Lubing bolts before torquing

[Gary B.]

Gary

[Jim L.]

Re: Lubing bolts before torquing

Unless GM explicitly calls out lubrication, I would make the assumption the bolts are to be torqued dry.

If you do decide to lubricate the threads anyway, just be aware that doing so REDUCES the torque value to which the fasteners are to be tightened. The amount of reduction is difficult to predict and is a function of the type of lubrication employed.

[Gary B.]

Re: Lubing bolts before torquing

Jim,

Just to be clear, do you think GM intended that no chassis or suspension bolts were to be lubed prior to torquing?

Gary

[Jim L.]

Re: Lubing bolts before torquing

Gary, if lubrication isn't called out in the AIM, then I would assume the fasteners are to be assembled dry.

Jim

[Michael G.]

[Gary B.]

Re: Lubing bolts before torquing

Does anyone know an example off the top of their head where the AIM calls out for the bolt to be lubed before torquing?

[Gary S.]

Re: Lubing bolts before torquing

Many years ago, I read that lubing of bolts that torqued is applied to allows excess torque to be applied since the oil adds some "slipperiness". I don't recall if it was in The Restorer or some other forum but I do recall that, unless specified, bolts are dry torqued.

Just my hazy remembering.

Gary

[Gary B.]

Re: Lubing bolts before torquing

Thanks everyone.

Gary

[Michael G.]

[Edward J.]

Re: Lubing bolts before torquing

Gary, I would clean the threads of all older bolts and nuts to have a better chance at getting proper torque.

[Michael G.]

Torque itself is unimportant

[Dick W.]

Re: Lubing bolts before torquing

Michael is correct.

Here is a chart that I found on the internet. Very similar to what I taught at the local community college over 50 years ago

When a bolt is lubricated - less torque is required to achieve bolt axial load or tension. Reduction of torques for lubricated vs. dry bolts are indicated in the table below.

No lube	0
Graphite	50 - 55
White Grease	35 - 45
SAE 30 oil	35 - 45
SAE 40 oil	30 - 40

Example

[Perry M.]

Re: Lubing bolts before torquing

Since we all use, or should use, anti-seize in certain instances such as head bolts, especially into an aluminum block, how is the torque effected then?

[Jim L.]

Re: Lubing bolts before torquing

Since we all use, or should use, anti-seize in certain instances such as head bolts, especially into an aluminum block, how is the torque effected then?

Perry,

If you are using an aluminum block, my own recommendation would be to use head studs instead of bolts. Torque a bolt threaded into aluminum and you wear the aluminum. Hand thread a stud into the block and no wear takes place. All of the wear, if any, will happen in the top threads of the stud when you torque the nut.

This is what I've done with the aluminum blocks I run in my vintage racer.

Jim

[Michael G.]