Primary chaincase Allen bolts - tightness

[Phil C]

I've learnt from this forum that the bolts which secure the timing side outer cover should not be tightened very hard atall. I wonder: does the same apply to the primary chaincase allen bolts? (There is a gasket on the pc side, but not on the timing side, if that is atall significant.) The reason I ask is that when I first removed my pc the bolts were very tight, and so I've done them up tightly, in order to avoid leaks. Maybe that's wrong? Maybe it's risky damaging the female thread (which would be a bit of a disaster)?       Phil

[A10 JWO]

The problem with Allen bolts is that everyone does them up too tight because they can. Thats why they were screws, that's all they need; a hand and screw driver. This is another reason that the threads get worn out in the cases. Does this make sense.

[Phil C]

The problem with Allen bolts is that everyone does them up too tight because they can. Thats why they were screws, that's all they need; a hand and screw driver. This is another reason that the threads get worn out in the cases. Does this make sense.

Okay, thanks, in future I'll be gentle with them.   Phil

[AdrianS]

I think it easier to get a uniform tightness with an Allen key. Screw heads were often chewed up because the wrong sized screwdriver was used. We have all come across heads that are that chewed up it is difficult to get any purchase on them and also vastly over tightened.

[Bess]

Hi,
    If you're worried about overtightening it maybe worth investing in an Allen screwdriver:

https://www.ebay.co.uk/itm/Bondhus-Hex-Screwdriver-Allen-Balldriver-Ballend-Imperial-Key-Lifetime-Warranty/251516663415?hash=item3a8f8fb677:g:aqcAAOxyBotTXRML

Best wishes...

[Rog1]

With Allen headed case screws, I do them up first using the short end for leverage, but not very tight. Because I find that when using the short end for leverage it's difficult to be consistent, to finish I reverse the key and use the long end for leverage to finally tighten each screw. But importantly, I do apply anywhere near full force. This has worked for me for years.

[Phil C]

Thanks Rog1, I think that's probably what I'll do, as it's cheaper than buying a set of screwdrivers (but thanks anyway Bess.) What I hope won't happen is that I tighten gently and it leaks, so I tweak it a bit more and it still leaks a bit, so...you can see where that could end up. I guess it's a matter of ensuring good surfaces and even tightening. I think maybe in the past I've been too reluctant to use much jointing compound, maybe I should use a bit more.  Phil

[PeteRae]

Phil,
when you are tightening them up, do it in a sequence like a cylinder head. Bit like opposites on a clock face....plus the one in the middle. If you've still got a leak have a go at smoothing off the casing faces by rubbing them on a piece of flat glass/mirror with some grinding paste. Tightening bolts/screws over the years can deform the alloy a bit.
Pete

[Phil C]

Thanks

[PeteRae]

If the picture has uploaded....this is why you need to check the bolt length and clean out the holes...
Pete

[Rog1]

If the picture has uploaded....this is why you need to check the bolt length and clean out the holes...
Pete

A drill bit fed in by hand (I only heard about this method recently) can remove a surprising amount of old gasket sealant etc from screw holes.

If a previous owner has been levering at the cases or been clumsy, that can cause raised sections on the gasket faces; something to watch out for. Careful use of a fine file can remove those bumps.

[DAVE BRADY]

Hi,

A light touch with a drill bit quite bit larger than the hole will also remove any bulging and tidy up the hole.  To get the threads really clean gently run a tap down to the bottom of the hole.  You may find another bit of depth so a slightly longer screw can be used which can come in handy if the shallower threads are bit worn.

Dave.

[Phil C]

Hello everyone,
I see that Rupert Ratio (vol.1, p.250) gives a torque setting for timing and primary cover screws of 3.5 - 4.5 ft/lbs. I'm not sure if this is for all models and years but it looks like it to me.
I don't know much about torque settings but I'm guessing that's a very gentle tightening indeed. For example, as a comparison, carb flange nuts he gives as 10ft/lbs.
So I think I'll be taking my primary chaincase off and when I put it back on it will be more delicately.
I've just ordered a torque wrench but it doesn't go that low. So I'll just tighten gently, turning the short end of the Allen key. In any case how would you fit a torque wrench to an Allen screw?
Phil

[AdrianS]

Hello everyone,
I see that Rupert Ratio (vol.1, p.250) gives a torque setting for timing and primary cover screws of 3.5 - 4.5 ft/lbs. I'm not sure if this is for all models and years but it looks like it to me.
I don't know much about torque settings but I'm guessing that's a very gentle tightening indeed. For example, as a comparison, carb flange nuts he gives as 10ft/lbs.
So I think I'll be taking my primary chaincase off and when I put it back on it will be more delicately.
I've just ordered a torque wrench but it doesn't go that low. So I'll just tighten gently, turning the short end of the Allen key. In any case how would you fit a torque wrench to an Allen screw?
Phil

You buy a set of Allen sockets.
For the timing side cover, just nip them up first , then go around again and tighten a tad more and that should be fine. Evenness is more important and also the length of thread that is engaged. The more thread, the bigger the safety margin before stripping.

[Bess]

Hi Phil,
           A torque screwdriver would be the best option:

https://www.machinemart.co.uk/p/wera-7445esd-torque-screwdriver-2-5-11-5lbfin/

Best wishes...