View Full Version : Air actuator bypass valve

06-27-2017, 05:35 AM

Years of trouble free service from my JRSC until recently and have traced it back to what I believe is the culprit.

At wot or close to it, I am only ever getting to 0 PSI on my boost gauge then it's back to around -20 at cruising or idle. I first thought that the belt was loose and checked that and it is tight but I adjusted it to be a tad bit tighter while making note of the original position and what I had increased the tension to with the adjustment screw.

I test drove it but it made no difference whatsoever. I got up underneath the car and since our actuator bypass valve is so conveniently located underneath the JRSC, I was able to, with a long screwdriver gently try to actuate the little valve that the actuator valve's rod hooks into. It only moved 1/16th if I had to guess and that makes me think that either the actuator or the valve itself is stuck closed and unable to be opened.

I forget which way it is on these units, if closed is for boost and open is for bypass.

Has anyone encountered this issue, did you end up replacing the actuator and if so, where did you purchase a new one from because the cheapest I could find the actuator for was a thieving 200.00 from none other than supercharger.com who doesn't even list our application any more.

I'm open to suggestions or options that may not have been thought of yet.

06-29-2017, 09:15 AM
Interested in a response to this too!

07-04-2017, 09:30 AM
Well my initial diagnosis was correct only in reverse. The butterfly on the bypass assembly was not closing completely, initially I though it was stuck closed but then upon seeing the state of the butterfly it was clear that it was allowing any possibility of boost to just circulate. Seeing that it's the long weekend I opted to just bite the bullet and take the entire unit off the car for a closer look and inspection.

What I found was that the butterfly was indeed stuck and unable to move which in turn I believe contributed to the wearing out of the vacuum actuator. I did a vacuum test and the valve could not hold so that will need to be replaced with a new unit for starters. Regardless the butterfly would not move at all it was seized.

The butterfly inside the actual bypass assembly needed to get removed first and lucky for me one of the two pinch screws came out without much fuss. The other required some dremel work in order to break it free.

After the butterfly was removed, the shaft was able to then be pressed out which takes care of the first needle bearing that must be removed. The second needle bearing is a blind bearing, roughly 3/8 of an opening with a 1/16 lip, if that. This was the culprit and the reason for the binding as the needle bearings got moisture inside and rusted themselves up due to a failing seal.




I tried all sorts of methods to pull/press that out but was unsuccessful including splitting a nut that would then fit inside and spread but in the end I ended up using a dremel and a grinding stone to wear down the race of the needle bearing so thin that I was able to fold it in without damaging the aluminum and it popped out.

I'm debating now on having the entire unit sent out for new rotor re-coat, this m62 has the epoxy coating that will wear/flake away with time and I would like to get the inner bearings and seals replaced in this unit. The rotors and case internals look great actually, no gouges or wear marks. Might be a great time to do the snout work as well and replace the bearings and coupler as well.

So now the waiting game for parts.

07-09-2017, 04:54 AM
Well the parts arrived quickly from David @ superchargersonline. I received them Friday evening and I was able to press in the new bearings in the housing. Now the supercharger should be able to build boost.



I took an additional step, seeing that the charger was off the car and on my bench, and decided to inspect the rotor pack and case for wear.





So from the above photos you can see that the rotor coating has indeed chipped away, in fact the previous owner had used methanol injection which is why the rotors are chipped however they have a few spots that have worn more and I found a chip inside the case floating around so it's time to get the rotors coated again and have the rotor pack bearings and seals replaced considering I only got about less than 1/2 oz of oil back out of the snout when I drained it.

Impatience is getting the best of me but it's better to get the rotors re-coated and new bearings pressed in and rotors timed than continue to run it like it is.

07-19-2017, 05:52 AM
Quick update. I send the rotor pack over to thehighspeedlab.com where the rotors will be re-coated, new bearings, seals, according to them they machine out the rotor pack bearing openings to accommodate larger bearings and seals which are upgraded viton double lipped seals. I'm going to re-build the snout and press out the needle bearings on the housing with new ones. Should be a brand new supercharger once it is fully reassembled.

I've not had a issue with belt over-tightening but I did come across this incase anyone else was wondering what could be done to give the JRSC more support.


