North Norfolk Canter

I thought I'd take the SQ4 out for a little gallop along the coast this morning. We had a nice little trip along to Holt, to visit the North Norfolk Railway. This is a most excellent standard gauge line, with steam and diesel engines running most days in the summer, and a variety of special events throughout the year. This is the end of the present line, where trains from Sheringham terminate after a 5 mile trip through Weybourne & Kelling. You can take a bus into Holt, or look around the museum, or take the train back again:

North Norfolk Railway - Holt Station

Then a trip north through the countryside to the coast at the aptly named Cley-Next the Sea

Cley

Then along the gloriously twisty A149 through Salthouse & Kelling:

Salthouse Marshes

Stopping at the Muckleburgh collection on the way home:

Muckleburgh Collection

Twenty-one miles in all, no mishaps, apart from the fact that the front brake is being 'grabby' again. We did some more temperature measurements when we got back, which you can read about here. At the end of the run the oil pressure was reading about 20 psi at 25 mph.

Temperature testing also revealed that the front brake drum was at 117°C when I stopped. Hmm...

Maintenance

Well, the Square is finally in the garage (as opposed to the workshop/shed/summerhouse where I restored it) and is getting into the swing of being a mode of transport rather than a project. Well, nearly...

I'm going to try and ride it a little every day now it is nearby, at least when I am not away working, and that should build up some miles: and of course that means maintenance.

I'd puzzled over the best way to fill the primary cases. The big filler hole is directly above the level plug and I had formed the opinion that dribbling oil into the filler ran down the inside of the case, around the footrest tunnel and out of the level hole, and that my primary case didn't have any oil in it, because none came out of the chain oiler. So I left the drain plug in and poured a decent amount of oil into the filler...

And out it came, pouring from the clutch cover drain! The primary case obviously doesn't hold much oil. I drained it all out again via the level hole, and hoped it hadn't gone all over the clutch plates.

A little trip out, to check the tyre pressures at the local garage, proved that all was well with the clutch.

I adjusted the front brake a little - it is really not very effective. The rear one is good though, fortunately.

  

Trip to the Seaside

After an uneventful run up to Sheringham, North Norfolk.

This may not seem much, as a 27 mile trip, but its the first time that I have been out riding on a route that was not circular around my home - the idea being that as you shake the bike down the radius gets larger. The first trip I do on a rebuilt machine goes out of the gate and I turn left and keep turning left until I get back, 10 minutes later. I increase the radius of the circular route as I get more confident with the machine.

As you all know, I have been having overheating problems leading to low oil pressure; as many people have said, Mk1 engines run very hot when newly built - at the end of this trip, the SQ4 had clocked up 117 miles since rebuild. 

So, following your advice, I am breaking it in slowly and keeping an eye on the oil pressure. I'll run it around each day and build up some miles.

Out & About

This is just an excuse to post a picture... Some more temperature testing today. 5 minutes warm up, some miles around town a bit of traffic, a little open road. Down to 10 psi at hot idle, 20 psi running at 25-30 mph.

Clamping Down

One of the many problems that have arisen so far during my shakedown period has been the inability to get my levers and twist grip to clamp onto the handlebars. The bars are polished stainless, and I guess that 19 mm OD stainless is of sufficiently less OD than chrome plated 3/4" tube, enough to allow the parts to move. They are not that loose, just enough to worry you. 

So, a few minutes with shears, a fine file and some 0.5 mm brass sheet produces a neat & tidy solution.

All is now rigidly clamped in place.

Oops

Well, I got out on my test drive, and it feels much happier - smoother, more torque at the bottom end...

Unfortunately, about 5 miles in, a misfire appeared and the engine stopped. Having experienced this many times during the fuel filter saga, I was quick to look for fuel supply problems and cracked the fuel supply banjo to find all was well. The bike started again, only to stop again after about 100 yards - this happened once more, and then I was close enough to push it home...

Charging had looked good on the ammeter from the first day. All the lights worked perfectly, apart from one indicator which persistently rotated around to face the floor, but in general everything had been fine. However today, when I had the bike running again, switching on the lights would kill the engine.

