Justin's Raven

[Jean Crous]

On stand-by Sir

[justin.schoeman]

OK, Finally got the case back on Friday. Unfortunately had to spend most of the weekend doing work around the house, but finally got a chance to assault the engine this afternoon!

Unfortunately, as usual, things did not go according to plan.

OK. Lets start with some of the stuff that happened while waiting for engine bits and pieces.

Here is the oil cooler/oil filter assembly. The AP was not happy with the rigid oil line, and the seat of the oil filter fitting was not great (had to really tighten the filter to stop leaks). So while waiting for everything, I replaced the oil line, and resurfaced the filter adapter.

After assembling everything, I pumped oil through it, then blocked it off, and hooked up the compressor. 120PSI and no leaks. This can safely be put back on the engine.

Now today's work. First issue was to drill the dowel hole for the prop bearing. I first fitted and carefully aligned the bearing on the oil hole (used a wire bent 90 degrees to feel the edge of the oil feed hole through the bearing feed hole).

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Next, once this was perfectly lined up, I took a round needle file, and made two little nicks in the bearing lined up with the parting line. At least this time, I can't accidentally erase the alignment marks!

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Now I put some engineer's blue on the bearing saddle around the remains of the dowel hole, and used this to transfer to the bearing. I then marked the centre of the transferred dowel hole, and drilled it out.

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Once the holes were drilled, and measured to ensure nothing was bottoming out, I put some engineer's blue on the bearing, fitted it into the case (with the dowel in place), and tightened it up. This is what it looked like when I took it out. Perfect transfer, with no high spots (so the dowel is deep enough, and the holes are properly deburred).

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Next I started measuring. First step was to check pinch. Since the desired pinch is smaller than what I can measure, I measured it indirectly by fitting the bearing, tightening one side of the saddle, and measuring the gap on the other side. All came out at around 0.02mm (which is apparently correct).

Then I fitted all the bearings, and started measuring oil clearance. I started with the prop bearing, as it is most accessible. This is where things stated going wrong. The front of the bearing measured perfect, but the back was out of round (0.02mm), with 0.06mm taper front to back. In fact, the prop hub can't even fit in the bearing once the case is torqued. So it seems like the engineers managed to make the pinch too tight, distorting the bearing.

Tomorrow I will re-measure everything to make sure exactly what is going on, then take it back to the engineers to have the pinch set properly, and the bearing bore trued up. I think I need to find new engineers.

[JvTonder]

Justin happy you are at least making progress but sorry it is so slow, maybe you should have bought a completed motor?

All the best.

[justin.schoeman]

Justin happy you are at least making progress but sorry it is so slow, maybe you should have bought a completed motor?

All the best.

True. I have now invested a lot more in this motor than I would have in a new engine. But it is too late now .

[justin.schoeman]

OK - the pinch is definitely too tight. 0.0015" vs 0.0005". But this does not explain the 0.002" taper in the bearing bore. Also need to trim the hub flange a bit for the taper to engage properly, so it is back to the engineers tomorrow to see what they can do. Hopefully it won't be another 3 weeks .

[Maybe]

romyrem......either youve got the wrong forum .....or a very poor analogy....

[Tailspin]

romyrem......either youve got the wrong forum .....or a very poor analogy....

Him no longer part of the Forum - He is the weakest link - Good Bye

[Jean Crous]

romyrem......either youve got the wrong forum .....or a very poor analogy....

Him no longer part of the Forum - He is the weakest link - Good Bye

Was.....Tailspin......Was, say nicely after me............wwwwwwaaassss Just pulling your socks

[Tailspin]

romyrem......either youve got the wrong forum .....or a very poor analogy....

Him no longer part of the Forum - He is the weakest link - Good Bye

Was.....Tailspin......Was, say nicely after me............wwwwwwaaassss Just pulling your socks

OK Ok Ok

Wwwwwwaaaaaaaaassssss . . . . . . . . . . You sounding just like my Kid now. Eish these tenses and grammer she get me confussed quickly jy Weet

[Jean Crous]

Tailspin............ Nou het ek lekker gelag.........

[Aerosan]

romyrem......either youve got the wrong forum .....or a very poor analogy....

Him no longer part of the Forum - He is the weakest link - Good Bye

Was.....Tailspin......Was, say nicely after me............wwwwwwaaassss Just pulling your socks

OK Ok Ok

Wwwwwwaaaaaaaaassssss . . . . . . . . . . You sounding just like my Kid now. Eish these tenses and grammer she get me confussed quickly jy Weet [/quote]

Tailspin has the same problem likes me, my mother shes Irish, my pa is n groot boertjie. growing up was interesting to say the least. Now we are grown up en ons weet nie wat de hel ons issie.....

[justin.schoeman]

Still waiting for the barrel shims from the US, but got the rest of the engineering work back. Spent the evening with a couple of micrometers and some mechanic's blue checking everything, and everything (at least the bottom end) is looking perfect.

Since the accessory case is still on the plane, I am heading to the airfield tomorrow to perform the two accessory case to engine case fit ADs.

Aside from that, I just need to find some thinner (<0.3mm) end play shims, as I need another 0.04mm of end play.

I also managed to find the source of a small 'bite' I have had on the crank since day 1... It has always had a slight bit of drag at one position, but everything measures perfect. All bearings are round, all journals are round, case is true, crank is true, etc. Then I realised that I was assembling the engine in the engine stand, hanging of one end... Took the case off the stand, put it on the floor, backed off the nuts, rapped the case a few times with an assembly mallet to seat everything, torqued it all up again, and TA-DA! Perfect! The case was flexing slightly hanging off the stand...

[Boet]

Sorg jy maar net dat jy alle "blik-shimpies" op hulle se plekke het! I admire your workmanship. Hopefully you will now have a reliable power plant for your aerie.

All the best.

[Jean Crous]

Hi Justin, any progress with your engine? Surely you must be chomping at the proverbial bitt by now
Regards
Jean

[justin.schoeman]

Hi Justin, any progress with your engine? Surely you must be chomping at the proverbial bitt by now
Regards
Jean

The final bits arrived last week, but unfortunately, work around the house is interfering with play at the moment...