Member Since: 08 Nov 2012
Location: Kent
Posts: 330
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.
Click image to enlarge
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: 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.
Discovery 2 4.0 ES 2001- Gone
Discovery 1 300Tdi ES '95 - Gone
Range Rover Classic '79 - Gone
8th Dec 2024 11:14 am
discostick
Member Since: 08 Nov 2012
Location: Kent
Posts: 330
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.
Click image to enlarge
Click image to enlarge
Click image to enlarge
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: 330
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:
Click image to enlarge
After Bake:
Click image to enlarge
Click image to enlarge
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: 330
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)
Member Since: 06 Mar 2017
Location: Lost
Posts: 5061
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: 330
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: 330
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: 5061
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: 330
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)
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
this morning but haven't found it yet.
