New project - winter model

[dickie]

got the top end and crank back from Scotty of DSC today. And they are really rather sexy; maybe I should get out more.

The SIL crank I was going to mistakenly junk, but now with yamaha 110 rod and RG500 big end bearing. Sitting teasingly alongside it is a rather seductive looking Ron Moss head.

DSCF0294_zpswb7rsiem by richardhenderson1968, on Flickr


And a Mitaka peephole piston again from Ron Moss but with cut-outs by Scotty.

DSCF0296_zpsstfecagv by richardhenderson1968, on Flickr

TS1 barrel with steel liner, MB manifold to help with frame clearance and RD350 reed valve. Scotty cut the reed guide to help clear the boost ports. Boost ports, you ask? Read on.

DSCF0298_zpsdux9tuil by richardhenderson1968, on Flickr

Not the best picture in the world but shows the boost ports he cut above the inlet.

DSCF0302_zpsqdf1fuyi by richardhenderson1968, on Flickr


And this is the bit I really like. Probably old news to lots of you, but I still dig it, man. Exhaust port wider at the top for rapid purge but narrow at the bottom where you don't need it and piston velocity is MUCH lower, thereby giving compromise between power and reliability. Rather elegant thinking.

DSCF0306_zpsh5jjuuga by richardhenderson1968, on Flickr

Current thinking is to use a TMX30 and Franspeed 3 to give a decent compromise between power and ride-ability. Only a few days ago I was determined to use the BGM clubman I have in the garage, but that looks destined for other things.

[Toddy]

Same as mine top touring set up from mr Scott , been well happy with mine

[dickie]

I'm going to have an inboard hydraulic with hidden master cylinder on this one. I nosed around the various options and chose the chas speed fabs hidden master cylinder.

I'm glad I did if only for the way he packed it. I'm a sucker for good presentation.


Seems a shame to hide it behind the horncast

[duncan1958]

Nice looking bit of kit there ,gave me neck ache as I was looking at it for too long with my head turned sideways

[steve t]

Master cylinder kit looks good was it supplied with a cable or do you have to cobble one together I have a hidden master on my series 3 I used piano wire with silver soldered nipples as it gives a much more positive feel than normal Bowden cables.

[dickie]

Master cylinder kit looks good was it supplied with a cable or do you have to cobble one together I have a hidden master on my series 3 I used piano wire with silver soldered nipples as it gives a much more positive feel than normal Bowden cables.

Not supplied Steve, I have to make my own.

I had thought I'd just use a Sr thick front brake cable with a a trunnion added in the master cylinder pivot but I'm now wondering if hard braking might pull the cable out the trunnion

[dickie]

Had a few jobs to do on my series 3 and a mate's suzuki bandit but they're out the way now so I can get back to building the engine.

First time I've done this and found it rather satisfying.

Matched the packer and transfers to scotty's barrel.
DSC_0403_zpscsyz9v5n by richardhenderson1968, on Flickr

[dickie]

Finished rebuilding the top end. I've really taken my time and made sure I did everything just right.

Then I did a leak check......
DSC_0454_zpsttgrgqwe by richardhenderson1968, on Flickr

the mag housing leaks, but just a small one. I'll sort it anyway.
DSC_0438_zpskjpxldkp by richardhenderson1968, on Flickr

Big leak on the inlet manifold

DSC_0436_zpsygcuytsa by richardhenderson1968, on Flickr

The last one is the only one that worries me as it's coming from a barrel stud and could well end up being a right pig to sort out.

DSC_0437_zpskkvt1dum by richardhenderson1968, on Flickr

[Warkton Tornado No.1]

The last one is the only one that worries me as it's coming from a barrel stud and could well end up being a right pig to sort out.

By the ‘barrel stud’ leaking, you must surely mean the base gasket is not doing its job.

If so, did you fit it dry or greased?

What torque did you apply to the head nuts & again, dry or greased?

If your threads are good, you can go to a higher torque (I have a safe maximum in mind that I won’t make public for fear of recrimination!) even with a dab of Copaslip.

[dickie]

By the ‘barrel stud’ leaking, you must surely mean the base gasket is not doing its job.

If so, did you fit it dry or greased?

