HOW TO DO AN ADVANCED SEARCH.

Mon Jul 08, 2013 3:56 pm by Admin


For the benefit of 944Hybrids users there are two search functions available for you to use.
The purpose of this sticky is to explain the "Advanced Search" function because it is much more powerful and is the best choice when researching information.

When you log on to the site a list of options is shown in a line at the top of the page. One option is labelled "Search", use this option (NOT the search box lower down on the right).

After you click on the upper search option, a drop down box appears. At the bottom of this box is a radio button marked "Advanced …

Comments: 0

Latest topics
» Poly based strut mounts on exchange
Yesterday at 10:16 pm by xschop

» 18x10" Enkei wheels
Wed Aug 16, 2017 9:59 pm by Sterling Doc

» Around the block
Tue Aug 15, 2017 11:46 am by Red944ls1

» RX7 Caliper Swap
Mon Aug 14, 2017 8:13 am by osx86ftw

» Cooling solutions please!
Sun Aug 13, 2017 3:15 pm by yamamtx

» Holley intake, vacuum pump and cross member spacer
Sun Aug 13, 2017 12:33 am by zeusrotty

» Sparkydog's Abnormal Build - 944 With L67 + Ford Stuff & CARB Legal
Sat Aug 12, 2017 3:42 pm by sparkydog

» LSA Supercharged 86 Porsche 944
Sat Aug 12, 2017 7:41 am by haroldk

» Coolant / header tank cap
Wed Aug 09, 2017 7:56 pm by Arthropraxis

» Cadillac ATS Brembo Front Brake Swap
Tue Aug 08, 2017 6:43 pm by superman22x

August 2017
MonTueWedThuFriSatSun
 123456
78910111213
14151617181920
21222324252627
28293031   

Calendar Calendar

Log in

I forgot my password


Proper way to set valve lash

View previous topic View next topic Go down

Proper way to set valve lash

Post  bluehellfire666 on Thu Jun 11, 2009 11:09 am

hey all, it's nice to see some familiar faces!

i found this out the other day when i started the car and heard a horrendous tapping from the top end...i pulled the valve covers off and found all of the nuts loose, and two almost backed off of the rockers on the left side. I found out that there are several ways to set valve lash, one way is to set tdc and adjust 8 of the valves, and then rotate the engine 180 and set the other 8. HOWEVER, i learned that with an aftermarket cam, or even with the stock cam, this can cause problems...because at top dead center the valves you are adjusting might not be at their lowest point (the base of the circle of the lobe) so they can still be loose once adjusted...the proper way is as follows!

1. Remove the valve covers, and pick a cylinder you are going to set the preload on.

2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder’s intake rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)

3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)

4. Now spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the pushrod, you are at “Zero Lash”. Turn the adjusting nut down one half to one full turn from that point. Lock the adjuster into position. The intake is now adjusted properly.

5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

i was very lucky, and i will be using this method and checking it frequently to see if it will hold better...good luck guys!
Ethan Cooper
avatar
bluehellfire666

Posts : 209
Join date : 2009-06-09
Age : 27
Location : Bowie, MD

Back to top Go down

Re: Proper way to set valve lash

Post  suboptimalfit on Fri Jun 12, 2009 1:31 am

I have found, that if your adjusting nuts are "backing off" they have lost their "locknut" pinch points. This means the more you wrench/adjust 'em the freeer they get... when I get into this loop it's time for new "locknuts" or, (my favorite) Poly-Locks. (the adjuster nut is hollow and an allen set screw is tightened downward into the top of the rocker stud, wedging the two together) install and forget.

suboptimalfit

Posts : 61
Join date : 2009-06-11
Location : SF Bay Area

Back to top Go down

Re: Proper way to set valve lash

Post  ffmedic on Thu Sep 17, 2009 1:35 pm

Ok got a question on pushrods. Specifically length anyone know how to measure the pushrod length so it is accurate with the cam you are using. Do you need any special tools ect... for the procedure?
Thanks ahead of time.

ffmedic

Posts : 103
Join date : 2009-06-08
Location : Michigan

Back to top Go down

Re: Proper way to set valve lash

Post  bluehellfire666 on Thu Sep 17, 2009 7:39 pm

try reading this, it might help...

