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Discussion Starter #1
I'm (finally) about to start putting my `70 T120 back together and have a few questions about it.

1. What bearing retainer to use on the crankshaft bearings? (and other bearings?)

2. What to use to seal the case half's together?

3. Should I use gasket compound on the various engine gaskets - and, if yes, what (e.g.., Permatex 2?)

4. should I use LocTite on the cylinder studs? (if yes, which LocTite?)

5. Also, any info on using LocTite on any internal engine fasteners would be very helpful.

Thanks much.

-- alonzo
 

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I recommend this, which will cover the work on the engine.
He describes which type of loctite to use for the various applications.


I used Loctite green 620 bearing retainer for the main bearings.
Blue Hylomar for both case halves and the gearbox cases.
Some bearings/bushes are interference fits and dont require anything, other than heat.
There are lots of kinds of loctite for the job in hand, not a magic universal type.
Beware!
Also be careful with gaskets, some dont need anything (oil pump springs to mind).
Generally I use grease for gaskets.
 

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1./You would only use Loctite between the inner bearing race and crank mainshaft,if you have a loose fit.The bearings are clamped to the crank by the rotor nut and timing pinion nut.If you have a loose fit,even loctite 620 may be only temporary.Hard-chroming to restore the fit would be a better option.
If the bearings are loose in the crankcase,they will be about 0.0025" looser when the engine warms up and no amount of Loctite will help.

2./It's hard to beat Loctite 518 as a crankcase sealant,and it won't set until you close the cases together.It gives you plenty of time.

3./Dry for the cylinder base gasket.Spray the head gasket with silver paint and allow it to dry (after you've annealed it).You can use grease on the others.If a gasket needed sealant,then it's not a gasket.

4./Seal the studs into the crankcase to prevent oil leaking up the thread.You don't need a strong Loctite.Any blue Loctite will do.Loctite 243 will do.You shouldn't force the studs tightly into the case;Loctite will hold them in position.

5./I'd use Loctite 567 on the sludge trap and carefully punch plug metal back into the existing dimple in the crank.Use 243 or something blue on the flywheel bolts.You need Loctite on the rotor stud and nut.You need it on the clutch centre nut and on the other end of the gearbox mainshaft.Tab-washers can be worse than no washer at all.Loctite works.

Don't waste your time using Loctite on conrod nuts.Either tighten them up dry to 22ft-lbs (not 28 ft-lbs!),and risk thread damage on dry threads;or lubricate the threads with oil and measure the elastic bolt extension (0.004"-0.005").Bolt extension is a better indication of bolt tension than torque measurement.The actual pre-load on the bolt is what is important.

If a rod bolt ever loosens,it's because the bolt has stretched (yeilded),or because it has hammered into the rod.Holding the nut on with Loctite will still not stop the bolt from breaking in a very short time.
 

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Discussion Starter #4
I recommend this, which will cover the work on the engine.
He describes which type of loctite to use for the various applications.
Thanks Caulky.
Yep. Got his DVD. I don't remember his being specific about loctite. I'll have another look.
-- alonzo

I used Loctite green 620 bearing retainer for the main bearings.
Blue Hylomar for both case halves and the gearbox cases.
Some bearings/bushes are interference fits and dont require anything, other than heat.
There are lots of kinds of loctite for the job in hand, not a magic universal type.
Beware!
Also be careful with gaskets, some dont need anything (oil pump springs to mind).
Generally I use grease for gaskets.
 

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Discussion Starter #5
1./You would only use Loctite between the inner bearing race and crank mainshaft,if you have a loose fit.The bearings are clamped to the crank by the rotor nut and timing pinion nut.If you have a loose fit,even loctite 620 may be only temporary.Hard-chroming to restore the fit would be a better option.
If the bearings are loose in the crankcase,they will be about 0.0025" looser when the engine warms up and no amount of Loctite will help.
Yes, but... I should still use LocTite on the outer race, no?

2./It's hard to beat Loctite 518 as a crankcase sealant,and it won't set until you close the cases together.It gives you plenty of time.
Didn't know about LocTite 518. I've used Hylomar but I'll look into the 518.

3./Dry for the cylinder base gasket.Spray the head gasket with silver paint and allow it to dry (after you've annealed it).You can use grease on the others.If a gasket needed sealant,then it's not a gasket.
By 'silver' paint... is there anything specific about this or just plain silver paint?

4./Seal the studs into the crankcase to prevent oil leaking up the thread.You don't need a strong Loctite.Any blue Loctite will do.Loctite 243 will do.You shouldn't force the studs tightly into the case;Loctite will hold them in position.

5./I'd use Loctite 567 on the sludge trap and carefully punch plug metal back into the existing dimple in the crank.Use 243 or something blue on the flywheel bolts.You need Loctite on the rotor stud and nut.You need it on the clutch centre nut and on the other end of the gearbox mainshaft.Tab-washers can be worse than no washer at all.Loctite works.
OK. I'll use 243 on the crankcase studs and will look for some 567 for the sludge trap plug. I didn't take the crank/flywheel apart so I'm leaving that alone.

