Pigsmightfly

Why are the engine mount screws on FGs so small?

There is adequate space for larger mounts which would allow drilling and tapping for larger fixing screws. I use decent quality allen keys with stainless screws yet can't put any real torque on the key without the screw heads getting messed up.

Maybe Torx screws are a viable compromise but they're like rocking horse poo around here.

chevyman_de

The advantage of stainless screws is that they're stainless. High stregth is not exactly part of the game. Get some high grade screws; 10.9 is fine and 12.9 would be better, but you may have a hard time to find 12.9 screws in small quantities for a decent price. Drilling and retapping the holes for M5 bolts is also a good idea. The M4 bolts will do, but the allen hex on a M5 is 20% bigger.

Pigsmightfly

Thanks

I'll re tap the holes to M5 next time engine is off the car and see how it goes. Wasn't sure if it'd compromise the mounts or not.

cmar-ireland

I was wondering if tapping out to an M5 size would weaken the mount, can anyone confirm?

Cheers

kengentry5000

My Feedback: (2)

I drilled out to M5 completely through the large plastic mount. I did not tap threads into the hole. Instead I screwed an M5 machine screw into the mount while it was off the car. Then when I mounted it all on the car I put the screws on as tightly as possible. Seems solid.

One oddity on at least the Firehammer...The screws that run horizontally in the 'back' of the mount that hold the engine bracket were in the way of the vertical screw coming through the chassis into the mount. This made the vertical screw hard to turn in and the threads on the screw were being scraped away by the tip of the horizontal screw. When mount the engine I did not drive the horizontal screws all the way in. Then I mounted the chassis screws (vertical ones) almost all the way. Then I ran the horizontal screws in place. I set the mesh and then ran the vertical screws the rest of the way.

Ken

cmar-ireland

Yeah, I had thicker screws when I had the plastic mounts. Now I have the alloy mounts, but the 2.5mm allen head strips too easily when torquing it down. If I can tap out to an M5 then the allen head will be 3mm, and allow better torque.
I think there will be still enougn material in the mount to be secure, but I'd like to hear from anyone else that might have done it.