340 not pulling the way it should

Author Topic: 340 not pulling the way it should  (Read 6947 times)

Offline Moparal

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Re: 340 not pulling the way it should
« Reply #30 on: May 13, 2008 - 11:20:08 AM »
it's a 3000 stall with 4:11's and 26.5'' tires.
even if my stall was bad, wouldn't i still see a change when adding over 10* of timing.

Does the stall flash to 3000 and lock up on a launch?  Your distributor if it is working right, will go full advance at 3000 and stay there all the way down the track.  Adding 10 degrees isnt going to really a make any type of change other then more bottom end if it doesnt detonate from lack of octane. Never really seen anyone run much over 38 total full advance.  I'm betting your converter is too tight. Or your cam is just plain wrong in your combo.  If you could chassis dyno the engine, that would tell you hp and tq. And whether you have a lack of power in the cam, or a wrong converter.  What's your car weigh and what mph?  This will help show your hp your useing in your engine. Is your car a 3600 lb ebody?

Here's an example. 3600 lbs at 380 hp should go around 12.30's at 108 mph

280 hp would be around a 13.65 at around 98 mph   doesnt matter if it is mopar chevy ford or what ever. This is hp at the ground.




Offline Moparal

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Re: 340 not pulling the way it should
« Reply #31 on: May 13, 2008 - 11:22:06 AM »
There are many places to check et times on the site for a reference.  Here's this one to lend a hand. Morroso sells a slide graph bar for pwr to weight ratios also
http://www.wallaceracing.com/et-hp-mph.php

Offline moper

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Re: 340 not pulling the way it should
« Reply #32 on: May 13, 2008 - 12:18:15 PM »
The engine has issues. 3K stall and a 26"tire with 4.11s that thing should be much quicker off the line, but die up top. What rpm do you hit the traps at? How sure are you you have full throttle? Have a friend floor the pedal while you look at the carb butterflies (need I say NOT RUNNING). If it doesnt go wide open then fix it. If it goes wide open, goto a dyno and do some testing. It will be cheaper to buy and use dyno time than to simply buy parts.

Offline 73Chally

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Re: 340 not pulling the way it should
« Reply #33 on: May 13, 2008 - 12:26:18 PM »
 :iagree: A chassis dyno might be your best bet if you have access to one.

nivvy

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Re: 340 not pulling the way it should
« Reply #34 on: May 13, 2008 - 03:52:19 PM »
I dont like locking out the distributor just because of kickback issues....  :2cents:

when i bought my car of ebay several years ago the guy used old pictures and completely lied about the motor and car.... rather than deal with all the crap cause he said he posted the car for his buddy crap I stuck it out....  :working:

Im leaning towards your car is what it is.......and maybe thats all the motor has if its pulling good... a chassis dyno would be very helpful to you.....

Offline jeryst

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Re: 340 not pulling the way it should
« Reply #35 on: May 13, 2008 - 04:10:44 PM »
He still should have seen a difference when he fixed the springs unless the advance isnt working at all, right?

Offline leanburn

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Re: 340 not pulling the way it should
« Reply #36 on: May 13, 2008 - 05:34:06 PM »
that's what i'm getting at. if the car is maxed out at 13.8 i'm fine with that but as ive been saying when we first timed it i could only get 24*, once we got the weights working it would get 38* as it should and i never saw any gain or loss, cough, sputter, ect. i'm going to try a different light tonight and i will check for a dyno but i believe the closest dyno to me is a 5 hour drive [edmonton].
 question: if my cam was wiped would i see other signs such as a miss or bog ?

Offline leanburn

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Re: 340 not pulling the way it should
« Reply #37 on: May 13, 2008 - 09:14:29 PM »
o.k so i ran some lights on it and this is what i came up with, by the way my expirience with lights is limited so i can talk the talk but not necessarily walk the walk.
 i timed by ear at 3000 rpm and this is definately where the car wants to run, i timed with dial back light and came up with 25* initial and 45* total  :clueless:. so i put the cheapo light on it and i don't know inital cause indicator only goes to 10* and the timing mark was clean out of sight and when i buzzed her up to 3000 rpm the second timing was at the 10* advanced  :screwy:.
 i went for a rip and it pulls the same and the only time i get any pinging is the odd time down around 1500 when i floor it and it imediately goes away.
am i reading these lights wrong somehow or do i have a problem?
by the way i measured the distances between the timing marks and i came up with 2.5''.

