valve adjustment observations (long)
09-04-2002, 09:56 PM
#1
Rennlist Member
Thread Starter
valve adjustment observations (long)
How many of you folks do your own valve adjustment? A couple days ago I adjusted the valves and replaced the spark plugs for my first time.
Observations:
1. Brian Smith's article in the tech section is a pretty good guide.
2. It took me longer than I thought it would (but next time I'll be faster), but I had fun.
3. Very important to have the right tools, sockets & box wrenches etc., including universal joints, various extensions for the sockets, and a small flashlight.
4. I tried using a bump starter/remote starter to turn the motor (basically a normally-open push button switch between two 5 or 6 foot lengths of electrical cable terminated with clamps, connect them to the starter solenoid and then bump the switch to engage the starter) but the motor turned too fast for me to stop it with precision, and besides that after the starter disengaged the compression in the cylinders bumped the crank forward or back to one side of TDC. So, I removed the lower set of plugs and rotated the crank using the fan/alternator pulley. That worked very well. I was not inclined to tighten the alternator belt until the alternator pulley would turn the engine through full compression, I think that level of tension would ultimately destroy the alternator bearings.
5. After trying multiple times to insert the gauge blade to check valve clearance before adjusting anything, I gave up. Too much aggravation. Thereafter on all the valves I simply loosened the locknut, backed the tappet out to give lots of clearance, slipped the gauge in, snugged the tappet down to a proper clearance with the gauge, tightened down the locknut, and removed the gauge. I also wiggled the rocker before and after adjusting the tappet to get a ballpark check on the clearance (I readjusted and checked an easily accessible exhaust valve several times until I was sure that the gauged clearance was correct and I was getting a good idea for what the "feel" should be).
6. Labeling wires and placing fasteners in labeled ziploc bags on disassembly, saved time on reassembly.
7. It is easier to get at the upper plugs with the valve covers removed (may be impossible to remove the upper #6 plug without removing the valve cover)
8. To remove one of the forward 4 cat bolts (that clamp the crush gasket at the inlet of the cat) I had to use two 13mm wrenches, there was no clearance for a ratchet with socket.
9. For the #6 intake valve tucked against the right firewall underneath the power steering pump, I could not get both hands in (one to hold the tappet screw and one to tighten the locknut). So I tightened the adjustment down, and backed off enough to compensate for the tappet screw drifting a little when I tightened the locknut. The screw slot in the tappet screw provided a visual reference for the tappet adjustment; I checked its orientation with the locknut loose and the tappet properly adjusted (but not backed off to compensate for drift), and then checked for that same orientation after tightening the locknut.
10. The offset 13mm wrench in the Porsche tool kit was useful on the tappet locknuts (that lock in the valve adjustment) because the offset allowed the wrench handle to clear the valve cover studs. My standard flat box wrench also worked, but less conveniently.
Final note, the last adjustment was about 20,000 miles ago... all the clearances (before I re-adjusted them) seemed fine by feel, but the tension on the locknut for the #3 cylinder intake was *very* light.
Bottom line: I'm glad I did the adjustment, I'd do it again.
Observations:
1. Brian Smith's article in the tech section is a pretty good guide.
2. It took me longer than I thought it would (but next time I'll be faster), but I had fun.
3. Very important to have the right tools, sockets & box wrenches etc., including universal joints, various extensions for the sockets, and a small flashlight.
4. I tried using a bump starter/remote starter to turn the motor (basically a normally-open push button switch between two 5 or 6 foot lengths of electrical cable terminated with clamps, connect them to the starter solenoid and then bump the switch to engage the starter) but the motor turned too fast for me to stop it with precision, and besides that after the starter disengaged the compression in the cylinders bumped the crank forward or back to one side of TDC. So, I removed the lower set of plugs and rotated the crank using the fan/alternator pulley. That worked very well. I was not inclined to tighten the alternator belt until the alternator pulley would turn the engine through full compression, I think that level of tension would ultimately destroy the alternator bearings.
5. After trying multiple times to insert the gauge blade to check valve clearance before adjusting anything, I gave up. Too much aggravation. Thereafter on all the valves I simply loosened the locknut, backed the tappet out to give lots of clearance, slipped the gauge in, snugged the tappet down to a proper clearance with the gauge, tightened down the locknut, and removed the gauge. I also wiggled the rocker before and after adjusting the tappet to get a ballpark check on the clearance (I readjusted and checked an easily accessible exhaust valve several times until I was sure that the gauged clearance was correct and I was getting a good idea for what the "feel" should be).
