Torque specs carbs to manifolds

Yes, there is a torque spec. But those 16 nuts are exceedingly difficult to get to and impossible to put a torque wrench on it. All I ever do is use a open wrench and tighten it ... good and tight.

 

Not familiar with the carbed 308s, but for hard to get to nuts, that what they make these for.

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Not too tight -- you don't want to warp the carb baseplate.

 

Well, you use a 6-inch long wrench, how much torque are you going to be able to put on that nut while contorting your hand/wrist to do that job?

 

True, but, IMO, this is a good example of where if you just looked up the "typical" (steel-on-steel) torque spec online based on the stud's thread size, and used that torque value = you'd probably pull the stud out of the Aluminum manifold .

 

so 20 - 25 ft lbs?

 

Will not fit. As already explained it requires an open end wrench.

 

Way too much for any standard 8mm fastener and assures destruction of Weber carbs.

Just how are you planning to torque them with an open end wrench?

 

Not to mention irreparably bending the carb housings.

 

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I guess you have never removed/installed a set of Ferrari carbs.
You need an open end wrench.

 

Sooo much easier to get a wrench on them if you replace the factory nuts with reduced hex flange type, which take a 10mm wrench. That allows you to use the box end of the wrench on most nuts (I would suggest a 12 point box wrench). I also added a stubby 10mm combination wrench to my toolbox which also helps. But I've never felt the need to use a torque wrench on any carb nut on any vehicle. Maybe if I was doing vintage aircraft engine work I would feel differently.

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Some things its advisable to use a torque wrench. Everything else we just tighten. Been working for hundreds of years.

I fail to understand the fetish for torque wrenches especially when (as in this case) we would have to guess and make up a number to set it to.

The other day I was told by someone here he used a torque wrench on trim screws. My God, get a life.

 

Old story is that the first time torques specs were ever published by Ford, they handed their experienced mech a (newly invented) torque wrench and told him to assemble an engine. He did so by feel, as all mechs did, and the boffins noted the individual torque reading that resulted for each fitting. Those were then published as the "torque specs."

Doubt that it's a true story but it's a good one!

 

I believe it and I know the real pro's can do it by senses. At the same time I try to live by some guidelines. I'm sort of a big guy and strong and sometimes my version of tight is different than someone else. BUT I also break things so I know a have to be careful and think about how I assemble. So for something like this and the oil pan(s), it would be good to say a number or just a even a range like somewhere between 10-15 ft lbs.

 

Its pretty well established more things are damaged or broken by over tightening than by being too loose. You car retighten things. You cannot undamage threads or warped carb bodies. I have seen far too many Webers so distorted by over tightening that the throttle shafts siezed. . Pierce used to offer a service to straighten them.

 

Super helpful info!