V-12 Engine into 308 Build, over on Grassroots

I just tried to calibrate the tach and discovered it stops at 8k. Years ago the ferrari tach died and they are stupid expensive to get fixed so I bought a tach at the parts store, ripped out the guts and installed them in the ferrari housing. The numbers were close enough to right....but now I can program whatever I want so I added a calibration. Last run I played with the range I was using so it read mostly right but today I made the cal method better and loaded a little program to test it.....the tach stops at 8k. ☹️ I guess I figured that was fine when the redline was 7700....I'm going to need to buy a 10k tach and redo the guts swap it appears.

 

I was just reminded that if I'm working on the tach the face will need a reprint.....so it goes to 11!
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Still no word on the block tach mods it is.

I did have a "spare"....which means a 2nd broken broken one all in bits...I think this is the original and badly faded, perfect for a redo.

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Last time i worked on this I was looking for a tach with similar number spacing so it would read about right, but this time what I really need is enough sweep. So, I made a high tech measurement

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and went shopping on amazon

This one is better than what I have, but still not enough as I don't want to count on being able to drive it past the final number

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Winner-winner chicken dinner, more than enough! I wanted something smallish so I know the gut will clear the indicator lights at the bottom of the factory face so this seems perfect, even the screw holes look close, and just $14 delivered so its in budget. This is a 13k tach, but the numbers don't matter, I will use the ECU to calibrate it to match the new face.

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Next I need to create the artwork I want on the face...it has the work art in it so its not really my thing but I'll give it a go.

 

I believe I have the answer to the custom face.....dryrub. One place I found shows a custom speed as an example.

They will do a 3 color transfer for $168.
http://www.drytransfer.com/pricing

This company will put 3 1 color transfers on a 4x11 sheet for $64 - the difference being for the lower price I need to align each transfer, for the higher price I just align to the face 1 time so less chance for error.


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finished the numbers tonight....I think they look pretty good...and it goods to 11. Changing the colors makes them look a little slimmer than OEM for some reason....may need to fatten them up, but they are drawn not just pasted images so its easy to adjust anything, but it looks right with the backgrounfd off. The rest of the stuff I'm going to try to paste on, we'll see how that goes.

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I think that's the face. the small font stuff disappears in the render with the black background on but that is just a software thing.

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decided the numbers weren't quite fat enough to look right

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That is awesome!!

 

Thanks....now I just need to make it real.

Since I've given up on getting the brake warning light working so I guess that will become the shift light.....and will come on a wee bit before 11

 

Very cool...
Side story...
The pic of the factory gauge face with the dots reminded me of something. So on the old mercedes dd, the gauge face has these oddly space dots... Couldn't figure out what they are for, owners manual had nothing on it..hmmmm. oh well.. Couple yrs go by and I have to replace the vacuum modulator on the trans, then set the pressures... Gauges installed lines running into car and onto the road test... Yes you have to do all this whilst driving.. lo and behold the wsm points out the freaking dots! It's the shift points for the transmission...duh!
No other car I've ever owned has markers on the gauge for shift points... It's on the spedo not tach btw. Funny Germans...

 

Backside... Surface mounted leds... That light up with the tach arm swinging by...ooooo racey!

Or the tach needle is clear plastic, and lights up or changes color as it swings round...

 

LOL..yeah, no!

The goal with pretty much everything on this project is that at first glance it look stock...something the factory might have made/could have made in 1984. I'm not planning any boy racer mods

On a serious note, modeling the tach in CAD is a s..ck job. I'm using the free onshape which means all files are public if anyone wants the file, changing it back to stock would be pretty quick. Not sure if the link will work and you need to register to use it.

https://cad.onshape.com/documents/50d61be1093999cfd2313ea6/w/2f9172a7f864efbf352b2015/e/7a26519a49c27d100299e073

 

"No other car I've ever owned has markers on the gauge for shift points... It's on the spedo not tach btw. Funny Germans..."

my Fiat 850 sedan has shift points on the speedometer. The sedan did not come with a tach, so I guess they had to put it somewhere.

 

The ideal shift rpm drops as you go to higher gears so marking the tach gives the wrong answer, marking the speedo the right answer, but its not where most would think to look.

The math of it is that you want the higher torque at the wheel. Wheel tq=engine tq x gear ratio. so in 1st when you have a big gear reduction you are putting a lot of tq to the wheels so generally running to redline before upshifting is the right answer up in 4th and 5th where the gear ratio is much lower though the wheel tq lines will almost always cross well before redline. The best way to get shift points is a spread sheet with a graph or the gear ratio x tq every couple hundred rpm.....you shift where the lines cross. This is why a tach based shift light isn't really all the helpful, the light needs to be ECU driven to be right.

 

Mark, my take on the whole 11k rpm thing is that you want to start all over again in a year or two (with a new block.)

 

LOL...yeah....

I THINK peak hp will be around 9k the way the headers and intake are tuned and cams timed....so not a lot of purpose going past 9500, maybe in the lower gears it will make sense. The valve train is motorcycle and good to ...12.5k probably. The bottom end I'm sure will do 11k in short bursts, like a drag race but not say flat out on a road course. Its a log decay kind of thing on engine life run time to rebuild, 7500 for 10k hrs, 9500 for 10 hrs, 11k for 10 minutes...just guessing but about like that. Its more you CAN hold your foot down and not take the 1/10 or 2/10th sec shift loss, but don't make a habit of it. I'll probably setup the shift light to get increasingly angry as it moves past 9500.

