71 Dart / 5.9 Magnum / Procharger

-
I had to leave before he ran. There were lots of A-Bodies. Freiburger made a joke that it was the most darts he had seen! Good luck guys!

6042BFB5-2773-48DF-A525-A5A3A0B3048D.jpeg


E5A78A4A-16DC-4A45-A4E2-A65CD2A708A3.jpeg
 
It was good to meet you Dusted. Thanks for posting a few pics. Best pass all week was 10.43 @ 119. I chased ignition troubles all week that ended up being the MSD Box. Once I got that replace I lost 2nd gear. Last day, it went 10.45 @ 129 shifting directly from 1st to 3rd. Transmission troubles ended up being band adjustment. Now I have all three gears and haven't been back to the track. I hope to get this thing in the 10.15 range before the end of the season. Drag week is like murphy law. Still had a blast and averaged 10.68 for the week. Not too bad.

Drag Week 5.jpg


Drag Week 9.jpg


Drag Week 12.jpg
 
I give you huge thumbs up for completing the entire event with minimal setbacks. Well engineered. I watched the live stream everyday to see who was still in. I had a blast the first day and I was just spectating!
 
Okay guys, finally getting the tune dialed in on the Dart. Went down to a MoparVSBrandXshowdown in Alabama. Went 6.42 @ 106 MPH in the 1/8th mile. Wish it would have been a 1/4 mile track because that would have been a VERY low 10 second run. Best of all I beat a big block, big tire, gutted, wheelie bar having straight up drag car. Awesome and cool car by the way just wasn't as quick as I thought it would be. Starting to love the boost. It's sooo driveable.

Dart 41.jpg


Dart 42.png


Dart 43.png
 
Okay guys, the last pass I made down in Alabama the car slowed down a bit. I had hot lapped it so I didn't think much of it. The Next day when I was unloading the car off the trailer it was missing. I pulled the plugs and the #5 cylinder's spark plug looked like the picture below. Ground strap had been punched into the electrode. I borrowed my friend's bore scope and there was evidence that something had been in the cylinder but was no longer there. We checked the compression and it was good, same as the other cylinders. Can't figure out what could have gotten in there. Carb looks normal, hat, ect. I checked every tooth on the procharger…. everything looks good. I checked the vale lash and all was normal.

So, I thought it must have somehow sucked something in that cylinder but then spit it out the exhaust valve. I swapped to colder spark plugs and have been driving on the street a few days with no problems. However I have been driving like miss daisy not getting on it. Since racing season is over around here I decided to get on it yesterday to see if I still have problems. Sure enough, heard a pop on the 1-2 shift and shut it down. It was missing. Limp back to house and once again my #5 plug had the ground strap mashed into the electrode.

Any ideas? If it were the piston hitting the plug would the scars on the piston be in the same place? Could something still be in that cylinder I just haven't seen it with the bore scope? You would think if something were in the cylinder it would be loud at idle. This thing sounds completely normal at idle and low RPM. I'm baffled. I'm going to bore scope it again but If I can't find anything I guess I'll pull the engine back out and inspect everything.
 

Attachments

  • Dart 44.pdf
    93.8 KB · Views: 337
  • Dart 45.pdf
    92.6 KB · Views: 334
Pulled the engine. When I got the heads off 7 out of 8 pistons were hurt. Turns out 27 degrees of timing and pump gas was causing detonation during drag week. Once I realized I started adding race gas and backing off the timing but it must have been too late. I think the engine was finally happy at around 22 degrees of timing with a 50/50 mixture of 110 and 93 pump gas but by then the damage was done.

Luckily it appears the pistons were all that was hurt. The rings were gapped at .022 top and .024 bottom. I'm thinking this was too tight and the rings butted together exploding the tops of the pistons. Everything else looks good so I've ordered new pistons and will gap the rings bigger. Any suggestions on the gap? This is 10 lbs of boost.
 
Here’s a guide you can use, there maybe other charts that you can use. Just google ring gap for boost

10DEBC8F-6D1B-409D-BA62-6937FFE42BED.png
 
Hey guys, it's been a while since I've updated on here. The car was down most of the winter due to me being very busy and waiting on the machine shop. Anyway, we are now freshened up with new pistons rings and bearings.

I did take almost 150lbs of weight out of the car over the winter. Everything is tuned up and I'll be hitting an 1/8 mile track tonight for a few passes. I'm going to be EXTREMELY careful with the tune. I've got it set at 20 degrees of timing right now and my distributor is locked out. I'm running 50% 93 octane and 50% 110 Race Gas. I'm going to keep an eye on the spark plugs after each pass. Just don't want to screw this one up like I did last time. I'll let you know how it goes.
 
Here is a current picture. Finally converted to disk brakes up front this winter which was part of my weight savings. The HUB on the wildwood Brakes was too big for my front steel wheels so I switched to these American racing rims (More weight savings). I don't mind the new look but someday I'll probably want my steel wheel look again. We'll see.

Dart 1.jpg
 
130 in the 1/4 mile with drum brakes....
They work well when adjusted properly!
I like the “new look”
 
TT5.9mag said:
What did you gap the new rings to?
Click to expand...
I think we went .024 and .026 but I'll have to look to be sure. Last go round was .022 and .024. Although when we took it apart it looked like pure detonation... it didn't look like the rings had butted together to explode that part of the piston.
 
Last night went good. New Brakes felt good and held the car good on the line lock during the burnout. Only made one pass and it went 6.60 @ 105 on a very conservative tune. After that pass I realized I haven't run the valve lash since break in so I need to do that before I make another pass. I think it will go 6.30s as I start to ease in another degree or two of timing later. That should be good for a 9.90s 1/4 mile pass before Drag Week I hope...… that is if we still have drag week.

Dart 2.jpg


Dart 3.png
 
Looks like it’s progressing well and making damn nice power.
Walker434 said:
I think we went .024 and .026 but I'll have to look to be sure. Last go round was .022 and .024. Although when we took it apart it looked like pure detonation... it didn't look like the rings had butted together to explode that part of the piston.
Click to expand...
Do you have any pics of the old pistons and plugs? I’d love to see them. For my own curiosity.
 
On your 6.60 pass, how much boost was it set for?
 
You must log in or register to reply here.
-

Back
Top