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Hi-

Being a cheapskate, I was thinking of getting used atmospheric DV from eBay. A lot of people aren't clear about the exact specs of what they are selling, but am I correct that as long as I get a piston type, it should be OK?

I would guess that if I do get a twin piston type, it won't actually do any harm, even though I don't need it, is this right?

It seems that the worst that could be wrong is the spring strength, and this is cheap to sort out, right?

Is there any risk in getting a second hand unit? As far as I can tell, they are long lived items, unlike the diaphragm ones, and not much prone to wear or problems. Is this right?
 

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Hi John,

Was thinking exactly the same myself. Can only seem to think, like yourself, that the spring strength is the main deciding factor (e.g. my 2.0 LPT will not create enough pressure to operate a device for a 2.3 FPT). The other factors are tubing sizes - will you have to bodge the unit in with some sort of reducer pipework; and recirculating valve or atmospheric valve - the arguments pro/con have been discussed here recently.

Good luck, just don't get into a bidding war with me - I'll just wait for your results before I go trying a valve of another vehicle

Cheers,

Pete
 

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you need a twin piston ..
otherwise the vacuum will open the valve and you will suck air in and it will idle erratically..
I have put one on myself(bailey) you can stabilise it by bleeding off some of the vacuum but you need a one way device which closes when there is pressure (a one way winscreen washer valve with a filter works )

I have since changed this set up for a proper twin piston forge jobbie
 
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