Elio Engine Valvetrain

[skygazer6033]

At the start of this thread I was asked where I had found the information on classed shims for valve adjustment. Well I just found it again. It was on a picture of the IAV data sheet for the ELIO engine displayed alongside the plastic engine replica at the tour stops. " Valvetrain: switchable tappets".

 

[goofyone]

At the start of this thread I was asked where I had found the information on classed shims for valve adjustment. Well I just found it again. It was on a picture of the IAV data sheet for the ELIO engine displayed alongside the plastic engine replica at the tour stops. " Valvetrain: switchable tappets".

Nice find! Unfortunately this information by itself does not really answer our questions as switchable tappets are available in both mechanical and hydraulic versions and their purpose is actually for variable valve lift.

 

[skygazer6033]

I have to admit the term "switchable tappets" is pretty vague but I feel that if the engine had hydraulic tappets they would say so. With this type of valve train classed shims are the simplest since there are no rollers or rocker arms. This method is used on bikes that turn 12,000 to 14,000 rpm. With the Elio engine probably red lining at half that rpm you'ld probably only need to check the clearance at 35,000 or 40,000 miles. The early Suzuki G10 and the turbocharged ones used shims.

 

[skygazer6033]

It seems the term "switchable tappet" really doesn't refer to valve adjustment at all. This design of cam follower has a electro hydraulic 2 stage stepped lift capability. It's part of the VVT system. However "switchable tappets" are available in both hydraulic and mechanical (shimmed) clearance adjustment so I still haven't answered my original question.

 

[powerup]

The Elio will be using a dual lift or shifting hydraulic bucket on the intake. This allows for high and low lift based on engine RPM and load demands. There are three lobes per intake. Effectively the same system as Porsche uses as it's Variocam Plus System. As pointed out earlier in this post the bucket tappets are hydraulic. The integral cam cover with integral cam bores, would require a lot of tooling to allow the use of a shim style mechanical adjustment.

To clear up any doubt, the cams run in the parent aluminum of the camcover and cylinder head. This is a proven method in engine design for 35 plus years. It does require tighter design and manufacturing tolerances with today's lower viscosity oils.

 

[Music Man]

will be interesting to see what the maintenance schedule is such as oil changes, valve adjustments, transmission servicing. Hopefully not too bad because some of the folks at pep boys aren't the best of mechanics and they will be practicing on the real deal.

WELCOME to the family, Tim!

 

[Music Man]

The Elio will be using a dual lift or shifting hydraulic bucket on the intake. This allows for high and low lift based on engine RPM and load demands. There are three lobes per intake. Effectively the same system as Porsche uses as it's Variocam Plus System. As pointed out earlier in this post the bucket tappets are hydraulic. The integral cam cover with integral cam bores, would require a lot of tooling to allow the use of a shim style mechanical adjustment.
View attachment 2219

To clear up any doubt, the cams run in the parent aluminum of the camcover and cylinder head. This is a proven method in engine design for 35 plus years. It does require tighter design and manufacturing tolerances with today's lower viscosity oils.

WELCOME, powerup. Looks like you are jumping in during a very interesting debate. . . . . Good luck.

 

[2.ooohhh]

The Elio will be using a dual lift or shifting hydraulic bucket on the intake. This allows for high and low lift based on engine RPM and load demands. There are three lobes per intake. Effectively the same system as Porsche uses as it's Variocam Plus System. As pointed out earlier in this post the bucket tappets are hydraulic. The integral cam cover with integral cam bores, would require a lot of tooling to allow the use of a shim style mechanical adjustment.
View attachment 2219

To clear up any doubt, the cams run in the parent aluminum of the camcover and cylinder head. This is a proven method in engine design for 35 plus years. It does require tighter design and manufacturing tolerances with today's lower viscosity oils.

Not sure of your source, but if true I'll be a happy camper I like the Variocam much better than some of the other variable valve timing methods when it comes to longevity.

 

[goofyone]

The Elio will be using a dual lift or shifting hydraulic bucket on the intake. This allows for high and low lift based on engine RPM and load demands. There are three lobes per intake. Effectively the same system as Porsche uses as it's Variocam Plus System. As pointed out earlier in this post the bucket tappets are hydraulic. The integral cam cover with integral cam bores, would require a lot of tooling to allow the use of a shim style mechanical adjustment.
View attachment 2219

To clear up any doubt, the cams run in the parent aluminum of the camcover and cylinder head. This is a proven method in engine design for 35 plus years. It does require tighter design and manufacturing tolerances with today's lower viscosity oils.

Not sure of your source, but if true I'll be a happy camper I like the Variocam much better than some of the other variable valve timing methods when it comes to longevity.

Welcome powerup and great first post!

I can verify that powerup is correct about the variable lift system.

Also I can confirm that variable valve timing is not currently planned for this engine.

I had to go back and re-read the Tech Talks a few days ago and discovered that Elio Motors has actually all along stated that this engine would feature variable valve lift and not variable valve timing. In the very first Tech Talk IAV/Elio states that this engine will use 'two-step variable lift technology' and in Tech Talk v24 EM confirms that VVT will not be used in this engine. This information is further corroborated by the IAV/Elio demo engine spec sheet stating that 'switchable tappets' will be used as switchable tappets are specifically used to change lift. Switchable tappets are commonly used as one component of a VVT package however there is nothing to say they can not be used on their own. You can also see the arrangement of the intake cam lobes in the Elio engine animation video.

Tech Talk V1: http://us6.campaign-archive2.com/?u=24b371802c83d81776b06aa68&id=545e7f615f
Tech Talk V24: http://us6.campaign-archive1.com/?u=24b371802c83d81776b06aa68&id=4801365dc7

 

[Jim H]

The Elio will be using a dual lift or shifting hydraulic bucket on the intake. This allows for high and low lift based on engine RPM and load demands. There are three lobes per intake. Effectively the same system as Porsche uses as it's Variocam Plus System. As pointed out earlier in this post the bucket tappets are hydraulic. The integral cam cover with integral cam bores, would require a lot of tooling to allow the use of a shim style mechanical adjustment.
View attachment 2219

To clear up any doubt, the cams run in the parent aluminum of the camcover and cylinder head. This is a proven method in engine design for 35 plus years. It does require tighter design and manufacturing tolerances with today's lower viscosity oils.

Powerup, welcome from New Mexico. Hope you find the forum informative and entertaining and the members friendly and helpful.