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Post by Johansson on Jan 30, 2012 17:30:27 GMT -5
I try my best to never fully grow up, not mentally anyway. The hair is already starting to thin out... ;D I heat treated the coating today and fitted the housing on the engine. Then it was time to weigh the engine, we had somewhat of a betting over at the swedish sportbike community I am a member of and the bets ranged from 9.5kg to 21.835kg. First prize was a Mobacken Racing t-shirt. 16.5kg is not bad at all considering the heavy mild steel NGV, if I wanted to I could easily remove 2-3kg but I don´t see why since it will stay on the ground. Hopefully. Cheers!
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Post by racket on Jan 30, 2012 18:21:04 GMT -5
Hi Anders
Good weight :-)
LOL, we need a bit more "containment" than the aero guys , so those extra Kgs don't go to waste .
Cheers John
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Post by Johansson on Feb 4, 2012 15:31:28 GMT -5
Today I made a 0.2mm thicker shim for the compressor housing to get rid of the slight rub I had with the old one. After that I torqued the bolts with Locktite to make sure they would stay in place, I have had enough of things coming lose on this engine now... We had -36.2°C here this morning, +3°C in the workshop so it was nice and cosy. Cheers!
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Post by racket on Feb 4, 2012 17:26:19 GMT -5
Hi Anders
Minus 36 C ........fire her up , another ~25% more mass flow than the map indicates :-)
+3 C ........cosy?? .............................you guys are crazy .
How did you go torquing the comp nut using the Garrett Specs , what sort of Nm peak when giving it the specified rotation ??
Cheers John
Cheers John
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Post by Johansson on Feb 5, 2012 1:57:57 GMT -5
As long as the beer doesen´t freeze the workshop temp is ok. I used the T-handle when I torqued the comp nut so I didn´t get a Nm reading unfortunately, I thought about it but decided that I didn´t want to risk bending the shaft.
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Post by racket on Feb 5, 2012 3:27:56 GMT -5
Hi Anders
Did it feel like a lot more torque than last time ??
Cheers John
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Post by Johansson on Feb 5, 2012 4:50:23 GMT -5
Hell yeah, I was not even close to this torque before.
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Post by racket on Feb 5, 2012 17:05:49 GMT -5
Hi Anders
Thats good :-)
Cheers John
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Post by Johansson on Feb 6, 2012 1:01:31 GMT -5
During the final assembling the threaded impingement tube broke so I will have to take the engine apart again to replace it, the three of those threaded tubes coming through the diffusor plate (fuel, propane and impingement air) have been a concern since the material thickness after cutting the threads wasn´t much to speak of. I will make new thicker ones in stainless so I can torque them down properly, without a good tight fit air can leak out from the engine at these points. While I am at it I will make some air tight lids for the intake and exhaust so I can do a leak test of the entire engine, I have a strong feeling that those 100C TOT that shouldn´t be there are caused by leaking air. Why do I suspect this you might ask, well if I had used the inside of my head for a change earlier I would have put some more weight to the fact that oil leaked right past the O-ring seal for the engine cover that one time when the oil banjo bolts had loosened... If oil can leak without any pressure inside the engine there would be lots of air sneaking out there as well, so it is no use running the JU-01 again before it is air tight. Back to the drawing board! ;D
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Post by racket on Feb 6, 2012 3:32:12 GMT -5
Hi Anders
The alloy comp cover/diffuser will expand a fair bit during operation as the T2 rises , ~0.5mm at 100 deg C and should start to seal against the outer can , as long as your O'ring is projecting a bit above the alloy it should seal the air , a problem might arise if theres too much gap initially and the escaping air also heats the stainless can and it expands away faster than the alloy case .
I generally needs some "brake rubber lubricant" on my sealing O'ring and a smear around the can ID to facilitate sliding on of the outer can, even then it needs a firm push .
I'm still not certain that those 6 fasteners at the rear end are going to effectively seal it even with the extra thickness being added, I'd like to see at least another "screw" in between each pair , LOL, ...I had 18 screws around the back of the 9/94 engines can and was still worried about it leaking :-(
Hope you don't find any major leaks :-)
Cheers John
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Post by Johansson on Feb 6, 2012 7:38:37 GMT -5
Hi John,
No firm push needed to slide this cover in place, I can just feel a slight resistance but nothing more than that. The fact that I am using a glued black O-ring string instead of a red silicone O-ring is most likely not helping either.
You are probably right about the rear of the cover, but before I make any major modifications to the turbine housing I will try to find a thin heat resistant gasket sheet/glue that can be used instead.
In fact I am hoping I find a major leak, then I have a reason for the high TOT. If the engine shows to be air tight something else must be wrong...
Cheers!
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Post by racket on Feb 6, 2012 16:36:24 GMT -5
Hi Anders
Yeh , gotta use silicone O'rings , those black ones are too hard , we need a soft silicone that can be squashed a bit as the can is slipped over , the black ones in our large size are too difficult to work with , I tried them with FM-1 and again with the much smaller 9/94 before finally realising they're not the right compound , I eventually used silicone with FM-1 and the 9/94.
LOL, you're right , you do need to find a big leak , otherwise we've got a bit of head scratching to do to find that temperature increase :-)
Cheers John
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Post by Johansson on Feb 6, 2012 16:50:57 GMT -5
I will order a silicone O-ring tomorrow, probably better to get a ring than glue together a silicone rope. You got me thinking about the 6 bolts on the rear of the cover, I don´t want to weld anything to the NGV since I might damage the coating but I could drill and thread holes in the turbine housing between the existing bolt holes so the engine cover and turbine housing can be bolted together. I don´t think you follow me since that explanation confuses even me, but bear with me and you´ll see what I mean. Cheers!
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Post by racket on Feb 6, 2012 19:00:20 GMT -5
Hi Anders
LOL......will do ;-)
Cheers John
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Post by Johansson on Feb 7, 2012 1:08:15 GMT -5
Hmm, I wonder if a silicone ring would work at the rear end as well?
If I mill a groove in the turbine housing and use a high temp silicone o-ring as a seal between the housing and the engine cover it should be air tight without much force needed, might even make it without adding the extra bolts.
Most likely I will have to fit a new ring every time I take the engine apart since its max rated temp is 250C but hopefully it will seal as long as it is in place.
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