Bilstein B4s shorter than original oem. Anyone had issues?

[red rocket]

As part of my front suspension refresh i purchased OEM springs direct from OPC and Bilstein B4 dampers from Design 911. I checked the part no on Bilstein's website in advance. Today i tried to fit spring and top mount which proved impossible with my spring compressor. Fortunately local indy, Marque 21, were willing to help. Initially they thought the damper looked a bit short so they checked both spring and damper part no's and confirmed correct. Nevertheless it took 2 guys, using very heavy duty kit plus additonal compressors and brute force pushing down on the set up, half an hour to get the nut on.

On return home i checked the second new damper against the one i removed from the car and it is indeed quite a bit shorter. I am led to believe this means the front ride height will be lowered and, unless rear is changed, likely create handling. I have checked Bikstein website and confirmed part no again. 

Anyone had similar issue? 

I reckon anyone using standard compressors would find it impossible to fit oem spring on these.

 

[andygo]

I would imagine that compressing the spring to such a degree would introduce a lot of preload into the spring which would affect damping etc and therefore handling as well.

[red rocket]

8 minutes ago, andygo said:

I would imagine that compressing the spring to such a degree would introduce a lot of preload into the spring which would affect damping etc and therefore handling as well.

Thanks for that. I'll check it out with Marque 21.

[Lennym1984]

That doesn't really sound right. I have Cayman r springs and bilstein b8 dampers (shorter) on my Cayman and I could get the nuts on with just hand pressure. 

I assume that it is the piston that is shorter (not the body)? 

Edited May 20, 2021 by Lennym1984

[red rocket]

1 hour ago, Lennym1984 said:

That doesn't really sound right. I have Cayman r springs and bilstein b8 dampers (shorter) on my Cayman and I could get the nuts on with just hand pressure. 

I assume that it is the piston that is shorter (not the body)? 

Yes, it's the wider part of the piston.

About 4cms difference. Really not sure what to make of it.

[Lennym1984]

Is it possible that the damper itself is duff and that piston isn't fully extended? That looks a LOT shorter. For context, my B8s didn't look that much shorter than the stock dampers. I could tell then were when it came to fitting the springs but visually, it wasn't that obvious.

I think that there is definitely something amiss there.

[red rocket]

1 minute ago, Lennym1984 said:

Is it possible that the damper itself is duff and that piston isn't fully extended? That looks a LOT shorter. For context, my B8s didn't look that much shorter than the stock dampers. I could tell then were when it came to fitting the springs but visually, it wasn't that obvious.

I think that there is definitely something amiss there.

Thanks. They are both the same. I will discuss with my indy. May need to follow up with Bilstein and/or Design 911 wher i bought them.

[Patt]

Fitted B4's with the OEM M030 springs to Molly (986S) a few years back now.  No issues at all.

The fronts didn't require spring compressors at all.

I was of the understanding that the B4's were the same length as OEM, just a bit uprated.

[deanmr2]

I also fitted B4’S on my 986 last year with new springs from OPC and had no issues I used a cheap set of spring compressors but probably could have got the top nut on without them 

[Lennym1984]

To be honest, the piston stroke on those dampers (assuming that that is fully out) just look way too short for any car. The springs must be quite compressed even at rest. I'd definitely be on the phone to Design911.

[red rocket]

1 hour ago, Lennym1984 said:

To be honest, the piston stroke on those dampers (assuming that that is fully out) just look way too short for any car. The springs must be quite compressed even at rest. I'd definitely be on the phone to Design911.

Design911 are checking their stock. However have just checked yesterday's completed shock with the one I removed from the car this morning and they are near as damnit the same height!  So, I can only assume that the piston was not fully extended and it's freed up during the fitting yesterday. Does that seem plausible? The remaining new one is still short but I guess I could try pushing/pulling to see if piston frees up more?

[Lennym1984]

Do they return to that height if you compress them (just with your body weight)? Usually if you depress the piston, it will return to it's original, resting position.

[red rocket]

1 hour ago, Lennym1984 said:

Do they return to that height if you compress them (just with your body weight)? Usually if you depress the piston, it will return to it's original, resting position.

Yes if I push down it returns to same height.

[edc]

I think they may be faulty. The B4 is meant to be the same length as your original damper. The spring controls the damper but if the damper rod is already depressed in the spring won't do as much and you have less damping. 

[red rocket]

13 minutes ago, edc said:

I think they may be faulty. The B4 is meant to be the same length as your original damper. The spring controls the damper but if the damper rod is already depressed in the spring won't do as much and you have less damping. 

I am wondering.....Design911 haven't got back to me......surprise, surprise. I may call Bilstein for guidance.  Strange though that the first one was definitely short yet now, with spring and top mount attached, it's exactly same as the one i took off the car today. I'll discuss it with Marque 21 when i take the second one there tomorrow.

[edc]

Somewhere like Centre gravity can test them on a damper Dyno rig. 

[red rocket]

Just now, edc said:

Somewhere like Centre gravity can test them on a damper Dyno rig. 

Good thought, thanks.

[beaks]

also - if you have to compress them to make them bolt up... when the car goes into a rebound state (especially over a hump in the road etc) you may well 'lock out' the dampers and thus the car body takes the wheels with it, which will mean you're either airborne or compromised on grip...

seems to me like these 'might' be dampers that are meant to go with lowered springs... 

hope you get it all figured out mate !

[Lennym1984]

23 minutes ago, beaks said:

seems to me like these 'might' be dampers that are meant to go with lowered springs...

The b8s are painted yellow so I think that may just be faulty

[red rocket]

Just back from Marque 21 who fitted the spring and top mount to the second damper and all is good. Both new dampers are same height and same as old one. They had to use the same kit and effort as before; definitely not a DIY job. Maybe Bilstein have modded something recently. 

Just shows the benefit of having a great indy 20 minutes away! Would have been screwed without them.

Will do a final update once the car is back together and see how it handles.

[edc]

Glad you are sorted and happy. Worth mentioning that any decent garage should have the tools to build the strut.

[½cwt]

Just a thought on this, the Koni shocks I recently fitted to my 986 were shipped in a compressed position with a wire hook that you remove and discard. Do Bilstein do this using a different method but that results in a shorter shock for packing and shipping purposes that might be the cause of this issue?

[red rocket]

On 5/21/2021 at 1:25 PM, ½cwt said:

Just a thought on this, the Koni shocks I recently fitted to my 986 were shipped in a compressed position with a wire hook that you remove and discard. Do Bilstein do this using a different method but that results in a shorter shock for packing and shipping purposes that might be the cause of this issue?

No hooks or anything else to hold piston down.  Marque 21 have never come across it albeit they do more air cooled than modern cars. And none of my fellow PCGB committee members are aware of it either.

Edited June 24, 2021 by red rocket

[sa utah]

I fitted new B4 to my 987 when I got it and and no problems.   Also from Design 911.    Maybe a production problem or even incorrectly labeled parts.

 

 

[BBB]

I’ve just received my B4s for the front and they’re the correct model number according to Bilstein’s catalogue. I don’t suppose you measured the rod length did you @red rocket? I’m trying to anticipate problems before I start taking things apart.