The Lucas C35SD gives 70 W at about 1700 rpm which equates to 32 mph in top gear, but when you are running around town the ignition, brake light and frequently used indicator loads soon drain the battery, which appears as a fuel-starvation-like misfire. I cursed that fuel line again until I realised what was going on, and a CTEK battery charger came to my rescue. Actually you need about 20 W for the ignition alone, or about 3 Amps; in top gear, you get 3 Amps from the generator at an average of 23 mph – these bikes are really not for town use.

My 1951 Mk1 has a 20 Ah battery bank hidden in the Lucas GU11E style fibreglass box. I'd be surprised if you could even get to the shops with the earlier small battery...

Valve Timing

So, we had another nice little run out yesterday, on a shopping errand this time. No dramas, Amelia running nicely with her new brake shoes. She attracted some attention from a cyclist who came over exclaiming: "Oh, a Squariel! I haven't seen one of those in years!" He proceeded to tell me about his Triumph TSS and T120R, which apparently was fitted with a Morgo pump as well.

You meet the nicest people on an Ariel.

I'd heard mention of the effect valve timing has on overheating, and it occurred to me that in the joyous response to the problems I had had setting up the valve timing initially I had possibly not been too careful to get it spot on, being happy to go with the factory timing marks. Ariel folk lore tells us this is not wise.

So, when I arrived back from shopping I whipped off the offside rocker cover, the #1 plug and the front crankshaft cap and had a look - and it looked like number one inlet valve was opening near TDC - it is supposed to be 3/16" before TDC.

So, late in the night, and with the head torch on I took off the timing cover. I discovered that if you remove the dynamo sprocket you can reset the valve timing without removing the camshaft sprocket (and hence you can leave the oil pump in place too) After 4 or five attempts I finally got the timing as close as I could - which I think is spot-on. The cam chain tension makes a big difference, and you have to test it with tension on the cam chain.

I may need to change the cam chain at some point - a worn chain affects the valve timing.

So that done, I reset the ignition timing, a job which is very easy in the dark, because you can see when the points open if you turn the ignition on, since there is always a little spark when the points open. However, testing it all again the next day revealed the valve timing was indeed spot-on, but the ignition timing was way to far advanced, as evidenced by several kick-backs and spitting at the carburettor. Realising what these symptoms meant, I reset the points gap and the ignition timing again.

And after all that, as usual, she starts easily; but probably more easily than ever; she runs eagerly (though I could only manage a couple of miles) and she idles very much more smoothly.

We have some errands tomorrow; we will see what happens on a longer run

17 mile test run; fun with brakes

Lovely test run out to Bawburgh today, about 17 miles around the countryside. Bike is definitely running less hot, since after 8 miles I still had maybe 25 psi oil pressure at 30 mph, but that was dropping to 10 psi on the gauge at the end of the trip. I measured the oil temperature - 95 degrees C in the tank (about 200 F), which is much higher than I have seen after, say, a 5 mile trip.

As you can see the bike is on the sidestand - what I noticed later was that the carburettor drips fuel onto the dynamo in this position. I had left the fuel on though. 

The engine sounds happy enough; I'm not too sure about this gauge - I keep wondering how I would feel if it had never been fitted. I'm tempted to buy one of the club reproduction gauges, or to get this one calibrated.

Out on the road though, the Ariel was handling fine for the first few miles until I became aware of a juddering from the front end, which I initially put down to the road surface. On braking however I found no movement in the front brake lever, and realised the brake was seizing on. Near home, I stopped for traffic lights and saw smoke coming from the front brake (I've been here before, with the Bantam)...

Arriving back I was greeted with grease everywhere. As we all know, hot brakes cause the grease in your hubs to melt...

Stripping the brake down revealed some serious damage to the linings, and bits of lining (2-3 mm bits) all over the drum. The linings you see in the pictures are greasy, but those matt grooves in the middle are way below the wearing surface:

Greasy

Cratered Lining

Now, I don't know if this is a result of heat, or the heat is a result of this breaking down. I'll take it back to the supplier tomorrow and see what they say.

Odd, since it had been bedding in nicely and getting quite effective.

Michelin...