The original plan was that when I had spare time I'd pull the tach and reprint the face with a 9 or 9.5 redline. When I discovered the needle doesn't go past 8300 the other day this all moved up in priority, at which point a buddy said "you have to make it go to 11!", in reference to this classic:

[youtube]

 

Transfers ordered. The cheap price is for 20 day max to ship then cheap shipping is 10 days, so by the end of Jan I guess....unless its 20 business days then mid Feb, $76.

I realized why the images looked different with the background on or off....hide edges command was needed. Then the fight to go from CAD to graphic. Th transfer place had a link to an illustrator like program "inkscape" which I literally could not figure out how to make it do anything, anything at all useful or otherwise. I exported the model as an STL, paint3D imported that and exported a pgn, I found "GIMP" which imported the png and the pdf template from the transfer place as xcf, and once I figured out the correct scaling I could edit the graphic in .xcf format, paste it the now xcf template, then export the finished product as a pdf again because the transfer place doesn't support xcf....but that was good because then I could open the pdf with adobe and print it 1:1 to confirm everything looked right.

Clearly there must be an easier way but this worked I think and here is the result. There was room so I decided extra harsh marks would be the best way to register the 3 prints on the the face. The white I left full, again for registrations to see where everything will be before transferring anything. Image Unavailable, Please Login

 

For vector based graphics I use corel... Not intuitive though but works seamlessly with CAD. No idea what's out there in free ware land.

I thought you worked with 3dS software?

 

The only 3dS I know about is my son's Nintendo. Me and software of any kind generally don't mix....I make a great beta tester though because you can pretty much guarantee I will click in new and unexpected ways until it crashes. As I said, no doubt there had to be an easier way........but hopefully this comes out right enough that I never have to think about it again.

 

Hahaha...
For some reason I thought you worked with CAD programs. There's so much shareware out now that makes it easier for the novice to get something done, I think you did a fantastic job. Trust me the big boy programs like Acad, solidworks and Catia have brutal learning curves and you'd get nowhere near what you want done in less then a month.
It's funny, I've been using CAD programs since '89.. and the share ware stuff trips me up, even AutoCAD sketchbook is goofy to me, kinda PS but not. Though once I started on solidworks I stopped updating my seat license for Acad... That was... Crap..15yrs ago!... Sheesh.. Time goes.

Your prints look great.

 

Nope, mostly I work with a sawzall and welder

I CAD stuff when I have no choice. The cams and flywheel were done in proE, cylinder liners and head gasket in solidworks. Now I use onshape because its pretty good and free so the velocity stacks, wheels and now tach face are onshape.....but most stuff is lucky to get a hand sketch before I start cutting.

 

Tonight I ripped apart the new Chinese tach, fixed the a few cold solder joints on the board, ground the board to fit the Veglia mechanism, added a jump because my grinding removed a trace and the tach is working. All easier than I expected. I'll strip and repaint the face and its ready for the transfers I ordered.

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It just occurred to me that the tach doesn't need the circuit board at all. 8 volt zener on the power to the gauge drive coil, other side to the ECU with pwm ground which it already has, same as I have the other gauges working. All the other stuff is to let the tach read a coil signal which it doesn't need to do anymore, so I wasted $14 on the Chinese tach....live and learn.

 

It turns out the tach doesn't need anything but the drive coil to work just fine...it needs to be cleaned to free up the mechanism a bit after sitting apart for 20 years but other than that its good. I just connected the ground wire and the signal and put a 5V pullup thru a 240 Ohm resistor, the PWM in the cal table it about 92 at zero, 15 at 11k so the resistor is pretty near perfect.

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Spent a ridiculous amount of time messing with the tach as cleaning helped but wasn't really the problem, it had to do with the coil in the tach and PWM duty cycles under 25%....I changed the supply voltage to avoid the problem DC and it works wonderful.

Today I thought I'd finally get the shift light setup....that only partially happened. I had the shift light and the exhaust valve to connect and 2 remaining ecu output pins....no wait....where is the 2nd one? gone to coil #11 it seems. I forgot that way the engine lab guys gave me instructions on how to get 12 coil pins when the spec sheet says 10, it cost a HS output pin. hmmmmm.....I was able to rewire the relay panel nd reclaim 1 output.

-Connected up the a wire for the shift light

- Added a wire for the exhaust valve...decide to test the valve....it clicks but doesn't do anything??? fast forward an hour and I realize the little solenoid is switching air ports and the valve itself, a pneumatic valve and needs high pressure air to operate.....DOH! There is a chance I don't need a valve, the vacuum actuators on the valves go at about 5 inhg....decided to leave the wire and see if I need to find a new valve once the engine is running again.

Which brings me to a moment I've been dreading.....wrapping up the wires in the trunk and making it look at least intentional if not neat. It was everything I fear it would be, much like 10lb of **** in a 5lb bag....but it went. Shift light tomorrow.



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