The Official 356Talk Forum

And now a higher resolution photo of the Faux Cam motor on the dyno. The motor uses the Wilhoit 2133 kit which has about 160 hp in single plug form. Gregory’s motor is twin plug so it will be interesting to see if there are any Hp gains due to the second plug.

More to come. Thanks for following along.

Well, it has been a while since I last posted - I have been busy getting the new home in Seattle ready to live in and getting ready to retire. Gregory has his faux cam motor running in his 904 clone and those of you at Monterey last week and this week may see him driving the car around town. He says it is race car fast, and he should know. The car was built by Martin and Walker in the UK, where I also have one on order. Gregory's motor is a 2133cc build using Wilhoit's heads and crank etc with the prototype of our pushrod distributor V drive. Zero problems with the distributor V drive so far. My 904 project will use the 4 cam motor currently in the 59A, and the 59A will get my faux cam motor when the time comes. I have been making updates to the distributor V drive CAD model to incorporate things Gregory and I learned from the prototype. We reduced the diameter of the mount bowl for Faux Cam motor use down to the same size as the normal 4 cam V drive, made the outer end cap part of the drive body, since the "guts" can be loaded from the motor side and made many changes that reduced the front to rear length of the mount bowl and V drive body by about 1.5 cm. If Gregory's measurements are right, this will allow the unit to fit on a pushrod motor with the stock rear engine tin in place. We plan to do a 3D plastic print to make final checks before we make another metal unit. Once everything is confirmed I will also make a second version of the mount bowl for use on pushrod motors still running the stock crank pulley and fan shroud. This version will have a larger diameter bowl to accommodate the stock pulley, which will make it viable for use on twin plug motors where the owner does not want to go the full faux cam route. I had planned on taking the 59A with 2 liter 4 cam motor down to Rennsport VI, but found an exhaust stud pulled from the head when I was in Seattle earlier this month. So I pulled the motor, crated it and it is on the way to Jacques LeFriant for a refresh. This was planned anyway, just not so soon. The motor has about 40 vintage race hours on it from use in Stan Gold's 904 and RS60 before I purchased it, so it is time. I plan to assist with the tear down the week after Rennsport. I hope to see as many friends as I can while at Rennsport in a few weeks. Or stop by Jacques shop the week after to see a torn apart motor.

Back in Beijing after a great trip to Rennsport Reunion VI and finishing up modifications to the pushrod motor distributor V drive to get ready for a 3D print prior to making a small “production” run. Lots of little changes but the major changes were to optimize the use of “space” inside the V drive body to make the entire unit smaller front to rear. Gregory determined that the front to rear dimension of the mount bowl and V drive body needs to be 120 mm or less to fit inside stock 356 rear sheet metal. I managed to remove another 5 mm from the V drive body, so the overall front to rear dimension is how 115.2 mm. Screen shots below show some of the work done. Cross section prior to optimization. Note space between the large diameter part of the yellow internal shaft and the red V drive body inner end cap that is part of the mount bowl. Cross section after optimization. Internal spaces minimized. Internal shaft has been shortened. Gray object at right is the crank pulley and nut. Note cut out in the mount bowl to clear the dry sump oil pump. All parts shown. T drive shaft is the green part in the center. Blue part in the bowl is the crank pulley and nut. Final cross section with T drive shown engaged in the crank pulley nut slot. Not shown is the pushrod distributor drive gear that fits on the large diameter part of the yellow internal shaft.

During the course of the optimization we removed 20mm from the overall front to rear dimension of the V drive body and mount bowl, we added thickness in some areas of the mount bowl to ensure a long life and we made the mount bowl diameter the same as a stock 4 cam V drive. Gregory now has about 3,500 km on the prototype V drive in his 904 clone, which you may have seen at Rennsport Reunion, which gives us a pretty good proof of concept.

Next step is to make a 3D print to check fit of the unit inside stock 356 sheet metal and confirm all dimensions before we CNC a unit in aluminum.

Thanks for following along.

Love it, but it seems you could add overhead cams and belt drive reasonably easy.

Chuck

I had a chat with Gregory on the phone and decided some more work was needed on the inside of the internal shaft of the V drive. This part carries the pushrod distributor gear, that normally resides on the crank in a pushrod motor, to drive the two distributors. Inside one end of the shaft is a section of DIN 5463 spline. The T bolt that fits into a slot in the crank pulley nut has a section of external matching splines. This is how the T bolt turns the internal shaft in the V drive. In the other end of the internal shaft from the splines is a smooth bore with a circlip groove 1 mm in from the end. The circlip holds a spring in the bore that places pressure on the T bolt splines. This keeps the T bolt engaged in the crank pulley nut slot and also allows the T bolt to be pulled out in order to change a broken fan belt.

