0W-20 and excessive nylon tensioner arm wear

[JohnBrowning]

JonnyG, Even the ones that use hydralic pressure still have a spring. This is what keeps the tensioner from retracting when the engine is shtdown. Most also have what apears to be a rack on the back and a little cam. As the tensioner extends the cam locks down on the rack. This prevents it from ever retracting. If you try to do a cam swap on this design you have to use wedge tools to prevent their movment before removeing tension from the chain. If you do not the second you remove the cam sproctes they extend out. IF this happens you must remove the timeing cover and rest them or you will never get the cam sprokets back on.

THe other design uses spring tension to partial extend the tension and shoe. This ensures that the shoe is always in contact with the chain. Then once oil presure is up it increases the force that the tension puts against the chain.

If either one of these systems fail you would get one of two things. A ton of timing chain wip and clatter or it would jump a tooth.

Some systems combine all of these features. Only a moron for an engineer would depend solely on hydralic pressure to tension the chain with no provision for cold start lose of prime situation.

I suggest you go to your local parts store and check out a timeing chain tensioner. If you want one I know can be retracted with no special tools after extending it out use a 1995 Toyota Tacoma 2.7 I4. The lever to retract it is on the back side.

If you want one with no lock use 1986 4Runner it has a spring with no lock. You can push it in and out like a shock absorber. Both of the above use hydralic pressure as their primary force to provide tension.

[ May 12, 2004, 09:56 PM: Message edited by: JohnBrowning ]

 

[JohnBrowning]

I think that the weight of oil and more inportantly the level of additives in it will have a major impact on the life of the timeing chain! Oils intended for HDEO are going to provide much better timeing chain life. Lots of ZDDP, Phos., and Boron are going to give good chain life. Antimony might also help but I have not seen any studies on it and have not tested it out myself so it is pure speculation on my part. SOme have also mentioned tungsten as an additive? The lower the weight of oil the more important these additives become!

 

[crashz]

Metroplex -

I frequent the F150 boards and some of the guys have aluminum tensioners and other have the nylon. I seem to recall that one guy had to replace his worn out nylon guides with the older aluminum guides under a "silent" recall. Evidentally the aluminum guides live much longer, however a lot of the blame was put onto the 5w-20 weight oil that is now specified.

 

[metroplex]

tpi: Interesting... I would have liked to see pics of those tensioners!

MolaKule: The tensioners themself are pressurized hydraulically by the engine oil.
In order to completely drain them, you gotta slap them in a vice and slowly compress it.
I've let my engine sit for about a week and the tensioners were still full of oil.

I agree in the respect that an oil that lubricates everything QUICKLY is required... but if you shoot the thinnest oil around just to coat everything doesn't necessarily protect it from wear.

With the xW-20 or xW-30 synthetic, it will drain off the tensioner nylon guides and the chain within a short amount of time. So when we start the car, we're relying on the short time it takes to shoot the oil to everywhere (I'm not too positive on HOW the oil gets sprayed onto the chains)... whereas wouldn't a synthetic xW-40 stick to the chain more and provide sound boundary lubrication between the chain and the nylon? And I think boundary lubrication is better than little to no lubrication in this application. Or am I wrong?

Does any of this make any sense?

 

[MolaKule]

Look at it this way, the nylon or aluminum rubbing block for the contact surface is used primarily as a solid lubricant.

Any other lubricant or additive that reduces wear is going to help, and there is always an oil film on the timing chain and the rubbing block. Oil flowing onto the chain and or rubbing block is going to cool it and provide a fresh oil film.

Whether hard nylon or aluminum, there is a finite life to either material.

 

[DavoNF]

quote:

---

Originally posted by MolaKule:

Whether hard nylon or aluminum, there is a finite life to either material.

---

End of warranty period?

 

[metroplex]

quote:

---

Originally posted by MolaKule:
Look at it this way, the nylon or aluminum rubbing block for the contact surface is used primarily as a solid lubricant.