Offline leanburn

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Re: 340 not pulling the way it should
« Reply #38 on: May 13, 2008 - 10:04:47 PM »
o'k i'm coming to the conclusion that i am reading those lights properly and i have a cam issue. i checked that the timing mark lined up with the 0 mark at #1 piston's tdc and it's dead on. thanks for your help guys.
 

Offline moper

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Re: 340 not pulling the way it should
« Reply #39 on: May 14, 2008 - 12:08:40 PM »
I have no idea what you just said about the timing. From the sound of it, the timing is way to advanced. Not because of the cam. The distributor. Tuning by ear is for backyard hacks. Regardless of what you ear says, it doesnt like the setting you have, because it's a performing like a pig. Timing by ear would only work if you were at full throttle with aload on the engine. Otehrwise, it just sets the engine up to free rev nicely. Not make power. The high stall blows thru where the advances would be helping you, so that car should be jumping off the line. That and the effective gear (comparing to a 28" tire car) is closer to 4.56s than 4.11s. If everything was right, I'd be expecting you to be 60' in the 1.95 range with ETs in the ultra low 13s or high 12s. You need two things. A decent timing light with dial in advance. Then you need to spend the time to tune the ignition curve. My starters for your setup would be 15-18° initial, with total in the 34-36° range, all in by 2500. Then, tune the carb. Then go to the track again. As a "for instance", my '74 3.23 4sp, with a re-ringed '69 340 longblock, stock Tquad intake and carb, Jacobs ignition, and 1 5/8 crushed headers with turbo mufflers and a Comp 268H cam (back in late 80s) would run 13.0 on stock radials. 12.40s on spray. You should be faster, and anything that indicates something out of whack takes away from your performance. Get it all perfect. Then if it doesnt run, its the engine.

Offline 422STROKER

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Re: 340 not pulling the way it should
« Reply #40 on: May 14, 2008 - 01:58:10 PM »
I don't know if this has been mentioned, but make sure you disconnect the Vacuum adv and plug it when setting the timing. :2cents:

Tom
Tom
12.77 @ 108.87 15" Street Drag radial tires 3.23 gear

Offline ntstlgl1970

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Re: 340 not pulling the way it should
« Reply #41 on: May 14, 2008 - 02:06:41 PM »
Please post your MPH and trap RPM through the lights, it would help figure out what to check. If everything else is set right, then I'm with Moper, might be cam timing or another thought is it's not really a 10:1 static compression engine. Low compression engines like more timing
70 Cuda, 7.0L Gen-III Hemi, Viper T56 w/9310 gearset, 3.91's, Megasquirt MS3x v3.57, Innovate wideband, Firm Feel upper arms, torsion bars, springs and strut rods, QA1 DA shocks. I did everything on this car except the fancy paint stuff and I drive it...and I can't seem to stop messing with it....

Offline leanburn

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Re: 340 not pulling the way it should
« Reply #42 on: May 14, 2008 - 02:26:21 PM »
i have no vacuum advance.

my trap speed is 100mph @ 5700 ish
60 ft time is terrible, 2.13 to 2.16 and thats buzzing the stall up in the 2900 to 3000 range.

i have all the cam specs, assuming they are the correct specs for the cam i have can i pull off a valve cover, bolt on a degree wheel to the balancer and use a dial indicator on my valve spring ? or do i need to pull off my timing cover to check cam timing?

nivvy

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Re: 340 not pulling the way it should
« Reply #43 on: May 14, 2008 - 04:06:17 PM »
what did this guy tell you the car would do in the 1/4..... ???

also what tires r u running???

Offline leanburn

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Re: 340 not pulling the way it should
« Reply #44 on: May 14, 2008 - 05:39:47 PM »
the guy that i bought it from claimed high 12's wich i guess would be possible at sea level- maybe but doubtful. and i'm running 26.5'' tires.