These are the tools I plan to use, whenever I change my spark plugs. How much torque should I add, to the 13ft lbs requred, for the spark plug swivel tool? I was thinking 15 lbft (+2lbft) would do it, but maybe not.

 

I don't think you need to add any extra, just try and keep the swivel to lowest possible angle . Most plugs are buried in a tube (4 valve, center plug) I find it hard it would matter .I have always just used stated figures in 30 yrs of working on cars .

PS: is that a ball swivel or universal joint type (looks like ball from pic), if ball I would not worry .

 

Yes, it's a ball. It's just that everyone on these forums is always saying how important it is to not tighten them too much (stripping the threads on the head), or not enough (plug comes loose and flies out). I guess I'm just too picky about things, and want everything by the book. I'm not an experienced tech, so I try to do everything exactly as the manual says.

 

Here link with some info on universals and torque wrench, it shows that as angle goes up valves fall way off .
Again if you can keep it at 90deg with ball type joint i think you can get away . I don't have any universal type joints as i hate them ,flopping around so much .

http://home.jtan.com/~joe/KIAT/kiat_3.htm

 

Thanks in advance for the link LPED. I didn't read it yet, but I am about to.

 

I read the link, and it answered my extension question. I'm pretty sure I will be able to keep the angle at 90 degrees, but it is a tight squeeze for the rear bank plugs. Thanks again.

 

yes, on such small torque value as 13lb that 3/8 extension is not long IMO . definitely in general you want no extensions or smallest length with largest shaft so the extension is not acting a a torque limiter .

I am sure you have seem wheel torque sockets for air impact that limit torque by there small cross section area of extension shaft .This affect you don't want when using torque wrench .