Site Information

 Loading... Please wait...
  • Closeup of the Tork Tek adjustable overflow valve for the Bosch P7100 pump. To adjust your fuel pressure, loosen the jam nut, and turn the hex plunger with a 5\/16 wrench.
  • Tork Tek Adjustable Overflow Valve Kit for Bosch P7100 injection pump includes one adjustable overflow valve, two banjo seal washers, and detailed instructions.
  • Overflow valve installed on Cummins engine with room to spare. There is enough room to make the installation and to adjust the valve.
  • Closeup of a sectioned OEM valve. The seat is hammered into the body. The Tork Tek design has a HD reinforced seat.
  • Macro image of our bullet proof, super finished seat. No more lost power and starting your Cummins is a lot easier.

Cummins Adjustable Overflow Valve by Tork Tek - OFV010

$52.49 $49.49
(You save $3.00)
$2.49 (Fixed shipping cost)

Product Description














After 14 months of testing, Tork Teknology is releasing the world's first ADJUSTABLE over flow valve for the Cummins 12 valve, equipped with the P pump. Every single problem that has plagued the Bosch design has been SOLVED, including eroded seats and broken springs. Finally, there is a reliable P pump overflow valve that is adjustable!

Talk to any owner of a Cummins P pump, and he will tell you he has replaced his P7100 overflow valve. Several of the HP guys are on their second and third return valve. WHY? The number one complaint that I hear is "My Cummins 5.9 diesel is losing power and it's difficult to start". With that information, we cut many over flow valves in half to find out why. We were shocked by what we saw! Through 14 months of testing on a flow bench and on our test truck, we know exactly why the Cummins return valve is not a good design.


How a better spring will raise your fuel pressure


The Bosch spring has a history of breaking and it loses its spring force. This dramatically reduces the fuel pressure in your injection pump. This causes low power and your Cummins will be difficult to start. To cure this problem, we use premium, custom made springs in our overflow valves. The leading spring maker in the U.S. has worked with us to produce a superior spring. The spring manufacturer tested the service life at 1,000,000 cycles to the second power. Basically, infinite life! Our new design seat and ball puts less fatigue on the spring, as well.

The Bosch overflow valve will idle at 15 to 18 PSI. Our valve will show 25 to 26 PSI at idle. The shifter on our test truck vibrates much less and the engine idles 30 RPM faster with the Tork Tek valve. Your engine will run with less vibration and experience an off-idle power increase (great for towing). Customers email every week and say that starting is much easier! The best return valve they have ever used on their Cummins.


Why bad seats cost you fuel pressure


bosch-overflow-valve-bad-seat.jpgThe other common defect in the original valve is seat erosion. Many of the Bosch overflow valves that we cut in half had rounded seats. Take a look at photo #4. The seat is supposed to be flat. It should look like a tapered cone. It's rounded from the hammering of the ball. With the seat rounded, the ball is now .050 to .075 deeper in the valve and your spring is now longer. The longer spring exerts less force on the ball. Less spring force equals less fuel pressure. That's why your valve quit working and you lost fuel pressure and power on your Cummins P pump.


p7100-valve-seat.gifEroded seats are the second leading cause of failed P7100 overflow valves. (We have sectioned many valves) The other bad design of the OEM valve is the lack of material supporting the seat. From the chord line where the ball touches the seat to the edge of the seat, there is only .009 (three hair thicknesses) of steel to prevent seat erosion. That is not enough material to support the ball. Over time, the ball will hammer the seat to the point where your valve will not work. Tork Teknology redesigned the Cummins return valve to eliminate failed seats. IT'S A BULLETPROOF DESIGN!


