Fly wheel bolts torque/lock tabs? and Damper bolt torque

[PodOne]

Evening all

Just been putting the short motor back together and fitted the flywheel and unlike what I've seen in the past on other engines there were no lock tabs and none shown in the WSM either. It would seem the bolts were fitted dry and torqued to 90ft/lbs that said they its lasted 50 years until now. So I've reused the bolts (which looked fine) blue lock tight, made two "strip" lock tabs and torqued them to 90ft/lbs.

Can those in the know see any issue with this?

Also the WSM also says fit the spigot bearing loosely to the fly wheel. Mine has a phosphor bronze bush pressed into the crank (long back) and nothing in the flywheel is this correct? 

Front Damper bolt it came out easy with an impact gun. However there is no torque fig in the WSM and a search gives me 90-100ft/lbs I'm thinking of dropping this to 85ft/ibs with some copper slip as I want to be able to get it out later! Ideally I'd like to use a new bolt as the head on the original looks like it was either made to have rounded edges rather than flats which might suggest the supposed Torque setting is too high? Or it's seen some abuse. Either way I'm not keen on using it.

Problem is all the usual suppliers are out of stock has anyone a new bolt kicking about in there spares that they would be willing to part with? Happy to pay.

Cheers

Andy

 

[RogerH]

Hi Andy,

The couold it be that the flywheel bolts are of the stretch type. Use once and replace. No lock tab.

These always make me wonder - what if you fit the flywheel and then remove it 10 minutes later to check something. Do you replace the bolts

The crank bolt at the front does have rounded off corners - keep is it if only for sentimental reasons.

 

Roger

[Lebro]

Front crank bolt tightening torque = 120 ft lb.   Spigot bush fits in the end of the crank.

Bob.

[wheeler]

Hi Andy

A few years ago I had a big problem when my flywheel on my TR6 came loose. I found a couple of the bolts had sheared and two were loose, fortunately the flywheel did not fly off! 

TR flywheels have only 4 bolts holding it to the crankshaft, most engines have six so it is vitally important that these bolts are of the highest tensile quality. I bought a new set made by ARP American Racing Products not cheap but a lot safer than the normal ones. MOSS do a set of special bolts not sure if they are ARP see here 

https://www.moss-europe.co.uk/media/catalog/product/cache/1/image/358x358/9df78eab33525d08d6e5fb8d27136e95/t/t/tt2223spic1_1.jpg

I would definitely recommend that you fit these special bolts, do not reuse the old ones, mine came with special lubricant and thread lock. 

Bill

[ntc]

New bolts and no lock tabs remove them as you will put things out of balance 

[Motorsport Mickey]

And definitely NO copper slip on the crankshaft pulley bolt. It’s 5/8 th UNF and good for 150 lb ft. All Triumph torques are made dry, using a lube will increase the clamp torque. The Stag has it showing as a 120 lb ft torque and that’s what I used on mine and all the 4 cylinders I’ve rebuilt. On those they are shown as 140 lb ft but that was over 50 years ago with new material, hence 120 lb ft seems a fair compromise whilst still remaining torqued.
The head on the pulley 4 cylinder bolts are rounded... because it’s a “dog bolt”. It has a spilt face to take a cranking handle and the rounded corners allows the crank handle to disengage rather than get stuck. I know a TR6 doesn’t get cranked so why your bolt has rounded corners I don’t know.

Mick Richards

[PodOne]

Thanks for the quick responses all. Much appreciated!

I'll remove the present fly wheel bolts and fit some uprated Kent ones with lock tight and without the lock tabs torqued to 65ft/lbs as I don't fancy it coming loose given its weight and proximity to peoples legs.

Damper bolt no copper slip and torqued to 120ft/lbs once I get hold of a new one. 

Thanks again.

Andy

Edited February 14, 2021 by PodOne

[Andy Moltu]

Gets slightly more complicated if you use ARP bolts - some of those require you to use their lube and a different torque settling.  (Presumably the lube allows a lower torque to achieve the same loading on the bolt/threads)