Engine mounts - arghhh

[Worty]

Afternoon fellas.

Returned from my mega run yesterday (245m or 200m depending on whether you believe the trip or odometer reading).  Found that I'd lost four engine mount nuts and one complete bolt (upper rear bolt and nuts completely gone, lower nuts gone but bolt half out).  Any suggestions as to how I combat this.  Originally lost a couple of nuts but put split washers on and checked them before and after every run - seemed reasonably ok.  Would star/anti-rattle washers be better?  Should I use a combo of thread locker and star washers?  Should I weld the b****y thing up   Are there any other clever suggestions that I'm not capable of thinking up.  Have got boxes of bolts I can adapt to sort out the missing items, but don't really want to lose more if I can help it.

[Rex]

Thread locker (Loctite)...do it once and forget about the regular retighten task.

[Worty]

I will Rex, I will 

[Triton Thrasher]

Forget any sort of spring washers or star washers.  They may be part of your problem.  Loctite, lock nuts or self-locking nuts probably will help.

It also helps to have original spec fasteners, tight in all the holes.  Some dodgy stainless kits have been marketed.

[Black Sheep]

Nyloc nuts should do the trick. It is important the bolts are a snug fit in the holes and the threads are in good condition. Do you have a vibration problem? I really would not expect your nuts to drop off quite so easily...

[Greybeard]

I really would not expect your nuts to drop off quite so easily...

Oh Matron!

Can you buy Nyloc nuts for Imperial threads?

[berger]

I have not been to the pub YET! greybeard yes you can I've got nylocks on the 6 spring clutch, they have worked really well too

[coater87]

 Use the thickest flat washer I can find on everything...lock washers, start washers,...I have just never had any luck with them.

 clean the threads and inside the nut really well with brake clean.

 Shake up the threadlock.

 Then tighten them down tighter than you think. then hit them again with more torque.

 The best advice I ever received about tightening bolts on specialty cars:

 Go back and loosen off some of the bolts you had just done- you will be shocked at how "untite" they are. Reason is everything is covered in new paint and chrome, you have a lot of time invested. broken, stripped stuff is expensive. You are barely going over finger tight with the torque because you dont want any problems or ruined paint, you dont realize your doing it but you are.

 Try to think of your beautiful bike as a dirty old street sweeper while you are torquing things down.

Lee

 

[scotty]

Also check your frame to cylinder head brackets (head steady)

[a10 gf]

This: https://www.a7a10.net/forum/index.php?topic=1401.msg9869

As bolt or nut may try to unscrew itself, the surfaces will move against each other and expand in a way to lock everything even tighter and stop the process.

Funny things, the more things gets lose, the more they get tight :O)

wedge loch washers, Wurth

[Black Sheep]

No problem getting cycle thread locknuts. Nooky's Nuts amongst others stock them. Handy to know that if your nuts drop off you can get newer better ones.

[bsa-bill]

Can you buy Nyloc nuts for Imperial threads?

ditto Black sheep, I use them, specially on places like the carb where you don't want to pull them up too tight but be sure they're not gonna come off

[Worty]

All comments welcome, thanks.  I searched around in the shed and found some threaded bar (metric sadly) a perfect length/gauge to replace the one I lost (thanks to my old dad for hoarding piles of junk).  I also found a couple of unused nylocs which were the correct size.  Was interesting getting the nut on the primary side, used a ring spanner and a couple of screwdrivers to get the thread started.  That should sort the upper mounting.  As for the bottom, I cleaned the threads, applied a load of threadlocker, and belted them up good.  Everything else, including head steady bolts seem ok. Have used Nooky's before, looks like a revisit is coming up. 

[KiwiGF]

All comments welcome, thanks.  I searched around in the shed and found some threaded bar (metric sadly) a perfect length/gauge to replace the one I lost (thanks to my old dad for hoarding piles of junk).  I also found a couple of unused nylocs which were the correct size.  Was interesting getting the nut on the primary side, used a ring spanner and a couple of screwdrivers to get the thread started.  That should sort the upper mounting.  As for the bottom, I cleaned the threads, applied a load of threadlocker, and belted them up good.  Everything else, including head steady bolts seem ok. Have used Nooky's before, looks like a revisit is coming up.

If you can fit 10mm studs in the bike then the holes are worn and this may explain why things are coming loose, an old racer once told me it was pretty standard to run a drill through old British engine/plates and use 10mm studs as it “tightened” things up nicely. Obviously if you want to stick to imperial (eg cycle thread) you would not want to do this!

[berger]

I have been to the pub-------but, don't use threaded bar, the vibes hammer the threads into the casting and when you need it to come out it says  and apart from that its bad practice lad as my dad told me