Car not running what is should, need help.

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340gts

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:( Here is the low down on my car: 68 dart, 340 auto, 3800ger
converter, 410 gears, bfg drag radials, ss springs and comp.
engeneering drag shocks. Motor is 30 over with trw forged replacement
pistons, heads are not ported, 509/280 MP mechanical cam, cheapie
headers, edelbrock air gap and 750 Holley DP.I have the new MP electronic ignition kit in it with 20 degrees initial and 16 in the distributor and no vacum andvance. Last year with old dirt tires and tm5 single plain and old avs it ran 13.4@101mph, 60ft was in the 1.95 range. Got it to the track on Friday to get jetting right and ran 13.7@97mph 60ft was 1.90. I did get a little wheel spin off the line with the tires at 16lbs, ran out of time to try 14lbs. I tried shifting at 6000 and 6500, but no difference. I go thru the traps at 5500-5600. My only guess is that the conveter is junk and is getting worse, I have not heard anything good about them.Anyone have any ideas on what else to check before I buy a new turbo action converter?
 
As far as why your going slower i hav no clue but to get more power do some work to the heads thatl move that 340 down the strip :salut:
 
What size rear tire? At what RPM is the timing all in by? Was the air worse than the day you ran a better ET and MPH? Any and all variables have to be considered. Did you launch at a higher RPM?

20046201534987237728030.jpg
 
something ain't right? how do you have the carb set up? jets-power valve-squirter size? also check to make sure you have full throttle. The 60 ft is good enough to run in the 12's easy so something else isn't working.

Do you run with full exhaust and if so what is it?

What are you RPM's doing when you shift. How much do they drop.

If shifted my 340 full roller at 6800 rpm's and went through the trap at 6600 rpm. If the convertor's holding at 5500 rpm's on the big end it's probably OK. It might be a bit tight even.

Have you checked your plugs at the end of the run? you could be real lean and starving the fuel, or way to rich. Get me some more info and we'll get it figured out.

Brett
 
I ended up with 76 primary and 84 secondary jets. 6.5 power valve and 31 squirters. I tried a 35 squirter in front and it seemed to like it. Yes I checked to make sure throttle was opening all the way. I left on the exhaust this time it is 2 1/4 exhaust and flowmasters. The timing is all in by 2500 rpm. The tire size is 235/60-15, they are 27 inches tall. Not sure how much the rpms drop off after shifting, I think it is around 4000 or so.
 
That all looks OK, Jetting is something you'll have to play with. Start low and jet up till your mph drops off. Then advance timing till you loose ET.

How much compression do you have?

Also try uncorking the exhaust.
 
If it was me here is what I would do.......

1. Get a good set of headers
2. Open the exhaust up or go bigger. 2 1/4 is way to small to let that motor breath.
3. Dump the GER
4. Get a MSD 6AL

You say the heads arent ported, What has been done to them?

Here is what I have on my 68 360 Barracuda.

360 Stock bore
unported "J" heads w/2.02-1.65 valves
Edelbrock Performer RPM
750 Holly DP
292/509 MP cam
727 Trans (no mods)
3.91 gears
245/60x14 rear tires (Kelly Chargers)
205/70x14 Front tires (Kelly Chargers)
Open headers (Hooker)

My best on a sunny day cool air was 13.21et @ 101mph
I launch at 2500 rpm and shift at 5500 rpm.
This is a pieced together set up I did just so I could go racing, The bigger and faster stuff may come later.
 
I started off with 72 primary and 80 secondaryand worked my way up, plugs looked a little rich. I freshened the motor last summer, it has about 190-200lbs of cranking compression. I did notice yesterday while driving in town while in D, it felt like something was dragging the car down. I checked rear brakes but they are fine so is the front. I wonder if one of the bands is too loose and is hanging up in D, 1 and 2 it does'nt do it. I ran it last year without the exhaust, but it still only ran 13.4 @ 101.
The heads have new hardened seats and guides and the seats and valves were touched up. I think the headers are flowtechs.
 
Your header's are 1 5/8 which I went 11.29 with and had a full exhaust on the car. I did step up to TTI's. You don't need them to run 12 sec quarter's.

I agree with Billy on the ign, get that junk Mopar conversion stuff off. I had ton's of problem's with that stuff. The MSD isn't that expensive. Now that alone will not gain a second but it's a start.

The 2 1/4 exhaust isn't helping either, if you don't want the expense of new exhaust throw some dumps on or just uncork it.

Do you know any tranny guy's that can diagnose what your feeling? Maybe something in there is draining your power.???? I'm no tranny expert so I can't help there. Have you checked your timing to make sure your getting full advance?
 
