GM 3.6 experts... Why the disparity between different LFX engines? (Page 4/7)
dobey SEP 02, 10:14 AM

quote
Originally posted by Reallybig:
Now I'm stuck driving a substandard Durango cuz it was the next option for seating 8 to my Saturn outlook. Pretty bad when a Durango beats any GM product.



The VVT in the Chrysler (and pretty much any other) engines all work pretty much exactly the same.
MarkS SEP 02, 12:32 PM
Funny how the same engine can be so dramatically different owner to owner. The LY7 in our '05 Rendezvous has been a joy. It is north of 150K miles now, everyday taking the missus up Rt I287 at better than 80mph sustained at times (this is normal rush hour stuff here). Have been pretty good with maintenance, Quaker State synthetic - conventional SUV oil since new. Its oil tight and doesn't use any oil between changes; no issues at all.

Having said that, it'll probably blow up tonight on the way home, but at 150K is it that bad?

With this experience to date, an LY7 with a 6 speed auto in my 86 has always been appealing to me but isn't the BCM an issue?

BR's,

Mark

------------------
86 SE V6 Auto
65 Tempest 400 CID
2008 G6 GT "Street" Coupe
2005 Buick 3.6 Rendezvous
2001 Olds Silhouette (AKA The Band Van)

Raydar SEP 02, 06:33 PM

quote
Originally posted by MarkS:
...

With this experience to date, an LY7 with a 6 speed auto in my 86 has always been appealing to me but isn't the BCM an issue?



Some of the folks on the Camaro forums are apparently running the LFX as a stand-alone. Harnesses are available.
The LY7 is older technology. I would suspect it's not any more difficult.
The transmission controller might be an issue. I think the standalone harnesses are for manuals.

But yeah... My mother in law has a CTS with the LY7 and 6 speed auto. I always thought that it would make a Fiero a pretty quick entity.
(Yeah, the CTS is longitudinal, but the gear ratios, compared to the transverse, are quite similar.)
qwikgta SEP 02, 07:25 PM
not sure if its been said, i didn't read every post, but i bet its also in the tune. if your selling a V6 Camaro you want to have the highest HP, if the tune can get you +30 hp and all you lose is a few MPG then you can sell more Camaros. If a buyer is looking at a V6 Mustang, V6 Challenger or a V6 Camaro, you need all you can get, MPG be damned. I was shocked to see what a good tune can do to a LS motor. Lose a little MPG to gain some HP/TQ... hell yea.

Rob
dobey SEP 02, 07:39 PM

quote
Originally posted by Raydar:
Some of the folks on the Camaro forums are apparently running the LFX as a stand-alone. Harnesses are available.
The LY7 is older technology. I would suspect it's not any more difficult.
The transmission controller might be an issue. I think the standalone harnesses are for manuals.

But yeah... My mother in law has a CTS with the LY7 and 6 speed auto. I always thought that it would make a Fiero a pretty quick entity.
(Yeah, the CTS is longitudinal, but the gear ratios, compared to the transverse, are quite similar.)



The LY7 I think is not SIDI, so should generally be easier. SIDI is a bit harder because the OEM ECMs have tended to be harder to break, and most "affordable" aftermarket ECMs still don't support SIDI yet, because the electronics for the injectors is a bit different.
cmechmann SEP 02, 08:51 PM
On the phaser problem. It's not just the 2mm oil feed to the phaser that hinders many VVT engines. It is also the tiny passages that are in a lot of the solenoid controlled phasers. Just like transmission solenoids that have a small grain of dirt, that can stick. So can the VVT solenoids. While most have some sort of screen, only only a few, that I know of, have a screen that can be replaced by itself easily.
By the way there is a screen in the LS series engines that have DOD. It is under the oil sending unit and a pain to get to. But replacing it as preventive measure can help save the lifters on those engines.
There are systems out there that don't need a heavy phaser assembly on each cam to add a lot of weight to the cam components. Honda Vtech comes to mind, but I would gather they have a copyright on that, Also it is not full VVT.
On older Toyotas. I liked the way they had 2 cams that ran off one cam gear then had different set of gears in the head that connected the 2 cams. That very much limited the lenth of the timing belt. I would very much like to see versions of these ideas incorporated into new engine designs. But don't count on it.
The best way to deal with the extra mass that has been introduced into the timing components, is to incorporate gear/chain design. Gears driving shorter chains, then chained gear driving 2 more gears for the cams. That also involves larger head/timing cover assemblies and added cost. Don't count on that. ECM controlled valving is looking better if they design good failsafes.
Another issue. This one is in reference to the demand for lessened tensioned rings to reduce free drag. While it "might" save a few MPGs, the concept shows it's ugly head when you stress these engines. Causing higher crankcase pressures.
It's not just the GM 3.6s. Seen a few past decent engine designs that have been offed due to the newer restrictions. And there are some current designs with known oil issues.
Our government will be getting even more strict with engine emission related factors and the problems will only get worse.
Raydar SEP 02, 10:20 PM

quote
Originally posted by cmechmann:

On the phaser problem. It's not just the 2mm oil feed to the phaser that hinders many VVT engines. It is also the tiny passages that are in a lot of the solenoid controlled phasers. Just like transmission solenoids that have a small grain of dirt, that can stick. So can the VVT solenoids. While most have some sort of screen, only only a few, that I know of, have a screen that can be replaced by itself easily.
...