6. Labeling wires and placing fasteners in labeled ziploc bags on disassembly, saved time on reassembly.
7. It is easier to get at the upper plugs with the valve covers removed (may be impossible to remove the upper #6 plug without removing the valve cover)
8. To remove one of the forward 4 cat bolts (that clamp the crush gasket at the inlet of the cat) I had to use two 13mm wrenches, there was no clearance for a ratchet with socket.
9. For the #6 intake valve tucked against the right firewall underneath the power steering pump, I could not get both hands in (one to hold the tappet screw and one to tighten the locknut). So I tightened the adjustment down, and backed off enough to compensate for the tappet screw drifting a little when I tightened the locknut. The screw slot in the tappet screw provided a visual reference for the tappet adjustment; I checked its orientation with the locknut loose and the tappet properly adjusted (but not backed off to compensate for drift), and then checked for that same orientation after tightening the locknut.
10. The offset 13mm wrench in the Porsche tool kit was useful on the tappet locknuts (that lock in the valve adjustment) because the offset allowed the wrench handle to clear the valve cover studs. My standard flat box wrench also worked, but less conveniently.
Final note, the last adjustment was about 20,000 miles ago... all the clearances (before I re-adjusted them) seemed fine by feel, but the tension on the locknut for the #3 cylinder intake was *very* light.
Bottom line: I'm glad I did the adjustment, I'd do it again.
02-17-2003, 01:42 PM
#2
Instructor
Hi Dave, Do you remember about how long this process took? I've done the valve adjustment on earlier 911s, where you don't have to take a bunch of stuff out of the way. I'm curious how long it will take me to do the 964 adjustment first time. Thanks, Jeff (also in Virginia- figure you're home looking at Rennlist since the big snow 
)
)
02-18-2003, 03:14 AM
#4
Burning Brakes
</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Dave Ream:
<strong>...
5. After trying multiple times to insert the gauge blade to check valve clearance before adjusting anything, I gave up. Too much aggravation. Thereafter on all the valves I simply loosened the locknut, backed the tappet out to give lots of clearance, slipped the gauge in, snugged the tappet down to a proper clearance with the gauge, tightened down the locknut, and removed the gauge....</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Great observations, Dave. Thanks.
I'm so happy to hear that I wasn't the only one who had trouble getting the feeler gauge in there. I gave up, too. It is MUCH easier to loosen, insert, and then adjust.
I even had difficulty re-inserting the feeler gauge immediately after adjusting!
<strong>...
5. After trying multiple times to insert the gauge blade to check valve clearance before adjusting anything, I gave up. Too much aggravation. Thereafter on all the valves I simply loosened the locknut, backed the tappet out to give lots of clearance, slipped the gauge in, snugged the tappet down to a proper clearance with the gauge, tightened down the locknut, and removed the gauge....</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Great observations, Dave. Thanks.
I'm so happy to hear that I wasn't the only one who had trouble getting the feeler gauge in there. I gave up, too. It is MUCH easier to loosen, insert, and then adjust.
I even had difficulty re-inserting the feeler gauge immediately after adjusting!
02-18-2003, 03:58 AM
#5
Race Car
The gauge insertion becomes an "acquired talent" after a few valve adjustments. 
I don't have a problem with it unless the valves are initially too tight.
ALL of your suggestions are valid, certainly...and there's no other way to do it if you're having issues with gauge insertion.
There is truly NO time amount one could assign to this job with the many variables involved...I tend to remove the whole engine/trans. when I make a valve adjustment, it's just easier and I would normally couple this with a few other tasks, of course.
You have rusted exhaust bolts to deal with, deciding on how much stuff to remove for clearance, etc. A shop that is VERY experienced can whip out the procedure in a couple of hours...although you're sure to be charged the FULL rate! <img border="0" title="" alt="[Wink]" src="wink.gif" />
Jeff W. - NO SNOW down here at the beach! ...it just rained cats and dogs all damned weekend!! <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />
I took a "break" from Rennlist for a few days and got my new rollcage welded in...whatta pain in the A__!! ...next time, I'll pay the shop fee. <img border="0" title="" alt="[Wink]" src="wink.gif" />
Yeah right! <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
I don't have a problem with it unless the valves are initially too tight.
ALL of your suggestions are valid, certainly...and there's no other way to do it if you're having issues with gauge insertion.
There is truly NO time amount one could assign to this job with the many variables involved...I tend to remove the whole engine/trans. when I make a valve adjustment, it's just easier and I would normally couple this with a few other tasks, of course.