I checked the advance with my timming light b/4 I made my first pass, it was at 36 degrees. Seems strange to me, it feels strong off idle no hesitation. On the street it will instantly break the tires loose until I let off to get it to hook. It also pulls thru 3rd gear, I can watch the tach and it is still pulling thru the traps. I am going to recheck the timing and make sure the balancer did not slip or somthing.
 
just keep on messin around with the timing and get your tranny checked if possidle! :scratch:
 
I got around to checking timing and advance today.
I checked it with the light and I had 20 degrees initial,
and when I reved the car up it went to 36 degrees. This
is where I stopped when I checked it at the track. Just
for the heck of it I kept on the throttle to about 4000rpm
and IT WENT BACK DOWN AND STAYED AT 30 DEGREES.
I think I may have found at least part of the problem.
I have the vacum advance unhooked and the allen screw
in the canister turned in all the way, but it can still move a
little inside the distributor. Anyone ever pull the canister
off and use somthing to keep the plate from moving? I am
not sure if that is it or the springs are too tight pulling the
advance in at high rpm. I might just try some light springs
I have and see what it does then. Any other ideas of what
may cause this?
 
I found an old engine pic. I zoomed in and circled the two tack welds. Do the tack furthest from the advance first, then pull the advance out. When you remove the vacuum bellows you can block the hole, and gain a tab for the cap, by using the cover from a lean burn distributor. I have light springs in the mechanical advance.

dist_welds.jpg


Walter
 
Thanks for the pic. I was in moparts and a member said the boxes have some degree of retared at high rpm, I am going to lock it out and see what it does then. Or possibly the advance is sticking a little. I think an MSD box would help.
 
I think I found the problem, the orange ecu is retarding the timing at higher rpm. I locked out the distributor and then set initial at 20degrees. I reved up the motor and at 2500rpm it retarded 4-6 degrees! Anyone think a chrome box would be better? Or could a weak alternator or battery cause more retard?
 
I have built a lot of mopar trannies... Which on you running? 727/904? For small blocks i like the 904's better. 2-3 tenths quicker too. Like the other guy said ditch the GER. Seen way too many of them ruin some transmissions. If it seems like it holding back or dragging in high gear. Be careful... Could be that the sprag is hurt. If it comes aparts it can come thru the floor and cause you serious damage. Want a great combo for a mild engine??? Get a load of this combo... Me and a friend built a little 4 dr. 72 Valiant Bracket car/mustang eater. It's a 360 with KB 10.5-1 flat top pistons, small 468 solid lift comp cam, LD340 intake with a 650 double pumper, Stock j-heads, my 904 with low panetarys, Manual Valvebody, And a SPECIAL torque converter that a shop here in town built for me. IT'S UNREAL!!! The car weigh's 3200lbs. with me in it. 8 3/4 with 3.23 gears, Thru 2.5 inch mufflers.. What would you think it would run? We only have 1/8 mile tracks around here. But so far best time is 7.58 with a 1.58 60 ft. @ 87ph. And thats going thru the 1/8 mile still in 2nd gear. We have been accused of it being a 408 stroker motor. We just laugh at them.... :mrgreen: The Converter does a lot of it.. It's unreal!!! I can hook you up with the # to the this converter shop if you interested? [email protected]
 
340gts said:
I think I found the problem, the orange ecu is retarding the timing at higher rpm. I locked out the distributor and then set initial at 20degrees. I reved up the motor and at 2500rpm it retarded 4-6 degrees! Anyone think a chrome box would be better? Or could a weak alternator or battery cause more retard?
Click to expand...

do yourself a favor and get that mopar ignition crap off your car. I had nothing but trouble with that junk. Get an MSD or Crane box.
 
Get rid of the GER and put an MSD on it. Spend the money for Turbo Action converter. I went from a Hughes 4400 to a T/A 4600 and picked up 7 tenths. That's not a mistake, 7 tenths.
 
I had an old stock ecu laying around and I put it on just to try it,
no more timming retard! I am going to try an FBO box and coil, for $109.00 I can still switch to MSD later. I am going to change out the converter next with a TA converter. Now I need to try it out at the track to see what happens.
 
Iam curious to hear your track results as I use an older MP orange box (before they were made in Mexico) and I also use a stock vacum advance dist that I do not use the vacum advance and I recurved the dist for full advance by 1800 rpm's in my sons 383 Dart. And it has worked fine since 1998. Its run 12.30's @ 110 with a basically stock 383 and bolt on's as I did not think it would run that good so I am very pleased with the low buck ign I have on it. I have thought of trying the MSD but really dont think it will help much if any on it. So I will be interested in your track results. Oh and good luck. :thumrigh: Ron
 
That MP suff is China made crap! Send your distributor to Don for a correct curve. That and his kit will make a huge differance. Cheapest time you could buy!
 
I ordered the kit last week and I was told he got the boxes in yesterday and is shipping orders out. I have the new MP distributor made by Mallory and a Mallory YH advance kit to set the amount of mechanical advance in the distributor and an assortment of springs. The kit has directions as to when the mechanical advance starts and at what rpm it is all in at with different spring combonations. It works really well. I have it set up with 16 degrees in the distributor and 20 initial. Advance starts at 1100 rpm and is all in by 2400rpm.
 
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