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JPI 900 install


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Hello, esteemed board.

I currently doing owner-assisted JPI 900 install.

image.jpeg.88c2bd711035cb7d48d3e006536e0c1b.jpegThe instructions prescribe the equal distance for EGT probe placements on the exhaust stack. I was going to re-use already factory-installed EGT hole on stack #3. However, if I replicate the factory distance for other EGT probes, I would have to install the #4 probe over the slip joint. This would go against the JPI installation instructions ("no install at the slip joint").image.jpeg.eef66993a451b9ebc11a82a842f60cdb.jpeg

After speaking with A&P, he told me that welding shop can weld shut the original hole so we can install the probes at the different distance.

Is there any specific way that this welding should be done? The probe opening is pretty small.

I will use this thread to bring up my other questions and suggestions through my installation.

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Yeah, I would get it welded, not difficult.    Then plan ahead for all cylinders.  I like drilling the holes on the inside, biting back at about 30-45 degrees.  Makes it much easier to route the wires along with the CHT wires.  And protected the probes from mechanical damage.

 

Aerodon

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2 hours ago, Aerodon said:

Yeah, I would get it welded, not difficult.    Then plan ahead for all cylinders.  I like drilling the holes on the inside, biting back at about 30-45 degrees.  Makes it much easier to route the wires along with the CHT wires.  And protected the probes from mechanical damage.

 

Aerodon

Thank you for all of the ideas!

I will do the inside install of probes, and use the tensioning rod of the lower baffling(in photo below) to attach the wiring and keep the probe wiring away from ignition wires.

image.jpeg.4a7066efd2583c880b16045af1329071.jpeg

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On 10/24/2023 at 10:29 AM, Aerodon said:

Yeah, I would get it welded, not difficult.    Then plan ahead for all cylinders.  I like drilling the holes on the inside, biting back at about 30-45 degrees.  Makes it much easier to route the wires along with the CHT wires.  And protected the probes from mechanical damage.

 

Aerodon

Don, do you have a photo with the inside install of EGTs and your wire routing? Can't find anything worthy on world wide web.

Took the #3 stack to the welding shop, more to follow

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1 hour ago, ukrsindicat@yahoo.com said:

Don, do you have a photo with the inside install of EGTs and your wire routing? Can't find anything worthy on world wide web.

Took the #3 stack to the welding shop, more to follow

Not the best picture, everything is hidden.  I use yellow painters tape to provisionally locate each EGT and make sure i am not 'painting myself into a corner' with slip joints, baffles etc.  A right angle drill with a short bit works well, otherwise you might have to take the exhaust off.  Distance from cylinder is not super critical, I worry more about getting a nicely mounted probe.  Half an inch is not going to make much of a difference in EGT and you are looking for trends and peak rather than absolute values.

 

Aerodon

IMG_0326.jpeg

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Thank you for the feed back, guys!

The install is coming along.

Did a dry-fit of 900 on the manufactured alum plate above radio stack. Pretty happy with the fit. Eventually, I'm thinking about cutting a carbon fiber board to cover entire right side of the panel to cover all of the holes and bare aluminum.

image.jpeg.ff0882c87979cc102ee5047fba7e5590.jpegimage.jpeg.e51b9517c1891a06b391b4c61f41bf37.jpeg

Installed the ground wire to the engine as RX'd. 

image.jpeg.97965cda7221a1954db0cfc899b53610.jpeg

Current head scratcher for me is the red power wire. The JPI instructs to "connect red 20GA wire(power) to the master solenoid at the battery to avoid the line drop when cranking. 5 Amp circuit breaker (CB) required." My master solenoid is located in far right side of the cabin and it has 1 CB that is not connected to anything ("Radio 15 Amp"), both of my radios CBs are on the separate avionics bar, connected to "Avionics" switch.   I'm planning on using this Radio spot to install the dedicated 5amp  CB for my JPI 900 EDM.  

image.png.0b80d4267096d73ce165593c382f0779.png

This is what the CB similar to Radio 15 amp CB looks like from the rear. Where can I source these kind of CBs? image.jpeg.130a0700ac9734c0021f2edab731212b.jpeg

Should I install the modern push-pull breaker?