08-03-2017, 03:45 PM
Ordered new gaskets from Moss and asked for bolt torque specifications for bolting the m62 back to their intake manifold. I spoke to a man named John who said they no longer support or carry parts or information for our particular kit. Sadly their website is severely lacking as when I placed my order I included a note asking for this information which John confirmed he had no record of. Disturbing is the fact that Jackson Racing, Moss and Magnusson all play games of "not my problem" and it's ultimately the customer who suffers.

When asked about the fastening hardware's grade that also drew up a blank so replacing the bolts with ones with a known grade will help me to calculate proper torque when reinstalling everything back together.

For those interested, https://itstillruns.com/determine-torque-specs-7505297.html

I also have the JRSC support brace on order from the U.K. So I will post an update on that as well. Still waiting on my rotor pack to get shipped back so I can reassemble.

08-07-2017, 08:15 AM
Thanks for keeping this updated. I dont own a JRSC but I'm sure this will help someone down the road.

08-18-2017, 03:18 AM
Thank you! That was my thought behind doing this, a reference for myself and others.

08-18-2017, 03:48 AM
Status update. It's Friday! I have received the CPL Racing JRSC snout support bracket. A tad pricey for what it is if I am to be perfectly honest and the shipping was no bargain either but the peace of mind I have from knowing there is a potential failure point sorted out is worth it.

In my spare time I've managed to rebuild the snout and utilize a spare shaft I purchased that is made from a stronger case-hardened steel to prevent the possibility of a snapped shaft. I still have the original as a backup.

Here is a photo of the complete new shaft assembly with bearings and new coupler all pressed back together.


Here is the original shaft and bearing. The bearings were fairly worn and showed signs of being overdriven.


I ended up removing the entire JRSC housing from the intake manifold and pressed out the original needle bearings and pressed in the new ones using the reverse end of a socket. Before I did this I measured with a depth gauge on the back side just how far to press them back in as on the inside of the housing you will see there is a tapered edge that the lip of the bearing will need to sit just a bit below, not flush with the inside of the housing.


Since everything was apart I opted to first fix the corroded and banged up snout.


Using a headlight lens polishing kit, some barbasol shaving cream and a drill, I was able to get the aluminum buttery smooth and back to it's original luster without getting into "bling" territory.


Next up I wanted to freshen up the JRSC housing so I opted to strip all the original coating off and coat it with wrinkle paint. This became rather addicting and a great way to pass time and I ended up doing the intake manifold, the intake tube, and a few other pieces of the kit, including the new bracket I got from across the pond.


In the oven curing


Finished product



I followed up with Moss about the correct torque specs and thankfully they passed my contact information over to the gentleman who handles the JRSC superchargers and I found that the torque specs is 16ft/lb with clean threads, dry no lubrication.

So all my parts are cleaned and re-coated and ready for the rotor pack to get back to me from The High Speed Lab. I was told via email last Thursday that my rotor pack was going to be worked on. Fingers crossed in a week or so I get it back so I can get this all back together before the snow flies.


That's all for now.

09-09-2017, 05:07 PM
Finally, I spent this Saturday re-assembling the JRSC and putting everything back together. The High Speed Lab in St. Louis was the company I went through and I opted to not swap my rotor pack but instead, have them rebuild my exact rotor pack. I received everything back in a very well protected USPS box along with bearings to rebuild the snout and additional needle bearings for the JRSC housing and some go/no go test strips of varying thickness to use for testing your rotors in your housing.

I did notice I had two small nicks that were not there previously upon shipping my rotors to them and they did not mention this until I asked. Apparently they take the rotors and fit them in a test housing to ensure correct timing and fitment. Odd, that mine had these small nicks but nothing was damaged in shipping and Wade, the owner/machinist at Embree did not seem concerned and since they are not on the rotors themselves I did not stress too much, still though.

Ok more pics of the finished project.

Here is the rotor pack with machined holes and my initials etched into the parts (I did not know this was going to happen nor was it told to me. I suspect it was due to the fact that I wanted my rotors and parts back rather than swap out with another. Odd to me, use permanent marker and I can wipe off afterwards.)

The plate behind the gears is a bearing retaining plate that Embree uses to hold the new bearings in place. Eaton never designed these to be rebuilt according to Embree which is why the plate is needed, to prevent the bearings walking out of the opening. The original bearings are sealed in place but that get's removed upon removing the original bearings.

Other companies sell kits that have aluminum washers that can be TIG welded but that can lead to warping if not done correctly due to overheating of the aluminum, and again if rebuilding again, the welds need to be ground down/out and then welded again. The plate made more sense as it's serviceable by the end user if need be again.


