DIY valve adjustments

[Paul Crowther]

Technically, valve adjustments are not that difficult, and one of the maintenance jobs that can make you feel like you are still a "wrench" for your car. But tackling this job on a 911 would seem to be pretty much impossible without a decent lift.

For those backyard mechanics that like to do what they can on their 911, how do you tackle this job?

[Flat6pac]

laying down, looking up, with the car up in the air on jack stands
Bruce

[redstrosekNic]

Originally Posted by Flat6pac

laying down, looking up, with the car up in the air on jack stands
Bruce

+1 on that.

[r-mm]

Did my first valve adjustment with pretty standard jackstands then got some monster 12tons and a beautiful quick lift alum jack prior to my first engine drop. Boy do i wish i had those earlier. Total investment under $300 and makes garage life much nicer and safer.

[Charles Freeborn]

You can do it from a creeper, or if you've got a lift from a rolling stool. Either way it's a pisser. Get the feeler gauge tool from here, with extra gauge tips, set aside a lot of time and go for it. The first one will take you at least an hour to get right, they get faster after that.
Get all new nuts, washers and gaskets for the covers.
-C

[LakeCleElum]

Jack one side at a time and you don't have to drain the oil. What works for me:

Loosen all the locknuts at once and back the adjust screw out a few turns. Get the crank in the proper position. Remove the .004 gauge from the set so you just have the one feeler in your hand. Slide it in and finger tight the adjust screw for "light drag" on the feeler. Hold screw with screwdriver and tighten locknut.

A hair too loose is better than too tight. It helps to have 50 years experience adjusting motorcycle valves? Have fun.

[shrtshck]

Do my valves in the fall along with an oil change, jack the rear and support with stands.
Lots of up and down from the creeper so limber up first. Have to admit though that doing it while the engine is out is sweet.

[Bob Kontak]

Originally Posted by Charles Freeborn

The first one will take you at least an hour to get right, they get faster after that.

That's the first valve.

You will feel like an idiot for taking the job on until the third valve, then you will be bored. It is just work.

Pull your plugs for easier turning of the crank but not required.

Rotate crank a few times to double check each valve.

You will become real familiar with the 120 degree marks on your pulley. They are your friend in this routine. Pull the dist cap off for reference. One turn of the rotor is two turns of the crank.

I just loosen the nut and back off the elephant's foot on each one. Trying to wedge the feeler gauge in one that is a tight is irritating. You will also be able to "feel" if you are close to four thousandths or not by rocking the rocker after a few adjustments.

One thing you will find is that the feeler gauge will feel perfect and then you will tighten and the gap will get smaller. Use a robust screwdriver and I read where some guys tape a piece of sandpaper to the handle for a real firm grip.

Regarding nut tightening. I suggest firm, which is a bit tighter than snug.

[Paul Crowther]

Originally Posted by Charles Freeborn

You can do it from a creeper, or if you've got a lift from a rolling stool. Either way it's a pisser. Get the feeler gauge tool from here, with extra gauge tips, set aside a lot of time and go for it. The first one will take you at least an hour to get right, they get faster after that.
Get all new nuts, washers and gaskets for the covers.
-C

The first valve will take an hour?

[Flat6pac]

I have the first feeler I bought in 1980 with the original blade. Then I saw the dial guage and valve adjustment fixture of the time, over the years went through about 3 of them. Now I have the Stomski valve adjuster and there is no apologies.

Bruce

[Jesse16]

I'd just been laying down and doing the job via the "no jack" at an oil change method. My last time, I did it via the no-oil change, jack one side method and that worked just fine also. I like removing the plugs even thought there are various warnings not to do that. Much easier to rotate to the correct position.

[santagrant]

I believe the reason not to remove the spark plugs is that a small part of carbon could be dislodged and catch between the valve and the seat. This happened to me doing a 3.3 turbo adjustment one day and had to re do the process.

One other trick is remove some of the material off the bend just before where the blade attaches. Also having the tip of the blade filed or ground off to make the blade shorter is a big help. Right before adjusting a valve, tap on the valve to get the oil out between the end of the screw and the "elephant foot."

I have been doing engine rebuilds and servicing 911/930 engines for over 40 years. It is getting harder now that I'm older and less flexible.

Hope this helps.

Grant

[SoCalSK8r]

I just did mine a few days ago with jack stands. It was a PITA for sure but a lift wouldn't have changed that as the hardest ones (physically) were on top.

The only thing that would make this easier is if the engine were not in the car....and then the lift is more beneficial.

[armand80sc]

I did my first valve adjustment and oil change without using any jack stands at all. There seemed to be plenty of room there

[Jay Laifman]

I have that little 90* tool. It is SOOO much easier than using one of the tools that folds out all the various sizes. I even bought one of those tools with all the sizes to take out the right size and cut it out to make new blades for the 90* handle. As far as I know, replacements are not available.

