Torque setting on B2800B compressor pump - order?

[Submariner1]

New compressor manual says you must check torque setting on Head bolts before first use (note The small print warns omission to do this will void warranty!).
1. The manual omits to say check when cold ... a usual convention. I assume this is also applicable for compressor pumps?
2. The manual covers 5 compressors ... my pet hate. So it shows a table for 5 cylinder head bolt sizes.
The cap screws on my pump are just under 13mm head diameter and take a 6mm Hex key. I assume they are therefore 8mm cap screws?
These require 22 to 27 Nm torque.
The next size down is an M6 bolt requiring 9 To 11 Nm Torque.

It would be reassuring to know if anyone has one of these B2800B 12 CFM 3HP pumps (used in Nuair, ABAC Fini etc.) and knows for sure, that its definitely an M8 bolt (I don't want to undo one, to definitely verify it’s an M8 bolt diam.

I only ask as mfg’s sometimes have access to odd head sizes, and Numatic do use a 15mm hex head socket on their 12mm diam wheel shaft. (M12 are normally 19mm spanners)

3. They do not specify the Head Bolt torque order of tightening in the manual
In the pic below is the Order / Sequence I would do it in ... but is this correct?

pump looks like this

Any advice appreciated

 

[Dcal]

I don't know about your compressor but the key size for a standard 8mm hex head is 6mm (just checked and the outside of the cap heads I have are about 12.85mm so close enough.)
I seem to remember from years ago on cars, alloy heads were done hot and cast heads were left to cool, but it'sso long ago so could well be wrong.

I would do it cold, let it run for a good while to get up to temp and check it when it's cold again.

 

[grim_d]

You read the manual?

I'd of just taken it out the box and plugged it in.

If no mention I would assume do when cold. It won't be overly critical.

 

[a111r]

That's daft...How would they ever know you'd not checked their poor workmanship?
Just use it. If it breaks, send it back.
If they then ask the question, lie ... then wait for them to demand evidence that your torque wrench is calibrated and traceable to National Standards, cos theirs ain't!

 

[carbon]

From an abac parts list

 

[Submariner1]

I don't know about your compressor but the key size for a standard 8mm hex head is 6mm (just checked and the outside of the cap heads I have are about 12.85mm so close enough.)
I seem to remember from years ago on cars, alloy heads were done hot and cast heads were left to cool, but it'sso long ago so could well be wrong.

I would do it cold, let it run for a good while to get up to temp and check it when it's cold again.

Thanks for the reply

 

[Submariner1]

That's daft...How would they ever know you'd not checked their poor workmanship?
Just use it. If it breaks, send it back.
If they then ask the question, lie ... then wait for them to demand evidence that your torque wrench is calibrated and traceable to National Standards, cos theirs ain't!

My sentiments too, but these compressor mfgs seem to have got away with it, so far.
My simple solution is , do it & record the video on the phone, and if later they try and screw me ... go straight to small claims court.

 

[Submariner1]

From an abac parts list

Thanks thats a definite much appreciated

 

[dannyp]

compressors arnt that fussy i normally just put them down firm with a 3/8 ratchet and that'll do if im feeling posh ill re nip them after a few running hours. tho that said i put the heads down on mine with the battery rattel gun and there are no head gaskets in it just a bit of rtv sealer, bodge but it works tho

 

[Submariner1]

compressors arnt that fussy i normally just put them down firm with a 3/8 ratchet and that'll do if im feeling posh ill re nip them after a few running hours. tho that said i put the heads down on mine with the battery rattel gun and there are no head gaskets in it just a bit of rtv sealer, bodge but it works tho

Thanks, mine says you must also recheck after a few hours intensive use.
Based on my limited mechanical knowledge air pumps must be very different to petrol engines, where you tighten down correctly and that is it! Probably have better gaskets?

 

[dannyp]

engines have fancy bolts, well they do now. a lot of old stuff you had to retorque after so long running or after you'd got it hot. well you din't have to but the gaskets lasted a lot better for it