Friday, April 18, 2014

What difference do Triumph green camshafts make?

This post starts off with a simple oil leak and ends up with a cam swap from Triumph green profile to blue profile. It means I now have first-hand knowledge of the performance difference between the two, all else being exactly the same.

Shimming the valves

7000 miles later
The oil leak from the cylinder head cover meant I had to remove and reseal it. I was surprised how dirty the cover had become, after having been so careful in my restoration and with the radiator cowls fitted. But that's because it seems like yesterday when I got Ruby back on the road when in reality a year and about 7000 miles have gone by since then.

Central bolts are awkward
I discovered that the cam retaining bolts were barely more than finger tight. I had torqued most of them down on reassembly. I guess the rubber washers under the bolts and large rubber gasket had settled. That was why I had a leak anyway. I was also reminded of how close the central retaining bolts are to the main frame tube. They are impossible to torque down because even my smallest torque wrench won't fit in the gap.

Oil had collected around the plugs
The leak was not just external. I found puddles of oil around the spark plugs where it had run down into the central wells in the cylinder head. These are all blind to the outside world so there is nowhere for any muck or fluids to go if they end up down there.

As I was dealing with the oil leak from my cylinder head cover, I decided to check my valve clearances. I do not have a special tool for swapping shims with the camshafts in situ, though such tools are available for about 60 pounds. I am happy enough to remove and refit my camshafts when the clearances need to be adjusted.

Two of my exhaust valves were out of specification, needing a change from 2.60 to 2.55. With the cams out, changing the shims is easy - lots of room to move and that in itself justifies the effort for me.

Camchain tensioner springs

It is necessary to remove the cam chain tensioner mechanism to get the cams out. I'd also wanted to replace the tensioner spring. Trevor at Sprint has started supplying replacements. The originals weaken over time and so can't make the internal tensioner ratchet take up the slack in the cam chain as Triumph intended. The picture below shows the difference between Trevor's replacment spring and the old spring I took out. It is photographed over the official factory manual with the minimum spring length.
Comparing old (top) and replacement (bottom) cam chain tensioner springs

Swapping T300 Camshafts

Whilst I was at it (famous last words for me) I decided to swap the original 'green' specification camshafts for the later 'blue' specification camshafts. This was just because I could ... the later motor I had bought had these camshafts in good condition and I wanted to try them out.

Blue cam (left) and green cam (right) side-by-side
The blue cams are far far milder - less lift (shorter lobes) and less duration (pointier lobes) as can clearly be seen in the two side-by-side pictures.
Cam Profile Blue Green Red
Inlet open 1 BTDC 21 BTDC 27 BTDC
Inlet close 30 ABDC 50 ABDC 55 ABDC
Inlet duration 211 degrees 251 degrees 262 degrees
Inlet lift 7.1 mm 8.9 mm 9.4 mm
Exhaust open 28 BBDC 51 BBDC 54 BBDC
Exhaust close 2 ATDC 25 ATDC 28 ATDC
Exhaust duration 210 degrees 256 degrees 262 degrees
Exhaust lift 7.0 mm 8.6 mm 9.3 mm
The table above shows cam timing in degrees relative to the extremities of the piston stroke: before top dead centre (BTDC), after top dead centre (ATDC), before bottom dead centre (BBDC) and after bottom dead centre (ABDC). The blue cams have relatively little overlap in period (58 degrees compared to 101 degrees for the green profile) meaning that the exhaust valves close early enough to maximise effect of the charge. The green cams overlap considerably.
Green cam (left) out and blue cam (right) in place

Manual says seal the ends
Plenty of Hylomar around the plug recesses
Finally, I was very careful to seal the cam cover with Hylomar, following the factory instructions. I was confident that this would work because the rubber gaskets have now thoroughly settled and I was more generous with the Hylomar (but still VERY careful) than last time.

So, what difference do blue camshafts make?