What torque did you apply to the head nuts & again, dry or greased?

If your threads are good, you can go to a higher torque (I have a safe maximum in mind that I won’t make public for fear of recrimination!) even with a dab of Copaslip.

Yes, you're right but it's not actually a gasket, it's a 3mm packer.

I used threebond on both sides of it then tightened up to 25Nm. I didn't use any lube on the head nuts but they're in good condition (brand new), so there's decent tension in them; maybe some threadlock would let them slide a little more?

You could PM me your secret torque setting and I promise not to tell. Honest.

[Warkton Tornado No.1]

I can’t remember when I last assembled an engine without a packer! They’ve been anything between 3 mm & 11 mm in recent times.

Threebond does have a good reputation & I’ve used it, but on the very bottom end, I’m not convinced it is any better than the sanitary silicone sealant that I’ve used for years. If I still had Golden, or even Red, Hermetite to hand I would use them on the base.

I cannot recommend you do as I do, but I’d use a dab of Copaslip & torque to 22-1/2 ft/lb (about 30 Nm)

There is no way you should be using a thread locking solution in that scenario, even if it imparts some lubricity. Cylinder head nuts need to stretch the studs to ensure tightness & integrity of the assembly. Correctly done, they will stay tight, just like wheel bolts on a car, which are often over-tightened by car tyre centres! I always check & re-do mine with Copaslip.

[dickie]

Threebond does have a good reputation & I’ve used it, but on the very bottom end, I’m not convinced it is any better than the sanitary silicone sealant that I’ve used for years. If I still had Golden, or even Red, Hermetite to hand I would use them on the base.

I cannot recommend you do as I do, but I’d use a dab of Copaslip & torque to 22-1/2 ft/lb (about 30 Nm)

There is no way you should be using a thread locking solution in that scenario, even if it imparts some lubricity. Cylinder head nuts need to stretch the studs to ensure tightness & integrity of the assembly. Correctly done, they will stay tight, just like wheel bolts on a car, which are often over-tightened by car tyre centres! I always check & re-do mine with Copaslip.

Thanks, I do have some red Hermetite but why do you think it's better than threebond on the base? I can obviously see that it's a different application to the head, but not what is better about it.

I have to admit to being slightly nervous about 30Nm plus Copaslip ; I reckon that's equivalent to about 40Nm dry! All my threads are brand new though, so I'll give it a go and take it up little at a time.

Thanks

[Warkton Tornado No.1]

As I said:

Threebond does have a good reputation & I’ve used it, but on the very bottom end, I’m not convinced it is any better than the sanitary silicone sealant that I’ve used for years. If I still had Golden, or even Red, Hermetite to hand I would use them on the base.

My unconfirmed, unscientific belief is that Threebond is a product that may work well or better @ the elevated temperature that are encountered @ the top end of the cylinder where you can accept, or prefer a bonded seal. I used to use (wait for it!) Green Hermetite there.

However, with the changes from hot to cold as an engine runs & then stands, inevitably, there will be some movement, or ‘creep’ that must be tolerated somewhere to maintain the integrity of the whole assembly.

My preference is to acknowledge that need by utilising a compound on the base that has some degree of flexibility to allow for that movement.

IMO the Red Hermetite would be my choice from what you have available.

Seriously, the silicon sealant that smells of vinegar (preferably the low modulus, more elastic type) is incredibly well suited to sealing tasks that need to accommodate some movement without failing. Sceptics cannot understand that it can cope with the temperatures encountered (I use it on the exhaust flanges) but when you consider that silica is the most common component of sand, you begin to understand why. I NEVER use Blue Hylomar. I'd sooner use Cow Dribble.

In all of this, I’m just trying to offer a little sideways advice from what is the accepted norm, to help you reach a solution. That leaves me often vulnerable to criticism, but I wouldn’t claim to be an expert @ anything.

I can only suggest what I would try….


As for:

I have to admit to being slightly nervous about 30Nm plus Copaslip ; I reckon that's equivalent to about 40Nm dry! All my threads are brand new though, so I'll give it a go and take it up little at a time.

If you can ensure that the compounds utilised to seal are the optimum, then you should not need the kind of torque you anticipate.

