Changing oil in dampers
 

Hello,

Does anybody change oil in dampers / shocks / struts ?

Changing to different oil ?

Friend of mine, he drill hole at bottom of stock dampers and fill some engine oil and close hole with bolt.. The dampers after that was very stiff and have good times at track..

It can be done on stock fc dampers ?

Are stock fc dampers just with oil or have gas too?

I was thinking to do that mode on stock dampers and put stiffer springs ( like 6 or 8 kg/mm springs )

I know there are aftermarket dampers, cheap etc.. But I am curious on this mode..

Thanks..

Changing the oil won't be enough to restore you shocks back to "new" condition. Also, motor oil shouldn't be used in shocks. There is specific shock oil that needs to be used, it can handle the foaming and energy that the shock produces.

Shocks are disposables, not worth agonizing over. If they need replacing, what you replace them with depends on several things. Do you track the car, DD, auto cross?


http://www.mobiloil.com/USA-English/...hock.aspx?pg=1

I have used different oils in struts before but they were on a FIAT and the struts were designed without an insert. When you unthreaded the top the shaft and valve came right out. I used motorcycle fork oil to change the feel. The problem with a worn damper isn't the oil, its the seals and sometimes the valve stack is screwed up from a hard hit.

Your idea is possible but I wouldn't advise it.

Thanks for replays..

I will change oil rings inside and put oil for shocks and try that.. will see..

Must be some difference before and after..

Does some have more info about fc shock itself..?

What year is your FC? You could just buy new inserts from Koni or Bilstein
http://www.negative-camber.org/crisp...c/fcpart10.htm


I'd just buy these and call it a day if you're going for stock
: http://www.rx7.com/store/rx7/tokicononadjustable.html

Most stock/stock replacement shocks aren't just oil and aren't rebuildable... they're oil and pressurized gas. You drill them, and you're likely to hurt yourself when they burst, and good luck getting gas back in them.

with no gas the oil will cavitate very easily, turning the shocks to shit.
bilsteins and koni yellows are both excellent shocks and dont cost too much.

So nobody really know are stock FC shocks gas filled.. ? If they are, I dont have tools to fill nitrogen back in, so nothing from this mode..

I am not cheap bastard, I just want try this mode.. I know that stock fc shock are not best shocks in world for peformance.

Does some have more pictures of shock inserts? When remove a stock "insert" are oil inside and gas..? or just oil..? Can someone inform more on this inserts..


Like i say before, friend did this and have great results..

they are filled in the factory where they make the shocks.. they arent servicable. just replace them

I believe it is oil, because when I disassembled one of my old shocks, there wasn't any pressure when I cut the top off.

Do you have pictures?

What did you do with yours shocks..

More info, please.. Thank you...:icon_tup:

Usually the best way to see if shocks/struts are gas charged they tend to want to stay extended all the way. If you have a strut that is known to be gas charged originally and it doesn't push the shaft out then the seal between the gas chamber and the oil chamber is shot.

You will have a hard time finding all the seals you will need to put things back together if the shock is OEM and that company doesn't offer any servicable dampers. I would suggest finding some used Bilsteins that fit your car. They are all servicable even when they say they aren't. It just takes some special tricks and tools mixed with the right knowledge. Bilstein offers entire kits to make your own shim stacks. They have linear and digressive sets for their racing shocks but the valve design is all the same on the street dampers, they just have two sizes of valves (38mm and 46mm IIRC)

The next thing you need to do things right is access to a shock dyno. They aren't cheap, I know because I have one.

Thank you for nice replay..

The shock dyno is very nice tool to have.. What dyno do you have ? Any worth from diy shock dayno?

Best thing is to check inside-out stock shock and go from there..

What kind of oil do you recommend for shocks?

Thanks,

Penske makes a 2.5W and 5W. Amsoil has a 10W.

I started out with a simple air powered dyno from here: http://shockdyno.com/

and just recently bought the stuff to make an electric one from here: http://sportdevices.com/

I'll be selling the old one soon if you are in the market.

I stumbled upon this: http://farnorthracing.com/autocross_secrets6.html

Thank j9fd3s.

Thanks for replays...

What oil is good starting point for stiffer springs..? autocross , track use..


2 lonetlan - thanks for link, good reading..

As you read through all the info on that site you'll understand that changing the oil viscosity won't always get you to the place you want to be. It may be fine for the low shaft speed part of the scale but then screw up your high speed or just the opposite. Or, your rebound will be good and your compression will be no where near what you want.

Short answer now: Higher number to stiffen the shock.

All understand now... :icon_tup:

Thanks,

Easiest test for a gas charged shock, is push down on the shaft (with spring removed) and it should rebound - unless totally shagged. Twin tube oil filled ones normally have a step in the body that's absent in a monotube. If the unit is old enough, you might also come across a De Carbon patent acknowledgment for a gas one.

You can release the pressure in the shock by drilling at the very bottom, it's a comparatively small volume, although, you're looking at about 10 bar....safety glasses advised to avoid swarf!