I just finished reading a statement from the performance people at CB and they state that valves are set at "zero lash" , when there is NO play but push rod uses are moveable. I don't understand that since "tight valves" can burn the valves...I set mine at .006. What do I do???
Meade
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that should read..."but push rods are swiveable"...
I set mine at .001 This is about one-half the width of one of your hairs and is as close as I want to get to "0" lash. I also like to adjust my valves in the proper crankshaft rotation (not backwards) and firing order to insure that all slack and backlash clearances are normal. Somehow I was just never comfortable with "0" clearance on anything unless there is a specific reason for it such as failure......Bruce
Keep in mind that the clearances get larger when the motor warms up...the heads and case are aluminum. The 0.00 cold could easily be .006" when hot.
ReV
Before you adjust your valves you need to know what type of pushrods you have. Aluminum is .006, Steel is .000. The reason for the difference in the two adjustment specs is that Aluminum push rods expand with the motor as it gets hot, steel do not.
Always adjust your valves when the motor is stone cold. I like to adjust valves after the car sits over night, this way you are adjusting them when the motor is at its tightest in pushrod gap.
Also, check and adjust as needed often. Every oil change at least.
If anyone needs a .000 feeler gauge I have them on sale.
Lol, Alex....
Meade: To find if you have aluminum (.004/.006" lash) or Chromoly steel (loose .000" lash), just pop off a valve cover, get a pencil-diameter magnet and touch it against the pushrod between the head and the rocker arm.
If it sticks, loose .000/.001 lash. If it doesn't stick, then .004/.006 lash (Intake/exhaust)
Zero lash is when the rocker arm is at it's peak (loosest) and you can gently and easily spin the pushrod with your fingers. Personally, I just grab the pushrod end of rocker arm and do a push/pull on it to see if it clunks (good) or clicks (loose) or nothing (too tight) when pulling it back and forth, but set yours with a feeler gauge and then try the push/pull to hear what it sounds like. You'll get used to it after a while.
Won't that lead to burned valves? My engine was supplied with the Beck, the 2015 120 hp version, therefore came with the chrome moly PR's. 0
Ok, let's see if I can 'splain this for ya.....
The coefficient of expansion, meaning how much something expands or contracts for a given change in temperature, is much different for less dense Aluminum than it is for denser steel.
The VW engine case is made of aluminum and it expands slightly as it gets hot, meaning that the heads will move slightly farther apart as the engine warms up.
The VW engine designers wisely chose a specific aluminum alloy for the pushrods that compensates for the expansion coefficient of the case such that as the case expands, the gap at the rocker arm end of the push rods remains relatively constant. Pretty clever for 1938 metallurgy, if you ask me.
So what happens with the chromoly steel push rods? Well, they expand much less than aluminum pushrods so when the engine is cold the valve gap will be almost zero (if they are set to loose zero when cold). When the engine warms up and it grows a bit, the pushrod gap at the rocker arm slowly increases and then sits within a range about equal to the end gap of aluminum pushrods. This range depends on how hot the engine runs (say, between 200° to 230°F) but the gap gets greater as the engine gets hotter so, if the pushrod gap is loose zero there will always be a pushrod end gap when the engine gets warm, the valves should always close when they should and you should never get a burnt valve.
But why go to chromoly pushrods in the first place? Well, the VW engine guys never expected their engine to be using heavy duty (sometimes double) valve springs which requre lots more pressure to open and the OE VW pushrods couldn't take the stress, either mushrooming the ends or bending. Either way, they turned to junk (usually above 4,000 rpm). The fix was to use chromloy steel rods that could take the longitudinal stress, but required a little different operational approach because they expand much less than the engine case. In essence, the engine grows to an optimal (more or less) valve clearence as it heats up and the pushrods last the life of the engine.
I have chomoly pushrods and set them to "loose zero". I checked and adjusted at 200, 500, 1000 and 3000 miles. I recheck them every 3000 and after the 1000 miles check most do not need readjusting. I put 10,000 miles on and maybe 2-3 needed to be readjusted. After awhile the engine settles down and they don't go out.
Gulp, thanks. I think I get it. So, if I go back to a VW .006 clearance, I will loose a bit of efficiency...
Glenn Ring posted:I have chomoly pushrods and set them to "loose zero". I checked and adjusted at 200, 500, 1000 and 3000 miles. I recheck them every 3000 and after the 1000 miles check most do not need readjusting. I put 10,000 miles on and maybe 2-3 needed to be readjusted. After awhile the engine settles down and they don't go out.
Off topic a bit, Glenn but you seem to be right on top of things. I just had my tranny rebuilt with heavy duty things and a 3.44 r &p and it's running well. What mileage should I drain and refill please ? Thanks...
David, what are your gear ratios and what speeds do you get out of each gear (not max, just usual)?
Meade
Meade posted:David, what are your gear ratios and what speeds do you get out of each gear (not max, just usual)?
Meade
Giday, Meade. I can give you a full answer for you late tomorrow. I've always thought my speedo is off so I'll check it with a gps. please understand that I have stock VW gear ratios but with a 3.44 :1 r & p instead of stock 4.125. I'll give you speeds in four gears at 3,000 rpm ? I'll measure the diameter of the tires too and specify brand etc.
Please understand that I now run a Soob Frankenmotor with a bag of early on and flat torque which wouldn't be suitable for all installations.
Numbers talk, nobody walks, Dennison, Union , NJ.....eh?
...sounds reasonable. More a a "just curious" type question so don't go crazy getting the answer for me.
Meade
I don't believe that Herr Porsche's goal in '38 was to keep a constant lash as the engine heated up, it was to keep the lash from decreasing as the (smaller) Aluminum pushrods heated and "grew" before the (larger) Magnesium case.