Any other lubricant or additive that reduces wear is going to help, and there is always an oil film on the timing chain and the rubbing block. Oil flowing onto the chain and or rubbing block is going to cool it and provide a fresh oil film.

Whether hard nylon or aluminum, there is a finite life to either material.

---

It's nylon, not aluminum for the Ford 4.6L SOHC V8/5.4L SOHC V8.

I'm interested in prolonging the life of the nylon guides.

If xW-20 is going to do it, then it's the oil to use. If xW-30 or a thicker oil is going to do it, that's what I will use.

I see a lot of debate on xW-20 vs xW-30 in terms of UOAs, metal wear, etc... and that's fine and all - but we're always dealing with PPM of some of the strongest parts of the engine.

The weakest link IMHO would be the nylon guides. Wear those out, and essentially your motor is "shot" or at least will see downtime for repairs.

 

[Schmoe]

Those modular engines, 4.6 and 5.4, have been in production since....97? 98??? and we are seeing them go to 2 to 300K. I haven't come across any mention of the nylon parts failing. This is not only this board but three other F150 forums that I visit weekly. Pretty much everyone with one of these motors have not gone past a 10W-30. I might want to re-think my next oil fill, I was planning on going with 3 quarts of 5W-30 and 3 of 15W-50 to thicken up a bit and increase the HTHS to get ready for these hot Oklahoma summers. Maybe not now.

 

[metroplex]

You might want to check out the "secret" recalls ford issued for certain MY 4.6s where they replace your tensioner arms, chain guides, tensioners, and timing chains if they find nylon in your oil.

 

[G-MAN]

quote:

---

Originally posted by metroplex:
You might want to check out the "secret" recalls ford issued for certain MY 4.6s where they replace your tensioner arms, chain guides, tensioners, and timing chains if they find nylon in your oil.

---

 

[darkdan]

/cough

http://www.blueovalnews.com/2003/powertrain/4.6l.crownvic.ref31507.htm

/cough

 

[G-MAN]

quote:

---

Originally posted by darkdan:
/cough

http://www.blueovalnews.com/2003/powertrain/4.6l.crownvic.ref31507.htm

/cough

---

I stand corrected. My

was prompted by the notion of a "secret" recall. Never heard of that, but I have heard of "silent" recalls.

 

[metroplex]

quote:

---

Never heard of that, but I have heard of "silent" recalls.

---

Sure

 

[gatesj]

I don't know how relevant this is, but I have a similar situation and some empirical information.

The VW VR6 uses a plastic surface spring loaded tensioner and guide rail for a bottom single row timing chain. There is also a large plastic oil pressure driven surface tensioner and guide rail for the upper double row timing chain. This design has been around since 1992 in the States, in the VW Corrado and Passat. The VW community has seen enough of these fail, mostly at just over 100k miles, that it's a fairly widely known and expected problem, although not all cars seem to have failures at all. Usually the chain rubs through the hard plastic material on the rail that the top chain rides on and that the oil pressure driven piston provides tension for. The plastic chunks that remain come loose from the rivets that hold them to the backing plate and drop into the oil pan. The chain continues to ride on the metal backing plate for potentially quite some time, making a lot more noise now, until there is a failure there and the chain either skips or breaks. Now you get valves hitting pistons since it’s an interference style engine and the obvious large bill to fix.

There was an updated design with a slightly different top tensioner rail and a large single row upper chain mid 1997 model year. This has proven slightly more durable but there have still been failures. I got the last of the old design.

Armed with this information from numerous forums and actually having seen a failure and the results thereof of an older style configuration myself at a local shop where I've spent a lot of time from childhood, I decided to change my chains, tensioners and guides at 115k miles on my one owner 1997 m/y VR6 car. There was only some very light chain noise but I was getting paranoid. Inspection requires just as much tear-down as replacement, so I just put in new parts. The components are at the back of the motor and require removal of the gearbox and clutch/flywheel assembly to even inspect a good chunk of them. Why not, the clutch and pressure plate can be replaced at the same time.