I have ridden about 500 miles since installing the blue cams. What difference do they make? A lot. Performance (better below 60mph, worse above) and fuel economy (between 5 and 10% better) have changed.

The engine now pulls solidly from 2000rpm. It is both stronger and linear, whereas previously it would pull but with some hesitation, especially around 2500rpm. The low-rev thrust is a transformation. That is a brilliant improvement. However, the cost as I suspected is that the old kicks at 4000rpm and at 6000rpm have gone. I am not surprised by this after having read contemporary road tests of the original and re-tuned Trophy 1200s.

I can live without the 4000rpm step because it was probably just a sign that cylinder fuelling wasn't working super well below that engine speed. However, the way the engine came on cam at 6000rpm was exhilarating and I miss it. Realistically, I might experience that once or twice on an average ride because the roads around here are not suited to high-rpm riding. But experience cannot be distilled into numbers like 'twice per ride'. I shall be reinstalling the green cams in the next few weeks when I swap the engine covers over for powder coating.

On the other hand, the blue cams make for a much more relaxing and secure riding experience so I have decided to use them in late Autumn and Winter when I think they would suit riding conditions perfectly.

Consequence: I now have two engine tunes available, one for summer and one for winter. Very nice.

Wednesday, April 9, 2014

Red is the colour - Painting a cam cover

Sorting out scabby cylinder head covers

I've been disappointed with my attempts to repaint the original engine covers of my 1991 Trophy 1200. Although I did my very best to strip off all the old paint, I was unable to get every last spec of failed silver paint off of the clutch cover because the casting has some tricky recesses for its retaining bolts. The cylinder head cover (or cam cover, if you prefer) and crank end covers are not as bad but still quite a bit less than nice. Time to do something about it - but how without being off the road?

'No' to being without working wheels; 'no' to scabby covers for Ruby

Dirty scabby sick 2001 engine
Cleaned but no less scabby 2001 engine
The new paint I'd applied to my 1991 Trophy engine has not adhered properly over the old failed paint. Result: new failed paint. Also, the VHT Clear lacquer has gone yellow and started to come away in some places. I used this clear coat over the silver heat resistant paint to get a finish that was close to the original. I now regret trying to repaint this with rattle cans and am going to go for a powder coat instead. However, I don't want to be without my 'triffic Trophy any longer than necessary, especially as the weather has been getting better. So I've been in a quandry about hating the insult of scabby cases that currently adorn my beloved bike and hating the idea of being off the road. Meanwhile, I hadn't done anything with the sick 2001 Trophy engine I'd bought last year, since stripping the top end. So maybe there was a solution here to my quandry?

Borrowed covers

I decided to use the cam, right-hand and left-hand crank engine covers from the 2001 Trophy engine as a temporary measure, plus the clutch cover from by Daytona engine. Yes, another piece of Daytona is temporarily migrating to the Trophy! Even then, the 2001 covers are even more horrible - and would need refurbishing anyway sooner or later. I decided I'd start the process off by working on the cam cover. It is a large casting and, as the picture above shows, had lost a considerable amount of its original black powder coat. I thought it would be a simple matter to shift the rest of it.

Paint stripper is rubbish, wire wheels are harsh and hard work ...

Well I was wrong. I used two types of paint stripper with Scotch abrasive scourers (fancy nylon scrubbers). Despite multiple applications, even leaving the cover in a plastic carrier bag with stripper over night, there were still some patches  that just wouldn't budge. Also, I was left with pitting and quite a number of blotchy dark grey areas in the casting where corrosion had wormed its way into the alloy.
After a lot of work with scourers and paint stripper, most of the powder coat has gone but pits and corrosion remained

In the end I had to resort to a wire brushes and a rotary ginding wheel on a drill and minigrinder (cheap Dremel clone). It took hours. I wouldn't do it again - taking it to a blaster would have been the smart thing to do. Oh well.