Our Trailblazer (4.2, I-6) had VVT. It was particularly sensitive to what weight of oil you used, and how often it was changed.
If the oil got too thick, it would set the "exhaust cam is too far advanced" code. As soon as the oil was changed, it cleared.
Joseph Upson SEP 03, 12:35 AM

quote
Originally posted by Raydar:
Our Trailblazer (4.2, I-6) had VVT. It was particularly sensitive to what weight of oil you used, and how often it was changed.
If the oil got too thick, it would set the "exhaust cam is too far advanced" code. As soon as the oil was changed, it cleared.



I've read about VVT motors being sensitive to increasing oil viscosity and would be looking at reprogramming to counter that in the same manner that was performed for the timing chain/VVT module problems that would trip the engine light. On a stock motor that has been modified to considerably increase power output or will be driven much harder than average spirited driving an oil viscosity change is in order to absorb the increased intensity rotating and impact surfaces would otherwise have to absorb. The thicker oil would bleed through the VVT module at a slower rate that would either cause VVT delays, or accelerations or both depending on the commanded movement direction that can be sensed as outside parameters. Keep in mind that although 5W30 is still the mark for HO motors from the production line, the PCM plays a big part in managing what can be considered abusive input at the throttle. 5W40-50 is what I use year round.


quote
Originally posted by cmechmann:
... Another issue. This one is in reference to the demand for lessened tensioned rings to reduce free drag. While it "might" save a few MPGs, the concept shows it's ugly head when you stress these engines. Causing higher crankcase pressures.
It's not just the GM 3.6s. Seen a few past decent engine designs that have been offed due to the newer restrictions. And there are some current designs with known oil issues.
Our government will be getting even more strict with engine emission related factors and the problems will only get worse.



I've come across a few modern 4 cyl engines mainly imports so far that have such a strong blow by pulse that you can feel it from several inches above the oil fill hole in the valve cover along with oil spray which makes me wonder why some cars are not equipped with oil catch cans to keep the intake and valves cleaner.

[This message has been edited by Joseph Upson (edited 09-03-2016).]

pmbrunelle SEP 03, 01:21 AM

quote
Originally posted by Joseph Upson:


I've come across a few modern 4 cyl engines mainly imports so far that have such a strong blow by pulse that you can feel it from several inches above the oil fill hole in the valve cover along with oil spray which makes me wonder why some cars are not equipped with oil catch cans to keep the intake and valves cleaner.




Baffling in the valve cover does the same thing, no?

Except that the oil is directly drained to the engine; no need to manually empty the can every so often.
Joseph Upson SEP 03, 07:43 AM

quote
Originally posted by pmbrunelle:
Baffling in the valve cover does the same thing, no?

Except that the oil is directly drained to the engine; no need to manually empty the can every so often.



No where near as effective and that's why every engine with a PCV system that I've torn down to some deg (many) has oil residue and carbon build up in the intake and on top of the valves on engines with low enough mileage to not be able to blame valve stem leaks as the cause. I haven't had to empty my oil catch can since I put it on the motor 5 yrs ago but there's oil trapped in it, then my motor doesn't blow oil mist out the filler neck like the late model 4 cyl engines I'm referring to. I've seen a near new car with an underhood mess in just a few short miles around the block because a tech forgot to put the oil filler cap back on after the oil change. A properly setup oil catch can, can be built and arranged to drain oil back into the engine automatically.

Oil in the intake is a problem with the 3.6 also, google it. My mom has one in her Saturn and during a spark plug replacement I ended up spending quite a bit of time carefully cleaning the MAF sensor because the tube coming from the air filter housing has a vent tube feeding into it from the valve cover. I turned the tube on end unaware of the oil that pooled in the bellows section of it until it started pouring out the end on an engine that had about 92k miles on it. Still runs great but I suspect it's pretty ugly up top on the inside considering I believe there's another vent tube going directly to the intake.

The four cylinders now often run 0W20 and along with low tension rings I imagine it's much worse with them as some tend to be down on the oil level a good bit at change interval. Again I'm referring to examples that do not have the mileage history to support such characteristics

[This message has been edited by Joseph Upson (edited 09-03-2016).]