Is the piece I highlighted in the picture below the overflow valve ?
Any thing special I need to know about replacing it ?

 

Yes
Don't drop the sealing washer

 

You may need to grind a little bit of the cylander head out to clear the valve. I have a new one on the shelf waiting for me to get around to clearancing the head so that it will fit in there.

 

i had to do a little grinding but it wasnt much, maybe 1/8"
it raised my fuel pressure from 8 psi at idle and 15 psi at wot, to 15 psi at idle and 30 psi WOT

 

 

DO NOT DROP ANY PART OF IT!! Put a cloth under to act as a catcher for any dropped item. This is where I installed a banjo with a barb for my return line when I replaced all lines in mine, works great.

 

Where do you guys get the overflow valves? How much?

 

Price may have changed but you won't find any better price

Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.

 

Genuine Bosch parts only!!

http://www.tstproducts.com/index.asp...PROD&ProdID=32


I have tried other peoples home-made ones, this is the one that doesn't tick!!!

Tom

I think the one above will only save you a few bucks or so..... his latest price was like $50 bucks....

 

They are $50 shipped from tomkins.

FYI, I put one of his in a month or 2 ago, had 20PSI idle, 30-35 at 1500Rpm's, I checked it last night out of curosity and its now 10-15 at idle, ant barely 20 at 1500Rpm

Clamped off the ret. line, and pegged the gauge at 60.

After checking the pre filter this week, if thats not clogged, I will be replacing the cheapo with a Bosch part

Fuel filter is 3 weeks old

 

are all over flow valves the same opening and closing pressure? i have a performance p7100 pump and abrasive injectors. would installing so called stock over flow valve make a difference in performance?

95 12v DR. Performance pump & injectors would like to keep new of for spare.
thanks.

 

Overflow valves come in all different pressures but as long as you are within stock specs it won't make any difference in performance. Pressures exceeding 45 psi can blow seals in your injection pump or crack the filter.

I've been using Marty's OF for years and haven't had a problem. They aren't cheapos but rather are the valves used on Mercedes engines and are made in Germany.
Last time I bought a OF valve from Cummins it had a Spanish sounding name on it and was made in Brazil even though it was labeled Bosch on the bag.

 

My over-flow valve that Van at Haisleys gave me is quite the unit...it was a stock valve that had the holes tig welded closed and then re drilled with way smaller holes. First time I had it on the truck running I couldn't figure out what the hissing noise was esspecially after I turned the truck off. I am guessing that it keeps the pressure pretty high in the pump...not sure of numbers though!

RyanB