Valve Clearance / Measurement Question

Hello

Everyone is talking about a valve clearance of 0.04 or 0.05 and so on. What is the measure you are talking about ? I do my valves at 0.4 and 0.5 mm. I hope this is a pure dispute of the measure used (I cannot imagine 0.05 mm would be correct as it would be thiner than paper).

Thanx for your insights.

Ed.

I always thought the number was .006"

.006" X 25.4("/mm) = .15mm

Maybe I'm thinking of something else.

Jerome

what pushrods do you have?? that makes a TREMENDOUS difference as chromoly and aluminum expand at way different rates and must be adjusted accordingly. If you have chromoly, toss the book settings out the window, they are way too much.

With aluminum pushrods set clearance to .004" intake and exhaust. I set my valves to .002" to .003" with chrome-moly pushrods. Operating clearances at full operating temp will be larger and a bit noisier with chrome-moly.

(Message Edited 10/25/2002 2:22:57 PM)

I've gone to setting one of mine just to where they turn slightly. They are chromoly. One the stocker, I like .004 on both. The book says .006 and .004, exhaust and intake.

I have aluminum pudhrods and I have taken the 0.04 and 0.06 from the paper I got of IMC for the 2.1 liter engine.

I think Jerome has showed the way: I gotta translate from inches to mm. Therefore I should set the valves 0.15 (0.06) and 0.1 mm (0.04) (as standard on Beetles). Thanx for that Jerome !

Suprinsingly the valve play was too much when I first got the car and is too much everytime I recheck. Also the engine runs nicely and sounds good. I will try the 0.1 and 0.15 and report back to the forum.

I run zero lash with Chromos, and whenthe engine is warm I have about .005 according to how hot the engine actually is..Too much clearance will zap valve guides, and hurt power, plus sound like hell.

se at zero my chromos are quiet as a mouse in my 912E.

Ed, if your valve lash is opening up more than a couple of thou each time you set the valves you may have a problem. Do you have hydraulic or non-hydraulic lifters? Have you noticed any gray particulate matter in the oil or oil filter (cut it open to check) when you change your oil? Are the rocker shaft supports loosening up (check the torque)? Are pushrod tips wearing (some have been known to have improper heat treatment)?

George

I am a complete idiot (when it comes to valve setting) anyway: I set my valve clearance wrong as I did not convert from inches to cm. I will reset them tonight.

I have non-hydraulic lifters, no gray parts in oil or oil filter but yes, one rocker shaft support loosened up the last time I set the valves. Pushrod tips look good to me. I will buy the torque tool and recheck asap (probabyly next spring).

Ed.

The Bentley book says .006 for both intake and exhaust; yet I've seen also .004 being mentioned here; what's the scoop?

.006 is the VW factory recomended adjustment that keeps the valves slightly loose....
loose is better than tight in a type 1 engine
The .004 adjustment is the optimum adjustment... it will allow the engine to perform a bit better.
The head torque. rocker shafts, rockers, valve springs all need to be nearly new and set correctly ...and most importantly, the engine doesn't have a problem of running to hot, if so the valves will tighten up the .004 adjusted valves quickly and can cause damage to the internals

My 2 cents,
Back in the 70's. I spent a few years building SCCA FV (40 hp. motors). When we got really serious, we bought a flow bench and a dyno. and spent lots of time (and 1 marriage) researching VW motor and how they work and what makes them work.
(the simple things were always the biggest surprises when looking for HP in a restricted formula type class of motors.)
This is what I learned about valve clearance.
On Each engine the piston cylinder/pushrod/head/cooling capacity isn't always the same. The whole mess grows and contracts with heat and cooling. Each component grows at it's own rate.
SO...
We ended up setting the valves at 0.0 (adjust until you can just twirl the pushrods)when the heads are COLD.
Then... run the motor up to temp and check the clearance. If you find any push rods that you can't twirl, the adjustment is changed to accomodate. (BUT that never happens)
What happens is this.
When you set your valves to .004 or .006 or whatever, COLD. When you run the motor up to running temps, you'll find that you now have something like .014 clearance (and noisy valve train). Check it out and see what you find! I find that at 0.0 COLD there's always more than .004 clearance when the temps are up to normal.
I've run my street VW motors at 0.0 clearance COLD with no problems, and the valve train doesn't get so noisy with the extra valve clearance and clatter.

Greg B.

Greg

I am with you in what you are saying but, I have been "taught" stock push rods require the minimun 004 ? As tight valves will spell an early engine failure as well as super loose.
Jake mentioned in a post, "chromos" can be set at zero ...I am always open to new suggestions
Alan

Jake,

What should I be running on my 2056 kit? I have the lash set at .004 (cold) right now. From the above it seems like I should be running at zero? Yes/No?

Greg, Thanks for the interesting post. Observing your mods via this forum over the past 2-3 years has been a learning experience. Keep on posting and sharing! Your method of adjustment almost makes too much sense. I think I am going to play with that a little tommorow while I mess with the car.

Greg: That's EXACTLY how Al Alden (1960's - '70's New England Porsche engine builder) used to set the valves in the racing engines he built.

The important thing to remember for the newbies, is that 0.0 lash only works on Chromemoly push rods, NOT on the stock aluminum ones (if in doubt, touch the pushrod with a magnet to see if it sticks - if it does, use 0.0 lash, if it DOES NOT stick, go to .004" lash).

The point is: (for solid lifters)
No matter what kind of push rods, rocker assys, cylinders, pistons, rods, case, cooling system, combustion chambers, valve material, etc. etc.

When the engine is COLD:
Make sure that the valves clearance settings don't leave the valve's hanging open. (so the engine will start)

When the engine is HOT:
Make sure the valve clearance settings don't leave the valves hanging open, when they should be closed. (so you don't burn valves)

The desired result is:
Run with minimum clearance and keep valve train clatter to a minimum.

Greg B.