The gearbox project begins

Maestro, SEI-V

Re: The gearbox project begins

Postby 72degrees » 24 Oct 2017 14:40

I followed the blue book figure on the 350 rebuild. As you say, the special tool for the new type nut doesn't seem very suitable for applying such a high torque.
Mine appears to be holding together so far, but then it hasn't covered many miles - though it has been revved to the ('250' tacho) red line at every opportunity.
How does the recommended figure compare with a 'general' setting for that size of thread? Is it significant that the pinion isn't keyed in any way?
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Re: The gearbox project begins

Postby penman » 25 Oct 2017 12:46

Continuing the torque figure saga for the oil pump drive worm gear, I contacted NLM this morning and they recommend the blue book figure of 5mkg. Their feeling is that 13 mkg is "silly" - their word, not mine. They strongly recommend a new nyloc nut, which is of course good practice anyway. Before I stripped it down I didn't know that was a nyloc, so I didn't get one and I've put the old nut back. I will probably open it up again and replace that nut. A bit of a drag, but not the end of the world!

Joe.
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1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
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Re: The gearbox project begins

Postby norbert » 25 Oct 2017 17:04

5 kgm is about the half of the flywheel and clutch center nut (recomended 9) :roll: That´s not very much, having in mind the purpose of that nut. Although here in germany people use to fix the center nut of the clutch with about 6 because there have some primary axles broken probably because of too much torque. I myself up to now never didn´t have to fix that oilpump nut during about nearly 200 000km with the morini twins. :roll:

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Re: The gearbox project begins

Postby harrymuffin » 25 Oct 2017 18:31

Having had a new nyloc come undone I now use low retention Loctite and if you have the correct tool holder that holds the pinion - two holes - then achieving the correct torque figure is very easy.
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Re: The gearbox project begins

Postby penman » 26 Oct 2017 09:49

harrymuffin - what do you regard as the correct torque figure for this nut?

I found it quite tricky even to get this nut up to 5mkg, maybe it's the tools I have (spoken like a true bad workman!). The holding tool and "socket" are:

Image

and the business end of the socket is like this:

Image

Both are a good fit, but both have their problems. The handle on the holding tool is short and really needs a length of pipe to extend it a bit. It then needs two hands to keep it securely engaged under pressure. The socket is quite long and since it can only engage to the depth of the nut, putting any strain on the torque wrench tends to pull it off the nut, so that needs two hands as well. I only have two hands in total!

I ended up clamping a length of pipe in the vice, with wood blocks spacing it so it went across the bench at an angle. I positioned the engine so that the holding tool engaged with the pipe. I then had two hands for the torque wrench, one to hold it engaged with the nut and one to heave on it. It did slip off a couple of times before I managed it and I really don't think I'd have got it up to 13 mkg. It might be easier with two pairs of hands and I'll try that next time. It may also be easier with a brand new nut, and I have one of those on order. I guess it might also be easier with the engine back in the frame, which is where it is now. I shall report back on how it goes!

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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Re: The gearbox project begins

Postby harrymuffin » 26 Oct 2017 12:34

Yes, your holding tool is about right but too short, mine is about 18" long (also has the holding tool for the camshaft sprocket on the other end) and with the engine in the engine work cradle/stand then you can also either use the bench or a peg through the cradle to resist turning. The socket you have for the nut looks nothing like the one I have, is it made from a soft material as the one I have is heat treated and hardened as with any spanner/socket. It has four pegs, 5mm long that locate into the nut and a 24mm hexagon that protrudes through the holding tool just sufficiently to get a socket onto it. This arrangement gives the holding tool a better location as everything is close to the nut and the socket acts as a spigot. I still have some original hexagon nylocs for this location.
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Re: The gearbox project begins

Postby penman » 26 Oct 2017 13:55

harrymuffin - the special socket I have is good quality, some kind of hardened steel and seems accurately made. The only problem is that it really needs two hands to use it because you are applying the torque too far out from the nut - I'm sure you know what I mean. I just received the new nut in the post, so I will strip the primary again and fit that. I'll try to get someone to help by looking after the holding tool.

As a matter of interest, what torque figure do you regard as correct for this nut? There seems to be a split of opinion between the 5 mkg specified in the blue book and recommended by NLM, and the 13mkg given in the Cagiva document. I really don't want that nut to come loose, but at the same time, 13 mkg (128Nm!) is a heck of a high torque and I don't want to break something.

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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Re: The gearbox project begins

Postby harrymuffin » 26 Oct 2017 14:54

P1030588.JPG
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I have an original workshop manual from the early seventies and the torque figure for this nut is 5mkg which is 36ft-lbf. The original nuts were hexagons headed so assume the reason for going over to the peg drive is because of problems that you are now encountering in that the sockets were difficult to keep on the nut. I have attached photos of my nut doer upper and the holder which is 151/2" long. The hexagon of the doer upper uses the shaft that sticks out as a dowel and only the hexagon is proud of the holder ring so everything is close up to the nut so can not lever away as you are experiencing. The socket also stops the holder ring from slipping out of it's location peg holes so you effectively only need to use one hand for the torque wrench and the other to push and keep the socket it where it should be.
As I mentioned before, I did have one of these nuts work loose, so I always drop a pin head of the low retaining strength thread adhesive just in case. Don't forget that the torque on this nut was calculated by the production engineers taking into account the materials and tensile strengths of the metals so would suggest that their figures should be followed rather than an uneducated mechanic with a kango air hammer or 6' long pipe.
Not sure whether the photos have loaded as i have not done this before - excuse the bread flour.
Attachments
P1030589.JPG
P1030589.JPG (169.11 KiB) Viewed 2450 times
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Re: The gearbox project begins

Postby Ming » 26 Oct 2017 15:31

harrymuffin wrote:...I have an original workshop manual from the early seventies...


