What's Next With HD Big Twins

[Ohio HD]

I've wondered since the M8 motor came out, just why HD went back to a single cam. I guess you could say cost saving, one less cam, one less cam bearing, one less machined hole and sized bushing for the cam plate. I can't see that as a tremendous savings, but then again, it's a savings.

I've tossed around in my mind the possibility that HD may be working their way towards Variable Valve Timing. I think that HD has come to grips with they can't stray too far from traditional 45° air cooled v-twin style. Twin cooled is acceptable to most, they don't change the looks that much. Variable valve timing and the M8 heads could lead to some interesting running motors.

just as long as they don't connect a hand grip cable to advance and retard the cam like the Pan Head and down ignition system.

[hrdtail78]

I think it is the next logical step, but don't know if that is the reason for single cam.  How I have it designed in my head would be with the Cam chain drive sprockets, and since the m8 and TC use the same.....?

The other side of removing the extra cam.  It does free up HP.  How much compared to spring tensioners to hyds to single cam.  I have no idea but gotta be something and I would bet it's enough to notice on an engine dyno.

[Ohio HD]

I think VVT would be pretty amazing. Not so much as to what HD would do with it. But what the aftermarkets cam business could do with it.

I need to dig into this VVT business, see what type of timing changes are made and when in the RPM they're made on production automobiles today. The Engine Analyzer Pro software has settings for cam specs using VVT when you input cam data. I've never really looked at how the software works with it, but may do so at some point.

[Oclaf]

As noted, for more horsepower with the new head and anyone not impressed with the M8 versus previous motors must have never had a stock twinkie, EVO or any other previous version. The air cooled V-twin is riding its glory days coattails, we the people have decided that the internal combustion engine is a threat especially these air cooled ones, why the new pan am and sporty have a water cooled motor...To the M8, they got what they and many wanted, a reliable, powerful stock engine...love my 2020 114...and i have had a myriad of Harleys 80's, 90's, 00's and now a 20's....

[Wookie3011]

They have it on the 975T and 1250. Just a matter of time before they introduce it. Best of both worlds. It would however be a very fast turn around for a engine model. M8 came out in 2016? They could add it to it I suppose. I would like to see it on a big twin also.

[Hossamania]

Can VVT be done easily on a pushrod motor, or would they have to go overhead cam?

[Ohio HD]

Can VVT be done easily on a pushrod motor, or would they have to go overhead cam?

My 6.4 liter Dodge motor is VVT. Valve opening method doesn't matter.

[Ohio HD]

They have it on the 975T and 1250. Just a matter of time before they introduce it. Best of both worlds. It would however be a very fast turn around for a engine model. M8 came out in 2016? They could add it to it I suppose. I would like to see it on a big twin also.

I suspect it would be a new motor release, using the M8 heads. Who knows what they'd call it.

[boooby1744]

They have it on the 975T and 1250. Just a matter of time before they introduce it. Best of both worlds. It would however be a very fast turn around for a engine model. M8 came out in 2016? They could add it to it I suppose. I would like to see it on a big twin also.

I suspect it would be a new motor release, using the M8 heads. Who knows what they'd call it.

M8V2

[hrdtail78]

Can VVT be done easily on a pushrod motor, or would they have to go overhead cam?

Some LS models have had it.  2007 I believe.   

[wfolarry]

Google Cam Phaser & you'll see how it's done.

[CndUltra88]

Google Cam Phaser & you'll see how it's done.

Then the nightmare would begin.
Cam Phasers or VANOS....
Clean oil and well maintained becomes very important in these VVT engines .
Rob

[kd]

Google Cam Phaser & you'll see how it's done.

Then the nightmare would begin.
Cam Phasers or VANOS....
Clean oil and well maintained becomes very important in these VVT engines .
Rob

Google Cam Phaser & you'll see how it's done.

