adjusting valves to zero lash. need some help.

[74superTN]

So I have a 1971cc camper special from Raby. I need to check my lash and probably make adjustments. Do I just take them in until touching and then tighten the jam nut back down? No feeler gauge needed correct.
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73 Thing
80 Vanagon Westy

[busdaddy]

Correct, best to go with the slightest perceptible feeling of movement until you get good at it, not enough to get a feeler gauge under but loose enough you can still feel a bit of movement between the valve tip and rocker once the nut is snugged up. The pushrod should still spin freely once it's all done.
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[Randy in Maine]

I use my thinnnest feeler gauge to help me get close to zero lash. Once everything is broken in, they rarely close up at all (at least mine never have).

[74superTN]

Ok thanks guys. I called aircooled technology because my carbs are popping when im low throttle and they said its almost always valve adjustments.
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73 Thing
80 Vanagon Westy

[Wildthings]

Your set may have a .0015" feeler gauge, try using that instead of setting them at zero.

[aeromech]

I've never heard of this before. I didn't know they even made a T1 camper special. How can they get away with no valve lash?

Ah, I misread 1971cc to be year 1971. Sorry. Still, if these are hydraulics then I thought you went zero plus 1 1/2 turns?
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[raygreenwood]

[aeromech]

So why are his engines so different that you don't go with .006?
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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
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VW Type 2 1971 (3 ea.) 1978, 1969
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[Randy in Maine]

Chrome moly push rods.

[Wildthings]

Can't say that they can, but can't say that they can't make up custom aluminium pushrods so that there is less chance the valves on a cold engine are held open.

http://www.pushrods.net/

[raygreenwood]

Yep...as Randy in Maine noted.....the chromolly pushrods are the reason.

Most of Jakes combos....really the few that I know anything,about...use a llittle bigger valves than stock and definitely use different cam profiles. To control the valves the springs specified are a little stronger (maybe more than a little.....I will know whenI start to measure pressure on the ones in my kit). ........and so most of them use chromolly pushrods.

The chromolly pushrods are a little lighter by about 10 grams...but stiffer. They expand less and much slower than the aluminum pushrods. So you set them at "0" lash when cold. That meand no actuall lift but no gap. A dead fit.

The case and heads exapnd....producig the required gap as the engine heats up. Ray

[74superTN]

Well the carbs are still popping. Adjusted valves to zero lash. Ugh
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73 Thing
80 Vanagon Westy

[Clatter]

"Zero Lash" can be a range of adjustments, actually, depending upon how precise you want to be.

With a new motor, or one that runs hot now and again, your adjustment would be free, but no slop; easy to spin but no up-and-down.

If you really know it, and it runs cool and is well broken in, you can run "a little hard to turn with oily hands".
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[Clatter]

[aeromech]

I've done a few engines with dual Webers or Dellortos and if the synch gets off, they pop like hell.

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Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[74superTN]

Wonderful. I don't have the tool to sync them.
_________________
73 Thing
80 Vanagon Westy

[74superTN]

The long linkage bar between both carbs has a little free at in it. Is this normal?
_________________
73 Thing
80 Vanagon Westy

[aeromech]

What kind of carbs and linkage? Pics?
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
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Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[74superTN]

Weber 40IDF carbs. Not sure on the linkage.

_________________
73 Thing
80 Vanagon Westy

[davada56]

Slowly turn out the idle jets on one side until that side stops any coughing or popping then repeat on other side popping is caused by not enough fuel in Idle. With out the sync tool you wont be able to sync the carbs and will make the engine run funky its easy to use one just disconnect the linkage between the carbs then slowly turn the adjustment screw on each carb the volume draw usually runs really great at 5 or 6 then the process of reattaching he linkage it will take awhile to get it just right you will be able to tell you don't have it just right as the motor will stumble if one side starts out first keep working on it until that stumbling go away it will and you will tell all is well as the motor will really sound strong also make sure you are using the center pivot to the linkage where the cable attaches as trying to just advance the carbs from one carb will give you a false reading on how synced the carb are