Direct injection and timing chain tough on oil?

[doublebase]

It's something I've heard a lot lately...that direct injection engines are tough on oil. Is that because the high fuel pressure pushes fuel past the rings, diluting the oil? Do these engines run "dirtier" than a conventionally injected engine? What's the problem?

And do timing chains shear oil? A lot of engines have gone back to timing chains...add them to the direct injection trend, are we now seeing engines that perhaps really need higher quality oil and perhaps shorter change intervals? Yet most manufacturers are pushing the intervals out further and further (probably to appear as if they are reducing maintenance costs). Or are direct injection engines NOT hard on oil?

 

[MinamiKotaro]

UOAs on direct-injection engines come back fine. Some are flagged with caution for fuel %, but I've yet to see a DI engine that has trashed its oil in a recommended change interval.

 

[gregk24]

Some are some aren't, I'm not entirely sure why. I suppose some have figured out how to design them properly! My girlfriends Jetta had directed injection, a timing chain, a turbo, and 10K miles oil change intervals 0.0 It has a maintenance plan so VW gives you a couple free 10K OCI's. Whenever I start doing the maintenance It will get 5K oil changes, probably with M1 or Castrol 0w40.

 

[gregk24]

Originally Posted By: MinamiKotaro
UOAs on direct-injection engines come back fine. Some are flagged with caution for fuel %, but I've yet to see a DI engine that has trashed its oil in a recommended change interval.


Have you forgot about the GM 3.6?

 

[MCompact]

Here's the final UOA from my 2007 MS3(I sold it and bought another car with a turbo GDI motor). Hard on oil? Not in this case...

 

[CT8]

Buy what makes you smile...
I haven't the resources to buy and maintain what would make me smile.

 

[UncleDave]

Direct injection is tough on oil because the direct injection pump creates a tremendous amount of pressure and is almost always driven off the crank or a cam assembly -

This high pressure pump is key to making the whole thing work.

This " squeeze" put a tremendous load 2000psi + on the local part and shears the oil.
This is why particulate contamination is so critical on DI engines.

likewise lots of chain is kept under tension and a fair amount of load to turn against the valve springs and resistance so every time that chain crosses the sprocket its squeezing oil - multiply this by lots of chains and sprockets and guides and you have shear occurring.

UD

 

[gabriel9766]

I've noticed on DI engines such as my car and some fords and kia's after u change the oil the oil is already dark even when fresh. Why is tht?

 

[KevinP]

From what I understand carbon build-up on intake valves is common with DI. You don't have the fuel washing over the valve which would dissolve some of that build-up. I would imagine your more dependent upon oil to scavenge those carbon deposits (just wild speculation on my part).

Timing chains... they have been around for ages. There may be model specific failures based upon oil circulation but I doubt the timing chain itself is an issue with oil.

 

[doublebase]

Originally Posted By: UncleDave
Direct injection is tough on oil because the direct injection pump creates a tremendous amount of pressure and is almost always driven off the crank or a cam assembly -

This high pressure pump is key to making the whole thing work.

This " squeeze" put a tremendous load 2000psi + on the local part and shears the oil.
This is why particulate contamination is so critical on DI engines.

likewise lots of chain is kept under tension and a fair amount of load to turn against the valve springs and resistance so every time that chain crosses the sprocket its squeezing oil - multiply this by lots of chains and sprockets and guides and you have shear occurring.

UD



you think the high pressure pump contributes to oil shearing? Interesting, I never really considered that. I just figured there has always been cam lobes that were asked to move a lifter under pressure...didn't really consider the pump/cam contact would be any worse. Maybe it is.

 

[UncleDave]

A 2 sprocket timing chain on a cam in block engine isn't an oil shear problem.

Double overhead cam designs with feet and feet of chains and multitudinous sprockets are the problem.

UD

 

[doublebase]

Originally Posted By: KevinP
From what I understand carbon build-up on intake valves is common with DI. You don't have the fuel washing over the valve which would dissolve some of that build-up. I would imagine your more dependent upon oil to scavenge those carbon deposits (just wild speculation on my part).

Timing chains... they have been around for ages. There may be model specific failures based upon oil circulation but I doubt the timing chain itself is an issue with oil.


Well one thing I hear about extended oil change intervals on timing chain engines is timing chain stretch. Supposedly soot can get between the pins and rollers and eventually loosen or expand the links. Seems implausible, but I guess it's the little things that wear engines.

 

[UncleDave]

Originally Posted By: doublebase
Originally Posted By: UncleDave
Direct injection is tough on oil because the direct injection pump creates a tremendous amount of pressure and is almost always driven off the crank or a cam assembly -

This high pressure pump is key to making the whole thing work.

