Can I borrow someone's bolt stretch gauge? PayPal available on my end

[Tippy]

Hello all, about to put my low end together for now and need to put my rods back on.

Can someone lend me their bolt stretch gauge? I no longer have access to one.

I can PayPal to your account.

Please let me know here or in a PM.

Thank you!

Cory

[bpu699]

I watched Turbocraft build a 911 motor on youtube.

They used ARP and they just torqued to spec. I didn't see them use a stretch gauge.

Seems to me if that's good enough for a 500-600hp 911 motor, should be good enough for me...

[Tippy]

Originally Posted by bpu699

I watched Turbocraft build a 911 motor on youtube.

They used ARP and they just torqued to spec. I didn't see them use a stretch gauge.

Seems to me if that's good enough for a 500-600hp 911 motor, should be good enough for me...

I hear you. Stretch is ideal as torquing can have varying results. The 3.2 rodbolts are small, so I put a lot more emphasis on them.

[Catorce]

Not necessary for this application. Torque to spec with new bolts.

[Tippy]

Originally Posted by Catorce

Not necessary for this application. Torque to spec with new bolts.

I have ARP, so reusing.

I have someone who will lend it to me. I'm good.

[Black_Hat]

I have a Jegs gauge local in central Austin
free to borrow if needed

[smokintr6]

by the time you've shipped one both ways, you could almost buy the jegs one... seems like a waste to me.

['76 911S 3.0]

Originally Posted by bpu699

I watched Turbocraft build a 911 motor on youtube.

They used ARP and they just torqued to spec. I didn't see them use a stretch gauge.

Seems to me if that's good enough for a 500-600hp 911 motor, should be good enough for me...

The torque value provided by ARP is a recommended value. Stretching the bolts ensures the correct clamping force, and even clamping force, on each and every rod bolt. When stretching my rod bolts, I found the torque value to be all over the place. Some were right on spec from ARP, others were well above.

Sorry to get off topic, but use a stretch gauge on your ARP's. Their documentation even states that stretching the bolts is the correct method and you should ONLY torque them if you ABSOLUTELY do not have access to a stretch gauge.

[bpu699]

Originally Posted by '76 911S 3.0

The torque value provided by ARP is a recommended value. Stretching the bolts ensures the correct clamping force, and even clamping force, on each and every rod bolt. When stretching my rod bolts, I found the torque value to be all over the place. Some were right on spec from ARP, others were well above.

Sorry to get off topic, but use a stretch gauge on your ARP's. Their documentation even states that stretching the bolts is the correct method and you should ONLY torque them if you ABSOLUTELY do not have access to a stretch gauge.

I hear you...

Just pointing out that on youtube, professional builders weren't necessarily doing that...

[m42racer]

Originally Posted by bpu699

I hear you...

Just pointing out that on youtube, professional builders weren't necessarily doing that...

You just exposed the difference between a builder and an assembler. Big difference and should not be confused.

[boyt911sc]

Originally Posted by Tippy

Hello all, about to put my low end together for now and need to put my rods back on.

Can someone lend me their bolt stretch gauge? I no longer have access to one.

I can PayPal to your account.

Please let me know here or in a PM.

Thank you!

Cory

Cory,

I did some tests and measurements to compare the stretch method to using just a torque wrench. The recommended torque will stretch the ARP bolts very close to the "recommended stretch value". However, the stretch method is a more precise method than the torque wrench method.

If the torque wrench is well calibrated it will do the job well unless you don't have a stretch gauge. If you have a gauge use both methods and compare your results. I applied about 90% of the recommended torque and measure the stretch. And finally apply 100% torque to get to the required "stretch value". If your torque wrench is accurate (correctly calibrated), you will get two similar results. Keep us posted.

Tony

[Tippy]

Originally Posted by Black_Hat

I have a Jegs gauge local in central Austin
free to borrow if needed

Thank you! I believe I will be getting someone else's nearby?

[Tippy]

Originally Posted by '76 911S 3.0

When stretching my rod bolts, I found the torque value to be all over the place.

^^^^^^THIS!!!!!!

I was pretty surprised how different the values were. I even used the ARP lube.

[Tippy]

Originally Posted by boyt911sc

Cory,

I did some tests and measurements to compare the stretch method to using just a torque wrench. The recommended torque will stretch the ARP bolts very close to the "recommended stretch value". However, the stretch method is a more precise method than the torque wrench method.

If the torque wrench is well calibrated it will do the job well unless you don't have a stretch gauge. If you have a gauge use both methods and compare your results. I applied about 90% of the recommended torque and measure the stretch. And finally apply 100% torque to get to the required "stretch value". If your torque wrench is accurate (correctly calibrated), you will get two similar results. Keep us posted.

Tony

Being a former aviation mechanic, I just don't trust torque wrenches on critical fasteners.

I will always use the stretch gauge. Great piece of mind for me!

[jdbunda]

Cory -
I was able to borrow a ARP stretch gauge locally - PM me for details. The JEGS gauge won't open far enough for the 911 ARP bolts.

John

[Tippy]

Originally Posted by jdbunda

Cory -
I was able to borrow a ARP stretch gauge locally - PM me for details. The JEGS gauge won't open far enough for the 911 ARP bolts.

John

jpnovak located one for me. If it doesn't happen, I'll get with you.

Thank you!!!

[Black_Hat]

scroll down

jegs gauge on a 964 turbo rod with ARP bolts

Forced to Deal with This

[Catorce]

Gentlemen,

Because of my case business, I am a limited dealer for ARP, meaning I have access to the Porsche products only. I am not a reseller, but I do get the product at wholesale as well as the tech info.

The exact verbiage for ARP rod bolts is this:

ARP recommends using the STRETCH METHOD when
tightening the bolts. Following the instructions for using a
stretch gauge, Stretch the bolts to . 0095 - . 0100 .

If you do not have a stretch gauge, torque the bolts to
50 ft-lbs using ARP Ultra-Torque Fastener
Assembly Lubricant.

Many of the ARP bolts (that aren't rod bolts) just have a torque spec, and no stretch spec at all.

Additionally, the Porsche WSM for over 40 years lists only torque values...It is just within the last 20 years or so that they have thrown in angle measurements, in which case they will specify an initial torque value followed by an angle measurement.

Lastly, I have done business with Chris from Turbokraft and I can tell you that he has forgotten more about building air cooled motors than most people here will ever know. There is nothing wrong with the torque spec - millions of motors have been built by Porsche and enthusiasts using torque specs alone.

Let me leave you with this tidbit for those of you who are still overthinking this. When When I was in Stuttgart at the factory, I did the tour. A machine assembles the rods onto the crank, and this dude comes along and grabs a wrench that is affixed to the ceiling. He puts the wrench on each rod bolt, turns, and then it glows yellow WHEN THE TORQUE IS ACHIEVED.

Imagine that! A torque wrench at the factory, no less. And it doesn't even have any numbers, it just blinks when the torque is achieved.

Good enough for Porsche, good enough for me.

[Tippy]

Atlas Copco torque drivers are far more accurate than your off-the-shelf click-type torque wrenches IMO.

Or whatever they use in Germany?

[Catorce]

You would be very disappointed in the factory assembly......most of it is robots. Speaking of engine assemblers, that is where they work out of. No builders there. Not one of those guys on the line knows how to assemble a complete engine.

One guy does rod bolts all day long with a wrench that lights up, as I stated. Another guy does nothing but put oil pans on, then the block moves to the next station and a robot puts in all the pan bolts.