16 replies to this topic

[se_juggles]

Hey all. I recently brought a full nuts and bolts kit from a series spares. I remember a while ago skmeone said not to used stainless for the engine as tightening them to much will cause damage to the block.

Is there a torque i can go by to make sure this doesnt happen or should i not use stainless full stop?

Cheers se

[Batmini]

Use the recommended torque settings in the Haynes manual

[AndyR]

Torque should be the same as above.  However if going into alloy housings / gearboxes i would use a good quality anti seize.  There will be a very minor amount of galvanic corrosion but as its the stainless that is the lesser quantity you should be fine.  I would not use the stainless for any critical fasteners unless they are ARP rated stainless fittings, as you just dont have the required strength with A2 stainless.

 

Andy

[dklawson]

The general advice is to not use SS fasteners where strength is of concern.  SS nuts and bolts are typically OK for ornamental and low strength applications.

[Spider]

Actually sorry guys (and in line with Doug's advice) Stainless Fasteners have next to no tensile strength, they just keep stretching and with little return. Torquing them as per the same as other fasteners will result in a fastener failure.

 

I wouldn't use them on anything on the engine.

[AndyR]

Hence why i said dont use them for any critical fasteners.  For holding on the wok or timing cover for example is such non critical stuff i would use it on, and at 18 ftlb is at the top of the scale, i wouldnt expect to see any sign of failure at that torque for a 5/16" .  For info, ARP stainless is rated to the equivalent of a 12.9, but they are expensive.

[A-Series Spares]

Hey all. I recently brought a full nuts and bolts kit from a series spares. I remember a while ago skmeone said not to used stainless for the engine as tightening them to much will cause damage to the block.

Is there a torque i can go by to make sure this doesnt happen or should i not use stainless full stop?

Cheers se

 

Hi,

Just to put your mind at ease, we do not supply any stainless steel fasteners that can be used in areas where they will fail due to stress loads.

The majority of the hardware present is SAE grade 5, SAE Grade 8 or 12.9 grade. Always check the torque settings required by the manufacturer, these can be checked against our recommended torque settings for the diameter and grade of material.

[Dusky]

Hence why i said dont use them for any critical fasteners.  For holding on the wok or timing cover for example is such non critical stuff i would use it on, and at 18 ftlb is at the top of the scale, i wouldnt expect to see any sign of failure at that torque for a 5/16" .  For info, ARP stainless is rated to the equivalent of a 12.9, but they are expensive.

I would call the clutch wok critical as these bolts have to hold the engine and counter the clutch arm movement.

But then again, I know next to nothign about tensile strenght etc

[AndyR]

 

Hence why i said dont use them for any critical fasteners.  For holding on the wok or timing cover for example is such non critical stuff i would use it on, and at 18 ftlb is at the top of the scale, i wouldnt expect to see any sign of failure at that torque for a 5/16" .  For info, ARP stainless is rated to the equivalent of a 12.9, but they are expensive.

I would call the clutch wok critical as these bolts have to hold the engine and counter the clutch arm movement.

But then again, I know next to nothign about tensile strenght etc

 

 

Its my understanding that it would be holding the weight of the clutch diaphragm, and at the heaviest orange being 87ftlb, i would expect 8 x 5/16 unc fixings to handle this fine, not a great yield strength of 50000psi for ss but still within acceptable use.  If you are in any doubt, just use the standard bolt. 

[Spider]

 

Hence why i said dont use them for any critical fasteners.  For holding on the wok or timing cover for example is such non critical stuff i would use it on, and at 18 ftlb is at the top of the scale, i wouldnt expect to see any sign of failure at that torque for a 5/16" .  For info, ARP stainless is rated to the equivalent of a 12.9, but they are expensive.

I would call the clutch wok critical as these bolts have to hold the engine and counter the clutch arm movement.

But then again, I know next to nothign about tensile strenght etc

 

 

SS here would be OK.

[Jonny1812]

I've rebuilt my engine with stainless nuts and bolts on the exterior and haven't had anything fail other than a couple of threads in the flywheel housing for the clutch cover. I used the correct torque with loctite and copper grease on each and every one. The only ones I've had come loose are on the subframe mounts but I only used copper grease then loctite when I found they were coming loose, no more problems ;)
Jonny.

[nz_seamless]

How does one use loctite and copper grease?

[Jonny1812]

How does one use loctite and copper grease?

Put a drop of loctite on the end 4/5 threads then using a small brush put copper grease on the next few threads...

[Jordie]

Greasing or oiling the threads changes the resistance when torquing up. Refer to a manual for torques if they should be dry or greased.

[nz_seamless]

 

How does one use loctite and copper grease?

Put a drop of loctite on the end 4/5 threads then using a small brush put copper grease on the next few threads...

 

But as you thread the bolt in you smear loctite all the way down the thread. Seems like a one or the other. Either you want the fastener to stay, or you want it easy to remove.