Hurrah for QD rear wheels:

It makes changing tubes so easy. A lot has appeared in the press lately about the quality of unbranded inner tubes, usually relating to poor vulcanising around the valve. The tube I took out was not unbranded, but wasn't one of the big names. It had a small split along one of the mould lines:

Its under that blob of Tyreweld. All fixed now, with a nice new Michelin tube from Vintage Tyres.

Oh, and it started first kick (well, first enthusiastic kick)!

Dealing with teething trouble...

So this week, I've been out and about for another short ride, but first I refitted the Morgo pump. I did about 8 miles as usual, out of town and up to 40 mph. The lubrication job I did on the speedo seems to have stopped it sticking at full range.

The Morgo obviously provides more oil flow than the plunger pump, and I finished the journey with about 10 psi on the oil pressure gauge.

I also finished the journey with a completely flat rear tyre, which looks like it might be a valve failure. I wobbled along the road, complaining about the tramlines the council left when they resurfaced, only to keep my wobble, rapidly turning into a squirm from the rear end, when I ran out of tramlines. I recovered the puncture with a handy can of tyre weld I had in the pannier.

Of course, the low oil pressure problem is not sufficiently improved with the Morgo to use the bike in anger. Lifting the rocker covers with the engine running (rather dangerous - they are very hot) you can see little jets of oil coming from the rocker oil holes. I've fitted three new old stock rocker shafts to deal with the wear I found in the shafts last year - one was already fitted due to a damaged thread:

A thought occurred to me, corroborated by AOMCC forum members - retarded ignition causes overheating. Checking accurately revealed that the ignition was indeed retarded: I moved the distributor about 10 degrees, equating to about 20 degrees at the crankshaft, to get it right (thanks MikeN!).

So we will have to see what happens. Just waiting for a new inner tube...

Another Test

Another little test run today: 8 miles or so out of town and at the end, 10 psi at tickover. And the speedo is sweeping round to full range and staying there (that is poor lubrication)

Oil again

So, I have changed the oil.

A week or so ago, I was getting 55 psi on cold start dropping to near zero when very hot, using cheapo 20W/50 for running in. 

I worked through the clearances I measured when I built the engine, to determine the flowing areas of each of the bearings, to understand where my engine was in relation to factory minimum conditions - When I rebuilt the engine I replaced all the bearings in the bottom end, but only changed one of the rocker shafts, because they are easy to change and Drags only had one in stock. What I found was that I can improve pressures by changing the other three, especially if I can return the rockers to minimum clearance as well.

However, obsessive tinkering is something I have always been afflicted with. I wanted to change the oil, since I knew the viscosity at 100 C for both 20W/50 and monograde 50, which are more or less the same; viscosity at 40 C is almost double for monograde 50 over 20W/50, and I know my oil sits in the tank at about 73 C, so I expected a significant rise from changing to monograde 50.

Today, I started out cold with 55 psi and the relief valve operating, so I know I will never see more than 55 psi with the plunger pump. After a 4 mile run around town, its dropped to 25 psi hot (idling), and the relief valve is not operating, which is as I would expect.

So, situation much improved, but more testing required.

Roadkill Customs

Maybe this is the answer. A better quality oil bought from the nice people at Roadkill Customs, Cromer:

Elixir of Life

In any event, of all the changes I could make, it is low-hanging fruit.

More on Oil

So today, we have something like 6 degrees Celsius outside. I've just completed about 3 miles around town and I have measured the oil temperature using a meat thermometer (not the one that was stuck in the Christmas turkey last week), and we have 73 degrees Celsius.

Please don't stick it in the Turkey

If you use one of these though, you will need to stop the engine first. The RF interference driven by the HT cables is phenomenal and stops the thermometer working at all. I guess the thermocouple wires pick up the RF.

Now, looking at the oil data sheets, we can see that the kinematic viscosities are similar at 100 degrees Celsius. Plotted they look like this:

This gives us a clue, but we can't get too excited because there are only two data points per grade. The temperature/viscosity relationship is not linear. Look at this, plotted on a logarithmic scale:

This gives us a better picture. Notice that the viscosity of the SAE 50 is about 20 cst at 100 degrees C, which agrees with the data in  the first chart, but that at 75 degrees C the viscosity is about 40 cst. That should give us about a bit more oil pressure for the same temperature than the 20/50W we are using now.

