991 GT3 Concerned Owners Group
06-22-2017, 09:44 PM
#331
Burning Brakes
Things are good, hope you're well also! I believe in the G engines they went with a slightly softer valve spring, but this is only controlling the valve's motion and "flutter" meaning that you need a spring of sufficient spring rate to keep the valve from bouncing off of the seat. Now I can't explain how/why one engine survives and another fails, but I can say that the current design has flaws and those flaws are the major driver of the failures. If those flaws are fixed (maintaining adequate space between the cam and finger follower for an oil film to form) ala a solid lash adjuster, then we believe the issue is no longer one to wonder about.
Since we're talking about lack of oil related wear, there are lots of things that could cause the issue, lots of starts and stops with cold oil, beating on the car when the oil is cold, tracking the car at high temps causing low oil viscosity, etc etc. These are all off the top of my head, I'm sure there are more. But the bottom line is, fix the issue at the source (keep oil between the cam lobe and finger follower) and all the other possible use correlations are no longer concerns.
Since we're talking about lack of oil related wear, there are lots of things that could cause the issue, lots of starts and stops with cold oil, beating on the car when the oil is cold, tracking the car at high temps causing low oil viscosity, etc etc. These are all off the top of my head, I'm sure there are more. But the bottom line is, fix the issue at the source (keep oil between the cam lobe and finger follower) and all the other possible use correlations are no longer concerns.
06-23-2017, 05:38 PM
#332
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
That said, the 991.2 is using a "lifetime" no adjustment necessary solid lash adjuster. It's yet to be seen how long a "lifetime" is... In the press release it was at least 300,000km. Which if it happens that way for every car, that essentially a lifetime of a GT car!
We're doing some simulations and wear testing on our parts to get a good idea of when to schedule the lash adjustment. Most engine builders would suggest checking the clearances on a regular basis (10,000-15,000 miles).
__________________
Dundon Motorsports
Gig Harbor, WA
253-200-4454
jamie@dundonmotorsports.com
www.dundonmotorsports.com
Facebook.com/dundonmotorsports
Instagram @dundon_motorsports
Dundon Motorsports
Gig Harbor, WA
253-200-4454
jamie@dundonmotorsports.com
www.dundonmotorsports.com
Facebook.com/dundonmotorsports
Instagram @dundon_motorsports
06-26-2017, 12:30 AM
#334
Burning Brakes
Typically solid lash adjusters (or solid lifters) need to be adjusted every so often (think of your old air-cooled needing a valve adjustment...). This creates an additional maintenance requirement and would increase the lifetime emissions of the car (additional oil changes) and when there's already pressure on reducing the vehicles environmental footprint it makes it harder on the OEM to use this solution. They also require a bit more time to build the engine as everything has to be checked for clearances after install typically.
That said, the 991.2 is using a "lifetime" no adjustment necessary solid lash adjuster. It's yet to be seen how long a "lifetime" is... In the press release it was at least 300,000km. Which if it happens that way for every car, that essentially a lifetime of a GT car!
We're doing some simulations and wear testing on our parts to get a good idea of when to schedule the lash adjustment. Most engine builders would suggest checking the clearances on a regular basis (10,000-15,000 miles).
That said, the 991.2 is using a "lifetime" no adjustment necessary solid lash adjuster. It's yet to be seen how long a "lifetime" is... In the press release it was at least 300,000km. Which if it happens that way for every car, that essentially a lifetime of a GT car!
We're doing some simulations and wear testing on our parts to get a good idea of when to schedule the lash adjustment. Most engine builders would suggest checking the clearances on a regular basis (10,000-15,000 miles).
06-26-2017, 01:49 PM
#335
Race Director
Thread Starter
Update: The meeting is confirmed for August 3rd. I will be contacting members of our delegation shortly to setup a call to go over the meeting agenda.
06-26-2017, 05:45 PM
#337
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
The parts are finishing mfg, we expect to have them by beginning of August. Lash specs would be cold... A talented Tech could do it in the car, we will see if we can source the tooling to get it setup to do it in the car, for now assume it's engine out.
06-26-2017, 11:30 PM
#338
Race Director
Originally Posted by Jamie@dundonmotorsports
Congrats! Very interested in the outcome!
I would think your expertise and opinions would be invaluable for the cause.
06-27-2017, 10:31 AM
#340
Rennlist Member
Is everyone aware of the effort Rob started in support of the Concerned Owner's Group?
