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Discussion Starter #1
Hello Gentlemen:
I fitted the S50 chain tensioner on my S38. The engine runs much quieter on start up but there is a whine that comes on at 3000 rpm is this normal? Should I be concerned
thanks
john
 

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I don't think it has anything to do with the tensioner. I understand between the lines that this "whine" was exactly (first time start with the new tensioner) there after you changed the tensioner?
If that's the case you would suspect it has something to do with it. The only thing I know is that de pressure of the S50 is higher then the OEM. Maybe the chain slider is already worn causing an increased noise due to the increased pressure.

W
 

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Discussion Starter #4
Crash and Burn:
this is my initial thoughts exactly too much tension. This would cause premature wear or is magnifying an existing wear condition. The car has only 76km so I would like to argue against the worn chain slider. I am concerned at this point.

Fordkoppie:
I am pleased to share a common experience and have a positive result. I also like Dr Sakke's response.
Still concerned but slightly less so.

thanks
john
 

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That mirrors my experience when going for the "upgrade" - my chain starting whining - I didn't think that was right so replaced the tensioner with a new original one - noise went - I guess you pay your money and take you choice (and chance?)
 

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I decided that the increased cam chain whine was purely because the chain was now under appropriate tension, whereas it hadn't been with the very worn OEM tensioner (which permitted rattling when cold - much more worrying). It depends on the volume of the whine, but I don't think chain whine is an inappropriate noise for an old mechanical engine like these.
 

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Discussion Starter #8
Gentlemen:

I intent to replace the original diaphragm style tensioner. For me the whine is unacceptable. It is no loud but present and I don't like it.

Stija: the upgraded tensioner is supposed to bring reliability and durability. look at raymond w's write up in the e28 faq section for complete description.

Baddie: were you able to determine where the "wear" was on the s38 tensioner?

day: I am with you and will abandon the upgrade.

thanks
john
 

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So....let me get this straight. Jsh, you tried the upgrade tensioner and got the whine so now you're reverting back to a OE replacement for s38 engine? So in other words, it wasn't worth the upgrade or it isn't really an upgrade?
 

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I'm with Baddie and please read the hundreds of posts around this subject in the former years. Maybe you can record the whine and post it overhere for what it's worth.
The tension of the S50 is a little higher. This is one of the reasons to use it. The rateling noise of the chain when cold is the scary part but heee who am I:):):)
 

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Discussion Starter #11
Stija: I think it is an upgrade my cold starts are silky so that's an improvement, could be I am needing to adjust to the new sounds and just relax.
Crash and Burn: " who am I " it is an existential problem not mechanical and i am ill equipped... I will try and capture sound and post it somehow. I do read the old posts the information is priceless.
thanks for you help
john
 

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Gents,

I just thought I'd add my experiences to this thread as well. I recently rebuilt my engine and put it together with the M3 tensioner. Like member jsh's engine mine was built with brand new chain, sprockets, tensioner arms.. you name it.

I also noticed a very slight whine which came on at about 2500-3000 RPM. when i say slight, it was very slight. Only with the heater-fan off, radio off, windows up was it evident.

For the sake of experimentation, I bought an original S38 tensioner including piston, spring and diaphragm and fitted that up. The noise is completely gone.

Given the M3 tensioner is very, very simple to install and I installed it while the engine was on a stand I doubt I could have fitted it wrong.

So maybe there is a pattern here? Maybe the M3 tensioner is good upgrade for an engine with a few kms under its belt but for new engines its best to stick to OE?
 

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So maybe there is a pattern here? Maybe the M3 tensioner is good upgrade for an engine with a few kms under its belt but for new engines its best to stick to OE?
Sounds like a reasonable conclusion based on experience , Pete .

After all , the OE tensioner is certainly the correct part for an S38 engine , although it's design is definitely less contemporary .

I have fitted many S50B32 tensioners to both the M88 and S38 engines without issue .

The M88/3 in my E28 M5 has the S50B32 tensioner which was fitted at the same time as new timing chain , sprockets , guide rails etc and there has been no issue .

This is my experience and I am interested to hear of different experiences ...... It's good to talk !

