Tractor PTO compressor Vapormatic V1710

[aidank]

I have a tractor PTO compressor not working correctly, pressure and output is poor.

This is the model, lubricated by grease on the piston rings https://www.ebay.com/itm/235417566125 . Its 30years old but does 2hrs work per year. It has always been greased, and plenty grease on the cylinder bore, I have just had it apart.

Anyway when I removed the head, I found the gasket separating the pressure side and intake side blown, thus a compressor repair man gave me some high temp gasket paper he uses for repairs and I fixed the gasket but output is still v poor.

I have a feeling I have worn piston rings. While I had it apart I put some diesel in the piston cylinder and left it for a few hrs but diesel didnt make its way down through the cylinder. Its a 75mm piston or thereabouts.

Any ideas what type of rings would be in the piston or how best to check is it piston rings or worn Reed valves in the head.

Its handy to have, and yes its easier almost get a new one, however nice to have a go at fixing something.

 

[knighty]

are the inlet/outlet valves/reeds ok?

I'd suspect them before the piston rings

not saying it couldn't be the piston rings... just inlet/outlet more likely - and an easier fix!

 

[aidank]

are the inlet/outlet valves/reeds ok?

I'd suspect them before the piston rings

not saying it couldn't be the piston rings... just inlet/outlet more likely - and an easier fix!

look fine to me, how would you fix/replace those. They look to be mounted via dowel pins, just driven in and clenched I guess.

when I removed that plate shown above in pic 2 one of the reed valves in its natural position, hangs slightly open. Its not damaged just hangs open. I thought that was the intake valve and that was they way it should be. When piston begins to rise the air pressure would push it closed. ?

 

[Robotstar5]

The usual check for piston rings is to measure the ring end gap at top, middle and bottom of the bore for each ring against manufacturer specs.

 

[Agroshield]

This is possibly clutching at straws, but perhaps a non-return valve on inlet and outlet (try one, then the other then both) could aid diagnosis.

 

[indykid]

Are the reeds just located on the dowels or riveted? I've had success in the past just by turning the reed over.

If one of the reeds is hanging down, is it possible to flip the whole reed plate over? It looks fairly symmetrical.

 

[aidank]

Are the reeds just located on the dowels or riveted? I've had success in the past just by turning the reed over.

If one of the reeds is hanging down, is it possible to flip the whole reed plate over? It looks fairly symmetrical.

dowels looked like they are pressed in, and possibly loctited in, was loctite in existence 30 years ago.

cant flip the reed plate over Im pretty sure, however I will check, reed plate has to be looking at the piston on the inlet side and facing away from the inlet on the pressure side.

 

[knighty]

look fine to me, how would you fix/replace those. They look to be mounted via dowel pins, just driven in and clenched I guess.

when I removed that plate shown above in pic 2 one of the reed valves in its natural position, hangs slightly open. Its not damaged just hangs open. I thought that was the intake valve and that was they way it should be. When piston begins to rise the air pressure would push it closed. ?

I think that loose one will be the problem... as above maybe flip it over?

 

[Seadog]

Possibly not dowels but hammerdrive screws.

 

[aidank]

Possibly not dowels but hammerdrive screws.

yes possibly, you can see both ends in pic 2 above. These guys https://www.accu.co.uk/hammer-drive...MI2oy7lIuUjQMVRZRQBh0sLAeQEAQYASABEgKNMPD_BwE

how are such screws removed, and I guess I cant reuse a hammer drive screw.

I would need to use a nut and bolt to reattach the reed spring using a nut and bolt. being careful they dont interfere with the piston, if that is possible.

 

[indykid]

Possibly not dowels but hammerdrive screws.

I think you can see the other end of the fixings on the exhaust reed diametrically opposite on the valve plate. The similar diameters and the through bores made me expect them to be parallel dowels, though given there only looks to be one intermediate plate in the brochure photo, the inlet reed would need to be positively retained. Cleaning up the schmoo might reveal more.

dowels looked like they are pressed in, and possibly loctited in, was loctite in existence 30 years ago.

cant flip the reed plate over Im pretty sure, however I will check, reed plate has to be looking at the piston on the inlet side and facing away from the inlet on the pressure side.

This is the flip I was talking about. The exhaust reed becomes the intake reed and vice versa

 

[Seadog]

I think you can see the other end of the fixings on the exhaust reed diametrically opposite on the valve plate.

So you can.
They're just rivets.

 

[Agroshield]

how are such screws removed, and I guess I cant reuse a hammer drive screw.

The easy way is to punch them through from the back. Even if they are in a blind hole, it can be easier to drill a hole to allow punching. Removing from the top is hard. With JB Weld, they acould be re-used if undamaged.

It struck me that if the reed valve is u/s, the picture looks very like a feeler gauge, with the advantage that feeler gauges are cheap and come in many thicknesses.

 

[GRW]

Vapormatic as a Brand/Co still exist (where I work is a Dealer for the brand).
It's a long shot, but I wonder if parts are available for the compressor from Vapormatic?

 

[aidank]

Vapormatic as a Brand/Co still exist (where I work is a Dealer for the brand).
It's a long shot, but I wonder if parts are available for the compressor from Vapormatic?

dont think so per a phonecall earlier to a local to vapormatic agent

 

[aidank]

given the tiny tank that is on the compressor should there be a non return valve between compressor head and tank. I must take it apart and have a look

 

[aidank]

I think you can see the other end of the fixings on the exhaust reed diametrically opposite on the valve plate. The similar diameters and the through bores made me expect them to be parallel dowels, though given there only looks to be one intermediate plate in the brochure photo, the inlet reed would need to be positively retained. Cleaning up the schmoo might reveal more.


This is the flip I was talking about. The exhaust reed becomes the intake reed and vice versa

View attachment 495647

dont think I can do that flip, there is a machined slot cut in the head 2mm deep for the reed valve and to accomodate the rivet heads, so they wont be contacting the piston.