Engine mount bolts

[Frank Corr]

Hi all, daft question time.

Can anyone throw some light on the best method of attaching an engine to the engine mount. I have seen some attached with self tapping screws. Some attached with bolts and nuts and some where the nuts were welded to the engine mount by heating the mount and forcing the nut into the hot material.

I suppose it is down to personal preference. however not being used to metric sizes what size bolts shoult I use to secure a Thunder Tigre .40 to the engine mount.

All advice and suggestions gratefully accepted.

Frank.

[Bruce Richards]

By preference I bolt my engines using 3.5mm machine screws either with nyloc nuts or double nuts with thread lock. It is often hard to find 3.5mm nyloc nuts so I use 3mm machine screws and matching nyloc bolt. I also use washers top and bottom.

I have also used self tapping screws, into plastic mounts, without too much problem. The key is not to drill too bigger hole in the mount or the screws will keep coming loose.

[Frank Corr]

Hi Bruce,

Thank you for the information and the advice.

[Andy Green]

I too use machine screws. M3 or M4 depending on crankcase hole size.

I like to drill and tap a tread in to the mount - yes even the nylon ones, and nip it up with a locknut.

I like hex head, that I can use allen keys on and for locknuts I use  a product called Aerotite, rather than have a nylon insert they rely on a part of the nut to hold on tight.

I've never used self tappers so can't comment.

Andy

[Frank Corr]

Many thanks Andy

[Chris Channon]

Years ago we used to attach the engine to the mount with elastic bands !!!!!

Nowadays, self tappers are fine or drill a clearance hole and use bolts with ny-locks.

Chris.

[Bob Cotsford]

bit  of a difference between the 049s that we used to laccy band on, and the .40 + engines in today's trainers!

I don't like self tappers as a rule, but dismantling the remains of my lately put to rest Flair Hooligan, I found the engine mount was fitted with - you guessed it , self-tappers.  That had survived 20 years without parting company so they can't be that bad.

[flytilbroke]

www.Modelfixings.co.uk

They can supply 3.5mm machine screws and nyloc nuts to match. There is some times a short delay in supply though. Our "normal" mounts take 25mm long bolts although I have bought 30mm ones as I can trim them to length.

My Irvine and OS are made for 3.5mm. I have also used self tapping screws without problem on Irvines up to .53 size. I just prefer to use decent bolts.