I found a problem with the length of the spring bore in the internal shaft (last photo in my previous post). We shortened the internal shaft so much that the spring bore was not long enough. With the T bolt pulled out there was not enough room for the compressed spring. The solution was to “bore” out a portion of the internally splined length of the internal shaft and adjust the length of the splines on the T bolt. The cross sections and part views below show the adjustment. Cross section with T bolt engaged in crank pulley nut slot. Part view of same thing shown below. Cross section with T bolt pulled out to change a fan belt. Part view of same thing shown below. We can purchase the 20 mm OD internally splined shaft in 40 mm lengths (we need 32mm) and the externally splined rod in 1 meter lengths (for the T bolt). We decided the easiest way to make the internal shaft was in two parts. A length of internally splined shaft (purple in above screen shots) will be interference fit pressed into a CNC machined shaft with a smooth bore that carries the distributor (yellow in above screen shots) drive gear. We then TIG weld the circumference where they come together and machine the bearing shoulder on that side from the weld bead.

I think this is the last of the changes needed. Now we see how the 3D print of the V drive body and mount bowl comes out. We will not print the internal shaft. The 3D print is to check fit within the stock 356 rear sheet metal and check belt removal clearance etc before we go to metal.

Thanks for following along.

Now that the forum has been upgraded to allow posting PDF files, I attach below a 3D PDF file of the pushrod distributor V Drive assembly. You will need the latest version of Adobe PDF reader to view the file. Once open, click on the small icon of the V Drive at the lower left - this should bring up a view of the V Drive. Then click "rotate" at the upper left and you can then click, hold and rotate the assembly to get a better idea of what it all looks like. The Solidworks files for all the parts have been produced and sent them to Gregory as that is the file format the on line 3D printing places seem to work with. Hopefully in a few weeks we will have some 3D print parts to show.

Thanks for following along.

Turns out that it is a LOT easier to get things 3D printed and CNC machined than it was back in 2015 when we CNC machined the prototype V drive that is running in Greogry’s 904. There are many on line services these days that connect customers with 3C print services in their area to get parts printed. Gregory found a service called 3DHubs.com and they have a petty slick web site. If you want a plastic print (either FDM which is fused deposition modeling or SLS which is selective laser sitering) you upload a .stl (solidworks format) file and it immediately error checks the part, with a 3D viewer to see where problems are, and provides you a price.

We wanted to make a plastic print of the V drive body, mount bowl and the internal parts in order to check fit in within stock 356 rear engine sheet metal as well as make a general check before spending more $$$ to make parts in aluminum. 3D Hubs connected us with a vendor in Vancouver who made the parts in under a week for $95 Canadian! Photo below shows the parts literally “hot off the press”. Compared to the photo below you can already see some differences. The outer end cap is now integrated into the drive body, the distributor clamp mount lobes are rotated to be in line with the bores to cut down height and the mount bowl is smaller in diameter. We will also shot peen the outside of the drive body and mount bowl to give them an appearance similar to cast parts. And for those of you that did not see Gregory’s 904 at Rennsport VI, the photo below shows a complete faux cam motor installed. Gregory’s motor is based on a 912 case with the Wilhoit 2133 kit, a Pauter dry sump oil pump, twin plugs and a 4 cam fan shroud kit from Ibrahim Kuzu. Next step is to make any changes to the parts after Gregory does the checks and then find a vendor to make the drive body and mount bowl in aluminum and one to make the part of the internal shaft that holds the distributor drive gear in steel. Gregory will make the internal splined part of the internal shaft and the T drive shaft on his lathe from a stock DIN 5463 splined shaft parts we can buy online.

Thanks for following along.

Next step is a faux 4 cam engine!

Chuck

Great work Bill and documentation for all to use......and wonderful retirement home. Inspirational.

Almost ready to make parts! The plastic 3D part prints nowadays are very cheap - it cost about $120 Canadian to print 5 parts. After the first set of 3D plastic print we made a number of changes to the V drive body to make sure it would fit within stock 356 rear sheet metal and also clear a Bursch exhaust. The final version for production is shown below: If you are using a dry sump oil pump like Gregory and I are, then oil supply and return for the V Drive is fairly simple. If you are using a stock wet sump you would need one of the oil pump covers that allows you to run lines to an external filter and/or cooler. You then tee off the line to the filter or cooler for the oil supply to the V drive body. We will need to think some more on where the oil drain from the V drive body would go on a stock wet sump set up.

I have learned that CNC machining is not just as simple as sending a CAD file. You also need to provide an engineering drawing for each part that show tolerances for things like bearing and oil seal seats. Also dimensions for parts that are press fit or slip in another part. So far we have 9 parts with an engineering drawing for each. We are in the process of checking the drawings prior to making metal parts. We hope to have the prototype production metal parts at the LA Lit meet.

Thanks for following along!

Were you able to make a prototype in time for the show? Very cool project. Excited to see the finished product.

Hi Tanner,

We were only able to show a complete plastic 3D print bolted to a 912 3rd piece at the LA Lit meet. The run of 5 metal units shipped from the CNC machining company on March 6th, so we should have them in the next week or so. We then need to make the male splined T shaft and insert and weld the female splined part into the internal shaft. This will take a few weeks. I will post some photos of the production units when we have them assembled.

Gregory's 904 with the prototype V drive continues to run well. He is using 009 distributors since they only have 25 degrees advance, which is what is needed for a twin plug set up, and are low cost. We plan to experiment with a 123 Ignition system set up with a master and slave distributor - this gives you spark on both plugs at exactly the same time. I am running this set up in the Speedco reproduction 4 cam distributors on my 2 liter 4 cam motor and it works well.

Thanks for following along.