Washed down with degreaser
Belt sanding ribs
Ultimately, I was pleased with the finish I obtained although to get rid of pitting I had to remove quite a lot of aluminium from the ribbing that runs across the top. I used a belt sander for that - very harsh but much more helpful than a rotary wheel for keeping the surface flat. A good wash down with degreaser and I was content to get the paint out again. This time, I decided to go red because I had a can in my garage and, as a spare, I am looking at the 2001 engine as an opportunity to experiment some more.

Shiney Red Cylinder Head Cover: Mission Accomplished

After the first coat of red, I could see that the dark grey areas were not covering over very well. I had a tin of VHT Black so I gave the cover a blow over with that as an even colour  - like a primer - to work with and then started again with the red. This time, the red enamel was covering evenly. I built up the coverage in thin layers, each time using a hot air drier to partially cure the paint as I went.

Finally, I decided to use up the last of my VHT Clear. Yes, the same lacquer that had failed on my other covers, Clear lacquer makes such a difference to solid colours I thought I'd risk it. Also, if it does yellow, the effect will be less noticeable over red than over silver. We'll see. 

Red enamel and VHT Clear - a bit of fun
The result looks good to me for now. So I'm ready to swap the cam cover over, maybe this weekend, and to take the originals to a local coater.

Thursday, April 3, 2014

Oily engine - proves its a real Triumph :-)

I'd noticed an oil mist around the cylinder head in the days running up to my winter clean up. Well OK, it was more than a mist. It was a seep. And then a bit more than a seep. And then it was obvious quite a lot of oil was escaping from the cam cover. I must admit I was disappointed by this because I'd replaced the large rubber gasket when I'd been through the engine in 2012. I had also gone along with applying instant gasket as per the factory manual's instructions though at the time I'd thought it was overkill. Oh well.

The fairing lowers had to be removed so I could get the cam cover off and anyway I couldn't bring myself to leave the engine so oily. Also, as I wrote in my last post, the left-hand fork leg was leaking badly and I couldn't get to the lower yoke to remove them with the fairing lowers on. So off they came.

 It hosed down nicely. 'No rusty!' as one of my German friends used to say about his leaky XS650. So degreasing, agitating with a brush and hosing down showed things are holding up well under it all. I was particularly relieved to see that the oil cooler was still in good order.

Oil soaked fairing inners. 
The oil had accumulated inside the fairing lowers. This was not at all nice, especially because the lowers in the early T300s have sound deadening foam pads adhered to the inner surface. They also turn out to be excellent gunge sponges. Yuk. However, Vanish Engine Degreaser did a great job on sorting them out, with a good hose down to finish.

When I'd refurbed the forks first time, I had just filled the rusty pits and repainted the lowers. I'd figured there was no point in putting any work into them until I was sure the filler has taken. I didn't even replace the fork seals in case the repair didn't work. Well the right-hand side has born up well so I'm confident I can sort the left-hand side and so will replace the seals and nylon fork piston ring. I popped by Trevors to get the parts so was ready to go. I tried to strip the forks but got stuck on removing the chromed stanchions from the alloy fork sliders.  Blast!. I'd made up a tool for my Daytona for  separating the sliders from the stanchions. It is necessary to stop the internal damper assembly from spinning when trying to remove the Allen bolt that holds the two large components together. But it was no use on the Trophy because, according to Haynes, it needs a 33mm hex end. The Daytona's adjustable Kayaba forks need a square section tool to stop the M8 allen from just spinning the whole damper assembly inside.

As Ruby is my daily transport, this represented something of a problem. So for the second time, the dear old Daytona came to the rescue by lending Ruby her forks. Further more, in case I had not properly sorted out the leaky cam cover, I didn't want to replace the fairing lowers without being sure it was done. So the Daytona also leant Ruby some little aluminium trim panels I'd made up years ago. The result is rather pleasing, at least for now.

Ruby with borrowed Daytona forks and aluminium fairing trim