If you are talking about the 'Harglo' Manual, I have one too, which is on my Google Drive.
If anyone would like access to it, PM me your email and I'll enable you (there's other stuff, too.)
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Re: The gearbox project begins

Postby norbert » 26 Oct 2017 16:26

I asked in the german forum and it looks like 10Kgm with a bit of loctite semifastenglue is what experienced people do aply here.

this is my tool
DSCI0154.JPG
DSCI0154.JPG (143.18 KiB) Viewed 2446 times


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Re: The gearbox project begins

Postby penman » 26 Oct 2017 17:30

Thanks for the replies guys, a lot of common sense there.

I have now replaced the nut and doing it up was a LOT easier with the engine back in the frame. I stuck a steel rod through the holes in the front engine plates and that formed a secure stop for the holding tool, so I could now get two hands easily on the torque wrench. In the end I compromised and set it at 9kgm. For some reason the metric scale on my torque wrench is calibrated in odd numbers 1, 3, 5 and so on, so 9 was a good number and felt tight but not excessive. Not too much science there though, I admit!

The engine’s out again now though as I have a new problem. I’ll describe it later, I’m cooking dinner at the moment and that’s got my attention!

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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Re: The gearbox project begins

Postby penman » 28 Oct 2017 09:17

I promised an update, and I must start with an admission that the latest setback was largely my fault.

After assembling the primary after fitting a new oil pump nut, I turned the engine over a few times, as you do and noticed a faint scraping noise on each crank revolution and covering about 30 degrees of rotation. This only happened if I turned the engine backwards and I couldn't "feel" anything, but I could hear this faint scrape. I'll cut a long story short, it turned out to be the large sludge trap plug which was just touching the crankcase casting beside the R/H main bearing. This was a new plug, which turned out to stand about 0.1mm higher than the old one when fully tightened. The old one must have been very close as well! It wouldn't tighten down any more, so in the end I ground about 1mm off the top of the plug and it now fits with plenty of clearance. This photo shows the problem, you can just see it through the hole for the rear cylinder. Sorry about the focus - the downside of using your phone as a camera!

Image

The good news is that the second time around I stripped and reassembled the crankcase in double-quick time, I doubt if this added 2 hours to the job, and that included taking the engine out of the frame again. If anyone else is doing this, do check the height of that plug, it may or may not be OK!

Now I'm just waiting for the heads and barrels to come back from the engineers, it should only be a few days now.

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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Re: The gearbox project begins

Postby penman » 19 Nov 2017 13:03

An update at last!

I finally got the heads and barrels back from the engineers on Friday and have started to reassemble everything. Just for reference, with the crankcase in the frame, you cannot install the rear cylinder barrel or head. If you support the engine with a jack, remove the front mounts and the upper rear mounting bolt, you can tilt the engine forwards just enough to allow you to put the rear barrel and head back - with a bit of jiggling! Getting the Morini pistons back into the barrels is simplicity itself - compared to a T160 Trident, it's a pleasure! You don't need a ring compressor, your thumbnails are well up to the job and because the barrel is sliding down those long studs, everything is kept square and under control.

Now a question. The blue book tells you to adjust the rocker arm side clearance to 0.05 - 0.15 mm before tightening the retaining nuts. How is this adjusted? On mine the clearance is about 0.5 mm, which is probably contributing to the noisy valvegear. Info on this adjustment will be much appreciated!

Next instalment coming up very soon (I hope!)

Joe.
1980 Moto Guzzi V50 II
1978 Triumph T140 E Bonneville
1975 Triumph T160 Trident
2014 BMW F800GT
1978 Morini 500
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Re: The gearbox project begins

Postby 'It must be a .....' » 19 Nov 2017 13:44

Hello, it is possible to remove and fit the rear barrel and head whilst in the frame if you tilt them and feed over the top of the studs.

The individual rocker end float is adjusted by a combination of moving the mounting blocks on the studs (rocker between the blocks) and the rocker shaft within the slotted mounting block (rocker outside the blocks).

Hope this helps, have fun

PS might be worth checking that the rockers, shafts, blocks etc have been put together correctly?
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Re: The gearbox project begins

Postby 72degrees » 19 Nov 2017 14:54

penman wrote:Now a question. The blue book tells you to adjust the rocker arm side clearance to 0.05 - 0.15 mm before tightening the retaining nuts. How is this adjusted? On mine the clearance is about 0.5 mm, which is probably contributing to the noisy valvegear. Info on this adjustment will be much appreciated!



Evguru has an excellent Youtube video on this:
https://youtu.be/QULLDS39gqI?t=12m50s
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