Every dollar donated is a "vote" for our cause, and a show of strength to Porsche. And of course it goes to a very worthwhile charity. It's all explained in an articulate first post by Rob:
https://rennlist.com/forums/991-gt3-...donations.html
This site has been up for 22 days and we are only at $3053.68 = 61% of the $5000 goal by 42 people (of the over 240 members of the Concerned Owners Group).
In a nutshell - rather than accept money from the group to reimburse delegate travel costs, Rob thought it would be a show of strength for our group to donate money to a worthwhile charity. The hope is to achieve the $5000 goal, and maybe Porsche will provide a matching donation.
Please take a moment to read the thread^, to support Rob and the delegates, and to send a message of strength to Porsche, and of course to do a good thing for people in need.
No donations in the past seven days.
Every dollar donated is a "vote" for our cause, and a show of strength to Porsche. And of course it goes to a very worthwhile charity. It's all explained in an articulate first post by Rob:
https://rennlist.com/forums/991-gt3-...donations.html
This site has been up for 22 days and we are only at $3053.68 = 61% of the $5000 goal by 42 people (of the over 240 members of the Concerned Owners Group).
In a nutshell - rather than accept money from the group to reimburse delegate travel costs, Rob thought it would be a show of strength for our group to donate money to a worthwhile charity. The hope is to achieve the $5000 goal, and maybe Porsche will provide a matching donation.
Please take a moment to read the thread^, to support Rob and the delegates, and to send a message of strength to Porsche, and of course to do a good thing for people in need.
No donations in the past seven days.
06-27-2017, 04:02 PM
#342
Race Director
Thread Starter
06-29-2017, 07:32 PM
#343
Rennlist Member
Since those reading this thread may not be aware of the other thread....
Here is a post from Rob that every one of the 250+ members of the Concerned Owner's Group should see:
______________________________________________________
Posted by Robmypro:
Thanks! We CAN do this! By my estimate this will cost each member of our delegation $1,500 easy, not including all the hours going into preparing for the meeting. Chipping in a few bucks would be appreciated, as it helps people TRULY in need.
We are definitely going to ask Porsche to make a matching donation, so let's do this people.
______________________________________________________
Originally Posted by needmoregarage:
Still painfully shy of the $5000 goal but at least some have stepped up to donate!
Currrently 51 people have donated $3621.87 which is 72% of the goal.
Hoping more of the 199 remaining concerned owners group members will consider donating for a good cause and show of strength for the group.
Thanks Rob for your efforts, and to all the delegates who are representing the group and paying from their own pocket!
____________________________________
Here is the link to donate:
https://www.justgiving.com/fundraising/991-GT3-COG
Here is the link to the thread Rob created explaining that instead of members donating to offset delegate travel costs - members can donate to a great cause and show Porsche the strength of our resolve:
https://rennlist.com/forums/991-gt3-...donations.html
Here is a post from Rob that every one of the 250+ members of the Concerned Owner's Group should see:
______________________________________________________
Posted by Robmypro:
Thanks! We CAN do this! By my estimate this will cost each member of our delegation $1,500 easy, not including all the hours going into preparing for the meeting. Chipping in a few bucks would be appreciated, as it helps people TRULY in need.
We are definitely going to ask Porsche to make a matching donation, so let's do this people.
______________________________________________________
Originally Posted by needmoregarage:
Still painfully shy of the $5000 goal but at least some have stepped up to donate!
Currrently 51 people have donated $3621.87 which is 72% of the goal.
Hoping more of the 199 remaining concerned owners group members will consider donating for a good cause and show of strength for the group.
Thanks Rob for your efforts, and to all the delegates who are representing the group and paying from their own pocket!
____________________________________
Here is the link to donate:
https://www.justgiving.com/fundraising/991-GT3-COG
Here is the link to the thread Rob created explaining that instead of members donating to offset delegate travel costs - members can donate to a great cause and show Porsche the strength of our resolve:
https://rennlist.com/forums/991-gt3-...donations.html
06-29-2017, 08:53 PM
#344
Nordschleife Master
Since those reading this thread may not be aware of the other thread....
Here is a post from Rob that every one of the 250+ members of the Concerned Owner's Group should see:
______________________________________________________
Posted by Robmypro:
Thanks! We CAN do this! By my estimate this will cost each member of our delegation $1,500 easy, not including all the hours going into preparing for the meeting. Chipping in a few bucks would be appreciated, as it helps people TRULY in need.
We are definitely going to ask Porsche to make a matching donation, so let's do this people.