There is a method to slide a blade in on the cam side. I tried and tried and tried - different valves, different positions. I still don't see how they actually get the blade there. But, if you can do it, it definitely takes the wiggle of the foot out of the equation.

Finally, I +1 the idea of going around again. Even if your "feel" for the right gap is different than someone else's "feel," getting them exactly the same with your feel is more important to the overall smoothness of that 911 engine.

Remember to err on the loose side. Loose valves make noise, tight valves break.

[Paul Crowther]

Originally Posted by armand80sc

I did my first valve adjustment and oil change without using any jack stands at all. There seemed to be plenty of room there

One of the little people...

[Paul Crowther]

Thanks guys. A lot of consistency in these tips. that's always good.

[Bob Kontak]

Originally Posted by Paul Crowther

The first valve will take an hour?

Just roll with it. Charles is simply managing expectations.

Just for fun, get the valve covers off, etc, and time how long it takes to set the first valve, spin crank twice, recheck it, re-do it (probably) till you are happy.

Also, gauge the noob sensation on the first vs. the last valve.

It's all good if you take your time.

[tazzieman]

See post #12 from Grady

Valve adjustment gone bad

Once you have access, oil drained, valve covers off, etc.; you need to rotate the engine (CW at crankshaft pulley) to TDC compression for #1 cylinder. There are two TDC choices: compression and overlap with the “Z1” mark aligned with the mark on the fan housing. The easiest method is to note if the rotor is pointing to #1 terminal and not #4 on the distributor cap.

If the rotor is pointing to #1, the next check is to confirm that both the intake and exhaust rockers on #1 have ‘click’ clearance.

Going to the next cylinder in the 1-6-2-4-3-5 sequence involves rotating the engine by hand with a wrench on the crankshaft – 1/3 rotation, 120°

It might be worthwhile to go through the complete 720° (two complete rotations) of the crankshaft checking each pair of rockers for ‘click’ clearance. It is useful to confirm that the rotor is pointing to the terminal of the cylinder you think.

Next is probably the measuring and adjusting technique. The cam housing design does not make this easy but we have been doing this successfully for 43+ years. Make sure you have your technique correct and your tool is correct – some have an improper angel. Each valve has a slightly different position and technique with the tool.

Setting the correct adjustment is a “feel” issue and that makes it very personal for something that is very mechanical. Become mechanical.

The type and amount of lubricant has an effect on the measurement technique. Cold, sticky lubricants will skew the settings – usually to the loose. At room temperatures, WD-40 works well. Just be sure you re-lubricate with proper oil before moving the engine to the next cylinder. The lubrication cam lobe-to-rocker arm is critical. Other, not so much.

Tightening the lock nut is the critical operation. It changes the setting. You must hold the (screwdriver) adjustment while tightening the locknut, anticipating the movement in adjustment (usually to loose depending on technique). This is the “art” of valve adjustment. It is useful to devise your own tools specific for this operation.

The “feel” of the movement of the tool with a tight, correct and loose valve is very small and subtle. If you have the opportunity to practice on a fresh engine on a stand, do so! If not, repeat your process many time to develop the feel.

Carefully inspect each feeler gauge stock for your tool. Edge burrs can fool your use of the tool. They can be removed with some 800-grit paper. Never use a wrinkled gauge. It is useful to have several tools (bent differently) to check your work.

Valves set too loose just make noise and don’t do any damage. It is possible to set a valve tight with no running clearance and still get the tool out from between the valve and elephant’s foot. Always reinstall the tool for ‘feel’ and check for ‘click clearance’ after you think you are finished.

Never be afraid of going through several 720° rotations checking your work. Good ‘professionals’ do that every time.

Moving the rocker axially on the rocker arm shaft is an additional ‘click’ check for clearance. It is useful to check for proper shaft position and fastener tightness.



Critical for a good, long lasting valve adjustment is driving situation. An engine with combustion debris (‘carbon’) on the valves and seats can be adjusted to spec. When the carbon burns off (like on the highway or an event), the clearance closes up – perhaps dangerously. A proper valve adjustment can only be preformed with the valve properly sitting on its seat, not interfered with carbon debris. ‘Carboned up’ valves are best left alone – so long as there is some clearance..



Our nice old 911s are relatively high maintenance engines. They also like (and were designed) to be run hard. They run best being run close to the ‘limit’ and done so regularly. “Resting quietly” was not a 911 design criteria.

[Charles Freeborn]

Originally Posted by Bob Kontak

Just roll with it. Charles is simply managing expectations.

Just for fun, get the valve covers off, etc, and time how long it takes to set the first valve, spin crank twice, recheck it, re-do it (probably) till you are happy.

Also, gauge the noob sensation on the first vs. the last valve.

It's all good if you take your time.

Precisely. But if you've never done it before, or on similar, such as air cooled motorcycle or VW engines (I've done both many times), I'll bet I'm not too far off. I'm just saying don't start in on the project 2 hours before you need the car to make it to a dinner reservation...Let us know how it goes (went).
-C