1971 front susp guestion. Spares & what oil?

[martensson]

Hi all.

I have run in to a few "bumps" during our restoration of the car & here is one of the problem. Pulled from a 911T 1971

These had a blue tape wrapped around them & when taking them apart, this is what I pulled out



can anyone say anything about these? Possible to buy spare parts? Any idea what oil to fill up with?

Is it possible to just refit these struts with after market shocks, just drop down & tighten?

My thought is to keep these since they seem fully ok & to experiment with different types of viscosity on the oil & see the results...

Thanks!

[RSTarga]

Uh, you need new shocks!

[martensson]

The plan is to start off with these & make any updates after the first season. So if you donīt mind I would appreciate a little bit more info than just that.

I have not found any excess wear or any leaks. So besides the fact that they are "old" & maybe not as high tech as modern shocks I see no reason why I need new ones?? At least not right away...

[Trackrash]

Yes, new shock inserts will just drop in and you will be good to go.

Only problem is, from your picture it is hard to tell which strut you have, therefore which insert would work.

[RSTarga]

Unless I am mistaken he not only removed the insert, he also took the shock apart.
It looks like those are Boge struts in which case he can use koni or boge inserts.
Can you see any numbers on your struts? Is it a t,e or s?

[martensson]

ok, nice! thanks so far

Regarding any kind of numbers, yes there is a 901 xxxxxx number & another one BUT I do not have this number close by, sorry.

I know that struts were marked with different tape colors (color markings) to indicate make. Mine had a blue marking...

The car model is a T.

The shocks are fully apart, top part (for fluid to run back & forth), piston & cylinder. Very simple construction & easy to put back together again...

Bikers often experiment with different type of oil in their shocks depending on what characteristics they want & I got the hint to do so on these as well. I would thou, like to know what kind of oil was used originally, just to have something to start with. This seems to be the hardest part thou....

[Flieger]

The original Konis for 911S were like that- the piston ran in the strut itself. You can rebuild those but the easier route is to buy the off the shelf damper insert and have it revalved for your car weight, springs, ride, etc. by someone like Clint at Rebel Racing. The oil weight is not usually used to tune the damping, rather the valving and blow-off valves.

The guys that re-valve do Bilsteins usually, but Bilstein also makes inserts for Boge struts (which you appear to have).

If you use the oil weight, you are pretty much on your own. I do not know of anyone here who has done that.

[martensson]

Thanks for the info. I will have a look around & see what I can find for future use

I got hold of some info regarding the grade of oil used in other car setups & bikes & I have some Porsche friends in town I can compare with as well. So by conducting some tests using their original shocks, same type, I will be able to match the grade to similar values.

Iīm not known for following others. I like trying ideas I have & if they fail....well, then I can always choose the easier way by following the crowd By this I do not say that it is wrong to follow others & the paths that have been tried out & do work....but it is not quite the same thing NOT to have tried

THanks again for he info

[piggdekk]

Marten, on motorbikes, typically harleys, people do play with oil viscosity, and it works. However, the hydraulics inside those suspension is very different and simpler (for example a needle entering a small tube with holes, the more the needle enters, the less oil will flow).
Porsche, even in old cars (or at least in the shocks i've pulled apart), used a more modern technology with shims and small passages. In this case You don't get much by changing the oil weight. The only thing You get with a higher viscosity oil is a harsh drive.
Since you're referring to bikes, You'll see that most suspension oils don't even state their wieght, but only the applications: forks, or shocks. Usually shock oil has a weight close to 2, and fork oil around 4-6. So as you see there is very little room to play with oil for this type of technology.
This has already been tested a lot....
luca

[Trackrash]

Someone just listed in the 911 used parts forum a pair of Konis inserts that would work for you at a very reasonable price.

I had also tried to re-oil some struts. The real problem is, if it leaked out once it will leak out again.