MOPAROFFICIAL
Well-Known Member
Spinning tires and boiling the tires are two different engines.
On paper it should be scary fast. On the road, not so much
- Thread starter Uglypedro
- Start date
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missing linc
Loose nut behind the wheel
Sounds a lot like my 1970 Dart, similar engine specs, same gears, and almost the same 1/4 mile times.
AbodyBB
Well-Known Member
Do you use stock points or Mopar spark box? If it’s the box, try replacing the box. I had an identical issue on a 318 where a decent build couldn’t get out of its own way.
I tried everything else related to tune. Then it quit and I found no spark. Tried connections etc and it started. Drove it home and on a whim put a new box in it. After that it ran great.
I never could get anyone to say they have had the same kind of failure since most of them just completely quit. But this box worked a while so I never suspected it.
I tried everything else related to tune. Then it quit and I found no spark. Tried connections etc and it started. Drove it home and on a whim put a new box in it. After that it ran great.
I never could get anyone to say they have had the same kind of failure since most of them just completely quit. But this box worked a while so I never suspected it.
M_Body_Coupe
Well-Known Member
Pedro may be MIA, regardless, as others may learn something from all the wisdom that's being bestowed upon the followers here (yours truly included)
HOWEVER
I must ask this question: with a 236@0.050" duration on 110LSA, are you guys seriously expecting this thing to be even able to get out of it's own way with 3.23 gearing???
To all the folks talking about tire frying beasts, etc, etc...what cam duration (therefore valve events) on what LSA with what stall speed on what gearing I ask!!!??? (oh, sure, and don't forget tire sizing, etc. etc..LOL)
My previous non-W2 experience was: 238/244 on 108 LSA, with 3.55 gearing and 2800 stall this thing did NOT impress anyone!!! Sure, once past about 3500 it raged, but anything below that it was just flat out LAZY!
Moving to 3.91 gearing woke it up...nice...now "we're cooking with gas", but moving to a 4000 stall converter right after made for a day & night difference!
So there is a very good reason why cams come with suggested power bands and the expectation of matching components, all of them, in the car.
HOWEVER
I must ask this question: with a 236@0.050" duration on 110LSA, are you guys seriously expecting this thing to be even able to get out of it's own way with 3.23 gearing???
To all the folks talking about tire frying beasts, etc, etc...what cam duration (therefore valve events) on what LSA with what stall speed on what gearing I ask!!!??? (oh, sure, and don't forget tire sizing, etc. etc..LOL)
My previous non-W2 experience was: 238/244 on 108 LSA, with 3.55 gearing and 2800 stall this thing did NOT impress anyone!!! Sure, once past about 3500 it raged, but anything below that it was just flat out LAZY!
Moving to 3.91 gearing woke it up...nice...now "we're cooking with gas", but moving to a 4000 stall converter right after made for a day & night difference!
So there is a very good reason why cams come with suggested power bands and the expectation of matching components, all of them, in the car.
mopowers
Well-Known Member
Alright, I'll play. The 408 my dad and I bolted together for my Duster when I was 16-ish was a total mishmosh of parts because I was a poor highschool kid.
This 408 had stock 360 heads that I port matched with a rat-tail file and even an old 1850 600VS carb on top of the air gap intake. The cam was the "Edelbrock RPM plus" hydraulic flat tappet - I think around 234/244 on a 112 if I recall. My Duster just had one-legger 3.23's out back with a stock converter.
I'm sure it probably wasn't even tuned very well because I didn't know any better, but even leaving easy off the line (remember it had open 3.23s), it would run 12.70's with the 2.2 sec 60 footers.
What I learned was these mild 408's don't need much gear. There's no reason why the OP's 408 shouldn't blast the tires loose and pin him in the seat as soon as he tickles the long pedal.
Uglypedro
Member
Still havent heard from guy I bought it from, but after talking to a tech at Blueprint, he said I need to check the stall speed on the Torque Convert. To him, it sounds like it's a low stall speed. He said, anything below 2300 would make it difficult to roast the tires. If I installed a TC with 2300 - 2600 stall speed, I should have no problem with low end torque.
So, what would I loose by increasing the stall speed? And what are the drawbacks as you increase SS?
So, what would I loose by increasing the stall speed? And what are the drawbacks as you increase SS?
abodyjoe
Well-Known Member
if you buy a nice quality one you won't really lose anything. you also need to make sure its spec'd to your combination (full combination) and intended use or you run the chance of not being happy with it.
The first thing to do is MEASURE the stall speed. A good 2500 stall converter is going to be 5- 600 bucks. More stall than that the pice doubles.