Your Cummins overflow valve leaks! Ours is leak proof


cummins-fuel-system-seat-photo.jpgWe have tested new Bosch overflow valves and most of them leak. In fact, there is a technical service bulletin stating that the Cummins valve is NOT a check valve and leakage is OK. Why would you want a valve that leaks? The Bosch P7100 overflow valve uses a machined seat, which is OK, if not subjected to heat treating. Machined seats leak after heat treat because of thermal distortion. The secret to a leak proof valve is super finishing the seat AFTER heat treat. (see photo #5) It took weeks to perfect the super finishing of the seat and the results are worth it! Our valve has zero leakage and acts as an anti-siphon check valve. The leak proof seat prevents back flow to the tank.Starting your Cummins will never be easier because your fuel system will always be in prime.


Starting your Cummins is now easier


Normally, the check valve in the Cummins lift pump would prevent back flow. Unfortunately, the lift pump check valve is not a good design. The check valve is the weak link in the Bosch lift pump. If a hose or tube develops a leak from the overflow valve to the fuel tank, fuel can flow by gravity back to the tank. This is made worse if you park on an incline. Starting the engine in the morning is next to impossible. Our design adds a secondary check valve into your Cummins fuel system and prevents back flow to the tank. Your truck will start easier with a leak proof Tork Tek overflow valve!

The Tork Tek overflow valve is adjustable! This one feature took weeks to develop. You can now adjust your fuel pressure without taking your valve apart to add shims or to stretch the spring. Simply loosen the jam nut and turn the hex plunger. This patent pending design has a range of 22 to 35 PSI. One customer purchased the valve for one reason. He said that if the spring loses a little tension in five years, he can increase the fuel pressure in minutes by adjusting the plunger.


Key to max power


Here's a tip for maximum power. Peak fuel flow on a stock system is 31 PSI. Fuel flow will fall off above 31 PSI. The Bosch P7100 lift pump is a pressure sensitive pump and pressures above 31 to 32 PSI will show less fuel flow. This has been verified with precise flow meters. Set your fuel pressure for 31 PSI for max fuel flow.


Little known secret why lift pumps are failing


bosch-overflow-valve-inlet-hole.jpgThe current Bosch over flow valve has a .105 inlet hole. The inlet hole size used to be .168 in diameter. Did you ever wonder why the hole size was reduced? The reason is, it protects the OEM seat and spring from damage. The small hole acts as an orifice snubber. Testing has shown that the hole diameter is too small !! The problem is, the small inlet hole has created huge pressure spikes in the fuel system and is wrecking lift pumps. The pressure spikes put a terrible load on the lift pump check valves.

The Tork Tek valve features an inlet hole size that reduces pressure spikes by 39.7%. Your lift pump will last longer because it is not subjected to the higher pressure spikes of the Bosch design. A small but critical change to the inlet hole size has a direct relationship on the life of your lift pump.

Bullet proof seat design

Our goal was to produce a valve that has superior seat life. After many tests, we discovered that the number, size and location of the outlet holes were critical to the life of the ball and seat. We engineered the new design to put minimal stress on the seat. Less stress means longer seat life. You can now run your Cummins diesel knowing you have the best overflow valve on your Bosch P7100 injection pump.

There is nothing worse than showing your buddy a new performance device on your truck and it's rusted. We don't black oxide any of our parts because it is not a rust resistant coating. Tork Tek plates all overflow valves in a two step process. The initial plating is coated with a second anti-corrosion sealant. Plating is a more expensive process, but it's worth it ! Your valve will look great and remain rust free for many years.


OFV010 Direct replacement for the Bosch overflow valve


cummins-adjustable-overflow-valve-for-the-bosch-p7100-injection-pump-ofv010.jpgThe OFV010 is for stock fuel systems that run on diesel fuel. Do not use this valve with WVO or biodiesel. These fuels will erode the ball and wreck the seal. If you have a stock fuel system and run alternate fuels, order the OFV020. The OFV020 is built with stainless components and a Viton seal. Included with the overflow valve are banjo seal washers and detailed instructions. Installation is easy and takes only a few minutes.

Every Tork Teknology product is covered by a 45 day money back return policy. We guarantee 100% satisfaction with your purchase or you get your money back.

The TorkTek adjustable overflow valve is second to none. It is a direct replacement for the Cummins overflow valve and will be the last overflow valve you ever buy! Order yours today and take advantage of $1.99 shipping.


 If you need help in selecting the right overflow valve, click on this link.



This is what our customers have to say:

I'd found your site with the adjustable OFV's after I went and spent $40 on a piece of $&*@ Bosch OFV off ebay.... That barely does 20 at idle and doesn't flow well at all.... (Pressure drops to 12 psi when under full throttle with a trailer)

Matthew Jorgensen

Thanks for the quick shipment. I installed it Monday morning, it worked perfectly.

A couple of years ago the original overflow valve was getting erratic. A pressure gauge showed less than 10 at idle and less than 20 at 2000 RPM. Also the pressure varied a lot. The local Dodge garage wanted $186.

I bought an overflow valve through eBay that was non-adjustable. It did not include new seal washers. The spring was retained by a ball bearing pressed in place. I wasn't impressed but I installed it.

Last week we took our fifth wheel trailer on a 250 mile trip through the West Virginia hills (with your valve installed). It performed better than it ever has. Seems to be fueling better.

The truck/trailer combination weighs 23,000 lbs.

Bob Robinson

Misplaced01 “Highly Recommended. Superior Supplier of a Great Product!!!!!!!!!”

Hey Rob,

Just want to let you what a great product your P7100 overflow valve is. I have a 95 2500 12 Valve and all of a sudden it was a bear to start in the morning. It would stall as i came to the first stop sign on my block, would start back up and once it was warm, there wasn't a problem. Did some research on the forums and tried replacing the Overflow valve located on the Injection pump with your product. Starts right up in the morning without any stalls...Thanks for the great product..easy to install as well with your instruction..once again..Thankyou I probably saved a lot of money....Probably would have cost me a small fortune to have a shop try to figure it out.     Dave Silverbloom

JR from Widcat Performance loves the overflow valve and snubber. This is what he says "The truck starts fantastic-crank and boom she's running. Watched the pressure gauge and it was as close to steady as I have seen!! ..... looks like your R&D paid off here"

….fantastic product!!!! Hardtailjohn purchased an overflow valve on June 16,2010.

skycucv "nice upgrade from stock and looks very well made, A+ Many thanks from U.K".

T. Dought  "Excellent Product, Works Great, Will Buy More Soon".

I have good news. After replacing the fuel filter, removing the fuel preheater (element looked okay), replaced the fuel feed hose to the lift pump from the tank, I found very little affect on the low fuel pressure I was experiencing. This morning I installed your OFV020 and bingo!, I now have pressure. Idles @ 22# and have 30# @ 2000 RPM's and @ 65MPH it is a steady 25#. Under acceleration it drops to 20# but recovers as RPM's increase. I will know better when I put my camper on the truck and take an extended trip to know how the overall operation will be but I believe I am back to normal with my 94 Cummins. I only have 88865 miles on it. Thanks again and I will look forward to your report on the P7100 pumps.  Duane Lietha

The trucks overflow valve was shot when i put the new motor in. I had to prime it every time i started it. I put your valve in there and it starts every time, no problem, even when its been sitting for weeks on end. great product!   JOE HILL  

I would definetely say yes. It starts a little faster. fuel pressure is steady at 25# at idle. I have only had the truck back from paint for a few days. So yes overall extremely satisfied with the product and it is everything it was advertised to be and more thanks.  Also very nice to have a company that actually cares about their customers very refreshing thanks again.  JOHN CHOLENSKI

John Hanson of Marion MT said it best! 

I just got back last night from a trip to Lincoln, NE and back, hauling Clydesdales. We crossed the scales at 23,500#. 4 Clydesdale mares, in a 6 horse slant Trail-ette Constellation trailer, pulled by a '94 Dodge 3500 4x4, with a 6 speed. I've driven big trucks (own Kenworths and Peterbilts) for over 30 years and that little 6bt Cummins just never ceases to amaze me! The valve works awesome! Going down the road, it stays right about 28-30 and stays nice and steady! I don't see the fluxuations I used to with the old valve, so I'm a happy customer. You do nice work!!

At any rate, thanks for the awesome overflow valve! I'll be watching for more products from you

The first article, written by Rob Parelli, on the Cummins fuel system and lift pump is done. Feel free to share the link with your diesel friends. Tork Teknology has made hundreds of tests on the P7100 fuel system and the information is available to you- FOR ZERO COST.

Article number two is ready for your reading. This 6 page article is not white bread fluff! It is a very meaty guide on the importance of the inlet line. Getting the inlet line size right, on your performance engine, is critical in achieving maximum diesel horsepower and torque.

Use this link to view the instuctions for the Tork Teknology Cummins Adjustable Overflow Valve :

Product Reviews

Write Review

  1. Perfect Product 5 Star Review

    Posted by on Mar 7th 2018

    I ordered this part for our old farm truck due to a few reasons, the part came fast and worked exactly how they said it would. Best thing yet is the personal message on the receipt saying thanks! Will certainly buy from TorkTeknology again!!

  2. adjustable overflow valve OFV010 5 Star Review

    Posted by on Sep 26th 2016

    I recently purchased 2 of these over flow valves, one for my custom project and the other for one of my company trucks. I never would've though that a slight change in fuel pressure going to the injection pump would make such a difference. The work truck since i purchased it was always sluggish of the line with the manual trans and would shake a bit on the take off. Now its a mule, and the shake is completetly gone. That same valve also make a huge improvement on my 400hp van project as well. excellent product and well worth the money. Thank you

  3. 5 Star Rating 5 Star Review

    Posted by on May 11th 2016

    Great product 

    Posted by Tommy owens on 20th Apr 2016

    My truck has 335000 miles on it so I expected it to show its age but it kept going lower and lower on the power starting became an issue after some research I found this best thing I could have ever done


    Posted by Brenden on 26th Feb 2016

    I haven't even installed the product yet but I want to say that this company has the best customer service! I ordered the product on a Saturday and within 45 minutes got an email telling me it had shipped already and received the product 4 days later. Very impressed thanks guys!

    Total life saver!!!! 

    Posted by Justin on 4th May 2015

    I had a problem getting any power on top end and it worries me. Then it progressed and got so bad I barely got over 40 mph. Finaly the truck kept dieing and after lots of research this product kept coming up to be the rite fix. Soooo, two days later after I ordered I swapped them out and my truck ran better than new and had so much power I didn't recognize my own truck. Thank you so much for this great product.

    Vibrating shifter stopped immediately, power backand then some, better start up

    Posted by Marty Macdonald on 12th Apr 2015

    The tork tek valve worked as advertised,It is the best option for cummins.

    Thank You

    Blue smoke on start up is gone. 

    Posted by Dewayne Cantrell on 27th Dec 2012

    Hey i would like to thank you for getting me my order fast. I ordered the overflow valve for my 95 12 valve, and It works Flawless and No more blue startup or Hesitation on take off. Thanks again and i will always be a customer to you.

    My truck performs!! 

    Posted by Johnas on 28th Jul 2012

    Bought an adjustable OFV for my 12v. WOW! I cant believe how much of a difference this one part makes. I am so happy with the truck now. Before it was a dog pulling a sled off the line.. Now its like a horse running with a saddle off the line. I posted my review on the cummins forum here is the link.

    The best valve for the P pump. 

    Posted by Sean Fox on 15th Feb 2012

    More beer nuts! You guys kick ass and your products are phenomenal!

    My Cummins runs smooth - now. 

    Posted by Davis Byrum on 14th Feb 2012

    I have a 94 12v dodge 5spd truck that i recently in stalled one of your adj overflow valves on. The truck did seem to idle and run a lot smoother after install, so thanks guys! I installed a guage and found that with your valve out of the box was flowing 27 at idle and about 35 at 2500 rpms.

    I love this valve! 

    Posted by Ronnie on 16th Jan 2012

    I love your adjustable of valve its great!!!!

    Excellent Insurance 

    Posted by Dale Hunt on 25th Mar 2011

    I was preparing to install a TST fuel kit in my 1995 Monaco 8.3 and while discussing it with a buddy who also has an 8.3 found out he had gone through a ton of power issues and finally pinpointed the overflow valve!
    So I'm looking for a replacement and find TORK TEKS site which was very well explained.
    I love to drive my Monaco but I hate trouble so this is just another precaution.

    Smooth Idle 

    Posted by Donald Wade on 28th Feb 2011

    I would love to tell everyone who is interested in purchasing any of Tork Teks products that you will not be disappointed. I have puchased two different product for my '95 Dodge Cummins and I was amazed with the quality and function that Tork Tek product claim. Adjustable overflow valve made my 12V idle smooth and make quicker throttle response. Exceptional service and short delivery time. Outstanding technical help over phone with great respect! I highly respect Tork Teks products, service, advice, and parts. Great Company, Great Products. I will recommend to everyone.

    Works fine 

    Posted by John Ward on 17th Feb 2011

    I installed the OFV010 overflow valve in hopes it would solve my starting problem. As it turns out I had bigger problems. I ended up replacing the relays to the manifold heaters, the lift pump, and the fuel heater. The truck now starts like a champ--with the Tork Teknology overflow valve installed.

    Your valve is awesome!! 

    Posted by Scott from Sheffield, England on 13th Dec 2010

    Hi there Rob, I bought one of these OFV010 valves from you a while ago, I got it fitted a few weeks ago after I found a fuel pressure problem. Your valve is awesome, it now starts easier, runs smoother and fuel pressure is 22psi at idle and climbs with rpm. My dad now wants one too, so will you still ship to United Kingdom for me and how much. I also want 10 of those 14mm banjo seals too. This valve is bang on buddy, it's the best and easiest upgrade anyone can do for very little money. My Cummins Suburban has been sat outside for 2 weeks under 12 inch of snow and it fired up with just a quick touch of the starter button. Everyone who has a Cummins 12V should buy your valves, it's made a big difference to my engine. I didn't even know I had a problem until a hooked up the pressure gauge and saw 10 psi at best. your valve is bang on, (that means perfect or spot on).

    Cured white smoke on start up!! 

    Posted by Berek Blackston on 14th Oct 2010

    I installed your OFV010 and was very impressed, today the temperature when I started up was 47* and it started like a charm, previously any temperature below 60* and I was greeted by a large cloud of white smoke, a rough idle, and the need to pedal it to keep it running. I have been very impressed in the 2 short days I've had your product on my truck. I am the second owner of my truck and it currently has 115k miles on it. I hope I can get another 100k miles out of your overflow valve and snubber. Thanks for the great customer service as well

    Great product Great price 

    Posted by Brandon on 28th Sep 2010

    After discovering I had low fuel pressure, I started searching out an OFV to remedy the problem. Cummins Westren Canada wanted over $250 for an OEM replacement. At $45 the Tork Tek OFV is a bargain and because it is adjustable it is even better than OEM. Install was a breeze and my low fuel pressure problems are long gone. Nice product!

    A great product! 

    Posted by Unknown on 27th Sep 2010

    I installed this on my truck because my ofv had almost 200,000 miles on it and was starting to cause problems. Cold starts were difficult and took a lot of cranking. While the truck was cold it would die if i let the the rpm's fall down to idle when i shifted. But since installing the tork tek OFV010 i have had no problems starting the truck in the cold and it no longer dies while it is cold. This is a great product and works really really well. It does everything tork tek claims it will do.

Find Similar Products by Category