V6 Engine Question

[440Magnum]

Originally Posted By: artificialist

That is why I love the VR6 so much. Almost all the smoothness of an inline 6 without a balance shaft, and without much challenge fitting it under the hood.

I don't like V6 engines because of the balance issue. That is the one reason I do not like the new Nissan GT-R the same way I like the older ones.


I think your dislike is misplaced. I think its *highly* debatable whether the residual imbalances with a 6-pin 60-degree v6 engine are even AS BAD as the residual imbalance in the oddball VR6, let alone worse. Have you actually driven a Nissan v6? You won't ever notice any imbalance, I assure you.

 

[rshunter]

Originally Posted By: artificialist
VW got around the limitations by creating a 15 degree V6 (Called VR6) which had the same firing order as an inline 6. They also created a way to use 2 cams to separately control the intake valves and exhaust valves just like a DOHC inline 6. Later they made a 11.6 degree VR6 which had the same advantages as the earlier engine.


The Volkswagen VR6 design was really a follow-on from a group of narrow-angle V4 engines that were produced by the Italian automaker Lancia. They had produced them for about 40 years, starting with the Lancia Lambda in 1922. It was quite a car for its time, being the first car with a uni-body as well as among the first to use an independent suspension. It was a rather attractive car, if the roadster I've seen is any example.

 

[JTK]

Interesting! I even had a 75° V6 in my 2002 Isuzu Rodeo 3.2L. Isuzu made those V6's from 1993-2004.

Joel

 

[BuickGN]

As ignorant as this sounds, I've never looked at any specs of the J32 V6 in my TL since I could care less about ever modding the engine. This thing is as rough if not rougher at idle than my GN. I know there are many factors such as motor mounts but does anyone know if this engine is a 90 degree, does it have a balance shaft, etc?

 

[rationull]

Not sure about balance shafts but the J V6 is a 60 degree V. Its predecessor, the C series V6, was a 90 degree.

 

[BuickGN]

Originally Posted By: rationull
Not sure about balance shafts but the J V6 is a 60 degree V. Its predecessor, the C series V6, was a 90 degree.


Thanks. I wonder why this one idles like it does. It's not enough to complain about but it's borderline in a car that costs this much. I've driven a few other TLs and they're all the same. Not sure if the 11:1 compression has anything to do with a lack of idle smoothness. It runs fine, no misses or anything like that.

 

[rationull]

Does your TL have an MT or AT? I know on the current Civic the upper torque mount is some kind of plastic or composite on the AT models but metal on the MT which I theorize may increase the amount of engine vibration that makes it into the cabin at idle. It does seem a little weird given Honda's reputation for smooth running engines (which my Civic violates too relative to plenty of other cars), and especially on a car in the TL's class.

 

[BuickGN]

It's an auto. There is a vibration dampner mounted to the front bumper only on the auto models. I removed it because it's essentially an 8lb weight mounted in rubber thinking it couldn't possibly make a difference. After a week of driving with the AC on at idle I put it back on. I know it has some fancy mounts that use engine vacuum to "soften" them up at idle and the get progressively firmer as you open the throttle. I did check the vacuum line to make sure that was not the source. But again, mine is no worse than other TLs I've driven. Again, I'm not complaining, it's not *that* bad but it's a little unexpected.

 

[440Magnum]

Originally Posted By: BuickGN
I know it has some fancy mounts that use engine vacuum to "soften" them up at idle and the get progressively firmer as you open the throttle. I did check the vacuum line to make sure that was not the source. But again, mine is no worse than other TLs I've driven. Again, I'm not complaining, it's not *that* bad but it's a little unexpected.


If I were you, I'd build another stout Buick v6 and drop in the TL.

I don't think the relatively high compression should be that much of an issue. Wife's old '93 Vision TSi had one of the first-year 3.5s that ran at 10.5:1 before they dropped it to 9.5:1 in '94, and you could balance an egg on the intake at idle if you wanted. VERY smooth engine. Now it had a pretty throaty intake roar that some people (not me) found annoying when you got on it, but it wasn't rough. I would just guess that the TL's engine mounts are either not working as advertized, or are just biased a lot more to the harsh side than other sport/lux v6 cars tend to be. I mentioned the Nissan/Infiniti v6 engine family earlier- it really is amazingly smooth. At least as smooth as most inline sixes, maybe smoother than many.

