Timing belts that run in oil bath
- Thread starter Shel_B
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Significantly less frictional loss vs chain (1% mpg increase in effeciency, allegedly)
I imagine some people have a problem with it because the belt material must be compatible for use with motor oil and belt material could clog the oil pickup tube so increased replacement interval is a requirement which means $$.
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Most sources state up to 30% lower frictional losses as compared to a chain system, along with noise reductions and options to make the system more compact in packaging as well.
This has come up before and it appears that few know the reason or design specifics.
For example, What needs to be lubed? Is lubrication of the belt even a consideration?
Regular timing belts aren't lubed. Maybe it's a space consideration.
For example, What needs to be lubed? Is lubrication of the belt even a consideration?
Regular timing belts aren't lubed. Maybe it's a space consideration.
dnewton3
Staff member
The perception most folks have is from a typical dry-running timing belt getting oil on it from a cam or crank seal leak, and then the belt degrades. This is because the chemical makeup of the belt was not designed for oil contact, and so the lifespan is greatly affected.
However, belts which are designed to be in an oil bath are made of different, more resistant materials. They can survive a long time in an oil bath, all other things being equal. There's nothing wrong whatsoever with a belt intended to be in an oil bath.
The real problem is that much of the time, because of the location of these internal wet belts, it's a PITB to get replaced (time and money very costly).
However, belts which are designed to be in an oil bath are made of different, more resistant materials. They can survive a long time in an oil bath, all other things being equal. There's nothing wrong whatsoever with a belt intended to be in an oil bath.
The real problem is that much of the time, because of the location of these internal wet belts, it's a PITB to get replaced (time and money very costly).
The whole point of using a belt rather than a chain is that belts don't require lubrication the way chains do.
The benefit of using a timing chain is that they don't need to be replaced regularly like timing belts do, but they do need an oil supply for lubrication.
A timing belt in oil still needs to be replaced while being messy to replace because of the oil, and the rubber being compatible with oil, possibly more difficult to replace, too.
Honda lawn mowers have used a timing belt in oil for awhile, but those are small engines where the consequences are less dire, and OPE engines are so loud that ANY reduction in noise is welcome and makes a huge difference, so it's worth it there.
The benefit of using a timing chain is that they don't need to be replaced regularly like timing belts do, but they do need an oil supply for lubrication.
A timing belt in oil still needs to be replaced while being messy to replace because of the oil, and the rubber being compatible with oil, possibly more difficult to replace, too.
Honda lawn mowers have used a timing belt in oil for awhile, but those are small engines where the consequences are less dire, and OPE engines are so loud that ANY reduction in noise is welcome and makes a huge difference, so it's worth it there.
The recent threads and teardowns by I Do Cars on youtube showed how such belts deteriorate when under severe overheating conditions. Many folks including myself were shocked.
More on point to your question, here is links from Dayco and Continental, both OEM and aftermarket suppliers. No doubt plenty of testing was done before implementation by the manufacturers and the benefits are written clearly by them on the links. I'm skeptical and still on the fence of any manufacturer that states its a "lifetime" part similar to how claims were made for lifetime sealed transmissions (innumerable) and quick change oil filters which doesn't change all the oil (John Deer).
https://www.dayco.com/en/product/timing-belt-in-oil-bio-system/
https://www.continental-aftermarket...y-our-new-belt-in-oil-runs-for-a-l-o-n-g-time
More on point to your question, here is links from Dayco and Continental, both OEM and aftermarket suppliers. No doubt plenty of testing was done before implementation by the manufacturers and the benefits are written clearly by them on the links. I'm skeptical and still on the fence of any manufacturer that states its a "lifetime" part similar to how claims were made for lifetime sealed transmissions (innumerable) and quick change oil filters which doesn't change all the oil (John Deer).
https://www.dayco.com/en/product/timing-belt-in-oil-bio-system/
https://www.continental-aftermarket...y-our-new-belt-in-oil-runs-for-a-l-o-n-g-time
Yeah, I think many of us are questioning it after the I Do Cars video. Allegedly 97k and the belt looked far from inspiring.
That said, it might have held on for another 200k as he was deliberately bending it contrary to how it would live, but that's not uncommon to inspect some rubber products IME.
The secondary question is if it starts to shed pieces or chunks, do they clog the oil pickup? And if belts can survive in oil, did Ford get this particular rubber formulation wrong just this time??
That said, it might have held on for another 200k as he was deliberately bending it contrary to how it would live, but that's not uncommon to inspect some rubber products IME.
The secondary question is if it starts to shed pieces or chunks, do they clog the oil pickup? And if belts can survive in oil, did Ford get this particular rubber formulation wrong just this time??
The belts aren't rubber.
Google Ford 1.0 eco boost oil pump belt. They shed bits which block the oil pick up resulting in low oil pressure. If not caught in time engine is destroyed.
How might the oiled belt compare with a dry belt in terms of efficiency?
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Its a silly design choice, motivated by cost cutting.
A timing chain (while not perfect) is a much more reliable choice, it appears.
Who are the manufacturers that are taking this route? So far I've heard of GM and FORD---both company's that have screwed over their customers in the past.
When Toyota jumps on board and starts using rubber belts in an oil bath, I'll be more of a believer. Toyota is usually pretty conservative in adopting new approaches, and prefers to stick with tried and true means.
A timing chain (while not perfect) is a much more reliable choice, it appears.
Who are the manufacturers that are taking this route? So far I've heard of GM and FORD---both company's that have screwed over their customers in the past.
When Toyota jumps on board and starts using rubber belts in an oil bath, I'll be more of a believer. Toyota is usually pretty conservative in adopting new approaches, and prefers to stick with tried and true means.
dnewton3
Staff member
This very topic was discussed at length in another thread.
The 2.7 engine which was torn down had suffered a major oil loss and the engine ran dry. It means the bathed-oil belt also ran dry (no cooling) as the engine got WAY too hot. And also the belt had an extreme load as the oil pump likely seized up, or at least suffered immense drag. That the oil pump belt looked that "bad" in the video is NOT indicative of a properly cared for engine. That belt could have lasted a LOT longer if the engine didn't run out of oil. So my point is that it's not fair to look at the belt and condemn it's condition because the condition wasn't "normal". The belt didn't cause the engine failure; the belt was a victim of the failure.
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For sure its in the Ford 1.0 Ecoboost, the 2018 and up 2.7 Ecoboost, and it is also now in the 21+ MY 5.0 Coyote V8 in the F150's, unsure in other applications.
Other known users include GM, Honda, and VW, though I am not familiar enough to know engines and whether they are used here in the US.
BIO and chain are more efficient than dry per Borg Warner. However that efficiency adds upto 1 percent difference in MPG. It's not a lot by itself which is why automakers are all about the aggregate increase in efficiency (low viscosity oil, EPS, BIO,)
It is one way to avoid terrible timing chain life with ultra low viscosity oils.
Are you serious? If so do not maintain your vehicle yourself. Are you confused about the difference between rubber and chain?
If you search " ford 1.0 eco boost" Im sure you will find more negative than positive things with wet timing belt. The thing is that the rubber swells in the oil and rhe belt gets a little wider så the pulleys chew the belts sides and the oil pickup in sump gets clogged up.
Take a look at youtube i guess you dont need to think if its a good or bad idea with the wet timingbelt.
Take a look at youtube i guess you dont need to think if its a good or bad idea with the wet timingbelt.
wemay
Site Donor 2023
There are many more incidents of failure dissimilar to the referenced video. How widespread is this? No idea, but we'll know in the next few years.