Sunday 22 May 2022

The Everyday TR1 - The oildrain desaster

The story starts at the very time, when I (again) had to swap starter clutches on the old girl and did an oil-change at the same time. As you've seen the title, you can probably guess how well that went. 

The first attempt (and here's a little tip for you fellas) to get a Mercedes oildrain-plug as it it the same M14x1.5mm thread as the stocker, but about twice as long, so if you only stripped the first one or two threads, you might get lucky. (Spoiler alert - I didn't!) To be fair, I didn't get lucky as the thread wandered out a bit and thus the new drain-plug wouldn't sit flat on the housing. Not terrible, but over night a little oil was to be seen on the pavement.

In general there are two kinds of thread repairs: Coil-based ones and full inserts. Coils are awesome, because they are cheap and are bit more elastic, meaning that if you don't undo the corresponding bolt frequently, you even have a certain level of bolt retention built-in. As much as the last bit would have been nice, an oildrain-plug is undone fairly frequently, thus repair inserts were the weapon of choice. 

The kit did come with a guide for tapping (worked fine), but did not include one for drilling. So I quickly made one on the lathe.

To cut a long story short, the inserts didn't work, because it was impossible to guide the drill onto the right track, i.e. it would follow the original hole. (Which under normal circumstances is outright perfect, just not this time...) So the next step was to get an old engine case out of storage, turn a top-hat bushing and see how good the engine cases can be welded. 

The answer is: not well. As much as I am a well seasoned TIG-welder on ferrous metals, aluminium is a different beast. I am pretty sure the more experienced guys can see at least ten mistakes that I made, but fact is, I for one will not be able to pull this off in a decent fashion.

BUT I do know my way round a lathe and with taps and dies. So I drilled out the old oildrain to 17mm and tapped it M18x1.5mm (the same thread as can be sound on AFR-probes).

Yes, it would have been smarter to do the tapping, when the old girl was still upright.

M14x1.5 on the inside, M18x1.5 on the outside all made from 1.4501 stainless, which is the stainless variant that is at least slightly less annoying to machine.

And then it was a case for the belt and suspenders approach: Loctite the insert into the thread and then seal the gap with some clear epoxy, pre-heat it so the capillary effect would suck it in and then let it cure for roughly 24hrs. (It says 12hrs on the box, but a bit of patience never hurt anyone.)

And that was quite literally that... no more leaks and an oildrain bolt, which now firmly sits in a steel bushing, i.e. can easily take the necessary torque. As I did a very similar repair on the old Turbo about 6 years ago (crank-case broken right next to the drain bolt) and that one has lasted a fair bit, I am cautiously optimistic that this will work just as fine.

Monday 16 May 2022

Turbo TR1 - The King is dead, all hail to the King

Now it's been a while since the last time the secret star of the show and the original reason for the motto of this blog made its appearance. Plagued by a lack of time and a manifold that just wouldn't seal right and now with all the other bikes within acceptable limits, it was time to put my money where my mouth is and get that old firebreathing, oil-smoking deathtrap back on its wheels and make some noise.

So first rip out the old manifold have a good look at it and then decide to salvage the flanges and get rid of the rest.

I remember a lecture at college, when a teacher once said: Engineering solves problems. Good engineering solves great problems in the easiest way possible. So the new design was a common plenum with roughly 30 degree cuts and a straight center section.

Turns out it needs tighter angles than 30 degrees.

After more than an hour of trimming and aligning the points A and B are connected.

Open up one side and use the mid-section as a real plenum. Distribution is definitely not going to be equal, but with sufficient boost... it's not called forced induction without a reason.

And guess what, it worked...

Due to distortion (again) I had a nasty boost leak on the front cylinder, but with a bit of extra gasket material, this was quickly remedied and...

The BST40 carb was actually giving me only very grief - a bigger pilot and mainjet (57.5 and 175) was all it took to get it to the point where it would happily idle and stop bogging down under load. But as the astute will have noted there's no exhaust or at least a screamer pipe in sight anywhere in the videos above.

A bit of stainless plate material (8mm thick, so it won't distort once I weld and exhaust pipe to it), was put on a spare Volkswagen GT15 turbo and drilled and milled to suit. Attempts at not setting the workshop on fire were of rather moderate success and ultimately I ended up with a flange which fits lovely on my spare turbo, but it turns out, the Opel/Vauxhall GT15 has got a different exhaust bolt pattern. 

As the Opel GT15-flange did not have any of those very handy studs in place, I used the old dirty finger technique to draw the flange bolt pattern on a bit of paper.

The dramatic lighting was by accident.

And then it was well about time to do what a Turbo-powered deathtrap has got to do...

Still suffering from some fuel supply issues and half throttle at the very most, but already at way beyond the originally planned 0.5 Bar (7-8 PSI) of boost and smoking like a two-stroke. (Because that turbo is "well" shagged.)

So what's the plan, you may ask. Just politely terrorize the neighbourhood or are there bigger plans afoot? Of course there are: More turbo, more carb, more cowbell. The next step will be to take the old pint-sized VM44 out of retirement. Then the next step is a completely new setup that will move the turbo to the other side, including a new manifold (already working on that one) and then (obviously) a bigger turbo. But with the added benefit of interchangeable up pipes to the various turbos, so I can play around more easily and find out what suits the old girl best. There's a range of turbos waiting: another GT15 off a VW 1.9TDI, a Toyota CT20 (my favourite as it comes with a carbon seal from the factory and I already have it - thanks Mr. Mouse), a small-ish TD04 and ultimately a GT20 out of an SR20 that can quite easily be converted to carbon seal. The one turbo that I would still have to buy, but which on paper sounds like the best choice.