Putting in spark plugs without a torque wrench?

I've never used a torque wrench for this. I would screw them in until they are hand tight and then another quarter turn with a spanner. It makes a bit of difference whether you are using a new copper washer or not. If the washer is not new, it won't be so ready to be squeezed so will make do with less than if it's a new one.

Rob Graham

Finger tight, then just enough to crush the washer. (If they have a washer) It's all done by feel. Too loose at first is far more preferable to too tight and stripped threads.

I've been playing around with the internal combustion engine for

45 years and have never used a torque wrench on a spark plug. (I have used one on more critical applications).

Before advice can be given you need to tell us the vehicle and/or type of plug. Some plugs screw down on to a compressible washer to form a seal, whilst others have a tapered seat.

Generally speaking the type with a tapered seat only need to be nipped up. The type with a compressible washer need to be finger tight, then perhaps an additional quarter turn for a first installation. If this type of plug is to be re-fitted it will not need to be tightened so much subsequently as the washer will already have deformed.

Always use a proper socket designed for the plug, and make certain that the socket is kept straight to avoid breaking the plug.

HTH

Chris

Wow! 3 virtually identical replies within 11 minutes! This must be a first for u.r.c.m.

Chris

The message from gazzafield contains these words:

The trouble is - this "mechanic's touch" which many of us have has been accquired over years of buggernig things up - and the poor bloke may not wish to do that.

ISTR taper seat plugs should only be another 1/16th turn? Not that I can recall using a taper seat plug on anything...

SNIP Not that I can

Well, not on any of those you wouldn't Can you take your plugs apart to clean them? :-))

Steve

except maybe the capri

NO NO NO - unless you know what plugs they are and what engine it is....

for tapered plugs in an alu head this technique could be disastrous

And if they are taper plugs in an alloy head you will then want a Helicoil!

1/16th of a turn for tapers at the very very most.

You know those "silly" spark plug wrenches with only about a 4 inch handle on top? Well use one of those or similar hand tight. If it's a cast iron head then it's not so critical.

True. I was talking about ones with washers but shouldn't have omitted the taper ones.

Rob

They're not my only cars you know! Just the classic fleet. I also run a Rover 218 (diesel, no plugs), a Toyota Previa, and I'm about to finish an Omega. Anything else I've ever owned is on my website.