This " squeeze" put a tremendous load 2000psi + on the local part and shears the oil.
This is why particulate contamination is so critical on DI engines.

likewise lots of chain is kept under tension and a fair amount of load to turn against the valve springs and resistance so every time that chain crosses the sprocket its squeezing oil - multiply this by lots of chains and sprockets and guides and you have shear occurring.

UD



you think the high pressure pump contributes to oil shearing? Interesting, I never really considered that. I just figured there has always been cam lobes that were asked to move a lifter under pressure...didn't really consider the pump/cam contact would be any worse. Maybe it is.


absolutely - this problem isn't new.

those gears have to squeeeeeeeze to generate 2-3K pounds of pressure..

Diesels have had it for a while - A heui pump in a diesel engine is even worse.

UD

 

[doublebase]

Originally Posted By: UncleDave


A 2 sprocket timing chain on a cam in block engine isn't an oil shear problem.

Double overhead cam designs with feet and feet of chains and multitudinous sprockets are the problem.

UD


Yeah today's engines don't look like the older pushrod engines when you take the timing covers off. Big difference.

 

[demarpaint]

Originally Posted By: KevinP
From what I understand carbon build-up on intake valves is common with DI. You don't have the fuel washing over the valve which would dissolve some of that build-up. I would imagine your more dependent upon oil to scavenge those carbon deposits (just wild speculation on my part).

Timing chains... they have been around for ages. There may be model specific failures based upon oil circulation but I doubt the timing chain itself is an issue with oil.


That's interesting, something I never considered. What about the carbon build up problems, did they get those resolved?

 

[UncleDave]

Originally Posted By: demarpaint
Originally Posted By: KevinP
From what I understand carbon build-up on intake valves is common with DI. You don't have the fuel washing over the valve which would dissolve some of that build-up. I would imagine your more dependent upon oil to scavenge those carbon deposits (just wild speculation on my part).

Timing chains... they have been around for ages. There may be model specific failures based upon oil circulation but I doubt the timing chain itself is an issue with oil.


That's interesting, something I never considered. What about the carbon build up problems, did they get those resolved?


Ford solved their problem by adding injectors back into the manifold for the new engine.

Going to be interesting to get a close look at that and how they implement it going between direct and port injected.

UD

 

[demarpaint]

Originally Posted By: UncleDave
Direct injection is tough on oil because the direct injection pump creates a tremendous amount of pressure and is almost always driven off the crank or a cam assembly -

This high pressure pump is key to making the whole thing work.

This " squeeze" put a tremendous load 2000psi + on the local part and shears the oil.
This is why particulate contamination is so critical on DI engines.

likewise lots of chain is kept under tension and a fair amount of load to turn against the valve springs and resistance so every time that chain crosses the sprocket its squeezing oil - multiply this by lots of chains and sprockets and guides and you have shear occurring.

UD




That's interesting, something I never considered. What about the carbon build up problems, did they get those resolved?

 

[chad8]

I own a 2011 sonata. First generation DI. First owner went 3000+ miles between changes.
I go 7000 with Quaker state Dino 5w20, which is OEM oil. 7500 is recommended interval.
Car has 58000 on it. Burns maybe 1/3 quart between changes. Hard on oil? Yes, but not any worse than other engines.
Main weak point is carbon in intake and injectors. I clean the throttle body and use good injector cleaner regularly . Also use top tier Costco fuel.
With a 120000 mile , 10 year engine warranty, I'll take my chances on longer oil changes.
I won't own it past 100000 anyway. I'm buying another . At almost 40 mpg on the highway, I wouldn't own any other kind of engine until battery or fuel cell technology gets better.
DI is the present and future. Get used to it.

 

[Gene K]

Originally Posted By: MinamiKotaro
UOAs on direct-injection engines come back fine. Some are flagged with caution for fuel %, but I've yet to see a DI engine that has trashed its oil in a recommended change interval.


Then you have not been watching 3.6 GM, 1.4L Turbo GM or Ford 3.5EB.

I've seen some 3.5EB that the IOLM called for 10,000 mi change and TBN was 0.1-0.3 on a synthetic with iron over 100 ppm. I've also seen some that went 10,000 mi with 1.0-2.0 TBN and sub-20 ppm iron on blends.

 

[Danh]

Originally Posted By: UncleDave
Direct injection is tough on oil because the direct injection pump creates a tremendous amount of pressure and is almost always driven off the crank or a cam assembly -

This high pressure pump is key to making the whole thing work.

This " squeeze" put a tremendous load 2000psi + on the local part and shears the oil.
This is why particulate contamination is so critical on DI engines.

likewise lots of chain is kept under tension and a fair amount of load to turn against the valve springs and resistance so every time that chain crosses the sprocket its squeezing oil - multiply this by lots of chains and sprockets and guides and you have shear occurring.

UD



Sorry, but aren't gasoline DI pumps electric? Every photo I've seen of DI pump who's a plastic body that would be mounted outside the engine.