Workshop compressor servicing

[Damo]

I bought a big 'ole compressor recently, and even though it works i'm not 100% sure if it's working like it should. Can anyone recommend a place in Brissie where can I take it in Brissie to get checked out?

EDIT: A pic of the bugger. I found a number for Acme Machine Works in Sydney, but all I got was this pissed off old Italian guy whinging that they got the number listed wrong

[Hekta]

I found a number for Acme Machine Works in Sydney, but all I got was this pissed off old Italian guy whinging that they got the number listed wrong

I wonder how many calls he gets to fix people's junk ?

[Damo]

I found a number for Acme Machine Works in Sydney, but all I got was this pissed off old Italian guy whinging that they got the number listed wrong

I wonder how many calls he gets to fix people's junk ?

If his mood was anything to go by i'd say quite a few

I did find somewhere that is helping me out with this. Pilot Compressors in Sumner Park have parts lists for these compressors, and can order the parts if need be. I'm going to have another look at it on the weekend and see if I can figure out what's wrong. I should be able to fix it myself now I know I can get the parts.

[udlman]

Did U get that one off Ebay??, I was looking at one the same.

It should be a simple matter of checking the poppet valves in the head.

It looks as tho it would be slow to pump up as it seems to be a single stage unit..

Brad.

[Damo]

Did U get that one off Ebay??

Yep

It should be a simple matter of checking the poppet valves in the head.

I think I will end up taking the head off if only just to check things.

It looks as tho it would be slow to pump up as it seems to be a single stage unit..

I've read that multi staged compressors only made a real difference to the pressure that can be made. But when I think about it 2 cylinders = 2 times the air displaced in each revolution. In any case yes it is slow to come up to pressure, but I think that is mostly due to the fact that the reciever is so large.

[Damo]

A little update on my compressor.

I cleaned out the filter on the inlet side. First screen is a kind of course steel wool (this shot is taken without the outside cover)


Then there is a finer, fibrous material. It looks to me like hessian.


The plate helps keep things together.


And this is the filter housing.


Seems like it would be easier for me just to replace it with an automotive air filter. The filter housing has a pipe thread on the back which screws straight into the head, so rigging up something wouldn't be difficult. Would it be worthwhile doing???

[Damo]

This is the water/oil seperator, it's mounted to a bracket on the reciever (tank). From the screw fitting on the top that looks like a wing nut i'm guessing this is a pressure regulator as well. Would that be right? Since the compressor is going to be outside I think I would just let the pressure come through at whatever is in the tank and put a regulator inside so it's more convenient to adjust when needed.


This is what came out of the tank. There was more than 2 litres in there!!! I really think I will have to put some sort of auto drain device on this once it's moved out the back in it's enclosure.

[Damo]

This is the unloader valve. The copper line coming into it was cracked.


So I replaced it with some new copper line and compression fittings. I had to replace the fitting where it goes into the unloader because it was an old thread that isn't really used anymore. I got these bits from Pirtek for about $5.


This is the unloader on it's own. Where the air comes in there is a chamber which, when pressurised, pushes down on a diaphragm. This diaphragm then pushes on the pin you can see coming out the bottom of the unloader. That pin then pushes down on the inlet valve, opening it slightly and thus venting the pressure in the cylinder to atmoshpere through the inlet air filter. This reduces the start up load on the motor.

[Damo]

This is the head looking from underneath. On the right is the inlet side, on the left is the outlet side. The valves are just spring loaded.


I was pleasantly suprised to find the bore in perfect condition.


I scraped off the old gasket and draw filed the surface to clean it up. There is a guy I have been talking to that is a compressor mechanic, i'm going to quiz him about what to use for a gasket as i'm not sure that normal 0.4mm gasket material will survive.

[Hekta]

Good compressor tech

[droopypete]

Have you got a new cam Damo?
Peter.

[Damo]

Have you got a new cam Damo?
Peter.

Uh huh. Sony Ericsson W810i

A way to test the valves is to place the head upside down and put a light spirit (i used petrol) on the valves and see if it leaks through. I did this and it did leak, though not as much as i expected it to though. I did discover though that the valve on the exhaust side did not seal to pressure coming back from the tank. On modern compressors this job is performed by a check valve at the tank, also known as a non return valve. On my compressor the exhaust valve performs this function. When I pressurised the manifold on that side I could see bubbles coming through the petrol past the exhaust valve. So there's one problem I have to fix.

