need help with 69 dart
12-04-2008, 04:31 AM
#1
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need help with 69 dart
i have a 69 dodge dart with a 383 block stroked and bored to a 496 and recently it started acting very strange it has a horrible ping and knock from the engine and the idle speed shoots up and it wont go away i have gotten it to go away for short periods of time after pushing it into high rpms for a period of time but the engine noise and raised idle always ends up coming back after about 12 hours while its making that noise there is also an extreme loss of power this all happened after recently changing my alternater does anyone have any idea what could cause this i was told by one shop i needed to run higher octane because of my 25-1 compression but im running 110 octane and the problem still persists i need help!!!
~~ I replaced the altenator because my starter positive post grounded to my block and blew the diodes on the altenater i also noticed to day while i was under the hood there was a small amount of smoke coming from the breather on the valve cover while idleing i need to get my car running soon and every time i take it to a shop and they fix something that causes something else to happen
~~ I replaced the altenator because my starter positive post grounded to my block and blew the diodes on the altenater i also noticed to day while i was under the hood there was a small amount of smoke coming from the breather on the valve cover while idleing i need to get my car running soon and every time i take it to a shop and they fix something that causes something else to happen
12-04-2008, 04:55 AM
#2
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What kind of oil are you running in it? If it does not have zinc you could be destroying the cam and in turn causing these problems.
Does the knock go away at high speeds, or can you not hear it anymore?
Does the knock go away at high speeds, or can you not hear it anymore?
12-04-2008, 11:59 AM
#3
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If that engine is actually a 25 to 1 compression, you've probably blown head gaskets, unless it's been O-ringed. 25 to 1 is an EXTREME compression, more than even diesel, and if you haven't blown the gaskets, then you're most likely getting pre-ignition WAY before TDC, just from the compression of the fuel in the cylinder, before the spark plug fires. A moderate compression ratio is about 9 or 10 to 1, racers will use 12 to MAYBE as high as 15 to 1, so you can see how high that ratio is?
12-05-2008, 02:50 AM
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ya the knock goes away at high speeds and doesnt come back even if shut off and turned back on till later the same day and im not positive on the compression i was just told its off the charts when i was having my tranny worked on the tech told me it was 25-1 but im starting to thing hes retarded especially because they put in a shift kit and it doesnt work with my hurst shifter but im starting to thing the only way to make this car reliable is to drop a new 383 crate engine in so i dont have to worry about more complications from the giant pistons in the 383 block
12-05-2008, 10:32 AM
#5
Mopar Lover
Just to give you a rough idea of what the compression actually is, get a compression guage, take a reading of any cylinder compression, then divide it by 15 (Mean atmospheric pressure) if it's 10-1, it'll be about 150 (assuming 100% efficiency). More realistic, figure 125-130 to be a 10-1 compression. If you turn the engine over and your compression guage blows up.... you probably DO have a 25-1 compression. I think most guages only go to about 300 lbs.
Just a chance, but take the cap off your distributor, and look at the mechanical advance system. Check for missing or broken springs, sticking weights, Sticking plates, anything that might cause it to advance timing and stick. If you don't want to go to all the trouble of taking the distributor down, just spray some WD-40 down inside it, generously, and see if that might help by any chance.
You might also make sure your distributor is tightened down , and your timing is correct, and make sure you don't have any kinks in your fuel line.
I don't think your problem is from extreme compression, I tend to think it's either timing or carb problems.
Just a chance, but take the cap off your distributor, and look at the mechanical advance system. Check for missing or broken springs, sticking weights, Sticking plates, anything that might cause it to advance timing and stick. If you don't want to go to all the trouble of taking the distributor down, just spray some WD-40 down inside it, generously, and see if that might help by any chance.
You might also make sure your distributor is tightened down , and your timing is correct, and make sure you don't have any kinks in your fuel line.
I don't think your problem is from extreme compression, I tend to think it's either timing or carb problems.
12-06-2008, 02:54 AM
#7
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Smack, that's probably a better thing to check than what I told him. It's simpler, and way more likely to be the problem. Dunno why I didn't think of that.
Look for hoses coming loose, cracks in hoses, bad gaskets, things like that. You start your engine, then spray something like carb cleaner or again with the WD 40, anywhere there is a vacuum source while your engine is running. If there's a leak, it will pick up the fluid, and your idle speed will change.
Look for hoses coming loose, cracks in hoses, bad gaskets, things like that. You start your engine, then spray something like carb cleaner or again with the WD 40, anywhere there is a vacuum source while your engine is running. If there's a leak, it will pick up the fluid, and your idle speed will change.
12-06-2008, 09:18 PM
#8
Mopar Lover
hey wyattmerk i think you are right about your tech being sort of out of touch with reality 
, you might want to check your pcv valve and i would check your timing mark to your rotor position and make sure when you have it at tdc your rotor is on the # one wire on your cap and also check to see how much play is in your t chain by moving the crank back and fourth and see how much it takes to move your rotor...
, you might want to check your pcv valve and i would check your timing mark to your rotor position and make sure when you have it at tdc your rotor is on the # one wire on your cap and also check to see how much play is in your t chain by moving the crank back and fourth and see how much it takes to move your rotor...
12-07-2008, 12:02 AM
#9
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P.S ..... might sound stupid but i would check to make sure that there is the right spark plugs in it and gaped right as when you have wrong plugs in it they tend to not fire right when they get hot and at pushing speeds
01-06-2009, 04:00 PM
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very doubtful on the 25.1, if that's what your builder told you, you might want to get a second opinion on your problem. Or if you know your bore/ stroke head cc etc etc you can calculate comp ratio.
01-06-2009, 04:02 PM
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very doubtful on the 25.1, if that's what your builder told you, you might want to get a second opinion on your problem. Or if you know your bore/ stroke head cc etc etc you can calculate comp ratio. Or do a leakdown test on the motor.
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