Machining/skimming a compressor

[Johnnyj]

Hi, i would like to ask a question regarding a head for a compressor.
I have a 200 L 3hp, 2.2kw Aircosse compressor that has some wear on the head
where the valves were moving around as the locating pins had worn away.
I can buy a new valve plate, valves and gaskets everything bar the head.
My question is has anyone ever skimmed a head to remove the damaged area
or could it be done? The area where the valve plate sits on the head is raised proud
and if it was machined to remove the damage it would leave it flush with the rest of the head
and the plate would sit on it then and located by the bolts that keep it all together.
What are the opinions on such a caper?

Best Regards
John

 

[Fazerruss]

I would be more inclined to get it tig welded to build up the worn area then a light tickle on a mill

 

[Nick67GT]

I would be more inclined to get it tig welded to build up the worn area then a light tickle on a mill

Best route to go if at all possible.

That way you will retain all the original design parameters (compression ratio, clearances etc) and not end up trying to resolve any unwanted side effects....

 

[pedrobedro]

You could put a thick gasket either side if the bolts will do the locating. Compression ratio is not that critical on a compressor pump. Some soft aluminium would do it.

 

[the snooper]

what are you saying is damaged ? the part arrowed should stop the reeds lifting too far, the reeds should be flat against the reed plate and either vacuum or pressure moves them away from the plate, if you machine the head flat the reeds wont be able to move

 

[Johnnyj]

Thank you for the prompt replies lads
It is hard to pick it up in the photo but there is a lot more wear on one of the reed seating
area than on the other, the area that you have arrowed is worn down more on one side than
the other and compared to the other side is significantly worn more and worn unevenly. I understand
what you are saying in that the shoulder stops the reed lifting too far but how much should it lift, 1mm
to 2mm? the area worn on one side is down 3mm on one side at least. Would TIG welding be ok to build
up the head? It wouldn't put too much heat into and damage it further

 

[the snooper]

what is the problem with the compressor is failing to reach pressure

 

[Johnnyj]

It takes a long time to reach the pressure that it cuts off at, it is running too long
and bit loud as well

 

[the snooper]

usually when the reeds are at fault they don't reach enough pressure to switch off, are they sitting flat against the reed plate and are they intact, no bits missing

 

[Johnnyj]

The reeds are intact, however there are 2 locating pins that locate the reed plate to the piston barrel
and locate the bottom reeds then protrude the reed plate and locate the top 2 reeds against the head.It is these 2
upper reeds that the locating pins had worn away and caused the reeds to move around and i think wearing the head
in the areas that i mentioned

 

[the snooper]

The reeds are intact, however there are 2 locating pins that locate the reed plate to the piston barrel
and locate the bottom reeds then protrude the reed plate and locate the top 2 reeds against the head.It is these 2
upper reeds that the locating pins had worn away and caused the reeds to move around and i think wearing the head
in the areas that i mentioned

I would concentrate on the pins and getting the reeds to stay in the correct place and that will probably cure it if it is the reeds not operating properly

 

[Johnnyj]

The trouble is that it has the damage done to both the reed plate and the head. it might be worth
getting the gasket and reed kit and fitting it. Do you think the wear on the head will affect it adversely
it the reeds are held in their proper place?

 

[the snooper]

no I don't think it will because once the reeds are held in their proper place their flexibility will limit their travel aswell

 

[Johnnyj]

Thats true what you say and it's worth trying it at any rate.
I can buy a new compressor for €645 and the reed plate kit is €223
so you would have to wonder is it worth spending too much money
on it.

 

[the snooper]

Thats true what you say and it's worth trying it at any rate.
I can buy a new compressor for €645 and the reed plate kit is €223
so you would have to wonder is it worth spending too much money
on it.

id be looking at repairing the pins that hold the reeds first, nothing to lose

 

[Johnnyj]

id be looking at repairing the pins that hold the reeds first, nothing to lose

True, i suppose they would need to be from a hardened material to stand up to
the constant pressure