Torque for coil packs

[jEt_jAk]

Sorry to make a new thread but can’t find this anywhere. Anyone know what the torque is for these screws that secure the coil packs?

 

[Ronnie]

Here is what my service manual for a 2010 242 ls with 1,812 cc engine says. This is the first time I’ve seen this. I usually just hand tighten the bolts and add another 1/4 turn with a ratchet wrench. The coils mounting holes are lined with a metal sleeve so you should not worry about damaging them by over torquing, just don’t get crazy when you reinstall the coils.

 

[HangOutdoors]

. I usually just hand tighten the bolts and add another 1/4 turn with a ratchet wrench

This is how I have been doing it. I always question if I had it tight enough. Wondering if I should pick up a torque wrench?

 

[tdonoughue]

I put a little dab of antiseize on mine and tighten them 'enough'. It is not a stress loaded point, so going crazy is not required. Never had an issue and never used a torque wrench on it either.

 

[svana]

I hit mine with a little anti-seize and one “BRRT” lol

 

[AZMark]

Here is what my service manual for a 2010 242 ls with 1,812 cc engine says. This is the first time I’ve seen this. I usually just hand tighten the bolts and add another 1/4 turn with a ratchet wrench. The coils mounting holes are lined with a metal sleeve so you should worry about damaging them by over torquing, just don’t get crazy when you reinstall the coils.
View attachment 144407

Wow my 2018 manual doesn’t seem to have that level of detail, just general torque for smaller/unspecified bolts.
I just did this yesterday and did the tight enough +1/4 method also. 6lbs isn’t much.

 

[jEt_jAk]

Wow that ain’t much. 120in /lb is min on my wrench!

 

[Ronnie]

Wow that ain’t much. 120in /lb is min on my wrench!

Your wrench is too big (she said). Scratch that, I have two with different ranges. Sounds like you only have one with a higher range.

 

[2kwik4u]

This is how I have been doing it. I always question if I had it tight enough. Wondering if I should pick up a torque wrench?

You should. Once you have it, find a local company that does calibrations and see what they charge. For a shade-tree mechanic like ourselves, a single calibration is worthwhile. I've seen quality wrenches come off the shelf as much as 15% off target. Don't pay over $50 or so for a calibration though.

You're most likely over torqueing everything you touch if using the "add a 1/4 turn" method. 5.9ft-lb is VERY VERY VERY low torque. You can apply this with a screw driver and a strong grip. 1/4 turn additional is most likely closer to 50-60ft-lbs depending on the joint.

Snug (in general) is defined as when the bolt stops rotating freely and all surfaces have come in contact with one another. Additional turning of the bolt (or nut) only adds clamp load and does not change the geometry of the joint. This additional clamp load comes from stretching of the bolt material along it's axis. You should always snug the joint, THEN apply proper torque.

The loading on those coils is very low. It's a positional load only, not a seal, clamp, or shear load. 1/4 turn past snug is significantly excessive.

Source: I design bolted connections for vibratory equipment. Here's my latest bolt stretch test with a custom designed fastener to achieve proper clamp load. Achieved a shade over 120,000lb clamp load on the 1-3/4in bolt with only 75 ft-lb of torque on the 3/8in jack bolts

 

[AZMark]

You should. Once you have it, find a local company that does calibrations and see what they charge. For a shade-tree mechanic like ourselves, a single calibration is worthwhile. I've seen quality wrenches come off the shelf as much as 15% off target. Don't pay over $50 or so for a calibration though.

You're most likely over torqueing everything you touch if using the "add a 1/4 turn" method. 5.9ft-lb is VERY VERY VERY low torque. You can apply this with a screw driver and a strong grip. 1/4 turn additional is most likely closer to 50-60ft-lbs depending on the joint.

Snug (in general) is defined as when the bolt stops rotating freely and all surfaces have come in contact with one another. Additional turning of the bolt (or nut) only adds clamp load and does not change the geometry of the joint. This additional clamp load comes from stretching of the bolt material along it's axis. You should always snug the joint, THEN apply proper torque.

The loading on those coils is very low. It's a positional load only, not a seal, clamp, or shear load. 1/4 turn past snug is significantly excessive.

Source: I design bolted connections for vibratory equipment. Here's my latest bolt stretch test with a custom designed fastener to achieve proper clamp load. Achieved a shade over 120,000lb clamp load on the 1-3/4in bolt with only 75 ft-lb of torque on the 3/8in jack bolts
View attachment 144425 View attachment 144426 View attachment 144427

Totally agree on importance of torque wrenches, especially on bolts going into aluminum.

That said, unless you're using a big cheater bar on that little 10mm bolt you aren’t going to put 50lbs on it by accident. The spark plugs are 18ft lbs and that required quite a bit of tug on a small torque wrench.

When I say +1/4 I just mean snug relative to the size of bolt. If the full 1/4 feels like too much then it gets something less.

 

[Canuckjetboater]

The idea of 1/4 turn became popular in mechanics' lore and has been passed along as a result of spark plugs that had compression rings that you tightened snug then added 1/4 turn to collapse the ring and seat the plug - that required practice became the "advice" for all tightening applications. As @2kwik4u stated in detail this should NOT be applied "across the board"....... While on the topic of torqueing/tightening parts I used to be absolutely against using thread ease because it made it easy to strip aluminum parts that had metal parts being threaded into them. I am questioning my thinking and questioning if using thread ease when installing spark plugs into the Yamaha heads might be a good idea as these plugs seem to extend into the combustion chamber with some threads then rusting, causing binding problems and then breaking upon removal attempts. IF I use thread ease I will have to be careful installing the plugs as thread ease does significantly change the amount of torque that should be applied. There is also excellent advice regarding calibrating your torque wrenches in this thread. Some auto parts stores NAPA used to have a calibration bench if you bought from them. I have been present when very expensive aluminum racing engines have been seriously damaged by a simple torque mistake.

 

[Brad460]

120 ft-lbs + 45deg....