Adjusting the Vac Relief Valve

[Jamesh921]

So, how do you adjust your relief valve for optimal vac and lift?

I've read a couple discussions on this subject over the years, but it wasn't long before the technical jargon started getting WAAAYYYY over my small vocabulary.

So, I'll tell you what I did and what equipment I have, and you guys can tell me what I did wrong. And HOPEFULLY will be able to agree on how to tell me how to set it correctly.

Equipment:
Powermatic Legacy 2100
25 HP Kohler Engine
45 Roots Blower

What I did:
1) Started engine and set rpms at operating speed (about 3000 rpms - yea, I know specs say to run it around 2650, but I overdrive it - sue me).
2) Blocked off vacuum port completely.
3) Turned butterfly nut on vac relief valve until it started opening @ 15 HG.

That's it.

Is it now operating at the optimal operational setting? If not, tell me how to set it properly.


I know Mikey will say that the first thing I did wrong was to buy a Powermatic :roll: BUT, my PM rocks. shiteatinggrin So he can just HUSH IT!!! 8)


Thanks

 

[Larry Cobb]

James;

You are pretty close . . .

With #1 & #2 done the level on your gauge should read 15" hg. (max. for your tanks)

Keep adjusting the valve until this is the value you get with the intake sealed.

The 15" hg. is the max for your older blower.

Larry

 

[Dolly Llama]

1) Started engine and set rpms at operating speed (about 3000 rpms - yea, I know specs say to run it around 2650, but I overdrive it - sue me).
2) Blocked off vacuum port completely.
3) Turned butterfly nut on vac relief valve until it started opening @ 15 HG.

That's it.

that's it, 'cept don't forget to tighten the jam nut against the wing nut


..L.T.A.

 

[Jamesh921]

Well thanks. That was easier than I thought. Judging from the past discussions on this subject, I feared there would be disagreements between folks. Glad to see we're all getting along today - well...at least for the moment. 8)