Then the nightmare would begin.
Cam Phasers or VANOS....
Clean oil and well maintained becomes very important in these VVT engines .
Rob

I tend to agree.  The 5.7 Hemi uses a specified oil weight since 2009 and it is critical to the operation of the VVT and MDS components.  They advance the valve timing to provide more torque so they have more power when running on 4 cylinders. Failure to use the recommended oil viscosity (5W20) will cause a failure with the MDS (multiple Displacement System / 8 to 4 cylinder) to function.  In fact, if you have any type of engine failure while on warranty, expect them to test your oil viscosity.  You will likely have an engine warranty claim denied if for example you used a 10W30 grade oil. Also late oil changes will have a similar effect. 

[Hossamania]

Google Cam Phaser & you'll see how it's done.

Then the nightmare would begin.
Cam Phasers or VANOS....
Clean oil and well maintained becomes very important in these VVT engines .
Rob

Google Cam Phaser & you'll see how it's done.

Then the nightmare would begin.
Cam Phasers or VANOS....
Clean oil and well maintained becomes very important in these VVT engines .
Rob

Google Cam Phaser & you'll see how it's done.

Then the nightmare would begin.
Cam Phasers or VANOS....
Clean oil and well maintained becomes very important in these VVT engines .
Rob

I tend to agree.  The 5.7 Hemi uses a specified oil weight since 2009 and it is critical to the operation of the VVT and MDS components.  They advance the valve timing to provide more torque so they have more power when running on 4 cylinders. Failure to use the recommended oil viscosity (5W20) will cause a failure with the MDS (multiple Displacement System / 8 to 4 cylinder) to function.  In fact, if you have any type of engine failure while on warranty, expect them to test your oil viscosity.  You will likely have an engine warranty claim denied if for example you used a 10W30 grade oil. Also late oil changes will have a similar effect. 

Yes, and yes.
A friend works on them often, he says change the oil much earlier than the recommended intervals, the orifices are extremely small, just the littlest bit of dirt will cause issues. 0-20, 0-10 oils is very common with these systems. Definitely will be a fully water cooled motor at that point. Bigger, heavier, more complex. The anti-thesis to current simple air-cooled, and even twin-cooled motors.

[Ohio HD]

You're all assuming HD would pull a system out of a Chevy and put it in the motor.

"IF" they ever go down this road, how do you know it won't be all electric?

[Wookie3011]

It wouldn't be a huge leap as for the engineering of it. It's basically a cap at the end of the cam and a oil feed to push the cams forward and return to position. Of course I make it seem easy, but it's not nothing that couldn't be done. Harleys biggest feet I suppose would be consistently producing the same oil pressure in order to predict the advancement and retard of the cam in one of their Big Twins.

[Pirsch Fire Wagon]

The REV-X (Sportster-S) has VVT and it will be replacing the M8 in all platforms - The V-Twin is a thing of the Past.

[Wookie3011]

You're all assuming HD would pull a system out of a Chevy and put it in the motor.

"IF" they ever go down this road, how do you know it won't be all electric?

Very Interesting Ohio HD. It would cure the unpredictable behaviors of one pump to another. Perhaps a cross between the two.

[Wookie3011]

The REV-X (Sportster-S) has VVT and it will be replacing the M8 in all platforms - The V-Twin is a thing of the Past.

Stop it, I don't see them eliminating the Potato all together. No need to reinvent the wheel to accomplish this. I have visited many HD dealers and the Sportster S isn't setting the world on fire nor the nightster nor the PanAm. Top selling is what you would think it would be.

[Ohio HD]

The REV-X (Sportster-S) has VVT and it will be replacing the M8 in all platforms - The V-Twin is a thing of the Past.

I seem to remember the V-Rod motor was going to be the new power plant....     

[Hossamania]

The REV-X (Sportster-S) has VVT and it will be replacing the M8 in all platforms - The V-Twin is a thing of the Past.

I seem to remember the V-Rod motor was going to be the new power plant....     

