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CAV unit injection pumps bleed screw seal.

MoominPapa

By MoominPapa
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MoominPapa Veteran II

MoominPapa

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The CAV BPF one-per-cylinder injection pumps fitted to my FR2 have a problem with the bleed screws weeping. Looking at the two in-service pumps and variety of spares yields a vast array of different sized copper washers and the odd fibre washer. The weeping screws have copper washers, but they don't seem to seal well. It's not possible to do the screws up very tight with only a screwdriver slot and I don't want to use sealant for obvious reasons.

 

What sealing washer should be there? Any tips to stop them dripping diesel?

 

 

MP.

 

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onionbargee Influencer

onionbargee

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don't over tighten the screws, they love to snap off, and that really ruins your day. A new ( soft ) copper washer should work if the sealing faces are in good nick. you can't tell with old engines whats been abused or worn out, without seeing the thing, the pump threads, the screws, or knackered washers ?

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BEngo Veteran II

BEngoDonate to Canal World

Posted
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The CAV BPF one-per-cylinder injection pumps fitted to my FR2 have a problem with the bleed screws weeping. Looking at the two in-service pumps and variety of spares yields a vast array of different sized copper washers and the odd fibre washer. The weeping screws have copper washers, but they don't seem to seal well. It's not possible to do the screws up very tight with only a screwdriver slot and I don't want to use sealant for obvious reasons.

 

What sealing washer should be there? Any tips to stop them dripping diesel?

 

 

MP.

If they are copper, anneal the washers- get them red hot (gas ring/blowlamp and some steel wire) and chuck them immediately into cold water. That makes them softer and they will seal better.

 

New ones should be available from a good diesel injection specialist that's been going a while. Carwoods or similar.

 

N

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casper ghost Influencer

casper ghost

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I had this trouble with my engine too. I used new washers but they still seeped a little, I then snapped one off while tightening it..

On my engine it's not too much of a problem as any leaks go into a small collection bucket, and not into the engine.

I want to try dowty washers but I haven't looked into getting any.

Casp'

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casper ghost Influencer

casper ghost

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The screws on the pump I have here are 0.223" diameter, say 7/32". I doubt that is a standard size, so perhaps 6mm (0.236")

 

Richard

On ebay all the dowty washers seem to be quoted in BSP size. Not sure if these threads are BSP?

Casp'

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  • 3 weeks later...
MoominPapa Veteran II

MoominPapa

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Reporting back.

 

Annealing the copper washer got me most of the way there, but still a bit of dampness, M6 dowty washers fit beatifully and seal likewise. Excellent suggestion, and thanks for the help.

 

MP.

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casper ghost Influencer

casper ghost

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Reporting back.

 

Annealing the copper washer got me most of the way there, but still a bit of dampness, M6 dowty washers fit beatifully and seal likewise. Excellent suggestion, and thanks for the help.

 

MP.

Now you've tested these dowty washers I shall have to place an order for some.

Casp'

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  • 2 weeks later...
by'eck Veteran

by'eck

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If they are copper, anneal the washers- get them red hot (gas ring/blowlamp and some steel wire) and chuck them immediately into cold water. That makes them softer and they will seal better.

 

New ones should be available from a good diesel injection specialist that's been going a while. Carwoods or similar.

 

N

 

I always thought letting metals cool naturally annealed them. With steel at least quenching in cool water after heating above critical temperature leaves it hard. It can then be tempered to different levels by heating to a lower temperature indicated by a certain oxidisation colour then quenching to lock the temper in.

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RLWP Veteran II

RLWP

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I always thought letting metals cool naturally annealed them. With steel at least quenching in cool water after heating above critical temperature leaves it hard. It can then be tempered to different levels by heating to a lower temperature indicated by a certain oxidisation colour then quenching to lock the temper in.

 

You are right about annealing, I get bored correcting that particular one

 

Carbon steel is a different animal though because of the - er - carbon, which is why you can harden and temper it

 

Richard

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BEngo Veteran II

BEngoDonate to Canal World

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I always thought letting metals cool naturally annealed them. With steel at least quenching in cool water after heating above critical temperature leaves it hard. It can then be tempered to different levels by heating to a lower temperature indicated by a certain oxidisation colour then quenching to lock the temper in.

 

Copper, Brass, Gold, Silver and I think Platinum are different to carbon steel and alloy steel- you can cool them rapidly from the annealing temperature and they will stay soft. They all work harden albeit I am told Gold does not harden much. Some Aluminium alloys can also be cooled rapidly from annealing temperatures and stay soft. Others HAVE to be cooled rapidly and will re-harden if cooled slowly or warmed up (precipitation hardening).

 

Mild steel will work harden somewhat and can be annealed by heating and holding at a high temperature (red hot) for about an hour per inch of thickness then cooling slowly but does not harden if it is heated and rapidly cooled. There simply is not enough Carbon in it for that.

 

N

Edited by BEngo
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