Jason @ Paragon Products

To the best of my knowledge, Corteco is the manufacturer of the Rein mount. Neither is available to us at this point...probably because the cost crept up to the Genuine Porsche level. Meyle and URO are the two aftermarket mounts you'll normally see at this point.

pfarah7

Ok... I guess my data sources are wrong.

neunfünfeins

Respectfully, google "overtorque vs overtension". What you did was the latter
It's also worth noting that fastener strength can vary quite a bit based on production factors. One could argue that's a QA issue, but...

tj90

I went to lowes and bought a class 2 3/8" X 28 bolt - very close to the stud dims. I torqued that bolt to 50 ft lbs before the threads failed. No noticeagle shank elingation. These are the cheapest chinese bolts you can buy at lowes.
I bought class 8.8 m17 bolt which is the standard grade in the Lowes hardware section for this size. Lowes doesn't carry a cheaper grade and is equivalent, slightly higher rated grade to grade 8 SAE fasteners. I took that bolt to 90 ft lbs before failure. this bolt was completely snapped with no thread failure and no perceptible shank elingation.
My conclusion here is that the meyle mm bolt with thread elongation and shank dia reduction is odd. It's like the bolt wasn't tempered or hardened. Interesting that the grade 2 bolt took more torque and failure mode was completely different. My money was that the stud provider skipped the tempering or quenching step of the fastener production to save money. URO or meyle should catch these things in qc. of course these are the same mounts that I had to chase with a tap on the 13 mm holes due to poor thread cutting. Complete garbage!

neunfünfeins

Interesting, thanks for posting the follow-up.
Comparing a grade 8.8 bolt was a bit unfair... the common low grade metric hardware is supposed to be 4.8. Maybe the mount studs aren't even that. Or that stud was just defective, which is a QA/QC issue. You did say that the other one took the 48 ft-lbs without failure, right? We can agree that the hardware very likely isn't as durable as it should be. I still say it shouldn't have failed at the proper torque, but we'll never know.

JET951

Jason is correct , Corteco was the original supplier to Porsche for 944 engine mounts , in the past 10 years or so most of the( less expensive) after-market engine mounts for the 944 series are just cheap Chinese copies and most of these are just dreadful , you get what you pay for

tj90

The new oe mounts are fantastic! went out for a ride and WOW! I noticed the porsche bolts on my a-arms are marked 8.8. my understanding was that all automotive hardware is specified at 8.8 or 10.8.

neunfünfeins

True, 8.8 or 10.9 is pretty much all you ever see on OE VAG hardware.
It's reasonable to think that the OE stud would have been 8.8, and in that case, the "cheap Chinese junk" theory holds more water.

Tiger03447

On a more common note...8.8 DIN is roughly equivalent to a grade 5 SAE bolt..10.9 is closer to a grade 8 SAE. There are higher grades to both SAE and DIN ratings...