It sure was.
The new Sportster S is double overhead cam (very efficient in terms of power), making the engine taller, like the V-Rod, and is 60° V instead of 45°. Helps with displacing the height a bit, but heavier, and definitely no more potato cadence.

[hrdtail78]

You're all assuming HD would pull a system out of a Chevy and put it in the motor.

"IF" they ever go down this road, how do you know it won't be all electric?

Complete control over solenoid operated valves would be the ticket.  Unfortunately I don't see the gasoline engine sticking around long enough to see some of these concepts make to a HD platform. 

[Ohio HD]

You're all assuming HD would pull a system out of a Chevy and put it in the motor.

"IF" they ever go down this road, how do you know it won't be all electric?

Complete control over solenoid operated valves would be the ticket.  Unfortunately I don't see the gasoline engine sticking around long enough to see some of these concepts make to a HD platform. 

I think we have a good 20 years before mainstream gasoline vehicles are out of site. I could be wrong, I just don't see the cost of electric cars / motorcycles attainable by the masses before then.

But that would be bad ass, having control of when and how much cam advance / retard from the tuning aspect.

[Hossamania]

As far as vehicles going away from being powered by fuel, airplanes, ships, heavy equipment, big trucks, trains, all have a LONG way to go before electric motors take over.
Automobiles also have a long learning curve ahead before they become mainstream and affordable.

I do see VVT being a boon to the HD motors, I started thinking that 20 years ago or more when the sport bikes started using it. Keeping it simple with electric solenoids would be a good way to go.

[Hossamania]

With the low rpm that the HD motors make, I'm not sure a Pre combustion chamber would be worth it, but just a little more tech for power and fuel efficiency.

[kd]

You're all assuming HD would pull a system out of a Chevy and put it in the motor.

"IF" they ever go down this road, how do you know it won't be all electric?

There are so many options already being used right now that it would be hard to predict.  That's if they even go to VVT or any of the systems out there doing that or a variation of sorts.  Toyota has been using more than one system and even building specialized engines to enhance controlling valve lift and timing. My 2022 Tacoma has innovative valve control.

Here is a place to start if you really want to see what is out there right now. You may be surprised.  If you want to go down the rabbit hole and get a better education, click on the see also section choices.

IMO it may be more likely that the MOCO wont use any variation of VVT.  It seems it is hard to get these equipped engines to meet the Euro IV emissions standard,  I think we all have seen changes in Harleys just to meet that level of emissions.  North America is following suit in many types of engine driven vehicles and devices.

[chopper]

All this "electric?" vehicle talk, regardless if feasible or not, begs ONE question: Where is all this extra electricity going to come from?  We've already been warned of rolling blackouts nationwide this summer.  We are building NO new power plants, water levels behind major dams are dropping. Solar is turning out to be a bottomless pit. Wind? Sporadic at best.
 So, where's the electricity going to come from?

As far as HD's future engines? I have a lot of doubts. I suspect the "potato" is going away. There are just far too many better, more efficient options out there. A V twin has inherent limitations. Especially when water cooled.

[barny7655]

VVT on a single cam engine im thinking wont be a over all advantage , more so on a twin cam motor with one exaust cam and one inlet cam running the two pots ,and able to advance,retard, either cam due to reves, or on some cars was only done on the inlet cam ,since the HDs are a low revving motor,and depending on the cam used, will enable the inlet cam to work on the higher revs may be an extra 250 to 500 revs for the exaust cam noot sure they would venture on that for VVT ,either electric or hydraulic VVT on the inlet  cam sprocket would do the trick ,or having two chains running off the crank ,one inlet ,one exaust with  VVT adjuster on the chain for the inlet,one adjuster releasing the other pushing changing the inlet cam position ,may happen , may not happen ,all up to the EPA and what comes out of the exaust ,cheers

[Hossamania]

Variable length intake runners to go with VVT?