Also as for inline 1 Amp fuse for the Amperage wires to shunt, where do you place them on the JPI wires? Closer to the  instrument, or closer to the shunt?

Thank you for all of the support and encourangements!

Yuriy 

 

 

Edited by ukrsindicat@yahoo.com
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1 hour ago, ukrsindicat@yahoo.com said:

What would be a good source for this replacement?

Read the part number off the 3A circuit breaker for the ADF and order that in the 5A spec.  That would reasonably be expected to match the removed breaker so that it fits seamlessly on the buss bar.

Alternatively, 55 year old original equipment circuit breakers probably should all be replaced.  The plastic (bakelite?) housings are all brittle and can fall apart with the simple act of removing the terminal screws (in my experience).  It’s better to plan and replace them all in advance rather than to be in the middle of a project and be held up because you have to source more parts.  

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19 hours ago, 47U said:

Read the part number off the 3A circuit breaker for the ADF and order that in the 5A spec.  That would reasonably be expected to match the removed breaker so that it fits seamlessly on the buss bar.

Alternatively, 55 year old original equipment circuit breakers probably should all be replaced.  The plastic (bakelite?) housings are all brittle and can fall apart with the simple act of removing the terminal screws (in my experience).  It’s better to plan and replace them all in advance rather than to be in the middle of a project and be held up because you have to source more parts.  

THank you. "ADF" 3 is being used for the GTX 320 transponder, but the adjacent Radio 15 is not being used by anything. I pulled this CB and tried to match it to push-pull CB in terms of size, but I can't find anything matching in terms of rear clearance (1.350"). Since I don't want to break apart the existing bussbar, I'm planning to get a regular modern push-pull 7274 Klixon and will build the a jumper wire to the existing bussbar.

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3 hours ago, Mooney-Shiner said:

After some pondering, I decided to replace all 7 CBs with modern 7277 at $24-sh each to adopt the bar to the new pattern.

Excellent decision.  When I went down this road, I discovered the outboard-most CB is very close to interfering with the fuselage tube.  You can see the vinyl hose in your picture that I’m sure is there to prevent arcing on the last CB.  The 7277 is just a little longer, increasing the possibility.

image.jpeg.fa0861ccb229c3fab22c87501adb5f83.jpeg

I angled (rotated) the last CB in the mount slightly to gain a little more clearance from the fuselage tube.  It looks really close in the picture below, but I also replaced the vinyl hose protection which is more clear, so it looks like it’s the fuselage tube itself.  The best solution I think, would be to leave that hole empty, if you have space for that CB somewhere else.

image.png.3227d7e26d2bc3662c122308092db510.png

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  • 2 months later...

Moving along with the install since holidays.

All the EGT/CHT probes are in, CB replaced with modern pull CBs,  and now the fun part - fuel transducer. I know that the fuel lines attached to transducer using 180 inch LBS https://www.jpinstruments.com/shop/fuel-flow-transducer-231/, but what about the rest of the fuel line? Like the fuel pump to the hose connection and the servo to hose connection? I looked through Lycs SERVICE TABLE OF LIMITS AND TORQUE VALUE, but couldn’t find it there.

Also has anyone tried to seal the transducer fire sleeve with Band-It Clamps as per manual? I ordered the clamps on Spruce, but have no such tool.  I found this tool on Amazon, but its pretty pricey for doing just two clamps. https://www.amazon.com/Center-Clamps-50pack-Diameter4-stainless/dp/B0CRRHNPYG/ref=sr_1_2_sspa?crid=1K65C08DNYWKK&keywords=band+it+tool&qid=1706411178&sprefix=band+it+%2Caps%2C172&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1 

Any insights are welcome.

 

 

 

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