Have You performed the brake-stall test as recommended earlier in this thread? A TCI Street Fyter should be stalling WAY over 2,300rpm,...
a 440 with a slightly bigger cam will stall a TCI Breakaway 11" 2,800-3,000rpm. I question what this 'tune' consisted of, and the specs therof,..... base/total timing, float levels correct/high enough...??
Also, did You upgrade from TA type tires to ET-Streets/Quicktime Pros etc.,...?
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abodyjoe
Well-Known Member
my question that was never answered also. seemed to be great for the previous owner. now all the sudden its a pig. something just doesn't add up.
mopowers
Well-Known Member
Exactly. And a 2300-2600 converter isn't going to solve whatever's wrong. That's barely over stock. Even with a stock converter, that thing should smoke the tires at will if it's tuned correctly.
Unless it's a really wrong converter. I'm not sure how that could happen with a small block mopar with a 904 but maybe.
I don't remember, but don't we have to know more about the tuning that was done? And answers to whatever other questions we asked Uglypedro? (In addition to getting a converter.)
@Uglypedro, what I'm saying is, while getting a converter could be a big issue, there could be other things holding it back. You're going to have to go through this thread and see if you answered everything for us. Meaning, post every question, and let's see what's what.
@Uglypedro, what I'm saying is, while getting a converter could be a big issue, there could be other things holding it back. You're going to have to go through this thread and see if you answered everything for us. Meaning, post every question, and let's see what's what.
abodyjoe
Well-Known Member
post #58 on april 16th i asked if it was the same, better or worse after you had it tuned. crickets
people have asked repeatedly what did the tune consist of? crickets
you were asked if it always ran like butt, or is this a new development? annnddd crickets
how can we help you if you refuse to give us any information?
this could be an incredibly easy fix-- distributor locked up and not advancing, carb out of whack-- or something more involved: cylinder down, cam going away.
but again, without any diagnostic work it's all shots in the dark.
at the very least you have to put in *some* work. do the brake stall test and eliminate that possibility, if it exists.
people have asked repeatedly what did the tune consist of? crickets
you were asked if it always ran like butt, or is this a new development? annnddd crickets
how can we help you if you refuse to give us any information?
this could be an incredibly easy fix-- distributor locked up and not advancing, carb out of whack-- or something more involved: cylinder down, cam going away.
but again, without any diagnostic work it's all shots in the dark.
at the very least you have to put in *some* work. do the brake stall test and eliminate that possibility, if it exists.
Uglypedro
Member
Sorry, alot of these questions are flying right over my head. I'm not a mechanic, but a always do what I know how to do, and often attempt what I shouldnt. I always want to learn more about what makes my car tick, but tracking down the correct info isnt always easy. But that's why I'm here.
Nothing, but 2300-2600 is a drop in the bucket for stall speed. I'd go straight to 3600 at a minimum for performance. This ain't 1978 anymore. Converter technology has advanced LIGHT YEARS. You can have a converter that will flash 3600 but ride around town like a stock converter. No way in hell would I go with anything less. Suit yourself.
First you've mentioned it. Again, if you tell us nothing, that's what you get.
It's possible it's not...but it's also possible the converter has failed. That's the whole crux of it. Internet diagnosis is impossible. If we get it right, it'll be a sheer guess.
Look, you have to put some skin in this game. You need to get a timing light and LEARN how to use it and learn how to do some simple tuning. You cannot expect to buy a hot rod and just PLUG AND PLAY your way through life. That ain't how this works. You are going to HAVE to learn a little something here and put some actual WORK in if you want our help. We need to know what the timing curve is. That means learning how to read a timing light. We need initial (idle) timing. We need timing every thousand RPM until the timing stops advancing. This will be a timing curve. You're going to have to learn to do this, OR grab a buddy that knows how and post up the numbers so we can help. We cannot do it all. We can't hand it to you on a silver platter. I wish we could.
According to one of his posts the original owner put a TCI Streetfighter convertor in it. Summit shows that it stalls 3-3600 and costs $850. I would definitely foot brake it and see where it stalls but wouldn't be the main focus of my investigation.
I'm curious about the use of a bolt on timing tab on a Magnum engine. Did the mechanic that "tuned" the engine know about this? Sure would like to know what he did and if it made any difference. If it didn't run better, I'd go right back there and ask why?
I'm curious about the use of a bolt on timing tab on a Magnum engine. Did the mechanic that "tuned" the engine know about this? Sure would like to know what he did and if it made any difference. If it didn't run better, I'd go right back there and ask why?
I just read the original owner's post. Said he put a TCI transmission in rated for 400HP. The engine is close to 500. This is pointing more and more to the transmission, IMO. TCI hasn't a good reputation at all. Even still, I think he should rule out everything else FIRST.
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