strange noise.
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From: ca
strange noise.
ok this is a strange question, ive just rebuilt part of my motor, cam, lifter, oil pan, oil pump, water pump etc. When I tried to crank it for the first time it just spit gas out the carb, obviously off time so I moved the distributer a bit and when i cranked it, it made a really strange sound, kind of like what a giant air bubble in a giant vat of molasses would make. I checked to see if my oil pan had like rupture even. when I turn the dist back the other way it ceases to make the sound while i'm cranking it. Im afraid just to let it make the sound and start it up.
Could anyone tell me what the problem might be? could it be something like sparks plug not screwed in tight or the distributor being 180 out? also it has just headers as exhaust which Ive never heard it start up with yet.
Could anyone tell me what the problem might be? could it be something like sparks plug not screwed in tight or the distributor being 180 out? also it has just headers as exhaust which Ive never heard it start up with yet.
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sounds like you could have had an air bubble in your cooling system very common. take off your highest heater hose at the motor and let the air bleed out if there is any left. in the future when filling collant after something like that kind of job I would leave that hose off and fill slowly till you hear that gurgling sound and then watch as the level comes up in the heater hose neck then put hose back on after you've bled it an finish filling
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From: ca
hmm that could be, but would that create a loud sound? this sound only occurs while cranking, and only when the timing is changed. which doesnt seem consistant with a cooling issue, or am I way off on this assumption? It certainly wouldnt be the first time today!
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well the more you crank it over the more air you work out so the timing issue may be a coincidence. bleed the system really good like I said earlier and let me know if it still does it. that gurgle sound is deep in sound and pretty loud. when you do a major repair and empty the block it will do that if not bled but i would bleed it real well and let some antifreeze come out of that tubue now cause there may be some on top of the air bubble but fill slowly and you can see the level rising in the tube the hose goes on if its not a smooth rise there is most likely more air in the motor. and you dont need to use air or anything gravity will do all the work. thats the only thing i could think of causing the sound you referred to and yes it is startling if you never heard it before because it cause from deep in the motor. or so it sounds
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the sound comes from deep in the motor or so it sounds is what I meant. sorry my typoes are kinda bad its late, and I have been on, around, and under my 78 all day replacing valve train so I just heard the sound a bit ago myself on my truck when I filled it with coolant and bled the system. if the air is not purged it can cause overheating issues which makes since, cause you have air in your block instead of coolant. oh and it is as easy as it sounds too. If thats not the cause of the sound let me know and I'll write it down cause thats the only possibillity I know of for what you described. so dont fret its a quick easy fix and good luck
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ok let me know how it turns out. I just did cam break in and I will be putting my inner valve springs back in today, one of the burdens of dual valve springs and large cams
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From: ca
I tried that water thing, it wasn't the problem. I also tried cranking it with the ignition coil un done. and when it has no spark it doesn't make the noise.
Could it be that i am in fact 180 out with the distributor and the engine is firing and the gases are escaping past the rings into the oil pan? because you can hear gasses escaping into the oil pan.
Could it be that i am in fact 180 out with the distributor and the engine is firing and the gases are escaping past the rings into the oil pan? because you can hear gasses escaping into the oil pan.
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yes blow by is possible but shouldnt make gurgle. Did it still make gurgle sound with ignition hooked up? usually you only hear a couple gurgles and its purged. so maybe it purged itself when you turned it over. which is lucky but not impossible. if you have the sound when ignition is hooked up and not when its unhooked other than a coincidence there is no other reason for the sound. oh just thought of something else. Did you fill your oil filter with oil before installing it and turn your oil pump shaft to get the oil up into your motor? that could gurgle but wouldnt be as loud. no special tool needed for this with distributor out I use a 1\4 inch socket or 5\16 "cant remember that was yesterday" and a long extension and turn it counter clockwise with a ratchet
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From: ca
now that i've heard it a few times it sounds like a explosion then an escape of gasses.
is there any easy way to tell if i'm on the compression stroke? I have the no.1 cylinder top dead and the distributor is ready to fire no.1 piston but I cant tell if its trying to fire on top dead compression or exhaust.
i'd just stick my thumb over teh plug hole but I cant tell because i am only able to turn the engine over really slowly while having one thumb on the hole and one trying to turn the motor over with a socket wrench
is there any easy way to tell if i'm on the compression stroke? I have the no.1 cylinder top dead and the distributor is ready to fire no.1 piston but I cant tell if its trying to fire on top dead compression or exhaust.
i'd just stick my thumb over teh plug hole but I cant tell because i am only able to turn the engine over really slowly while having one thumb on the hole and one trying to turn the motor over with a socket wrench
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From: ca
You know what I think i'm over reacting, now that ive cranked it a few times it sounds more like a extremely loud back fire.
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Ive never ran this thing with all the go fast mods on it, What does a 408 cubic inch motor sound like running 1/7/8 headers 3" collectors and no pipes at all sound like when it back fires?
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Ive never ran this thing with all the go fast mods on it, What does a 408 cubic inch motor sound like running 1/7/8 headers 3" collectors and no pipes at all sound like when it back fires?
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well at tdc on the correct stroke both valves should be closed. if you can see the rockers thats a sure way to tell . because the cylander will give a puff on both strokes but one is more powerful and thats the one you want. even at a slow turn by hand you will have the puffs. but even 180 off doesnt explain the gurgle.
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I think the gurgle may be the motor back firing through the carb because it does shoot a lot of gas up into the air when it back fires.
and now it sounds less like a gurgle and more like a potato gun being fired and then a hiss.
and now it sounds less like a gurgle and more like a potato gun being fired and then a hiss.
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From: Crete, NE
My 78 is running now with open headers, It is VERY loud. should sound like a racecar. Double check plug wires are on correct cylinders, another idea, sometimes while pulling the twirly out the oil pump shaft will stick to the bottom of the dist. and fall into the pan; WHile cranking with coil wire off does the oil pressure come up?