Calling Sherwood 1st Stage gurus

[Ghetto Diver]

I am in the process of rebuilding my Sherwood SRB3200 pre-92 blizzard and noticed that the new piston seat is a bit larger than the original.. new = .0191 old=.0142
Doesn't sound like much, but it would take considerable force to seat...
Don't want to jack it up, so here I be....

 

[dave4868]

I'm sure you meant 0.191" (new) and 0.142" (old)....

My old Blizzards are from the mid-80's to early 90's and they all have the non-crimped, replaceable seat, pistons, which I think yours should have also, if it's been serviced in the last 20 years.

I just took some measurements and the new seats are around 0.190" diameter. They get forced into the hollow end of the piston shaft, which measures about 0.170" inside diameter.

When removed, old seats will quickly rebound to about 0.185".

What's the actual inside measurement of your piston shaft seat holder? Is it non-crimped?

Dave C

 

[axxel57]

The Hp seats are the same since twenty years as far I remember, but I checked in the SRB 3200 repair manual and it says that until 1988 the pistons had to be changed together with the HP seat and only then the changeble HP seat 3801-5 came on the market. If you should still have the original piston and somehow managed to remove the seat, this one could have had a different diameter or lenght.
You could either get yourself one of the newer pistons or find one of the old ones.
Also check if the piston is not damaged (has fallen down, is not round), and therefore has a smaller diameter.
I tried to send you the repair manual, but the file is too big to do it here in the forum (1.3MB). You can contact me and get me your e-mail, then I send it to you.

 

[Ghetto Diver]

Thanks for the reply...and yes your measurements are correct

This was an e-bay special that I picked up....as near as I can tell it has the newer piston (flat, not concaved bottom). I measured the seat holder and come up with .146.
Pic of piston....

ETA, sorry cell phone pics

 

[axxel57]

The photo is not sharp enough to see the details, but for me it looks like the old type of pistons

 

[axxel57]

Sorry, overread this. If it has the flat bottom it should be the new type of pistons

 

[dave4868]

Does your piston appear to have been crimped?

By the way, I have a crimped-type that has a flat piston, so I don't think that will be definitive. Unfortunately, a measurement of this one won't be useful, as it's already been "customized" to remove the crimp....

The area below the crimp (now removed) has a 0.170" inside diameter....

Dave C

 

[Ghetto Diver]

ok, feel pretty stupid now...

Put on my glasses and the bottom does have subtle dish, not as dramatic as in manual..
Now search begins for new piston...

 

[dave4868]

ok, feel pretty stupid now...

Put on my glasses and the bottom does have subtle dish, not as dramatic as in manual..
Now search begins for new piston...

Great! By the way, now that you have your glasses on, do you see the crimp?

Don't forget to get the piston with the bleed element in the head.

Dave C

 

[Ghetto Diver]

I saw an apparent crimp, but the seat was easily removed...

Thanks everyone for your help