Don't waste your time using Loctite on conrod nuts.Either tighten them up dry to 22ft-lbs (not 28 ft-lbs!),and risk thread damage on dry threads;or lubricate the threads with oil and measure the elastic bolt extension (0.004"-0.005").Bolt extension is a better indication of bolt tension than torque measurement.The actual pre-load on the bolt is what is important.

If a rod bolt ever loosens,it's because the bolt has stretched (yeilded),or because it has hammered into the rod.Holding the nut on with Loctite will still not stop the bolt from breaking in a very short time.
You've got me a bit concerned here. I don't know about 'bolt extension' for determining proper tightness. I'm guessing you mean to measure the bolt length before and after tightening. And, I'm guessing you mean to use new bolts and nuts for the con rods? More info on this would be helpful to me.

Thanks much.

-- alonzo
 

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*Loctite on the outer races of main crank bearings won't work.There's too much differential expansion.They should be fitted when the case is hot and they will be very tight when it cools down.They should still turn freely when the case is cool.

*Any silver paint seems to work on a head gasket.Just spray it enough to make it look silver.

*If you haven't pulled the sludge trap plug out of the crank,you won't need the Loctite 567.

*You'll be safe to re-use the conrod bolts.Some people replace the nuts if the've lost some of their "self-locking".Most rod bolts you buy now are unknown quality,and could be a lot worse than what you take out.ARP rod bolts are good,not cheap.

The best way to tension rod bolts is to measure them with a micrometer.It will be easier if you flatten off the ends of the bolts.Measure the bolt before you start tightening.Use a torque wrench to tighten the bolt a little,and measure it again.Each time you tighten it,it should require a little more torque to move the nut.If the torque ever stops increasing,you have a problem and you should loosen the bolt and check its length.It should be the same as when you started or the bolt is junk.
When the bolt reaches 0.004"-0.005" extension,it's tight enough.If you plan to race it,go for 0.005" but no more.

If you can't get use of a micrometer,just tighten the nuts up dry with a torque wrench to 22ft-lbs.
 

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I use Copper coat. I dont expect it's too much differant from silver paint.
Case halves, Loctite grey 5699. Plenty of setup time.
Cylinder base nuts don't need anything. Good idea though to stop oil creep with the studs.
 

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I'm going through all this with my TR7 engine just now. I noticed that Triumph specifically recommend Loctite 270 for flywheel bolts, so that's what I used (also used on the sludge trap plug in addition to a careful punch, to be on the safe side). Loctite 270 is a high strength grade, intended for items you really don't want to come undone: might be a pig to get undone again, but where flywheel bolts & sludgetrap plug are concerned this should be very rarely. A kinder way to shift a stubborn plug is to weld a nut to it rather than resort to belting with an impact driver & lump hammer.

If you've removed the sludge tube you must have removed the flywheel bolt that locates it, so probably best to use what Triumph recommended when re-fitting (torque should be 33ft/lbs).
 

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Shrugger - when you say Copper coat, is this the same as Copaslip or other copper-based assembly greases? Or is it something quite different (I've never heard of it - maybe a brand only available in US?).

I must admit I don't really understand the silver paint idea: why silver, if any kind of silver paint will do? How does the gasket know what colour it's been sprayed?!
 

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generic name I called it. There are a couple brands. This is the one.
Spray it just before assembly, while it's still a little tacky

Copper coat
 

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Thanks for the link Shrugger. It seems this is something quite different to Copaslip, and only available in the US (and various other parts of the world but not UK for some reason). I wonder whether Loctite do an equivalent? I'll look into it - this looks like handy stuff, and better than paint!
 

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The silver paint is about 90% zinc when it dries.If it doesn't leak,it really couldn't work better.I've heard that gold paint works too,but never tried it.
 

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check your local Auto parts store. Should have something like it.
It's where I got mine.
 

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I'm (finally) about to start putting my `70 T120 back together and have a few questions about it.

1. What bearing retainer to use on the crankshaft bearings? (and other bearings?)

2. What to use to seal the case half's together?

3. Should I use gasket compound on the various engine gaskets - and, if yes, what (e.g.., Permatex 2?)

4. should I use LocTite on the cylinder studs? (if yes, which LocTite?)

5. Also, any info on using LocTite on any internal engine fasteners would be very helpful.

Thanks much.

-- alonzo
Alonzo...HOWDY BRO...I had a 59 Trophy 650...a lot of Bates Parts...I highly recommend GASKACINCH for sealing cases and gluing gaskets into place...no ooze, clean up, and will never burn away near exhaust...I owned several bikes...the 650 was 1st...Honda XL250 and 81 Suzuki GS1100EX...Good Luck Bro...
 
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