95 E300D my new tensioner modification - PeachParts Mercedes-Benz Forum

Texasgeezer · #1 01-14-2018, 11:16 PM

My old tensioner assembly was a little worn & bouncing. After researching what might cause wear, I decided to try adding a zert and mixing MoS2 powder with a Krytox grease. I used a small grease tool left over from my tractor tools that allowed a small quantity of grease to be loaded and gently tapped into the tensioner pivot arm. I quit tapping when it felt like all the air inside had been replaced with grease. The shock, pulley wheel, and arm are new. Stabilizer shock, INA arm and pulley. Old pivot bolt measured minimal wear so I reused it. Also reused the thin seal ring from the back of the old arm.

Pictures show products used to make the grease. I mixed about 10% powder to the Krytox. They are both top rated lubricants.

Also a picture to show that the tensioner bolt appears to go in far enough to contact a rubber seal with a hole that exposes the timing chain. I put a little silicon grease on that seal in an attempt to make it last longer.

I know it may not prove out, but I'll feel better knowing I can add a high quality lubricant when I want to.

Diseasel300 · #2 01-15-2018, 10:26 AM

You just kind of do your own thing don't you...

The 606 design was far superior to the 603 design with ball bearings. The 603 tensioners routinely fail around 100K miles, the 606 tensioners you rarely hear about failing except on extremely high mileage engines.

Lubrication is not your issue with wear, failure of the tensioning system (spring, belt, load, shock absorber) are your enemies. If your engine is functioning properly, you shouldn't even see or feel the tensioner move. Literally it should be completely still. Grease is a bad idea, the zerk is even worse because it encourages you to add more.

Might be a good time to laugh a bit, wipe the grease off (before it gets hot and blocks up the bearing pores) and wipe some oil in there like it was designed for and then forget about it for the next 150-200K miles like everyone else. Sometimes improvements are not improvements.

Diseasel300 · #3 01-15-2018, 10:26 AM

Forgot to mention:

Deja-Vu: http://www.peachparts.com/shopforum/diesel-discussion/390279-how-extend-life-pulley-tensioner-arm.html

Zulfiqar · #4 01-15-2018, 12:36 PM

Quote:

Originally Posted by Diseasel300

You just kind of do your own thing don't you...

The 606 design was far superior to the 603 design with ball bearings. The 603 tensioners routinely fail around 100K miles, the 606 tensioners you rarely hear about failing except on extremely high mileage engines.

Lubrication is not your issue with wear, failure of the tensioning system (spring, belt, load, shock absorber) are your enemies. If your engine is functioning properly, you shouldn't even see or feel the tensioner move. Literally it should be completely still. Grease is a bad idea, the zerk is even worse because it encourages you to add more.

Might be a good time to laugh a bit, wipe the grease off (before it gets hot and blocks up the bearing pores) and wipe some oil in there like it was designed for and then forget about it for the next 150-200K miles like everyone else. Sometimes improvements are not improvements.

Right on, The oiled bearing will be killed with grease.

Texasgeezer · #5 01-15-2018, 02:45 PM

It is not an oiled bearing, the thin bronze/brass type bushings have a solid lubricant built in. From the appearance it appears to be MoS2. The Krytox grease is inert and proven to be one of the best lubricants to prevent galling.
Stuff is so pricey in quantity that the main user is probably the government.

I did hours of research and contacted manufacturers of specialty lubricants.

Galling is the primary wear for the tensioner pivot bolt.

I agree that a bouncing belt will definitely wear the assembly much faster. Luckily with replacing the water pump and installing a one way pulley on the alternator the belt has no detectable bounce while the engine is running.

I do mess up now and then but I think I'm one of the few that got over 300,000 miles on a V8 Range Rover by doing most of my own maintenance. Still running good when I sold it but had some serious corrosion on the inside of the front cover. Had to have the aluminum particles from corrosion removed from the radiator cores from time to time. Would have used G-05 if I had known about it and if it was available in the early 90's.

I thought Mercedes parts were expensive until I had to buy a few Range Rover parts. The dealer wanted over $300 for a seat adjuster switch, I knew it looked like a Mercedes part and sure nuff Mercedes had one similar for $80, worked good after a bit of plastic trimming.

