by Clive » Fri Nov 01, 2019 3:51 pm
Well I suppose I can excuse myself for not thinking of what the problem could have been.....seeing that the combined knowledge of all those that viewed my post didn't suggest an alternative cause of the oil leak.
Kevin blasted the barrels for me so they ended up in a fetching matt black as Chris, my son, painted them with Kevin's recommendation of MipaTherm, we teated my wife to a cake icing stand so we could rotate the barrels as they were sprayed. Ended up with a lovely job of 4 immaculate cylinders. Interestingly, when they were naked they were two different types. 2 of one type and two of another, physically the same but definitely manufactured differently.
Right back to the rebuild. I incorporated the recommended updates from the manual, fitted the spreader plate and Nordlocsand when all was done as much as I could in the workshop I got a couple of guys at the airfield to help me lift it on and I hooked it up, fitted the prop flange prop and then oil pump. Just about when all the work was done my son turned up with his usual slick timing. It was just getting dark and I tried to start it, no joy....figured I'd add a big battery to get it to crank faster, with the honing she was a little tight. Still nothing.....ah yes, fuel was turned off a couple of weeks ago when I started, that might help.
Alas after 5 minutes the oil was back, still coming out around the two lower thru bolts on #3. I was losing the will to live as we crouched in the dusk with phone lights shining trying to see what we could of the oil on our immaculate black barrels. My eyesight close up needs various magnification of glasses but the lad had no such problem and there was a shout of a eureka moment, party burning his nose on the exhaust and partly seeing the problem. What, look there, what? Photo taken and enlarged and there it was, a hairline crack about 2 inches long above the forward thru bolt.
At last! the thought of more work was dismissed as I now knew we would soon have it fixed. I got the plane back in my hangar about 3 months ago and the pesky leak that had first been nothing at all but I wanted Chris to take the plane away to its new base near his new home in Hampshire snag free. Little did I know it was going to take me so much time and so many visits to the hangar.
I thought I'd test my old friend and experienced Jab engineer out and sent him a simple text, 'it's still leaking, it's not the thru bolt but we know what it is, guess?'
Instant reply 'hairline crack' maybe I shouldn't have been so confident in saying I knew it was the through bolt.
Kevin continued with his 'stardom' and said he'd have a useable second hand barrel in the post by the end of the next day!
He was annoyed that he'd missed the crack, he said the honing normally shows any flaws up, but it was a very fine one and I'd had a good look and not noticed anything. The barrel still has a fairly nice ring to it.
Good excuse for a fly so I flew up to Beverly in the 9 and had a quick lunch with Kevin and was soon flying back to Norfolk with a nice example of an early Jab barrel in the back.
I had it on and ready to fly a few hours later and this morning we ran it up and all is good, as is the way the weather is now going to be rubbish for a long while so flying will have to wait. The Jab's trip down to Hampshire will be later in the month as it will need shaking down after sign off so it has a good few hours on it before Chris continues to build experience after gaining his licence in the summer.
Thanks to Kevin for all his help, his supply of all the seals, shells and the bolts, the fettling of the barrels and his advice, his suggestions and customer focus, also to Roger who talked the whole thing through with me at his sons Wings ceremony 10 days ago at RAF Shawbury (fantastic event, I was honoured to be invited). I stripped a 3300 in the past and Roger supervised the rebuild, that was 5 years ago so my memory of it was a little murky. And my son who was actually at the strip for part and also most of the rebuild. Also to Jabiru for what is actually quite a good manual, there are easier ways to do many things but it you follow it you won't go far wrong at all.
Crack picture available but how do I upload it?
Forward plan is to fit Camit style barrels and Mahler pistons when Kevin has them available sometime next year, that will complete the 2000 hr rebuild and the early solid with big heads should be good for another 2000 hrs.
Regards, Clive
Jabiru SP with 2200 @ 1700 Hours