Member Since: 08 Nov 2012
Location: Kent
Posts: 331
AMK Compressor upgrade and service
Picked up a real bargain on ebay, car being broken for spares, compressor probably only fitted for 12 or 18 months from production date, looks immaculate so finger crossed its a good example. £39.90.
Going to retrofit my Hitachi (Dunlop replacement).
Got my faultmate to do the software.
Question is: would you replace the dryer material whilst its out, how quickly do they absorb and need repalcing?
I often wonder, they are exposed to a lot of air over the years, can only hold so much moisture? How are they effective being such a small quantity..... Thoughts welcome.
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Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
Member Since: 28 Aug 2014
Location: Norfolk
Posts: 4537
Yes, absolutely change the desiccant. It's a really easy thing and well worth it. I change mine annually (when I remember!) . If I don't the moisture in the desiccant freezes when its 0°C or lower, and I get a suspension fault on first start. Richard
D3 SE 2007. Triumph 2.5Pi 1973. Ferguson TEA20 1948.
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8th Dec 2024 11:14 am
discostick
Member Since: 08 Nov 2012
Location: Kent
Posts: 331
Agree, why not.
So ive taken a look and it looks like new in there, good start.
So, looks like molecular sieve desiccant.
Ive used this in products, its common practice to re-generate (heat up and remove the moisture).
Most lilely grade 4A. bead size is 2mm average.
Problem i have is the kits avaialble seem to include a larger bead size, this wont perform as well when drying air as it passes through such a small volume filter you need the surface area. So i am going to keep the 2mm and simply re-generate.
2 ways, heat in the oven to 220C for 4 hours, or microwave (being extrememly careful, 30 second cycles for 10 mins or so). I prefer the oven method.
Will see how it comes out later.
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New Engine - Fitted with body on...
Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
Member Since: 08 Nov 2012
Location: Kent
Posts: 331
Removed 11 grams of water (15.6% mass). Worth doing.
Typical mol sieve will hold 20-25% before saturation.
A niece cheap maintenance and no parts needed. O-rings all like new, just clean and silicone grease on assembly.
Before bake:
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After Bake:
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New Engine - Fitted with body on...
Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
Member Since: 08 Nov 2012
Location: Kent
Posts: 331
So for those engineers in the room.
If the desiccant can hold say 20% of its mass, thats approx 16 grams of water.
Say the compressor runs in an average 15degC 85% humidity ambient. Air holds 9g/kgAir at these conditions.
Then it wants to dehumidify the air in the system to below the dew point, if we want to prevent moisture down to say -10degC, the air needs to be redced to 1.6g/kgAir (the absolute humidity for air with a dew point of -10).
The 7.4g/kgAir removed from our 16g capacity gives a total air capacity of just 2.16kgAir.
At 1.28kg/m3 average, this equals 1.68m3 of air that can be dried in such conditions.....
At 15barg say, that is just 112litres of compressed air. I would estiamte the system holds 20 odd litres at one time, then a raise/lower use 4 litres, you get up to around 23 actuations.
I must be missing something.
Point is, its a very small dryer and will saturate in a short period..... New Engine - Fitted with body on...
Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
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Location: Lost
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The reservoir capacity is 9 litres and @ 16.5 bar or thereabouts.
It can hold higher pressure though.yµ (idµ - eAµ) ψ=mψ
8th Dec 2024 11:08 pm
discostick
Member Since: 08 Nov 2012
Location: Kent
Posts: 331
Thanks.
Just find it interesting they designed it with a dryer, no maintenance interval, with limited capacity.....
Will be drying mine out every other service from now.New Engine - Fitted with body on...
Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
Member Since: 02 May 2018
Location: Hertfordshire
Posts: 478
The dryer in the Hitachi has a bayonet and small screw to hold it in. I changed the screw to an Allen to make it alot easier to undo.
I don't know how your dryer is held, but might be worth considering how the removal can be made easier for your regular manual drying.
Member Since: 08 Nov 2012
Location: Kent
Posts: 331
Nice idea. The benefit of the Hitachi units, a semi quick release/twist design on the dryer was handy.New Engine - Fitted with body on...
Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
Member Since: 06 Mar 2017
Location: Lost
Posts: 5062
discostick wrote:
Thanks.
Just find it interesting they designed it with a dryer, no maintenance interval, with limited capacity..... .
It is listed in the service schedule for maintenance, can't remember if the interval is 2 or 3 years. If you're exposed to freezing weather conditions I'd recommend at least every 2 years, and with high humidity 1 year!
The exh valve is supposed to blow out the water but its never going to get all of it. yµ (idµ - eAµ) ψ=mψ
9th Dec 2024 11:46 am
discostick
Member Since: 08 Nov 2012
Location: Kent
Posts: 331
I’d be interested to see what the maintenance schedule mentions to do exactly?
Did they ever sell a service kit?New Engine - Fitted with body on...
Developer of the FBH Smart Control Module - Keyfob 3rd button control + USB Diagnostics + remote status LED + priming + battery protection + water temp control setpoint (or fixed run time)
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this morning but haven't found it yet.