I'm definitely a goof ball from time to time. I was driving the Range Rover from Lincoln NB to Dallas one late summer day and noticed a farmer harvesting acorn squash and filling up huge palleted boxes. I love acorn squash and turned around, talked to the farmer, bought a big tote box full, enough to fill up the passenger floor boards and the back area 1/2 way up on the glass. Had over 1/2 of it sold at farmers markets and veg stands on the way south.

Time will tell but the belt is so smooth now I think the assembly could almost be welded in place.

KrustyKustom · #6 01-15-2018, 04:15 PM

Not sure about the grease but I replaced my tensioner and bolt at 292k last year. The original was definitely galled and grooved out. The car has had 3 of the "shocks" that keep the belt from bouncing in its 23 years and in my opinon of watching these shocks that seems like the part to watch. Soon as the shock starts bouncing the tensioner pivot then moves a lot. Not to mention all the noise the shock makes banging.

Kudos for the craftsmanship, I enjoying tinkering as well. I open the hood on my E300 still just to look things over even thought its the most reliable car you can imagine!

vstech · #7 01-15-2018, 10:34 PM

Quote:

Originally Posted by Texasgeezer

My old tensioner assembly was a little worn & bouncing. After researching what might cause wear, I decided to try adding a zert and mixing MoS2 powder with a Krylon grease. I used a small grease tool left over from my tractor tools that allowed a small quantity of grease to be loaded and gently tapped into the tensioner pivot arm. I quit tapping when it felt like all the air inside had been replaced with grease. The shock, pulley wheel, and arm are new. Stabilizer shock, INA arm and pulley. Old pivot bolt measured minimal wear so I reused it. Also reused the thin seal ring from the back of the old arm.

Pictures show products used to make the grease. I mixed about 10% powder to the Krylon. They are both top rated lubricants.

Also a picture to show that the tensioner bolt appears to go in far enough to contact a rubber seal with a hole that exposes the timing chain. I put a little silicon grease on that seal in an attempt to make it last longer.

I know it may not prove out, but I'll feel better knowing I can add a high quality lubricant when I want to.

Well, time will tell...

Be sure to remove the belt every 20,000 miles or so, and post up your feeling on condition of the pivot...

andrewjtx · #8 01-16-2018, 01:18 AM

Switching out the alternator pulley for a clutched unit completely eliminated all bounce in my tensioner. As well as the annoying buzz that emanated from it.

tjts1 · #9 01-16-2018, 04:12 AM

Quote:

Originally Posted by andrewjtx

Switching out the alternator pulley for a clutched unit completely eliminated all bounce in my tensioner. As well as the annoying buzz that emanated from it.

THIS^^^

Texasgeezer · #10 01-16-2018, 03:18 PM

I think the one way pulley is one of the best mod's for the older serpentine belt vehicles. It would be great if someone would research and find a way to install the newer "OAD" type pulleys. From the little time I've spent looking at it, I couldn't find one that would 'bolt up'. Thinking there might be one that could be shimmed to fit.

Found this on one of pulley manufacturer's site:

OADs typically have one-way clutching capability, but also provide rotational isolation through an appropriate spring mechanism. The advantage here is that this spring arrangement allows small rotational displacements within the OAD to isolate the direct connection to the alternator. OADs are becoming the design of choice for many newer applications. OADs have both a one-way function and the spring which allows the OAD to isolate and dampen the drive from the alternator upon deceleration.

andrewjtx · #11 01-16-2018, 03:31 PM

From other threads, you should already have the INA pulley, right? Did you ever install it?

Took me all of 15 minutes. Pull the alternator, pop the nut on the old steel pulley with a impact wrench, then use a rental tool for alternator pulley (I used O'Reilly) installation and reinstall the alternator.

You don't need a decoupling pulley. I think that's overkill.

Diseasel300 · #12 01-16-2018, 03:50 PM

Unless you're running some enormous alternator, the decoupling pulley won't get you anything more than the typical OAP does. The 6 cylinders run smoothly enough that the OAP is more than sufficient to smooth out the belt flutter.