M30 engine: 5 mm ball for timing chain tensioner

[Dash01]

There is a spring and 5 mm ball that support the piston which adjusts the timing chain in the M30 engine.

Is this ball a steel ball bearing?

Or, is it plastic?

Should it fit through the hole at the narrow end of the spring?

[Dash01]

Well, when I took the works apart, saw no ball whatever. Later, found a green plastic ~5.5 mm ball on the ground under the car. ???

Looked on RealOEM parts drawings, and they show the part as a 5 mm ball that goes between the tapered spring and the piston, for $0.28 each.

The little green ball I found just barely slips through the tapered end of the chain tensioner spring. I dunno WTF the plan is here, or if the little green ball is even from the car, or what. I hope some smart person can tell us.

Is the purpose of the 5 mm ball to act as a check valve? What does it do?

[genphreak]

There is a spring and 5 mm ball that support the piston which adjusts the timing chain in the M30 engine.

Is this part #26 a steel balhttp://www.realoem.com/bmw/diagrams/c/f/4.pngl bearing?

Or, is it plastic?

Should it fit through the hole at the narrow end of the spring?This is a very good question. When I took mine out it was missing. It didn't coem in the gasket kit. Do you know it was 5mm? I can't work out what it does, but I guess it dampens the action of the tensioner. I've been meaning to get back in there and replace it, but like you had NFI what spec ball it is.

Someone will know! Thanks for bringing this up :)

[genphreak]

Well, when I took the works apart, saw no ball whatever. Later, found a green plastic ~5.5 mm ball on the ground under the car. ???

Looked on RealOEM parts drawings, and they show the part as a 5 mm ball that goes between the tapered spring and the piston, for $0.28 each.

The little green ball I found just barely slips through the tapered end of the chain tensioner spring. I dunno WTF the plan is here, or if the little green ball is even from the car, or what. I hope some smart person can tell us.

Is the purpose of the 5 mm ball to act as a check valve? What does it do?Yes it dampens the action of the tensioner piston by controlling smoothing the oil flow in and out of the piston. I was careful with mine, but a green plastic ball in there? Nothing was to be found.

Hmmm I'd like to know! I wonder if I will have to replace my tensioner guide again. :) Nick

[genphreak]

Yes it dampens the action of the tensioner piston by controlling smoothing the oil flow in and out of the piston. I was careful with mine, but a green plastic ball in there? Nothing was to be found.

Hmmm I'd like to know! I wonder if I will have to replace my tensioner guide again. :) Nick... bump!

Does anyone know if the M30 chain tensioner check ball tends to go AWOL?

I noted that a replacement does not come in an engine gasket kit...

Does anyone know if they a 5mm stainless steel ball bearing or are they plastic? ie what to replace it with?