______________________________________________________
Originally Posted by needmoregarage:
Still painfully shy of the $5000 goal but at least some have stepped up to donate!
Currrently 51 people have donated $3621.87 which is 72% of the goal.
Hoping more of the 199 remaining concerned owners group members will consider donating for a good cause and show of strength for the group.
Thanks Rob for your efforts, and to all the delegates who are representing the group and paying from their own pocket!
____________________________________
Here is the link to donate:
https://www.justgiving.com/fundraising/991-GT3-COG
Here is the link to the thread Rob created explaining that instead of members donating to offset delegate travel costs - members can donate to a great cause and show Porsche the strength of our resolve:
https://rennlist.com/forums/991-gt3-...donations.html
Here is a post from Rob that every one of the 250+ members of the Concerned Owner's Group should see:
______________________________________________________
Posted by Robmypro:
Thanks! We CAN do this! By my estimate this will cost each member of our delegation $1,500 easy, not including all the hours going into preparing for the meeting. Chipping in a few bucks would be appreciated, as it helps people TRULY in need.
We are definitely going to ask Porsche to make a matching donation, so let's do this people.
______________________________________________________
Originally Posted by needmoregarage:
Still painfully shy of the $5000 goal but at least some have stepped up to donate!
Currrently 51 people have donated $3621.87 which is 72% of the goal.
Hoping more of the 199 remaining concerned owners group members will consider donating for a good cause and show of strength for the group.
Thanks Rob for your efforts, and to all the delegates who are representing the group and paying from their own pocket!
____________________________________
Here is the link to donate:
https://www.justgiving.com/fundraising/991-GT3-COG
Here is the link to the thread Rob created explaining that instead of members donating to offset delegate travel costs - members can donate to a great cause and show Porsche the strength of our resolve:
https://rennlist.com/forums/991-gt3-...donations.html
Well put Carol, I second this.
Let's hit the target.
06-30-2017, 08:58 AM
#345
Banned
Things are good, hope you're well also! I believe in the G engines they went with a slightly softer valve spring, but this is only controlling the valve's motion and "flutter" meaning that you need a spring of sufficient spring rate to keep the valve from bouncing off of the seat. Now I can't explain how/why one engine survives and another fails, but I can say that the current design has flaws and those flaws are the major driver of the failures. If those flaws are fixed (maintaining adequate space between the cam and finger follower for an oil film to form) ala a solid lash adjuster, then we believe the issue is no longer one to wonder about.
Since we're talking about lack of oil related wear, there are lots of things that could cause the issue, lots of starts and stops with cold oil, beating on the car when the oil is cold, tracking the car at high temps causing low oil viscosity, etc etc. These are all off the top of my head, I'm sure there are more. But the bottom line is, fix the issue at the source (keep oil between the cam lobe and finger follower) and all the other possible use correlations are no longer concerns.
Since we're talking about lack of oil related wear, there are lots of things that could cause the issue, lots of starts and stops with cold oil, beating on the car when the oil is cold, tracking the car at high temps causing low oil viscosity, etc etc. These are all off the top of my head, I'm sure there are more. But the bottom line is, fix the issue at the source (keep oil between the cam lobe and finger follower) and all the other possible use correlations are no longer concerns.
Typically solid lash adjusters (or solid lifters) need to be adjusted every so often (think of your old air-cooled needing a valve adjustment...). This creates an additional maintenance requirement and would increase the lifetime emissions of the car (additional oil changes) and when there's already pressure on reducing the vehicles environmental footprint it makes it harder on the OEM to use this solution. They also require a bit more time to build the engine as everything has to be checked for clearances after install typically.
That said, the 991.2 is using a "lifetime" no adjustment necessary solid lash adjuster. It's yet to be seen how long a "lifetime" is... In the press release it was at least 300,000km. Which if it happens that way for every car, that essentially a lifetime of a GT car!
We're doing some simulations and wear testing on our parts to get a good idea of when to schedule the lash adjustment. Most engine builders would suggest checking the clearances on a regular basis (10,000-15,000 miles).
That said, the 991.2 is using a "lifetime" no adjustment necessary solid lash adjuster. It's yet to be seen how long a "lifetime" is... In the press release it was at least 300,000km. Which if it happens that way for every car, that essentially a lifetime of a GT car!
We're doing some simulations and wear testing on our parts to get a good idea of when to schedule the lash adjustment. Most engine builders would suggest checking the clearances on a regular basis (10,000-15,000 miles).
Kudos for the work you've done on this! Thx.