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Post by Johansson on Apr 5, 2012 0:06:44 GMT -5
A week ago I called the Swedish company that sells Jabsco pumps and after telling him what the pump was going to be used for he strongly suggested that I would choose another pump since the 15A Jabsco pump would most likely fail after being pushed to produce 5 bar for any longer periods. I figured that it was best to open up the purse a bit wider to get a pump that the salesman said would work better, a Marco gear pump that was built for pumping oil and had stronger gear casings than the Jabsco pump. Unfortunately it was three times as expensive than the Jabsco but still cheaper than a new rotary and bearing set in case I would use a cheaper pump that breaks down during a run. It should arrive in a couple of weeks according to the salesman, during that time I will tear the engine down and send the shaft away for balancing and fix a small leak on the fuel line. Cheers!
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Post by racket on Apr 5, 2012 4:20:11 GMT -5
Hi Anders
Are the Marco pumps 12 volt ??
Cheers John
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Post by Johansson on Apr 5, 2012 4:28:57 GMT -5
Hi Anders Are the Marco pumps 12 volt ?? Cheers John Most are 24V but the one I ordered is 12V.
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Post by racket on Apr 5, 2012 4:33:13 GMT -5
Hi Anders
Do you have a Link ?
Cheers John
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Post by Johansson on Apr 5, 2012 9:16:58 GMT -5
Unfortunately not, I have tried to google for the pump but never found one that matches the specs I heard from the seller.
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Post by Johansson on Apr 16, 2012 16:32:49 GMT -5
Finally I have cleared all motorcycle parts from the work bench so now I have some space for tearing down the JU-01 again. I found some soot deposits on the turbine wheel, they were caused by a small oil leak inside the engine that sent an oil mist through the bleed air holes used to keep the tubine hub cool. Another thing I found was that the compressor wheel spacer was badly worn, I never checked it after the "catastrophic" event when the comp wheel came off at 50.000rpm and this is what it has looked like since. The spacer came in contact with the aluminum housing when the rotor started to wobble, overheated and the piston ring went slack. You can see the difference between the worn ring and a new one here below. I designed the engine so I had to make a second spacer ring that fits closest to the thrust bearing behind the piston ring spacer, a friend with a grinding machine and a magnetic table will true it for me in case the surfaces aren´t perfecty parallel. I cannot measure any untrueness but I might as well have it checked by someone with better measuring tools than I just to make sure it cannot cause the shaft to bend when the comp nut is torqued down. The turbine wheel will be sent away for rebalancing, hopefully it won´t take too long to get it back. Cheers!
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Post by racket on Apr 16, 2012 22:58:58 GMT -5
Hi Anders
Just a couple of things to fix :-)
Could that turbine wheel soot have been caused by oil bypassing the turb seal ?? .............the reason I ask is because on shutdown of the 10/98 as well as the 9/94 and FM-1 , there is smoke and sometimes small flames as oil appears to contact "hot bits" in the turb stage , I don't run a scavenge pump so theres the chance of there being some "pressure" in the bearing cavity which could force oil past the turb seal , theres never been any indication of oil going past the comp seal though , perhaps because the drain is near it whereas the turb seal is at the distant end .
Could your failed comp seal have been allowing air to bypass and pressurising your bearing cavity with sufficient force that oil is forced out of the turb seal , your scavenge pump might not have been capable of processing the comp seal air as well as the lube , you might need a pressure gauge upstream of the scavenge pump to monitor bearing cavity pressure or lack of pressure depending on how well the scavenge pump is doing its job ....................we may need to have scavenge pumps capable of several times lube flow , perhaps pumps capable of 40 - 50 lpm ................having seen how much air is contained within the 10/98's oil drain , a decent sized scavenge pump is required .
Cheers John
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Post by Johansson on Apr 16, 2012 23:54:52 GMT -5
Hi John, Yup, minor issues only. Nothing gives perspective like a compressor wheel drop... ;D It might very well be oil passing through the rear shaft seal that leaves soot on the turbine wheel, I found traces of oil inside one of the bleed air holes so I just assumed that was where it came from. With a new spacer and piston ring it should show pretty quickly if the problem is solved or if deposits continue building up. A pressure gauge on the scavange line is a great idea! Never thought of that but it will instantly show if the pumps manage to pull an underpressure in the lines or not, I will fit one before the next run. Cheers! /Anders
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Post by racket on Apr 17, 2012 4:10:41 GMT -5
Hi Anders
I'll look forward to hearing if the scavenge pumps can pull some "vacuum" .
Did the "comp malfunction" cause any damage to the bore of the diffuser where the seal seats??
Cheers John
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Post by Johansson on Apr 17, 2012 5:50:31 GMT -5
Hi John,
There are some rubbing marks that I need to remove from the bore, hopefully I can stuff a rag in there so I don´t have to take the entire engine apart.
Cheers!
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Post by Johansson on Apr 25, 2012 15:30:54 GMT -5
I got my new oil pump today! It is one beefy pump so I cannot imagine it will have any problem delivering 6bar oil pressure all day long if needed. I will have to build an oil pressure regulator since there is no integrated regulator like it was in my old membrane pump, I considered PWM controlling the pump instead but a mechanical regulator is more fail safe and will keep the oil pressure constant which PWM controling won´t. My friend Lars-Erik has measured the spacer more closely and found that the thickness differs 0.02mm around it, so the imbalance was most likely caused by this ring and not the slight rubbing on the turbine wheel. I didn´t have digital calipers back when I made it so I wasn´t able to spot that rather large difference in thickness... He will true it in the grinding machine as soon as he is able and send it back to me, so I´ll owe him a bag of beer or two for the help. Cheers!
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wolfdragon
Senior Member
Joined: April 2011
Posts: 287
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Post by wolfdragon on Apr 25, 2012 16:20:44 GMT -5
Anders,
What is the link on the bottom right of the pump label ?
http://www.marco.___
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Post by racket on Apr 25, 2012 17:02:14 GMT -5
Hi Anders
Nice pump :-)
Have you considered using an automotive oil pump for the pressure relief v/v and filter , just machine up a part to fit into where the gerotor normally is , with a couple of fittings for the line from the Marco pump .
Cheers John
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Post by Johansson on Apr 25, 2012 22:56:48 GMT -5
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Post by stoffe64 on Apr 26, 2012 5:14:42 GMT -5
Hello Anders I have to redesign My designs of the oilingsystem For My Holset HX60 turbojet project,was originally Planning to use à power steering pump with à big Electric motor but instead i would like to get one of These Marco pumps. Where Did you buy it?and what did you Pay for such Unit?
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