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Thu Dec 26, 2013 7:36 am

I just noticed in my owners manual that it says set the valve clearance (all valves) to .004"

Why has everyone recommended doing .006"?

Should I switch to maybe doing a .005" ?

Thu Dec 26, 2013 8:59 am

Use the 'go-no go" to achieve a dead on .006..if a .005 slides in (go) but a .007 doesn't (no go) then you are exactly .006..

IMO don't set .004,these engines close valve gap with wear..an exact .006 is as tight as I would go.

Thu Dec 26, 2013 9:35 am

If you are accurate and diligent, you can use 0.004" for your valve gap. This as the published standard in the late '60s. The maintenance calls for checking and setting valve gap at each oil change (3months/3000mi).

Most people failed to check THAT often and the valve adjustment went too long between checks. The valve gap would drop to zero and the valves would not fully close. Since the primary way valves release their heat is through the valve seats the valves would overheat and burn/crack. All because the owners failed to maintain the proper valve gap. VW changed the spec to 0.006" which allows more time between valve adjustments and fewer burned valves.
(at least this is the story I heard).

BTW, this is one of the reasons most car makers switched to hydraulic lifters instead of solid lifters. Hydraulic lifters are basically self adjusting.

Thu Dec 26, 2013 9:40 am

ashman40 wrote: If you are accurate and diligent, you can use 0.004" for your valve gap. This as the published standard in the late '60s. The maintenance calls for checking and setting valve gap at each oil change (3months/3000mi).

Most people failed to check THAT often and the valve adjustment went too long between checks. The valve gap would drop to zero and the valves would not fully close. Since the primary way valves release their heat is through the valve seats the valves would overheat and burn/crack. All because the owners failed to maintain the proper valve gap. VW changed the spec to 0.006" which allows more time between valve adjustments and fewer burned valves.
(at least this is the story I heard).

BTW, this is one of the reasons most car makers switched to hydraulic lifters instead of solid lifters. Hydraulic lifters are basically self adjusting.

I check/adjust mine every 2k miles

Thu Dec 26, 2013 10:35 am

This is all assuming you have stock pushrods and not chromoly........Those get set to loose 0.

Thu Dec 26, 2013 10:53 am

andk5591 wrote: This is all assuming you have stock pushrods and not chromoly........Those get set to loose 0.

yes stock.

Thu Dec 26, 2013 2:10 pm

If everything is stock on the engine the do set the Valves to .006. Like described above. .005 fits and .007 does not its OK.

Thu Dec 26, 2013 2:14 pm

gt1953 wrote: If everything is stock on the engine the do set the Valves to .006. Like described above. .005 fits and .007 does not its OK.

cool.

Just understanding:

.005 Slides in SUPER EASY (yet falls out if I let go of the feeler gauge set)

.006 slides in slightly firm (yet hangs & does not fall if i let go of the set)

.007 Does not go in AT ALL (even with firm pressure will not slide in)

Thu Dec 26, 2013 2:23 pm

Also keep a log of when and what they measured at before and after each adjustment.
If you have one that keeps closing up then you have a stretching valve or pounded seat. Two that get loose on opposite sides of the motor, bad cam or lifters.

Thu Dec 26, 2013 3:29 pm

Seems like the .004 gap was for older engines where the gap actually increased as the engine warmed up to .006. Seems weird to me, though.

I've always set my valves to .006.

Tim

Thu Dec 26, 2013 7:03 pm

Quote: Seems like the .004 gap was for older engines where the gap actually increased as the engine warmed up to .006
Huh? Haven't heard that one. As engine heats up, the valve lash will close up due to metal expanding when heated. Back in the late 70's, I had a service booklet (not Bentley's or Muir) which called for .004" exhaust and .008" on the exhaust.

Thu Dec 26, 2013 7:28 pm

Mr.Duncan
I like your description the feeling of the feeler gauge. That's about how I have done it.

Thu Dec 26, 2013 7:37 pm

If you hang around your engine long enough, you'll find that .005 or even .004 will work best on your engine. There is a good amount of variances in these engines. Depending on how yours is set up, the lash could vary .001.002 for best performance. I would look at .004 for intake and maybe just a touch more for exhaust.. Again, the more you do it the more you learn what your engine likes.

Thu Dec 26, 2013 8:15 pm

drs1023 wrote: Quote: Seems like the .004 gap was for older engines where the gap actually increased as the engine warmed up to .006
Huh? Haven't heard that one. As engine heats up, the valve lash will close up due to metal expanding when heated. Back in the late 70's, I had a service booklet (not Bentley's or Muir) which called for .004" exhaust and .008" on the exhaust.

The 1958-1960 Bentley manual specifically states that valve clearance increases as the 36 hp engine warms up. I was really puzzled by this claim but I have tested it and found it to be true especially for the exhaust valves.

This of course is not true for the newer engines where valve clearance decreases as engine warms up. I have heard the suggestion that this was because of the different style of push rod that 36 hp's had with a wooden interior core?? Not sure.

The Bentley manual even gives a different valve clearance for when the 36 hp engine is not stone cold to compensate for the increasing clearance. With a cold engine, suggested clearance was .004. I have tried both the .004 and .006 adjustments on my 36 hp and really can't really feel much of a difference, perhaps a little noisier with .006.

The .006 clearance with engine stone cold is good advice.

Thu Dec 26, 2013 8:24 pm

Even the owner's manual for 36 hp equipped cars stated that "valve clearance increases as engine warms up. ( 4th paragraph under 'Valve adjustment')

Fri Dec 27, 2013 5:29 am

I have only actually seen two 36 HP engines in my life, and I didn't work on either. Thanks for your correction.

Fri Dec 27, 2013 9:45 pm

My 1971 manual states .004" for both intake and exhaust. I have a Haynes manual that says VW changed their tolerances for all previous .004" lashes to .006".

Fri Dec 27, 2013 10:54 pm

Noah's owners manual for the 1972 Std Beetle has a pasted in supplement that changes it from .004 to .006 on both intake and exhaust valves.

It also has a sticker on the doghouse just behind the A/C compressor that shows valve clearance of .006 .

https://www.thesamba.com/vw/gallery/pix/1103641.jpg

Fri Dec 27, 2013 11:54 pm

ashman40 wrote: If you are accurate and diligent, you can use 0.004" for your valve gap. This as the published standard in the late '60s. The maintenance calls for checking and setting valve gap at each oil change (3months/3000mi).

Most people failed to check THAT often and the valve adjustment went too long between checks. VW changed the spec to 0.006" which allows more time between valve adjustments and fewer burned valves.

Ashman is exactly right.

If you check your valve clearances regularly, then you can safely use .004 on most aircooled VW engines.

The standard setting was changed to .006 to allow for some slackness in maintenance.

I have always used .004 on all my engines (1200 40hp, 1500sp and 1600 twin port), checking them every 3000 miles, and have never had any valve issues. The engines run a bit quieter with the .004 setting.

Sat Dec 28, 2013 6:14 am

I like to set mine to the loose side. With the cylinder at TDC on compression, I place a .006" feeler gauge between the adjusting screw and valve stem. I rock the rocker arm back and forth and adjust until I feel no more play. This makes for a free-feeling .006". I may leave the exhausts with even a slight amount more play in summer. I adjust my valves every 6000 miles, sometimes more. For the life of the engine, I've never had to add clearance, only had to take up clearance.

This may create a little more wear on the valve train although the screw tips still have a nice radius (I use OEM harden screws). I've always felt that when I didn't hear the valves clacking away I would be in trouble. I'd trade a little noise and wear for a sucked valve any day.