Here's the engine bay prior to the project for reference:


Rotor scuffs due to being test fit into Embree machine assembly. (Will not affect boost but I consider this odd and should have been corrected prior to being shipped. then again if something enters the supercharger anyways it will get scuffed but at least it's not on the business end of the rotors.)



Sealant ready to go in.

Close up of wrinkle finish

All done!

Overall it was worth it to know that I have a completely rebuilt JRSC, new bearings, stronger snout shaft, and the CPL racing bracket, actually is a nifty little addition as it does strengthen and support the snout better than just having it hang off the head. While it is a tad pricey, it was worth it for extra peace of mind and I know that I won't have to worry about potential issues of a cracked intake manifold from over tightening.

I added some energy suspension motor mount inserts as well and they were also a great improvement and greatly reduced the back and forth motion of the car between shifts.

I have also reached out to Moss for instructions on the JRSC Street/Race installation manuals that are no longer available on their website for posterity and when they get back to me, hopefully with PDF's I will submit them here.

Overall the project was fun, albeit time consuming mainly for the VHT wrinkle paint but I would encourage anyone else wanting to rebuild their JRSC to do so as it isn't overly taxing and you get to learn more about the inner workings of the supercharger as well and the satisfaction of a job well done.

09-10-2017, 03:23 PM
Beautiful work. Thank you for including as much info as you did. I will be needing to sort through this myself as i need to finish rebuilding my JRSC as well. I am in dire need of a snout shaft, mine is broken i and ran into the same issue you did... no one wanted to help me find one.

I also ported my bypass valve. Made a larger butterfly and used a brake hone and dremel to port the bypass. Im actually really excited to see the difference compared to how it was before.

09-11-2017, 08:53 AM
Beautiful work. Thank you for including as much info as you did. I will be needing to sort through this myself as i need to finish rebuilding my JRSC as well. I am in dire need of a snout shaft, mine is broken i and ran into the same issue you did... no one wanted to help me find one.

I also ported my bypass valve. Made a larger butterfly and used a brake hone and dremel to port the bypass. Im actually really excited to see the difference compared to how it was before.

Thank you!, glad I could help! I reached out to "scuffers" on clubrsx for my spare shaft, you may give him a shout and see if he has any left. I'd love to see the work you did on the bypass valve, did you start your own build/rebuild thread yet?

09-11-2017, 10:29 AM
I have a thread yes but my current car is a K swapped 94 coupe. An accident claimed my 05 EP years ago. I used Photobucket to attach all pics... and apparently Photobucket doesnt wanna do things for free anymore so im stuck having to manually D/L all my pics to have them once again.

When i couldnt find a shaft i stopped working on the SC. Seemed a moot point then. My rotors are in the same condition as yours. Needing a recoat. I wanted to get the inner body of the charger ported and coated as well. There are a lot of Mazda Miata owners that have great results with having the body coated as the charger builds a few more psi at the same rpm. More efficiency never hurt anyone, especially when rpm based heat is your enemy.

If i can track down another shaft i would be all over slappin the SC back on the car. I prefer the 2.0 with the charger for reliability versus a high strung NA k24 for daily use.

I actually have two PB accounts, so once i come across the pics for the bypass mods ill find a way to get them to you. In total i opened the butterfly almost 2mm. More importantly though i cleaned up the really rough casting to help with airflow.

My engine build is a bit of a hybrid, k20a3 bottom end with k20a2 pistons, using a k24a1 CRV non LMA head with three lobe cams and rockers from a k20z3. Since there are no LMAs, you flip the pins in the rockers to hold the VTEC rocker in position when the engine is on the low lobe (economy). This also puts one valve in each cylinder on both IN and EX sides on the VTEC lobe all of the time. After a lot of tuning i netted 150lb/ft wtq between 2900 and 4200 rpm. On the dyno it is flat as glass. With my trans ratios, this is perfect for daily driving as i usually three gear the car (1,3,6 or 2,4,6 never going over 4500 rpm. VTEC crossover is 4800 rpm. Max power was 227whp/152wtq (might be 162wtq... cant remember lol) at 8200rpm on a roller dyno.

Imagine 8psi off the charger tossed in the mix...

The purpose of modifying the bypass as i did was to complement my engine build at part throttle during daily driving below 4800 rpm. While the changes are minimal, im sure it would allow for usable TQ out of boost. Anything to maintain those great MPGs!