 

[BuickGN]

Originally Posted By: 440Magnum
Originally Posted By: BuickGN
I know it has some fancy mounts that use engine vacuum to "soften" them up at idle and the get progressively firmer as you open the throttle. I did check the vacuum line to make sure that was not the source. But again, mine is no worse than other TLs I've driven. Again, I'm not complaining, it's not *that* bad but it's a little unexpected.


If I were you, I'd build another stout Buick v6 and drop in the TL.

I don't think the relatively high compression should be that much of an issue. Wife's old '93 Vision TSi had one of the first-year 3.5s that ran at 10.5:1 before they dropped it to 9.5:1 in '94, and you could balance an egg on the intake at idle if you wanted. VERY smooth engine. Now it had a pretty throaty intake roar that some people (not me) found annoying when you got on it, but it wasn't rough. I would just guess that the TL's engine mounts are either not working as advertized, or are just biased a lot more to the harsh side than other sport/lux v6 cars tend to be. I mentioned the Nissan/Infiniti v6 engine family earlier- it really is amazingly smooth. At least as smooth as most inline sixes, maybe smoother than many.



FWD burnouts FTW! I have a healty stockish engine sitting on the stand, waiting for the Opel GT to be done. Should be a fun 2,200lb ride.

I agree with you on the Nissan V6. I only wish my car idled as smooth as the girlfriend's Murano. If it weren't for the exhaust note I wouldn't be able to tell if it was running.

 

[ekpolk]

Originally Posted By: 440Magnum
Originally Posted By: artificialist

That is why I love the VR6 so much. Almost all the smoothness of an inline 6 without a balance shaft, and without much challenge fitting it under the hood.

I don't like V6 engines because of the balance issue. That is the one reason I do not like the new Nissan GT-R the same way I like the older ones.


I think your dislike is misplaced. I think its *highly* debatable whether the residual imbalances with a 6-pin 60-degree v6 engine are even AS BAD as the residual imbalance in the oddball VR6, let alone worse. Have you actually driven a Nissan v6? You won't ever notice any imbalance, I assure you.


His dislike may or may not be misplaced (that's up to him, of course). On the other hand, you simply can NOT get around the inherent nature of the V-6 -- it is what it is. The Nissan VQ has been very, very well tamed (I owned one myself), but it's still a V-6, and it still has inherent V-6 characteristics. I could feel it in my VQ, no question about it.

The VR6, however, is a different beast altogether. It's really a straight-6 squished in some. It has one block without two separate banks of cylinders. Each rod has it's own bearing. As far as inherent balance and shake, it's a slightly warped I-6, not a V-6.

 

[FrankN4]

I guess my friends 260 HP, 6000 RPM Buick 3.8 is kind of tame, overall. But, he does not have balance shafts. Did those high HP, high RPM 3.8 engines have the balance shaft, or did/do they just shake and use compensating motor mounts such as Harley Davidson does?

 

[BuickGN]

Originally Posted By: FrankN4
I guess my friends 260 HP, 6000 RPM Buick 3.8 is kind of tame, overall. But, he does not have balance shafts. Did those high HP, high RPM 3.8 engines have the balance shaft, or did/do they just shake and use compensating motor mounts such as Harley Davidson does?


I don't think there has ever been a high revving 3.8L production motor. Mine has a factory redline of 5,250rpm. Even now with a larger cam and good heads it makes peak hp at 5,600rpm and peak torque at 2,900rpm. In stock form the turbo motors made peak hp around 4,000rpm and torque around 2,600rpm. Above 4,500 they fell on their face. I rarely spin it above 5,000 on the street, but it goes through the traps at 6,100rpm which is scary on the stock bottom. The series II revved higher but not much.

The factory captive mounts were soft and on the turbo versions they would lock metal to metal at WOT. My GN vibrates about the same as my TL and that's with one urethane mount on the driver's side and rubber on the passenger side.