Oil & Oil Pressure

So this is one of those posts that we use to collect thoughts.

Amelia has done about 25 miles, and has had her head torqued down and the oil pressure relief valve spring replaced. She is running in on Tetrosyl 20w/50 multigrade oil, to API SE spec. When cold, the oil pressure gauge shows about 55-60 psi at idle speeds; after a 6 mile run around town, at speeds up to 25 mph or so, the oil pressure drops to almost zero at idle.

Darcy's Law tells us that flow through an orifice is proportional to the area of the orifice, the pressure drop across the orifice and the viscosity of the fluid.

The viscosity of the 20w/50 will be something like 18 centistokes at 100°C, rising to something like 135 cst at 40°C. After the run, the oil was visibly very free flowing and hot.

The relief valve may be controlling the pressure at idle - it may prevent the pressure exceeding 55-60 psi, but if this is the case it will have no effect at higher temperatures unless it is stuck open which seems unlikely given that the pressure displayed on the gauge falls gradually as the temperature rises.

Additionally, the effect is repeatable - the cold idle oil pressure is always 55-60 psi, and it always drops to near zero when it is hot, so I do not think we are seeing mechanical changes in the relief valve or the engine clearances - yet.

The Morgo is a gear pump which requires clearances between its gears to operate, and these clearances will allow more fluid to slip ineffectively around the gears when the viscosity is low. Are we right to fit gear pumps when the engine runs so hot?

And then there is the gauge. Ariel indicate that these engines should run at about 40-45 psi on SAE 50, so my gauge readings are not unreasonable, but we don't really know how accurate the gauge is or even if its accuracy is linear.

But one thing is clear - when the oil is hot (and we don't yet know how hot it really is) the loss in viscosity is such that the pump can push its full flow capacity (which itself may be compromised by low viscosity) around the engine without creating any pressure in the system.

And pressure is needed to prevent the bearing surfaces coming into contact with each other.

Oil... everywhere

So a few days later and I run the engine with the front main bearing cap off. I'm not going to show you a picture, because there would be oil everywhere, but you can see from this shot with the cap loose that there is oil there; with it off it gushes out:

And here we have a new spring just arrived from Draganfly, about 25% longer and somewhat stiffer than the old one:

And here we have an oil pressure gauge showing a previously unreached figure, 55 psig, at tickover - engine relatively cold (about 5 minutes running). Thats more than 50% up on last time.

So now we need a road test. Yippee!

Another Four Miles

Well, I have had the timing cover off and the pump is solid, so I have stripped the relief valve to reseat it. Oil pressure after a four mile run today is much the same, as we await the new spring.

Still, she's running a treat and she looks lovely!

So to get my head around engineering behind the oil pressure regulator I need to confirm what size the ball seat is, i.e. the diameter of the oilway in the offside end of the front crank. The ball is 3/16", so the seat must be maybe 5/32"? I'm trying to understand what the spring rate would need to be for a given back pressure in the system.

For example, a 5/32" seat would give an area of 0.019 sq in. exposed to pressure, so a 1 lb spring would give me about 50 psi. My existing spring is not that heavy (its the original one, new one on the way) and, surprise surprise, does not achieve 50 psi on the gauge - thats assuming the valve is ever opened!

I plan to have a look and see if the regulator valve is used next time I run the engine, and I will have to find a way of calibrating the pressure gauge..

Latest trip

Well, a bit more news today, and a four mile trip around town. 

The fuel filter has gone back in the spares box to be replaced by a plain pipe and a gauze strainer in the carburettor banjo - all air locks now banished to the spares box along with the fuel filter. Apart from a very fast tickover, all seems well in the fuel department.

I've been looking at more loose ends. I had meant to look at the chain oiler screw in the primary case for a while, since the thread in the primary chain case was refusing to allow the oiler screw to pass through it. I measured it, found it was 2 BA and cleaned it out only to realise that the screw I had was just an old carburetter mixture screw and was way too short. This is what it is supposed to look like:

Thanks to Steve Clarke for this picture.

