MGA engine mounts, Moss Motors USA items 413-010 and 413-020 were ordered 3/19/07. These parts were stored in a heated garage for 14-15 months before use. Installation was 'attempted' on 7/2/08 with engine mounted on an engine stand (easy access), using new unmarked SAE nuts and lockwashers. Left side engine mount 413-020 was first, installed on engine bracket with two nuts and lockwashers, first finger tight, then gently with a wrench. When further tightening the top nut with a 6-inch wrench the torque 'feel' was soft like the nut was not tightening properly, and then the stud broke with only moderate pull on the wrench. After the stud broke I was able to unscrew the nut from the broken stud with finger tips, meaning there was no damage to the nut.

I immediately dismounted the part and clamped it in a bench vice. I installed four flat washers and a new nut on the other stud, then tightened it slowly using a bending beam 3/8" drive torque wrench (600-lb-in max scale). This also 'felt' soft, and it proceeded to strip the threads on the stud at 210 lb-in (17.5 lb-ft). I think that 5/16" fine thread fasteners should take 25 lf-ft torque with at least 30% margin before yield, so this one was only taking half the normally expected torque capacity.

For additional check I took the undamaged nut from the top stud (shown in the picture above), installed it on a new grade-5 bolt (SAE J429 Grade 5 or ASTM A449 - 3 radial lines), using four flat washers for spacers. I clamped the bolt head in a vice and used the same torque wrench to tighten the nut to yield. This ultimately stripped the threads of the nut at 400 lb-in torque (33.3 lb-ft), fairly close to expectations. I repeated the test with another new nut and bolt with the same results. Conclusion is bad engine mount with soft studs.

I installed the right side engine mount 413-010 being careful with a torque wrench to stop at 180 lb-in torque. This felt somewhat soft too, meaning I may have slightly exceed the yield point of the studs. No good, so I then re-installed the old engine mounts (August 2000 purchase), pulling the nuts right up to 25 lb-ft torque (300 lb-in), solid as a rock, and I'm sure it would take more.

Moss Motors was notified. They report no record of any returns in the past 15 months due to weak studs. They promptly sent a new pair of motor mounts for replacement.

I was intending to put these new parts in inventory for future use, but having some suspicion of this problem I wanted to test them immediately. I placed one in a vice, fitted with four flat washers and a new nut, and applied the torque wrench. The threads started to strip promptly at 200 lb-in torque (17 lb-ft), and continued turning would bring no more torque. One more phone call, and Moss said, "Send them back so we can test them", so I did.

I am amazed if it is true that no one else has complained about this problem in the past 15 months. I have no expectation whatsoever that Moss would do anything to attempt to track down or replace any parts previously sold. That leaves it up to the customers to review their purchase records, check their inventory, and check engine mounts they may have already installed on cars, going back at least to March 2007 (and possibly earlier).

I have received a Credit Memo from Moss for the returned parts. Follow up word from Moss is that they will put a stop on any sales of these parts until all parts can be tested or new parts can be procured. - 18 Aug 08

Latest word is that these parts seem to be single sourced at this time, meaning that any current source for MGA mounts may provide the same part with soft studs. Moss Motors still has a block on sales of these parts, but othere vendors may still be selling them. Moss is looking into having new parts made to order with stronger studs as well as continuing to look for any current source that may have some better parts.

Meanwhile, if you must use these mounts with soft studs, I recommend using self-locking nuts and limit tightening not to exceed 12 lb-ft maximum torque. Also make a note that can stay with the car advising not to tighten the motor mount studs higher than 12 lb-ft torque to avoid breaking the parts until better parts can be procured. - 12 Sep 08

FIXED: Moss Motors has tested new motor mounts from multiple sources, and 7 out of 8 failed at substandard torque. The better one was from "QUINTON HAZELL MOPROD (QH)" This one can be tagged for installation at 19-22 Lb-Ft torque. It is the only one Moss has been selling since mid-2009. Parts from other sources may still be bad. It you have a Quinton Hazell part it should be good at the specified torque. See Moss Motors Supplimental Information Sheet for this part at:
www.mossmotors.com/graphics/products/PDF/413-010_413-020.pdf
Note that this information sheet should be included in any shipment of these parts.

Addendum April 11, 2013:
I just received a report that someone received new Q-H engine mounts from Moss Motors, but the information sheet was not included. Bummer.