You have rusted exhaust bolts to deal with, deciding on how much stuff to remove for clearance, etc. A shop that is VERY experienced can whip out the procedure in a couple of hours...although you're sure to be charged the FULL rate! <img border="0" title="" alt="[Wink]" src="wink.gif" />
Jeff W. - NO SNOW down here at the beach! ...it just rained cats and dogs all damned weekend!! <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />
I took a "break" from Rennlist for a few days and got my new rollcage welded in...whatta pain in the A__!! ...next time, I'll pay the shop fee. <img border="0" title="" alt="[Wink]" src="wink.gif" />
Yeah right! <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
02-18-2003, 11:26 PM
#6
Rennlist Member
Thread Starter
Jeff C's got it right.
And maybe next time I'll figure out how to insert the gauge... <img border="0" title="" alt="[Wink]" src="wink.gif" />
Jeff W, if you set aside a weekend (2 days) for your first time I suspect that would be sufficient.
I spent several hours on a Friday eve, then got up early on Saturday, worked steadily and finished up by nightfall. I did not hurry, took time to set down plastic drop sheets, thoroughly clean the valve covers, admire things I don't usually see, mess around with the bump starter, deal with a partially stripped valve cover stud, retrace a few steps, and so forth. I wanted to enjoy the work. Next time will undoubtedly go faster.
And maybe next time I'll figure out how to insert the gauge... <img border="0" title="" alt="[Wink]" src="wink.gif" />
Jeff W, if you set aside a weekend (2 days) for your first time I suspect that would be sufficient.
I spent several hours on a Friday eve, then got up early on Saturday, worked steadily and finished up by nightfall. I did not hurry, took time to set down plastic drop sheets, thoroughly clean the valve covers, admire things I don't usually see, mess around with the bump starter, deal with a partially stripped valve cover stud, retrace a few steps, and so forth. I wanted to enjoy the work. Next time will undoubtedly go faster.
03-24-2011, 10:05 PM
#7
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gotta bump this for help: Performing my first valve adjustment tomorrow and wanted to drop a call to all those who could offer any good tips or small details to make this first adjustment go well. I've worked on 996's for years and know them inside out, yet the aircools are new for me, so bare with me. I've read all the literature, i'm prepped on the DIY, but starting saturday(after my friday tear down) i will be in the middle of the mix, so please don't hesitate to drop some dimes this weekend. On, my general plans I will be doing the oil change, valve adjustment, and fuel filter change. If I find time I'll drive into verifying if my oil temperature sensor(not sure if my fan is coming on as it should) and other oil cooler fan issues.
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03-24-2011, 11:20 PM
#9
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There is an article in Pelcan parts.com in the tech section "911 Valve Adjustment - Backside method" that shows you how to do the adjustment at the rockers; I have used that method twice, seems easier and avoids those issues.
biggles
biggles
03-25-2011, 12:36 AM
#10
Rennlist Member
Its not as hard as you think. DO drop the exhaust, the cat and the secondary, you can leave the primary in place.
It helps to have the right tool to turn the crank. The double square tool that turns the alternator/fan is what I use.
The tricky part for me was to get the right feel from the feeler gauge. You want it to have a consistent "drag" from valve to valve.
Drop me a note if you need a cheerleader.
It helps to have the right tool to turn the crank. The double square tool that turns the alternator/fan is what I use.
The tricky part for me was to get the right feel from the feeler gauge. You want it to have a consistent "drag" from valve to valve.
Drop me a note if you need a cheerleader.
03-25-2011, 10:00 AM
#12
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yeah, newsboy, i completely pushed this part out of my mind as i was so caught up in the actual adjustment procedure. I dont' have a new gasket, so I'm going to have to reuse the old one and if needed go back and address it after the adjustment.
@Campoj2 - Mexico? were you battling drug cartels?
@Campoj2 - Mexico? were you battling drug cartels?
03-25-2011, 10:06 AM
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oh and no gasket sealant used right? Just clean the groves, put in the new gasket and tighten to wrist tight correct? Oh, and I actually do have new exhaust gasket in my kit too, so thats good to go. THe pelican parts backside method GO/no GO actually confused me a bit. Since I don't have the VAS tool, my plan is to tighten the valves all the way down, then open up 30 degrees or so, and start to use the .004 feeler gauge for final adjustment. Does that sound about right?
Last edited by bmohr; 03-25-2011 at 11:08 AM.
03-25-2011, 02:26 PM
#15
Glad to hear they all went to good use. It was a noble effort!
Cheers