These are the rates for unalloyed metals, and everything in the engine is an alloy of some sort, but it's instructive.
Steel doesn't expand anywhere as fast as Magnesium or Aluminum. Set the valve-lash stone cold at loose .000, and it'll never be tighter than at that moment. As the engine warms, the Magnesium and Aluminum parts are going to grow at a faster rate than the steel push-rods. Always.
The only advantage to Al is that the valve-train is lighter, and quieter. Those are good reasons, and they almost sold me on HD Al pushrods, but in the end: loose zero is just pretty darned easy to set up every oil change.
David Stroud posted:Glenn Ring posted:I have chomoly pushrods and set them to "loose zero". I checked and adjusted at 200, 500, 1000 and 3000 miles. I recheck them every 3000 and after the 1000 miles check most do not need readjusting. I put 10,000 miles on and maybe 2-3 needed to be readjusted. After awhile the engine settles down and they don't go out.
Off topic a bit, Glenn but you seem to be right on top of things. I just had my tranny rebuilt with heavy duty things and a 3.44 r &p and it's running well. What mileage should I drain and refill please ? Thanks...
What did the tranny rebuilder recommend?
I would change the gear lube at 500 miles and then every 30k.
thanks for that , Glenn. He said, three...I've got two and good weather tomorrow..
There are advantages to the heavy duty aluminum for pushrod material over chrome moly- lighter valve train parts means higher revs before the valves float, and the springs will last longer. The only thing chromoly will do for you is tell you when the engine is getting hot- the lash grows so large that the engine gets noisy.
Chromoly can handle heavier dual springs that will bend aluminum.
I have Manton dual taper chromoly which are lighter than most chromoly pushrods.
OHTAY, after a good nights sleep of about 5 hours, I REALLY get the valve clearance thing, and understand about the expansion of different metals. Thanks Glenn, et al.
I'm hoping to get my pepper mill back today, allowing the REAL mechanics to put it back together. When I took it over yesterday, I was getting 120# on 1 & 2 but only about a 100-95 on 3 & 4; I may be replacing the piston set and we're rechecking the head, also.
Meade
ps, I still haven't received my "SALVAGE TITLE" back from the state of Georgia yet. (that's how they handle Beck Speedster and other similar kit cars that utilize "assorted parts" from various vehicles...but it's only been 8 weeks...
David: Sam Shackleford at Rancho Transaxles recommends the same transaxle oil changes that Glenn mentions; "I would change the gear lube at 500 miles and then every 30k."
As a valve lash side-bar story (and to show that some engine builders are way better than I'll ever be), I set my valves for the season early last Summer, but one of the swivel-adjusters must have been cocked out of flat when I did it. It sounded fine when I left the house, but really started to hammer about half-way to visit Charlie Padulla, of Charlie's Rod Shop here in town. When I pulled in to his shop it was hammering away to beat the band and Charlie comes out and says, "Jaysus, Gordon......Sounds like one-a them valves is set at 40 thousandths!".
So I do what I went there for, then drive home and let it sit overnight. Next morning, I find the loose one (it was pretty loose) and tried a bunch of different feeler gauges til I got one that slid loose/tight, just to find out. Sure enough.......Exactly .040"
But then, Charlie has been building high-quality engines (American and European) since 1960 - Like "Farmer's Insurance", He's seen (and heard) just about everything.
Here's his personal '35 3-window coupe (he also built the '32 in back of it), which looks shabby compared to his wife's gorgeous '37 Ford Phaeton, but I couldn't find a shot of it. His '41 Studebaker shop pickup is wicked cool, too.
Glenn Ring posted:Chromoly can handle heavier dual springs that will bend aluminum.
I have Manton dual taper chromoly which are lighter than most chromoly pushrods.
While that's true, Glen, there are aluminum pushrods out there that will easily handle most VW size dual springs, and unless you're making power above 7,000 rpm chromoly isn't needed. I don't know of a Speedster owner here that's running an engine that high strung. The advantage of chromoly is they are significantly cheaper (74.95 vs 119.95 at ACN).
On the lighter side, I'm borrowing a post from Ron O...
How many internet forum members does it takes to change a light bulb?
1 to change the light bulb and to post that the light bulb has been changed
14 to share similar experiences of changing light bulbs and how the light bulb could have been changed differently
7 to caution about the dangers of changing light bulbs
1 to move it to the Lighting section
2 to argue then move it to the Electricals section
7 to point out spelling/grammar errors in posts about changing light bulbs
5 to flame the spell checkers
3 to correct spelling/grammar flames
6 to argue over whether it's lightbulb or light bulb ... another 6 to condemn those 6 as stupid
2 industry professionals to inform the group that the proper term is lamp
15 know-it-alls who claim they were in the industry, and that light bulb is perfectly correct
19 to post that this forum is not about light bulbs and to please take this discussion to a lightbulb forum
11 to defend the posting to this forum saying that we all use light bulbs and therefore the posts are relevant to this forum
36 to debate which method of changing light bulbs is superior, where to buy the best light bulbs, what brand of light bulbs work best for this technique and what brands are faulty
7 to post URL's where one can see examples of different light bulbs
4 to post that the URL's were posted incorrectly and then post the corrected URL's
3 to post about links they found from the URL's that are relevant to this group which makes light bulbs relevant to this group
13 to link all posts to date, quote them in their entirety including all headers and signatures, and add Me too
5 to post to the group that they will no longer post because they cannot handle the light bulb controversy
4 to say didn't we go through this already a short time ago?
13 to say do a Google search on light bulbs before posting questions about light bulbs
1 forum lurker to respond to the original post 6 months from now and start it all over again.
1 mod to lock it down after it goes off-track for the nth time...
This really is a 'plug and play' list, isn't it. 
EXCELLENT!!
