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My 68 Barracuda
https://slantsix.org/forum/viewtopic.php?f=6&t=61820		 Page 1 of 12
Author:  DadTruck [ Wed Jan 10, 2018 4:47 pm ]
Post subject:  My 68 Barracuda
I had a thread going over on Sixers Gallery, the .org drag racers post here on the Virtual Dragstrip , and as that is where the 68 Barracuda is now I thought I would join in.

MPFI has been active for the past year on this car, the car has not got out much. Posting today as I got the MS3 Pro also running the ignition side. Nothing real exotic here, MDS box running a lean burn distributor, small MDS coil, but it works. The Mega Squirt has multiple options for ignition control, I sorted through those and have a few that run.

here is a video
https://www.youtube.com/watch?v=Q34zKinZ83E

a basic curve, 10 degrees at low RPM, 32 degrees at power

It is just nuts being able to change ignition curves with a key stroke, it can take hours taking down a distributor and changing springs / weights.
Well it can still take time getting the right MS settings, but once there you are there, you are key strokes away from a distributor re curve.

So this is done for now, I will be building a better Slant Six motor over the next few months, other than that,,waiting out the winter till spring.
Author:  Dart270 [ Thu Jan 11, 2018 5:07 am ]
Post subject:  Re: My 68 Barracuda
Sounds great, John. I hope to join you soon with my MS3X doing fuel and ign.

Cheers!

Lou
Author:  DusterIdiot [ Thu Jan 11, 2018 5:54 am ]
Post subject:  Re: My 68 Barracuda
Quote:
It is just nuts being able to change ignition curves with a key stroke, it can take hours taking down a distributor and changing springs / weights.
Well it can still take time getting the right MS settings, but once there you are there, you are key strokes away from a distributor re curve.


When I started developing the ignition maps for my next motor, I always laughed that about 30 minutes of populating cells
and the curve is done, and you can tweak it on the fly if needed with a person in the passenger seat. Sure does beat
time it takes to pull and tear down a dizzy for a respring, even if you spool it up on a machine instead of being in the car...

:)
Author:  Dart270 [ Thu Jan 11, 2018 6:46 am ]
Post subject:  Re: My 68 Barracuda
This is even more convenient for fuel tuning, since you can tune all parts of the map rapidly.

Lou
Author:  slantzilla [ Sat Jan 20, 2018 11:40 am ]
Post subject:  Re: My 68 Barracuda
I'm planning on doing efi on Mike's car. At my age learning to tune with a laptop seems more pleasant than playing in gas. :shock:
Author:  DadTruck [ Mon Feb 05, 2018 4:49 pm ]
Post subject:  Re: My 68 Barracuda
another part of the plan is for the motor being built to run on E85

going to do the setup and change over on the existing slant motor in the 68 Barracuda

got these parts in the mail today:
GM flex fuel sensor, will interface with the MS3 Pro ECU
Walbro E85 compatible fuel pump, rated at 450 LPH, should be a direct fit into the existing fuel pump canister in the Tanks Inc fuel tank
E85 fuel tester

Attachments:
flex fuel.jpg
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Author:  DadTruck [ Wed Feb 07, 2018 6:31 pm ]
Post subject:  Re: My 68 Barracuda
pulled the fuel pump canister and got it changed over today,
and also installed the flex fuel sensor.

here are photos
https://www.flickr.com/photos/13718356@ ... 0240676452

the pump in the black rubber wrap was the existing gas pump, the pump in the silver housing is the E85 pump.

will be a while before I actually make the fuel change, I need a few 50 degree days so I can back the car out of the garage and have the engine running while putting in the initial setting,

maybe in March...
Author:  DadTruck [ Sun Apr 15, 2018 3:48 pm ]
Post subject:  Re: My 68 Barracuda
ran in to a few EMI / RF issues affecting the MegaSquirt ECU that is controlling fuel and ignition. The good news is, that is resolved, so back on getting the 68 Barracuda prepped.
On my list of items to resolve was a 'whirring' noise from the differential during deceleration. I have an 8.75 / 742 cone sure grip with 3.55 gears installed. Originally the car had an 7.25 rear end, I had picked up the 8.75 as a complete package, was told it was from a '69 Dart, that rotted away parked in a field in Norther MI. I went through the 742, changed out all the bearings, seals, disassembled the sure grip, the cones had not bottomed out, but I had them trimmed .010 to account for use, re used the original 3.55 ring and pinion. Put it back together and ran it.
That was about 3 years ago, and maybe 35 runs down a strip. I wanted to take it back down, verify that bearings / races were OK and resolve the deceleration noise.

https://www.youtube.com/watch?v=A1qj6LA39Sc

taking things apart is always fun.
it gets serious when wrenching components together.
Author:  DadTruck [ Sun Apr 15, 2018 5:27 pm ]
Post subject:  Re: My 68 Barracuda
pulled the ring gear to check pinion bearing loading,
it was turning at 2.5 inch / lbs with the seal installed, that is fine

Attachments:
2018 4 april diff 1.jpg
2018 4 april diff 1.jpg [ 160.43 KiB | Viewed 14298 times ]
Author:  DadTruck [ Sun Apr 15, 2018 5:31 pm ]
Post subject:  Re: My 68 Barracuda
, the existing ring gear bolts /threads looked fine, I cleaned the Loctite off with a wire brush,
re applied blue Loctite to the threads, put a light coat of ARP bolt lube on the under side of the bolt head and re installed

Attachments:
2018 4 april diff 2.jpg
2018 4 april diff 2.jpg [ 209.35 KiB | Viewed 14295 times ]
Author:  DadTruck [ Sun Apr 15, 2018 5:43 pm ]
Post subject:  Re: My 68 Barracuda
the 'chunk' is back together

concerning the whine on deceleration, I also checked ring and pinion backlash prior to dis assembly.

the spec for a new gear set is .006 to .008 backlash,, I found .017 ,,, double the backlash specification,

as the gear set I am using is used, I believe it is the original to the 742 case it certainly did not wear in to cause the excessive backlash, possibly I did not have enough pre load on the carrier bearings and the carrier just shifted a bit, or I just missed the set up during assembly.

To eliminate one root cause, I spent a lot of time making sure the side adjustors moved freely in the housing caps, cleaned up a few thread burrs ,,,The side adjustors run in easier now that they did before.

I was really careful this time, I set the back last at .010, that is on the high side of the tolerance but I believe that is fine with a used gear set.

the plan for tomorrow is to set the center section back into the rear housing, re install the axels / brakes..

Attachments:
2018 4 april diff 3.jpg
2018 4 april diff 3.jpg [ 214.54 KiB | Viewed 14294 times ]
Author:  Dart270 [ Mon Apr 16, 2018 3:57 am ]
Post subject:  Re: My 68 Barracuda
Looks good. See you at M-D, eh? Hope we can get a 50 pointer this May!

Lou
Author:  DadTruck [ Mon Apr 16, 2018 6:58 am ]
Post subject:  Re: My 68 Barracuda
I have no plan to be at the M-D spring race, however the fall race is a possibility.
Author:  DadTruck [ Sun Apr 22, 2018 5:57 am ]
Post subject:  Re: My 68 Barracuda
the rear end is back together,
got a call from Ed's Machine Shop,
the '87 crankcase is ready for pickup,
I'll be building a motor in May. :D

Attachments:
diff 4.jpg
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Author:  slantzilla [ Sun Apr 22, 2018 8:58 am ]
Post subject:  Re: My 68 Barracuda
Sweet! :D
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