D
 

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I've also noticed the whine post-install, but for me - it's a non-issue. The peace-of-mind in knowing that the tensioner is fully-functional is worth it. Plus, it sounds kinda cool. (LOL)

Once I get the mill out to do the bearings and whatnot, I may replace the tensioner with the OEM one, but that's down the road.
 

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Guys, I am sorry but i really don't understand what is going on here and your comment AtlantaDan just seems to confuse me more.

As i understand it you have just installed a different timing chain tensioner in your S38 as an upgrade to the OE one. Now you comment that once you open it up you may install the OEM tensioner again. So are you happy with this upgrade or are you not?

Additionally, can someone shortly try to explain why there is a need to upgrade to OE tensioner at all??? Is it a known problem and fails more often than not? Why?
 

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Additionally, can someone shortly try to explain why there is a need to upgrade to OE tensioner at all??? Is it a known problem and fails more often than not? Why?
It's considered an upgrade for reliability.

the OE tensioner is comprised of 6 pieces and 4 sealing rings. It has a tendency to leak after a while (due to all the joints). This is quite bad because the original tensioner relies heavily on oil pressure to create appropriate tension. Its spring is quite weak and the big diaphragm filled with oil is what keeps the tension up.

The M3 tensioner is 2 pieces only with a strong internal spring which is not reliant on oil pressure to keep tension. However it does use oil pressure once running to apply further tension similarly to the OE tensioner. The strong spring in the M3 tensioner is what alllows it to produce good tension on cold start up and why all cars with the M3 tensioner have no chain rattle on start up.

If you have a good OE tensioner which doesn't leak and the piston/running bore are not worn, there is no real benefit in getting an M3 tensioner. however, if you are replacing an old, worn, leaking one, the M3 unit makes financial sense and is far, far easier to install an stays sealed!

What we're discussing here is whether or not using the M3 tensioner creates an RPM based timing chain noise for whatever reason.
 

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Although Konfused petes explanation is correct, I would like to add the following. The internal spring of the OE tensioner is indeed weaker and the oil pressure ensures the correct tension. In addition to this you have to take into account the following:
When engine is cold the oil is cold and the pressure of the OE tensioner is higher due to the cold oil making sure the chain stays on the sprockets!! When the enigne gets hot the pressure of the tensioner decreases causes less wear on the guideband in the chaincase.
The M3 tensioner relies more on the springtension then the oil pressure during cold start (Has to because no diaphrama to hold the pressure:)). When engine is hot it could very well be that the total tension (fixed spring tension + dynamic oil pressure tension) is slightly higher with M3 tensioner then the OEM one. Hope this explains somethinh.....
I did replaced the tensioner with the M3 one at 200.000 km. Starting perfectly with no whine when hot.
 

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I am somewhat doubtful that the diaphragm actually stores oil pressure for cold start ups.
 

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I am somewhat doubtful that the diaphragm actually stores oil pressure for cold start ups.
Sorry if my explanation was a bit vague. I didn't mean the diaphragm stores oil pressure.

I believe what it's for is that while there is oil pressure in the engine it displaces the diaphragm by filling the chamber with pressurised oil. If oil pressure decreases such as at shut-down, the diaphragm reacts by relaxing and consequently displacing oil which has nowhere to go other than acting as a force on the tensioner piston.

This probably is also a factor at start up when there is a volume of cold, thick (all be it without pressure) oil in there, which resists the piston being forced back by the chain guide.

I'm not sure if this is 100% correct but looking at how it's all put together and where oil goes in the system, it's what I suspect the case to be.
 

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Sorry if my explanation was a bit vague. I didn't mean the diaphragm stores oil pressure.

I believe what it's for is that while there is oil pressure in the engine it displaces the diaphragm by filling the chamber with pressurised oil. If oil pressure decreases such as at shut-down, the diaphragm reacts by relaxing and consequently displacing oil which has nowhere to go other than acting as a force on the tensioner piston.

This probably is also a factor at start up when there is a volume of cold, thick (all be it without pressure) oil in there, which resists the piston being forced back by the chain guide.

I'm not sure if this is 100% correct but looking at how it's all put together and where oil goes in the system, it's what I suspect the case to be.
That makes sense from what I gathered from the post mortum on my old tensioner
 
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