The thing I should empathise is I advocate some lubricity between the cylinder head nuts & studs that will remain despite the cycles of hot & cold, which Copaslip will do. This facilitates re-torquing if required. A tiny dab is all that is necessary.

My own practice has been to studlock the studs into the crankcase, often V*spa rolled thread studs with as deep as an engagement as possible. If threads (rarely) pull, I am fortunate enough to have Helicoils which many engineering manufacturers insert @ manufacture, rather than just as a fix.

[dickie]

Oh poo.

I had a nasty feeling that the leak at the base might be a bit of a pain.

I've stripped and rebuilt but it's just the same.

With better light and a look from a few different angles, I can now see that it's from a porous weld which was done during the modification to accept a 200 spigot.

I'm going to fill it myself by dremelling it out then using either plastic metal or I'd like to try those low heat aluminium welding rods; anyone got any experience of them?

[Warkton Tornado No.1]

Oh Dear!

After all that debate, eh?

Ho Hum.

I only have heard that the alloy ‘brazing’ can be very successful. I thought Frosts sold the rods, but these do:

http://www.aluminiumrepair.co.uk/index.php/ct-menu-item-4/ct-menu-item-6

Having said that, Frosts do an aluminium paint for porous castings, which, again, I have no direct experience of.

No doubt, you are aware of the preference for low temperature to avoid distortion.

One thing you may not have heard of is aluminium Helicopter tape. Now that, I have used! It was on a badly porous welded up race crankcase cover & worked to great effect.

However, you could always consider ‘patching’ with some thin sheet aluminium secured in place with fasteners well away from the leaky part. After making it fit, it should finally be laid on with a compound you trust (I’ll let you choose!) & the fasteners added which will only be there as ‘belt & braces’ to ensure the patch doesn’t lift.

[dickie]

I had to refit the mag flange with threebond. Had to strip and rebuild the reed valve and manifold twice plus add threebond. I had to remove and refit the barrel three effing times as well as having to 'repair' porous weld with JB weld, but in the end it's air-tight.

How much difference this makes to reliability or performance I honestly don't know, but it's given me a sense of satisfaction knowing that I've done it reet.

Another thing I've learned from this forum; thanks folks.

[Digger]

That was close - I thought I was looking at an exhaust pipe for minute or two.

[Warkton Tornado No.1]

I’m pleased you seem to have got to the root of the problem but I guess it has been @ considerable cost in time & money.

In my experience, welding of Lambretta alloy components has always been fraught with problems. It’s my understanding that the zinc content, by which the castings are so good, is detrimental to the process of welding as its lower melting point causes the gas which then results in porosity.

For straightforward conversions of small block cases, the process of machining to accept a threaded insert to suit large block cylinder centres was pioneered some years ago, or so I thought. Spanish 150 cases with their larger ‘200’ area were ideal for the process.

The ‘Keensert’ type inserts are the type I would prefer as they have standard outer thread sizes to suit commercially available taps. They also don’t unwind themselves once the keys are knocked into place.

attachment=0]Keensert.JPG[/attachment]

[dickie]

I’m pleased you seem to have got to the root of the problem but I guess it has been @ considerable cost in time & money

attachment=0]Keensert.JPG[/attachment]

Cost nothing but my time, and as I only do this as a hobby, I almost welcome problems and the challenges they present. Or let me put it another way; there is not the smallest chance that I would ever buy a lambretta that didn't need a lot of work.

Interesting what you say about zinc content.

[dickie]

Top end sorted now, so I'm turning my attention to the gearbox. I decided to lighten the clutch sprocket for no reason other than I felt like it. It was 800g before I started and 750g after I'd finished; a much smaller reduction than I expected. The likelihood of it making any noticeable difference is negligible but so what?

First I drew up a template for the centre on autocad and centre punched for some 20mm holes.
DSC_0475_zps1rrrcuqb (1) by richardhenderson1968, on Flickr

Then I cut them out with a 20mm holesaw
DSC_0477_zpssgr4dmed by richardhenderson1968, on Flickr

I should have made some templates for the edges but I did them by eye. Unfortunately they're (unsurprisingly) not as good as the centre but it's of no real consequence.
DSC_0478_zps6etrjjce by richardhenderson1968, on Flickr