Oil needed for Bilstein front struts?

[GH85Carrera]

I am still searching the site but I have a quick question. I am ready to install the Bilstein shock inserts into my old struts. The Boge inserts had a lot of funny smelling oil in there. Do the Bilstein inserts need any oil? If so what type and how much?

I want to get them finished today but I don’t want to install them without oil if it is needed.

[Steve@Rennsport]

Originally Posted by GH85Carrera

I am still searching the site but I have a quick question. I am ready to install the Bilstein shock inserts into my old struts. The Boge inserts had a lot of funny smelling oil in there. Do the Bilstein inserts need any oil? If so what type and how much?

I want to get them finished today but I don’t want to install them without oil if it is needed.

Glen,

What you are smelling is old shock oil.

As you can see, Bilstein front cartridges are self-contained, however the strut housing needs some oil or antifreeze in there for heat transfer to keep the shocks running cooler.

[cary]

I was hoping Steve would chime in. I remember asking him the same question many years ago. I couldn't remember how much. But I remember it was for cooling.

[GH85Carrera]

The searches I found listed the reason for the oil was cooling. No one ever listed how much and just what type of oil to use. I will be asking Chuck and Elephant racing. I figure if anyone knows he will.

[Rot 911]

Plain old 30 weight or whatever you have laying around works just fine. As stated it is for heat transfer so weight doesn't matter. Doesn't take much, about an ounce. Put some in and then slide in the insert. If it overflows just wipe it up.

[robmog]

i read here you can also use antifreeze, i think that what was in my konis

[JP911]

Wouldn't the oil just leak out where the roll pin holds the shock in place? Bilstein and Boge struts hold the insert differently.

[Steve@Rennsport]

Originally Posted by JP911

Wouldn't the oil just leak out where the roll pin holds the shock in place? Bilstein and Boge struts hold the insert differently.

Nossir,....

Given his description, he has Boge struts from which he extracted the hydraulics.

Bilstein inserts are self-contained cartridges and are mounted & retained in the same fashion as the Boge internals so unless there is a hole in the strut housing, nothing will leak out.

[911st]

So the question still remains, is it suggested to add oil between the new Bilstein insert and the strut to aid heat transfer?

[Flieger]

I have heard both "yes" and "no, not required". I do not think much harm can come either way. Just decide whether you want less extra unsprung weight or cooler dampers. Whether you need the cooling depends on how hot your dampers get: stiffness, piston velocity, stroke frequency...

[Steve@Rennsport]

Originally Posted by 911st

So the question still remains, is it suggested to add oil between the new Bilstein insert and the strut to aid heat transfer?

Yes, just as I wrote above,....

[Flieger]

Do original early 911S Koni struts with standard adjustable hydraulic Koni inserts have/need/benefit from the oil?

[Steve@Rennsport]

Whenever you find a gap between the strut housing and a replacement insert, it behooves one to put in some oil or antifreeze to facilitate heat transfer. Koni's benefit just as much as Boge or Bilstein.

Most folks have no idea how hot shocks can get during normal operation and how much they fade when the oil gets hot. We see this on the shock dyno and thats why I know its worth the efforts.

[GH85Carrera]

OK thanks for the answer. I don't have any 30 weight oil in my garage so I guess I will use straight anti-freeze, no water added. I also love the irony of using anti-freeze in a 1985 Carrrera.

[911st]

Excellent into!