prodracing.com

Unofficial SCCA Production Racing Forum
It is currently Sat Sep 26, 2020 8:57 pm

All times are UTC - 8 hours




Post new topic Reply to topic  [ 28 posts ]  Go to page Previous  1, 2, 3
Author Message
PostPosted: Wed Dec 11, 2019 7:02 pm 
Offline
User avatar

Joined: Wed Jan 13, 2010 10:58 am
Posts: 1220
Protech Racing wrote:
This rule was written when all of the cars required some lash. Pretty sure the 72 GCR reads the same way. I figure it is merely an oversight and a failure of the CRB to keep up with the modern valve train technology.

I checked a couple today. The best method is to depress the valve ( tell it a sad story), and set the dial indicator to zero, rotate the engine until the valve is full up. Read the value. Simple and fair to all of the valve trains .

We should not reduce the competitiveness of the old engines any more than we already do.IMHO
Thanks for your input .MM


So you say the spec has been written the same way since 1972, and then say we shouldn't reduce the performance of the older cars... But no one is suggesting a change to that rule but you. :ask:

_________________
99 HP Toyota Yaris
2005-2008 SCCA Solo National Champion
2017-2018 SCCA Runoffs Champion


Top
 Profile  
 
PostPosted: Thu Dec 12, 2019 5:37 am 
Offline

Joined: Fri Dec 23, 2011 6:59 am
Posts: 1389
Location: Spring Hill, FL.
My point is that the 60 yrs of valve train development can be equalized by checking the lift at the valve, as raced. That is all .
Push rod racers. Please Support letter # 27977.

_________________
Mike Ogren/Protech Racing, http://www.FWDracingguide.com http://www.ogren-engineering.com/ 352.428-8983 mogren@tampabay.rr.com


Top
 Profile  
 
PostPosted: Sun Dec 15, 2019 5:26 pm 
Offline

Joined: Tue Dec 31, 2013 10:40 am
Posts: 468
Location: Huntsville, AL
In this specific case, what engine is driving this request? What car are you building at the moment?

_________________
Brett W
Huntsville, AL


Top
 Profile  
 
PostPosted: Thu Dec 19, 2019 7:24 am 
Offline

Joined: Fri Dec 23, 2011 6:59 am
Posts: 1389
Location: Spring Hill, FL.
I have 2 cars . One runs at zero - 004 lash. The other runs at 010-16 . My cam events are about the same for both cams, but the actual valve events are far apart .


I know it sounds crazy to worry about losing the 010 thou of lift, but it could be 2HP .
The cars that need it the most, LBC, my Toyota , all have push rods and crappy old rockers.

_________________
Mike Ogren/Protech Racing, http://www.FWDracingguide.com http://www.ogren-engineering.com/ 352.428-8983 mogren@tampabay.rr.com


Top
 Profile  
 
PostPosted: Thu Dec 19, 2019 11:25 am 
Offline

Joined: Sun Dec 14, 2014 11:06 pm
Posts: 128
Location: Portland, OR
And Honda’s. And everyone hates those. So. Ya know.

_________________
Ian
FP CRX Si


Top
 Profile  
 
PostPosted: Thu Dec 19, 2019 4:36 pm 
Offline

Joined: Tue Dec 31, 2013 10:40 am
Posts: 468
Location: Huntsville, AL
Protech Racing wrote:
I have 2 cars . One runs at zero - 004 lash. The other runs at 010-16 . My cam events are about the same for both cams, but the actual valve events are far apart .


I know it sounds crazy to worry about losing the 010 thou of lift, but it could be 2HP .
The cars that need it the most, LBC, my Toyota , all have push rods and crappy old rockers.


Or it could be no HP loss. :roll: If you had everything else done to the engine, chassis, drivetrain, etc to absolutely max out the platform, .010 might matter, but in this case, I doubt you can see a measurable increase or decrease. Put the head on a flow bench and measure the difference in flow at .010 intervals. I would posit the difference in carb flow from one cylinder to the other will more than dwarf the change from .010 worth of lift.

_________________
Brett W
Huntsville, AL


Top
 Profile  
 
PostPosted: Thu Dec 19, 2019 7:28 pm 
Offline

Joined: Fri Dec 23, 2011 6:59 am
Posts: 1389
Location: Spring Hill, FL.
If there is no difference, why would you oppose checking the lash the same method for all of the cars?
Seems to make sense .
What logical/fair reason could you put forward to not check lash as raced?

_________________
Mike Ogren/Protech Racing, http://www.FWDracingguide.com http://www.ogren-engineering.com/ 352.428-8983 mogren@tampabay.rr.com


Top
 Profile  
 
PostPosted: Fri Dec 20, 2019 7:25 am 
Offline

Joined: Tue Dec 31, 2013 10:40 am
Posts: 468
Location: Huntsville, AL
Protech Racing wrote:
If there is no difference, why would you oppose checking the lash the same method for all of the cars?
Seems to make sense .
What logical/fair reason could you put forward to not check lash as raced?


I would ask the opposite. Since there is no measurable gain or loss, why bother dying on this hill? Save it for something meaningful.

_________________
Brett W
Huntsville, AL


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 28 posts ]  Go to page Previous  1, 2, 3

All times are UTC - 8 hours


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group