[You must be registered and logged in to see this link.]
avatar
bluehellfire666

Posts : 209
Join date : 2009-06-09
Age : 27
Location : Bowie, MD

Back to top Go down

Re: Proper way to set valve lash

Post  ffmedic on Fri Oct 02, 2009 6:25 pm

Ok got a question on valve lash I have the 1.6 rockers non-adjustable that come with the hot LT4 hot cam kit. My question is the valve lash set the same as the stock adjustable rockers?
Is their a different method usng the non adjustable rockers?

ffmedic

Posts : 103
Join date : 2009-06-08
Location : Michigan

Back to top Go down

Re: Proper way to set valve lash

Post  bluehellfire666 on Sat Oct 17, 2009 7:22 pm

oooo...i have no idea, i would think that you would set it the same way as i listed above, but i would call a place like jeg's and get their tech center on the line, there are some pretty knowledgeable people over there that might be able to point you in the right direction
avatar
bluehellfire666

Posts : 209
Join date : 2009-06-09
Age : 27
Location : Bowie, MD

Back to top Go down

Re: Proper way to set valve lash

Post  gt1scca on Sat Oct 17, 2009 10:37 pm

ffmedic wrote:...1.6 rockers non-adjustable...
This is from CompCams Magnum Roller Instructions...
[You must be registered and logged in to see this link.]

Hydraulic cams are set @ zero lash...

Hydraulic Lifter Cams / Intake: Tighten the adjusting nut until all the slack is taken out of the rocker arm and pushrod. By lightly turning the pushrod with your fingers as you tighten the adjusting nut, you will discover or feel a point at which there will be slight resistance. At this point, you have taken all the excess slack out of the pushrod. You are now at what we refer to as zero lash. Turn the adjusting one-half turn more. This will give you the ideal pre-load of the rocker arm, pushrod, and
lifter. Following this procedure, carefully adjust all intake valves.

Solid Lifter Cams: Consult cam spec card or cam manufacturer for correct lash specifications.
Tighten adjusting nut, while proper feeler gauge is between roller tip and valve, to the point at
which there is a slight drag when moving the feeler gauge. On solid lifter cams you wish to use
4602-16 (3/8”) or 4603-16 (7/16”) polylocks. Following this procedure, carefully adjust all intake
valves.

Hydraulic Lifter Cams / Exhaust
: To adjust exhaust valves, turn the engine over until the intake pushrod moves all the way up. Rotate past maximum lift, approximately one-half to two-thirds of the way back down. The lifter is now on the base circle and the exhaust valve can be adjusted.
Rotate the exhaust pushrod with your fingers and begin to tighten the exhaust adjusting nut. When
you feel the resistance on the pushrod, you are at zero lash. Tighten the adjusting nut one-half turn
more. Go through the exhaust valves and repeat the procedure carefully. Now all of the valves are
adjusted with the proper pre-load.

Solid Lifter Cams: To adjust the exhaust valves, turn the engine over until the intake pushrod
moves all the way up. Rotate past maximum lift, approximately one-half to two-thirds of the way
back down. Tighten adjusting nut, while proper feeler gauge is between roller tip and valve, to the
point at which there is a slight drag when moving feeler gauge. Following this procedure carefully
adjust all exhaust valves.

gt1scca

Posts : 795
Join date : 2009-06-08
Age : 48
Location : Belton, SC

Back to top Go down

Re: Proper way to set valve lash

Post  RobotMachines on Sun Oct 18, 2009 8:58 pm

I assume that you're having this problem with an LT engine?
avatar
RobotMachines

Posts : 156
Join date : 2009-08-09
Location : Connecticut

Back to top Go down

Re: Proper way to set valve lash

Post  ffmedic on Tue Oct 20, 2009 6:01 pm

RobotMachines wrote:I assume that you're having this problem with an LT engine?
Yes LT1 bought the LT4 hotcam kit with 1.6 rockers, in the rebuild book LT1/LT4 they said torque to 18 ft lbs with the lt4 which I thought was odd not setting to the zero lash deal, like the stock rockers, though I have found some other mistake within the book just double checking before I adjust the valaves withe rockers I have.
Thanks for the input on this subject.

ffmedic

Posts : 103
Join date : 2009-06-08
Location : Michigan

Back to top Go down

Re: Proper way to set valve lash

Post  RobotMachines on Thu Oct 22, 2009 7:35 pm

Like what gt1scca posted above, it probably depends on the type of lifter. The 18 ft/lbs probably refers to the torque to place on the lock nut... but I've never done it.
avatar
RobotMachines

Posts : 156
Join date : 2009-08-09
Location : Connecticut

Back to top Go down

Re: Proper way to set valve lash

Post  gt1scca on Thu Oct 22, 2009 8:07 pm

RobotMachines wrote:The 18 ft/lbs probably refers to the torque to place on the lock nut...
With #1 piston @ TDC (Top Dead Center) on the compression stroke, the #1 intake pushrod should spin freely between your fingers. Torque the locknut to 18 ft./lbs., or if using poly locks, the torque is applied to the set screw. The outer nut may be locked down last with a box-end wrench, but hold the set screw itself with an allen wrench while tightening the locknut to guarantee a positive lock on the stud.

In other words, the 18 ft./lbs. part is correct. The LT4 did come from GM with Crane Gold Series roller rockers and poly locks...

LT1 vs. LT4

gt1scca

Posts : 795
Join date : 2009-06-08
Age : 48
Location : Belton, SC

Back to top Go down

View previous topic View next topic Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum