Injector Pump, Tranny

New ‘IDI-Online’ C6 VRV (Vacuum Regulator Valve) Progress. For Sale Possibly In August.

Since the IDI C6 VRV (Vacuum Regulator Valve) was discontinued years ago, they are becoming scarcer and scarcer.  I’ve been working on developing a new IDI-Online VRV based on the old design for the 6.9 and 7.3 IDI, but with a few enhancements to make the part simpler and easier to maintain.

The older VRV is plastic and eventually breaks down.  Since there are no replacement parts for sale, this leaves the IDI owner with a tough decision: either replace the transmission with the inferior E4OD or scrap the vehicle.  My goal is provide a new VRV that takes the place of the older part.

I’ve been waiting to announce this for a few weeks because it required a lot of research to document everything, but I’m getting to the point where I feel I’m only a few weeks away from having a functioning prototype.

Ultimately, when this is done, I’m going to provide two types of products.  First, I’m going to develop an inventory of replacement cams, cam links, covers, and parts for the existing VRV.  Next, I’m going to provide finished product VRV’s, that are custom designed by me to eliminate some of the unnecessary components that either wear early, breakdown, or really don’t need to be included on the VRV for the IDI IP.  I’m hoping to have functioning prototypes soon, and if all goes well, new IDI-Online VRV’s for sale by the end of summer.

If all goes well, I might develop an aluminum VRV, that should last substantially longer than any plastic part.

I’ll continue to post more information on my progress as things develop.  I hope to have the first round of prototypes mailed to me in a few weeks.

Update: 6/14/2018:

I got all the stock parts modeled and prepped.  It was a lot of work.  I’m pretty happy with the detail I was able to model, including all the weep holes, notches, ports, etc.  I was even able to get the housing completely designed in 3D, which was probably the most complex solid-model that I even built.

Using assembly design, I was able to virtually-test the model and its action.  Everything pretty much worked out, except the castle nut and cam housing cover.  I used the 3D clash detection to make sure everything fit just right, and made adjustments accordingly.

So far so good.  After testing various mesh resolutions, I found a good balance of file-size and mesh detail.  Checked it in another program before sending the files off for prototyping.

I chose three different types of plastic for the testing phase of this project.  I’m going to make these in what-they-call “Professional Plastic.”  They claim the nylon plastic is good up to 350 deg F, watertight, tensile strength (up to 6960 psi), and chemically resistant (to oils, greases, allphatic hydrocarbons, and alkalies).  Ideally, I need these VRV Parts to be high-temp rated and have good abrasion resistance, but I ordered two other types of plastic that I’m pretty confident won’t work.  I’ve done quite a bit of prototyping, and the cheaper plastics won’t hold up in an engine bay.  But regardless, I ordered them just to see how they compare to the professional-style plastic prototypes.  I’ll post images once they arrive.


If the prototypes work out, I’ll order a bulk shipment and begin the first phase of this VRV project.  I’ll set up a store selling replacement parts for the VRV, like new cams, cam-links, housings, etc.  Then I’ll work on new diaphragms for the VRV.  Also, I’m doing some legwork for finding decent spring replacements.  And ultimately, I want to get to work on my custom VRV design.


Update 6/17/18:

I’ve been working with another plastics supplier to figure out an alternative for the diaphragm setup on the stock VRV.  We’ve narrowed it down to two types of plastics/resins, and we are developing a strategy to prototype an array of thicknesses to optimized the flexibility where it counts.  Also, there are other factors in the prototyping process that make this really difficult to produce; like flexibility, durability, longevity, and rigidity.  The sales rep and engineer at my supplier have been instrumental in making sure I can model up something that will suit my needs for the VRV.

I’ll keep on moving forward.  This diaphragm resin is pretty expensive (along with the other prototype plastics), but I’m willing to make the investment to make sure I get a diaphragm that is the precise thickness to ensure 5 in-hg to 13 in-hg as per the service manual specifications.



Update 6/19/18:

The first round of diaphragm 3D models got approved, so I progressed with modeling an array of various dimension and shape diaphragms for prototyping.

Also, I’m still debating on how to connect the diaphragm to the camlink.  I’m testing springs and different elastic plastics.  I’ve been talking to a large spring manufacturer in the hopes they have something VERY similar to the stock spring already exists in their inventory.  Maybe with a bulk purchase, I can make this assembly somewhat affordable.

With the latest prototyping processes, I can make pretty much any amalgamation I can think of.  So to simplify the whole component, I’d like to explore concepts that reduce the overall count of parts in the VRV.  Less parts usually means less possibility for failure.

Once I get more of the prototypes, I’ll learn more of capabilities of the plastics, and then I’ll keep progressing on IDI-Online version of the VRV.



The latest set of prototypes is “in production.”  I snapped some photos of the facility’s mesh reading software….

Looking good!  They estimate delivery of the rigid plastic prototypes around June 29.

Still no word back from the diaphragm plastic cost estimates yet.  Their facility is a little smaller so I’m cutting them some slack.  I run my own business and know how hard it can be to keep a balance of work-and-life.  I’m hoping for the estimates any day now.


Update 6/20/18:

Some bad news.  The diaphragm 3D model didn’t pass the more advanced examination.  Something about the connection material was too small for the resolution of the printer.  I’m not really sure how to resolve this yet, I’m brainstorming a new solution.  I don’t have a lot of options, because the diaphragm diameter is really small, so extending it will mean creating a larger footprint, thus reducing the flexing capacity of the diaphragm plastic.  Back to the drawing board.

As for the spring manufacturers, I’ve been going back and forth on that whole ordeal.  We have tried to get some early cost estimation, but since the springs are so odd, they don’t have a good number yet.  I’m currently at the point of modeling up the current springs and producing some drawings to aide their bidding.

Some set backs, but I’m going to keep moving forward.   The first quote for the springs came out to $400-500 per spring.  LOL.

I’ve been trying to make sure that all my products are American Made.  So I’m shopping around for more spring manufacturers anywhere in the 50 states.  Any suggestions, leave a comment below.


Update 6/22/18

I’ve made the latest revisions to the diaphragm prototypes and sent them off for approvals.  I have four different designs (2-way flat disc, 4-way flat disc, 2-way domed-disc, and wide slot flat disc).  I’m still confounded on why the last two prototype meshes were rejected, and their explanation was really enigmatic.  If they reject this latest design, then I’m going to have to talk directly with their production team, because the sales staff is giving me the run around.  Also, I might have to move toward building my own metal mold and pouring my own diaphragm plastics/resins…. Until then here are some pictures:

Update 7/4/18

The first round of prototype plastics arrived!

I’ll start testing the plastics for their longevity, durability, etc.



Update July 20, 2018

Got the diaphragm prototypes.  Lots of issues.  Those parts will require a full redesign, with the orientations revised.


Update August 3, 2018:

I’ve done an early assessment of the prototypes, and there are issues.  I need to revise the 3D models and send out for a 2nd batch of plastics to make sure the proper tolerances are met.  Some of the 3D printers must have varying printing tolerances that are affecting the sizing of these meshes, but overall, I’m pretty pleased with the output.  Maybe a less fastidious designer would accept the models as is, but I want to make sure they fit together perfectly, and that means more prototyping.  I’m quite sure this means I won’t have anything ready for sale by the end of August, but Autumn 2018 is definitely in play.

The first round of plastics were considered “Professional” plastics, with supposedly quite good heat, vibration, and tensile resistant properties.  If the product ever went up for sale, I would insist I use this material, because structurally, it is supposedly the best of all the printable plastics I could find.  The only downside to this material is the graininess.  The material comes in grey and black, and in the future, I’ll just stick with the black.  The grey looks really speckled and odd.  I’m not really impressed with that variation.

With respect to mating tolerances, the castle nut and VRV Cap models appeared to have printed perfectly, thus allowing for a great fitting.

With the castle+cap combined, the top housing threaded on with ease.  One issue here was the tolerance on the threads.  It made the cap wobble a bit, but knowing my stock VRV, the cap wobbles on that too.  I think I’ll adjust the 3D offset tolerance on that in my parametric 3D model when I send for the second round of prototypes.

Unfortunately, the cam seems slightly off with this particular printed plastic.  I would like that to fit a little better and more snug, rather than the slop that is visually apparent in the previous photo.

Also, the Cam Cover fit well, but it appeared to be too thick.  Or maybe the receiving-groove in the main housing wasn’t deep enough.  Regardless, if I revise that, the top surfaces would be slightly more flush.  Not a big deal, just had to mark down in my notes for revising the 3D Parametric model.

The second type of plastic I tested was the white “processed” plastic.  This too had a good deal of graininess that I really didn’t want to see.  I’m worried this kind of abrasiveness would inhibit good cam and cam-link movement and possibly induce premature wear on the system.  I don’t know until I conduct extensive materials testing.

At least with the processed plastic type, the tolerances seemed to fit better.  The cam sizing was perfect, so that wouldn’t require any additional prototyping remodeling.  Also, the rotation of the cam with the cam-link was smoother.  I guess with proper lubrication, the abrasiveness of the printed plastics might not be an issue.  In fact, it might help the grease cling to the pockets in the plastic, thus allowing for a better lubricity and retention of parts.  Just speculation at this point.  I’m still hesitant to lube this up until I get better diaphragm prototypes (see below) and some company to accept my drawings for spring production.