I've also decided to replace the unloader and pressure switch with a more modern unit. This will mean removing the unloader (as pictured above) and just plugging that hole in the head. I will have to then place a non return valve in line with the pipe that goes from the compressor exhaust to the tank. The non return valve has a hose which is then connected to the new pressure switch. The main advantage of doing this is the non return valve. It does not let hot, moist air back against the exhaust valve. This is what has caused the corrosion etc on the exhaust part of the manifold.

[V8Patrol]

Moved to Gen Tech @ Damo's request



Kingy

[Brett S]

definately an ol girl.
all the chonda stuff is cheap as chips these days.
But they do fail we got a 8 horsepower 3 cylinder and have had two of the conrods seize on the crank on two seperate occasions, but nothing a bit of wet and dry and hydrochloric acid couldn't fix.
Yep that bore looks good surprisingly

[460cixy]

i have the exact same compressor its prety slow to pump up but the tank is huge and has no trouble keeping up when i spray. if you find some one that can get parts for them let me know i wouldent mind re ringing mine theres a little oil getting in to the tank its getting a bit tired. i love the noise it makes when its running but the folks next door dont.

[Damo]

i have the exact same compressor its prety slow to pump up but the tank is huge and has no trouble keeping up when i spray. if you find some one that can get parts for them let me know i wouldent mind re ringing mine theres a little oil getting in to the tank its getting a bit tired. i love the noise it makes when its running but the folks next door dont.

Pilot Air Compressors can supply parts. They bought all the old stock when Acme (the manufacturer) went under about 10 years ago. You can find their contact details on their web site www.pilotair.com.au. If you have troubles getting info out of them contact Bob at the Brisbane store, he's been really helpful.

You should be able to get most of the parts for these, i'll be doing the valves on mine once I manage to get the head apart!

[460cixy]

mine has no decomp valve so i have to wind it round to tdc before i flick the switch. only drama i can see is new rings

[Damo]

mine has no decomp valve so i have to wind it round to tdc before i flick the switch

Is that a standard thing? Sounds wierd to me. I have a spare one if you need it

Got a bit more progress yesterday. Got the head pulled apart. The plug on the exhaust side did NOT want to come off. I dont have my shed setup at the moment so I didn't have a chance of getting it off, so I dropped it off at my local tyre place. Tyre place because they have a 3/4" drive rattle gun but it still needed a heap of heat to free it.

I still need to clean up the valves and refit them and see if that makes a difference.

[bazzle]

Replace the old 240v lead, wires and mains plug too

Bazzle

[460cixy]

mine has no decomp valve so i have to wind it round to tdc before i flick the switch

Is that a standard thing? Sounds wierd to me. I have a spare one if you need it

Got a bit more progress yesterday. Got the head pulled apart. The plug on the exhaust side did NOT want to come off. I dont have my shed setup at the moment so I didn't have a chance of getting it off, so I dropped it off at my local tyre place. Tyre place because they have a 3/4" drive rattle gun but it still needed a heap of heat to free it.

I still need to clean up the valves and refit them and see if that makes a difference.

well the decomp is there but its rooted

[Damo]

Replace the old 240v lead, wires and mains plug too

Bazzle

I'll definitly be doing that, all the wiring is original!

[Damo]

A little update. I've got more done than this, i'll have to take some more pics though.

I needed to replace the rotten filter media in the screw on filter. Just recently I had to put new filter media in our fishtank filter, so I thought I would give it a go in the compressor filter!!!


I put in plenty as it squashes down easy


With the cover clipped back on. Dunno how long this stuff will last, but i'll see how it goes


The exhaust valve was in pretty bad shape. There was a noticable lip around the outside, it was pretty easy to see why it wasn't sealing. I used a plate of glass (lid off my missus' fishtank!) and put a piece of 400 grit (I think) wet & dry on it. Lubed with Kero I ground the sealing surface down using a figure eight. It took a while but eventually got it nice & flat.


Once the valves were ground down with the wet & dry I lapped them in with some lapping paste. Hopefully the sealing surfaces are matched now


I made a new headgasket out of some gasket paper I had. I have doubts about whether this will hold up, but i'll try it and see what happens


The regulator got treated to a new guage and some new fittings. I blocked off one outlet all together, and put a T-piece on the other side. I'm only using one side of the T at the moment, it has a 1/4" ball valve on it

[Damo]

Got it all back together and gave it a test run. Still not happy.

It looks like the crankcase is getting pressurised now, so i'm guessing there is a problem with the rings. This is kinda suprising as the bore looked to be fine. If there was some problem with the rings I thought there should be some scoring etc on the bore?

Anyway, i'll pull the barrel off and see what I find.

[460cixy]

could have a broken ring ot there just lost there tension and with the added sealing of the top end its getting blowby