Lash adjust Go No Go approach?
09-12-2015, 05:35 PM
#1
Burning Brakes
Thread Starter
Lash adjust Go No Go approach?
Think I will try this next valve adjustment. Also, gonna make a 9m 36 degree "thing a majiggie" ....
Regarding backside method, when using the feeler gauges, it assumes the rocker is sitting on the backside of cam lifter, correct? And as feeler is inserted, we lift the rocker as we slide the .0025 for GO and .0030 for NO GO...
My question;
AS a general Rocker function question, what has rocker tensioned to always rest on cam lobe in general? Help me to understand my silly little question.....
Another way to say it, there is lash clearance at the tappet, so what keeps rocker foot on cam lobe at all times?
Regarding backside method, when using the feeler gauges, it assumes the rocker is sitting on the backside of cam lifter, correct? And as feeler is inserted, we lift the rocker as we slide the .0025 for GO and .0030 for NO GO...
My question;
AS a general Rocker function question, what has rocker tensioned to always rest on cam lobe in general? Help me to understand my silly little question.....
Another way to say it, there is lash clearance at the tappet, so what keeps rocker foot on cam lobe at all times?
Last edited by C4inLA; 09-13-2015 at 12:09 AM.
09-13-2015, 07:43 AM
#2
I just finished an adjustment on my 89, and used the Kirk tool which is similar in theory to the 9m thing. For me this is personal preference, but I'll go back to feeler gauge. The need for visual inspection in some of the odd angles you might have to contort your body made my confidence level a little lower.
I have some ideas, but no real answers for your other questions. I can say based on VW engines valves that metal expands, and may take up some of the lash. I suspect this is accurate for the Porsche engine as well, but have not validated this.
I have some ideas, but no real answers for your other questions. I can say based on VW engines valves that metal expands, and may take up some of the lash. I suspect this is accurate for the Porsche engine as well, but have not validated this.
09-13-2015, 10:04 AM
#3
My question;
AS a general Rocker function question, what has rocker tensioned to always rest on cam lobe in general? Help me to understand my silly little question.....
Another way to say it, there is lash clearance at the tappet, so what keeps rocker foot on cam lobe at all times?
AS a general Rocker function question, what has rocker tensioned to always rest on cam lobe in general? Help me to understand my silly little question.....
Another way to say it, there is lash clearance at the tappet, so what keeps rocker foot on cam lobe at all times?
09-13-2015, 01:30 PM
#4
Rennlist Member
Join Date: Jul 2003
Location: Peachtree City, Ga
Posts: 1,940
Likes: 0
Received 60 Likes
on
50 Posts
Some time back - there was a special valve adjustment tool that was made by a rennlister or a family member. Was a very simple device that measured the turn to the amount of adjustment. Can not recall who contributed info - appeared to be a good device and a good deal for the $$ - should have grabbed one then -
Anyone recall who posted -
Really made the operation simple -
Anyone recall who posted -
Really made the operation simple -
09-13-2015, 02:03 PM
#5
Burning Brakes
Thread Starter
Sorry, didn't get my question answered. It's a Rocker function thing..... Assume lash is perfect at 1.0 mm... Go/No Go perfect at rocker foot. So with both tasks complete, is rocker floating? Or, does foot rest against cam at all times? Because, if not, foot and cam have many impact events to each other at same spot on cam over time vs cam and foot always in contact 360 degrees of rotation.... ?
09-13-2015, 02:08 PM
#6
Rennlist Member
Some time back - there was a special valve adjustment tool that was made by a rennlister or a family member. Was a very simple device that measured the turn to the amount of adjustment. Can not recall who contributed info - appeared to be a good device and a good deal for the $$ - should have grabbed one then -
Anyone recall who posted -
Really made the operation simple -
Anyone recall who posted -
Really made the operation simple -
https://rennlist.com/forums/964-foru...available.html
09-13-2015, 02:37 PM
#7
Rennlist Member
Sorry, didn't get my question answered. It's a Rocker function thing..... Assume lash is perfect at 1.0 mm... Go/No Go perfect at rocker foot. So with both tasks complete, is rocker floating? Or, does foot rest against cam at all times? Because, if not, foot and cam have many impact events to each other at same spot on cam over time vs cam and foot always in contact 360 degrees of rotation.... ?
Trending Topics
09-14-2015, 06:33 AM
#9
Some time back - there was a special valve adjustment tool that was made by a rennlister or a family member. Was a very simple device that measured the turn to the amount of adjustment. Can not recall who contributed info - appeared to be a good device and a good deal for the $$ - should have grabbed one then -
Anyone recall who posted -
Really made the operation simple -
Anyone recall who posted -
Really made the operation simple -
Which is what I used. Quality is top notch but I think I prefer the feeler gauge method.
09-15-2015, 11:47 AM
#11
Rennlist Member
Join Date: Jul 2003
Location: Peachtree City, Ga
Posts: 1,940
Likes: 0
Received 60 Likes
on
50 Posts
NO not that - this was very simple device you slid on to the screw drive - worked as pointer. Some one figured out that a 1/4 or 1/2 turn was equal to 1.0 mm ( required gap) . So you just slid this arrow like device on your screw driver, adjusted adjusted to "0 mm" then backed off the necessary portion of turn using the device to determine correct rotation. Simple and sweet. No check needed.
09-15-2015, 03:37 PM
#12
Burning Brakes
Thread Starter
Got a dial gauge coming to practice timing cams and will check lash on few... Feeler gauge backup, Go No Go double check back up... But, a one turn, no check, sign me up 
Last edited by C4inLA; 09-15-2015 at 03:38 PM. Reason: Valves
09-15-2015, 04:57 PM
#13
Rennlist Member
You are overthinking this whole valve lash setting thing. There is no magic tool that will give you spot on valve clearance of 0.1 mm every time, and you should definitely go back and check all the settings a second time. I use the Porsche tool with the small feeler gauge for my initial setting, then go around again and check them all using the back side method. It will take you a few try's with the Porsche tool, to get it right, but after that, it's pretty straight forward.
09-16-2015, 10:32 AM
#15
Rennlist Member
this was very simple device you slid on to the screw drive - worked as pointer. Some one figured out that a 1/4 or 1/2 turn was equal to 1.0 mm ( required gap) . So you just slid this arrow like device on your screw driver, adjusted adjusted to "0 mm" then backed off the necessary portion of turn using the device to determine correct rotation. Simple and sweet. No check needed.
The "9m" valve adjusting tool
https://rennlist.com/forums/964-1989-1994-911/466804-the-9m-valve-adjusting-tool.html