.50.jpg
There is no warning label, no part number, no manufacturer, no manufacturing date.

This strut looks OK until you compare it to the original Stabilus strut. Here's that comparison (click for full size):
2014-08-21 14.00.40.jpg
OEM Stabilus strut from 1981 comes in at 350 grams.
Later all black Stabilus from 1998 comes in at 350 grams.
Harvey strut weighs less than 300 grams.
As you can see in the picture the tube on the Stabilus is shorter but the total length is exactly the same. This means that the usable stroke is also shorter. Measurements show that Stabilus has 10 mm more stroke! The Harvey strut has exactly 133 mm while the distance between mounting points on the DeLorean is 135 mm. You might say that it's just 2 mm difference which isn't much... well, a millimeter is not a kilometer and it should be fine. Well... NO!

Here's a result on the lower mount, which apparently someone tried fixing:
2014-08-20 19.08.28.jpg

Here's a result on the upper mount which again someone has "fixed":
2014-08-20 19.09.48.jpg
It's going to take a lot of work to fix it right...

Here's a view of the lower mounting stud on another car. This one used different struts.
As you can see the OEM bracket is not strong enough to support the strut. If we decided to use even stronger struts the results would be disastrous. If you're lower mount looks like this you should seriously consider getting a reinforcing bracket.
2014-08-20 19.12.21.jpg
I will offer larger and thicker reinforced brackets along with the new door struts. They are currently in the works and should be available by the time the new door struts come in.

Just got a word from one of my manufacturers that the final test set is ready. It all goes well the production should start soon.

[hollywood2311]

Hmm. the struts on my car are marked Stabilus too, but they might be quite old. I'll have to decode markings.

Please put me down for a set of Stabilus struts too.

I changed the door struts not that long ago. Maybe 2008? I believe I got them from DPNW. The louver struts I never did replace.