Oil history:

* Castrol Syntec 5w-50 from 1,700 to about 15,000 miles (this was in 1997-1998, was this still Group IV at that time? Not that it really matters that much anyway...)
* Mobil 1 15w-50 to about 80k miles
* Alternating Mobil 1 15w-50 for summer and 10w-30 for winter after car was not garaged anymore up until timing component replacement at 115k miles.

Changes were done at 3000-4000 miles. The OEM quality oil filter, manufactured by either Hengst or Mann, whatever I sourced at the time (they look identical) was changed at each oil change.

After huffing and puffing for the better part of a day clearing all of the components out of the way and pulling the gearbox and flywheel/clutch, I found a chain assembly that was almost like new. There was enough wear to feel with a fingernail dragged *across* the face of the tensioners, but barely. The plastic is about 1/8” thick and there might have been a few thousandths of wear. In my case, I had done the work for nothing (clutch was like new too) but I guess I got peace of mind.

Anyway, the point is, most of the miles were done on Mobil 1 15w-50 and this is an engine known to have some problems with the plastic tensioner guides. I can’t say for sure the parts didn’t wear appreciably because of the heavier oil but I can’t discount that this wasn’t a large factor. The car was driven both city and highway and driven fairly hard (i.e. redline pulls every day) so it wasn’t babied either.

Incidentally, compression and bearing clearances as measured with Plastigauge are within new specs. The cam lobes look just as smooth and polished as you would expect to find in a 10k mile engine. The inside surfaces of the motor including valve cover only have some brown coloration but no buildup of sludge. The motor now has 130k miles on it. I would guess that frequent oil and filter changes along with a thicker oil used are the biggest factors, though I’m sure synthetic makes a difference.

So, one vote for heavier oil with plastic chain tensioners/guides.

 

[gatesj]

quote:

---

Originally posted by JohnBrowning:
JonnyG, Even the ones that use hydralic pressure still have a spring. This is what keeps the tensioner from retracting when the engine is shtdown. Most also have what apears to be a rack on the back and a little cam. As the tensioner extends the cam locks down on the rack. This prevents it from ever retracting. If you try to do a cam swap on this design you have to use wedge tools to prevent their movment before removeing tension from the chain. If you do not the second you remove the cam sproctes they extend out. IF this happens you must remove the timeing cover and rest them or you will never get the cam sprokets back on.

THe other design uses spring tension to partial extend the tension and shoe. This ensures that the shoe is always in contact with the chain. Then once oil presure is up it increases the force that the tension puts against the chain.

If either one of these systems fail you would get one of two things. A ton of timing chain wip and clatter or it would jump a tooth.

Some systems combine all of these features. Only a moron for an engineer would depend solely on hydralic pressure to tension the chain with no provision for cold start lose of prime situation.

I suggest you go to your local parts store and check out a timeing chain tensioner. If you want one I know can be retracted with no special tools after extending it out use a 1995 Toyota Tacoma 2.7 I4. The lever to retract it is on the back side.

If you want one with no lock use 1986 4Runner it has a spring with no lock. You can push it in and out like a shock absorber. Both of the above use hydralic pressure as their primary force to provide tension.

---

FWIW the VW VR6 has one tensioner driven by oil with no spring. But it has a check valve to prevent oil from draining to prevent it from retracting. They're nice, you bleed them out and make sure they're full of oil, then just loop your chain around, screw it in and start it up. The chain is loose until oil pressure builds but the tolerances are set up with new parts that there's no way it can skip after you screw the tensioner in, even fully retracted. Once it sets against the chain after that first startup, it never retracts.

[ May 17, 2004, 05:23 PM: Message edited by: gatesj ]

 

[Motorbike]

427Z06 dug this up

The timing chain is lube by metered flow not by splash so that little nylon piece probably gets all the oil it needs .

http://www.meadowlandford.com/ford-4.6L-engine-specs.htm