The clutch has seen some adjustment and a much better cleanup job on the splines. It's dragging a little, but a vast improvement over what I had. Changes whilst riding are noiseless - engaging first at a standstill is still noisy but much less so. By the time I had got back it seemed to have loosened up and needed adjusting again.

The electrics are all behaving themselves; the handling is also fine but as I have discovered before I need to keep an eye on the tyre pressures - 28 in the front and 24 in the rear seems to be about right, and the consensus of opinion canvassed on the splendid AOMCC forum.

I've re-torqued the head, as regular blog readers will know. Cold, the oil pressure is about 35 psi - but this dropped to about 10 psi with the engine hot, so do we think the relief valve could be due for a new spring? AOMCC wisdom suggests that the Morgo pump may have loosened off (thanks Mark) so we will have to have a look at that before the next trip. I will get a new spring for the relief valve as well. It's getting properly hot now, but the engine is quiet and I have no exhaust or oil leaks.

Looking forward to the next trip!

Settling Down

Time for some maintenance - re-torque the head. There are a few small oil leaks around the head gasket, so I pull the nuts down a little more, maybe a 1/4 turn on each - except these guys:

These guys are only hand tight. Now I know I made a better job of that when I pulled them down the first time...

So I've worked around the head and the base gasket, pulling everything down. I've also replaced the rocker cover studs, one of which was badly stripped (at the nut, not the head, fortunately!).

So I've also had to reset the tappets, and since all the plugs were out I have bent the terminals a little to improve the HT cable routing.

I've sealed the exhausts at the cylinder head with high temperature silicone sealant, so hopefully we won't have any more exhaust or oil leaks.

Next stop was the clutch, which I have readjusted.

The final job today was to take out the inline fuel filter which served only to cause air locks. You have to be careful with these - there does not seem to be much resistance to flow but really they are better suited to pressurised fuel systems.

So that's it. She starts beautifully, coming off the bi-starter after a few minutes and settles at about 25 psi oil pressure at idle, which I am very happy with.

Just running it on the stand, the clutch seems better but it will take a road test to check that out. Since there is builder-mess outside the workshop door and my back is now aching again, we will leave it for today.

Little steps

Well, its been 2 months since my last post, and you might be forgiven for thinking that nothing much was going on.

Soon after getting the bike started as I showed you in a previous post, the registration came through and I was able to order the number plates. 

There were a few little jobs left to do after start up, which got easier every time I tried it. I'd noticed when building the engine up that one of the rocker cover studs was damaged, not allowing the cover to be tightened down. I replaced them all with new studs from Drags. 

I made a spacer for the primary case to frame bolt, and filled the primary chain case up to the drain hole. This appeared to be necessary to get the oil level sufficiently high to lubricate the chain, but AOMCC wisdom suggests I may regret that later.

When I'm out for the first time on a newly rebuilt bike, I plan a route, around the house or workshop, not more than pushing distance away. That way, I can ride round and round and never be too far to push the bike home. When I've gained some confidence, I increase the radius – the idea being that I shake out the larger issues near home, and then if something happens when I am farther away I still only have the radius of the circular route to cover to safety.

Braving the mid-morning traffic on the first outing, the fuel line airlock returned just as I was passing a crowded pub... All the faces turned to listen to the old bike thundering down a shallow hill just as it spluttered to a halt before attempting the other side.

I pushed it down a side road and home, to arrive, in time honoured fashion, drenched in sweat...

Riding impressions? Initially I found the steering wandering, which was easily cured by backing off the steering damper. Its incredibly smooth – with a surge of torque as you open up. I didn't get out of second gear on the first few trips. Its easy to start, and every time I do it, I notice the engine's stiffness easing up. 

The fuel system is still plagued by air locks. Its not help by me filling the tank with barely a gallon – the tap is very high in the tank, especially since the tank mounting rubbers are not correct resulting in the rear of the tank being rather high.

The mixture needed setting up, as did the tickover, which resulted in me finding out that adjusting the carburetter with the engine running is a risky operation if you don't want to burn your hands. I made some special screwdrivers to get at oddly positioned screws.

The brakes are being adjusted on every trip, and they are still bedding in.

It seems to be charging happily - in fact the electricals are all ok.