With the white plastic, the cam-link BARELY fit in the housing grooves.  The black plastic was actually QUITE sloppy, so that’s one of the differences with the two plastic printing types.  The tolerances might be off by as much as 1/64″ which is kind of unacceptable.  I need this to be good down to at least 0.005″ if this is going to reproduceable and viable for sales.

Just like the black and grey castle-cap assy, the white parts fit perfectly and snuggly spun.  Also, the white cap fit on the cruciform of the main housing snuggly, so it didn’t wobble.  I liked it a lot better.  No need to adjust the threads on this plastic.

Sadly, the white VRV cap didn’t have a proper vacuum port.  The plastic must have gotten stuck in the hole when they pulled it from the bed.  Bummer.  Looks like Professional Plastic is the only way to go for the cap.

I also invested in the cheaper clear plastic as well.  It appears to be far superior to the other two plastics in terms of smoothness.  It is really spiffy, but it doesn’t have much for heat and strength resistance.  I gave it a shot anyway just to try it out.

One thing that was kind of cool was the ability to see the cam and cam-link thru the transparent plastic.


Sadly, as I was simply trying to push the clear plastic castle on the cap, it broke rather easily.  I basically handled this part for less than 5 seconds before it broke.  I think this confirms that the clear plastic cannot be trusted on this project.

My diaphragm connector testing went well.  The closest plastic to match the elasticity of the stock spring is the second and third shaft, but I need to freeze these and try the materials testing all over again.  If the temp affects the elasticity, then I’ll have to find a different solution.

Well, the diaphragm prototypes were all basically a bust.  They all had some kind of odd dimpling that was a result of the flexible printing process.  Bummer.  I talked to the manufacturing staff and we think we might have a solution.  I hate to have to send out for another batch cuz they are just so darn expensive, but if I remodel it, I think we can make it work.

Even with the dimpling though, I was able to install one of the thicker test diaphragms and see if it held against the vacuum pump.  IT DID!  That was pretty cool.  Now I just need to get the second round of flexible plastic prototypes and reinsert them into the plastic VRV cap and calibrate if for 5-7 in-hg.  Almost there!

Lots more to go, but seeing the light at the end of the tunnel here.  If I can get my suppliers to reign in the tolerance issues, and get my models refined, this could be a good Autumn.






I’d love to chat via email

My 6.9 IDI has a working VRV and I’d be interested in helping you out. I’m up for paying for one now and testing out prototypes on my tow truck as this is a big problem for IDI owners

I was building my own solution, using a TPS, Line pressure sensor on the case, and a service to actuate the normal modulator connection and had an Arduino controlling it so it was using tps to determine the requested line pressure, then verifying it against the pressure sensor and could adjust for abnormalities very quickly. I may be done with it soon but it’s pricey

I like your approach as well


I was thinking of arduino style controls as well, because I plan to redo my instrument cluster with a tablet, and use a variety of sensor and controls and relays to power stuff. I figured if the VRV ever went, I could so a similar method as you said with the tablet and arduino and some pc-controls stuff. But my VRV project is going to be a part-for-part supplier for people who want to replace their faulty VRV’s. I’ll email you soon once I get back on schedule.


So, if you are looking for better plastics, may I suggest PPE or PPE+PS, that’s what I use for high end industrial applications, very very strong


Thanks for the info. Everything I’ve read about PPE says that it’s still in its 3D-Printing infancy. Which basically means, the manufacturers aren’t ready for primetime, or the print prices are still too high. I gotta find a way to make these affordable to the customer, so that’s tough to accomplish with a PPE print process. I once got a quote from an industrial 3d-printing company that could provide VRV housings around $4000 per print. Yowza! I doubt people would spend over 4-big-ones for a VRV for an old IDI.

Mary Raymond

I need a replacement vrv and would like to be notified when these become available.


I’m still working on this project. I’m still doing plastic materials testing. The problem I have is finding a plastic that holds up to the stress and fatigue that a typical IDI can put upon it. But I’m working as fast as I can. I too want to have replacement VRV’s for my IDI’s, so I’m very motivated to get this project in a viable situation.

What part your your VRV failed? Maybe I have part of the VRV assembly that could work for you?

Eric Day

Please let me know when these are available as I am very interestd


I’m still waiting for the third round of plastic prototypes to be fabricated.


Leave a Reply

Your email address will not be published. Required fields are marked *