904 causing knocking noise?

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Slant6power

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Hi all! I just brought a Duster slant 6 back from a 14 year sleep. After much trial and error, she's running. BUT... there is a knocking coming from somewhere. Today I realized that when I put it in gear the noise seems to stop. Another thing is, when sitting still in gear, trans seems to go in and out of gear every several seconds on it's own. Could the knocking be coming from trans or torque converter area? Some onetold me flex plate? Not super versed on transmissions. Any help or suggestions would be helpful. Thanks!
 
Sounds like two issues; low oil level/restricted filter in the trans is one. Crankshaft end play could be the other, but on an auto car that would be rare.
try reving it up a little, is it idling a bit too slow, perhaps? or rough? Fresh gas I assume?
Was it, perhaps, parked for an expensive reason, such as a #6 rod ?
 
Thanks for your help! Plenty of oil and it's circulating. I pulled off the valve cover to see what is going on in there. All is well as far as I can tell. I started pulling wires from plugs. No change on #1 or #6. The sound seems at the rear for sure. The sound changes periodically. Mostly none at idle (except for a randomness to the noise such as in time with engine, and sometimes several seconds with no noise then a random tap here and there. What is the easiest way to check for a problem internally? And... why does it stop when I put in gear (coincedence), or?... Also this filter in the tranny. That might cause it to go in and out of gear?
Thanks for any suggestions or answers.
 
If it comes and goes, theres good news. Its not bearings.At least not likely.
Again I ask, does the engine idle smoothly, and at a reasonable speed. The slanty is generally a very smooth running engine. But if yours is missing, bucking, and farting, then all kinds of things, attached to the engine,could be a possible source.
However, since you are convinced its internal, Im going to assume that you are right.
Since, Im convinced its not bearings, or pistons, or valve train, based on the comes and goes knock description, there are only a few things left. Again crank endplay is first on the list. Next would be; loose starter, broken fuel pump return spring,maybe a cracked flexplate.
BTW, what oil is circulating, and how did you determine that? It seems you are referring to engine oil, and I specifically asked about transmission fluid level. Are we on the same page?Going in/out of gear is usually the pump sucking air, whitch would be low oil level. Old Mopes are checked in Neutral,on level ground, oil hot, with correct dipstick.Put the park brake on or block the wheels from turning, or use common sense, to not let the car roll away, or worse, over you.

To check the crank endplay, its a simple matter of, with the engine off, and with suitable tools, prying the crank out of the motor towards the rad and then slamming it back in with muscle power.If it makes a very audible noise, that sounds eerily similar to the noise you heard in the running engine, well then, there you go. This noise originates deep within the engine, and has a very particular deep clunk type sound.Try it several times. No sound is good news.
The broken spring idea is a completely different sound. Its more of a clacking sound. The pump is hanging off the side of the motor right near the distributor.
The broken flexplate I cant remember the sound, as Ive only heard it once in my life.I cant help you with that.
I guess theres one other idea. If the oilpan had received a dent in just the right place, I suppose some part of the spinning crank assy could be tagging it now and then. But thats kind of a stretch. Only one way to know.Slide under it.Put your hand on the pan with the engine running.Youll feel it.Watch out for moving parts.And the hot exhaust.
In post 3, you switch from clunk to tap. Now we are no longer on the same page. So whitch is it? The above is for clunks, only. Taps is a new page.
 
Thank you very much for your suggestions. I will go over all those and see where it gets me. As for the noise it is definetely both sounds. When I speed up the engine it makes a lot of noise, then as it idles down the noise sometimes goes random. At one point after stalling the engine seemed to get stuck. After trying a few times it cranked and started. I took video with my phone and I'm going to post on youtube for people to see and hear what's going on. Thank again.
 
I would have to suggest a trans pan and filter inspection, as well as flex plate bolts check.
That right there should tell a lot.
A trans that has been sitting for a long time very well could eat the pump on startup and that would show in the pan.
I have to agree that random coming and going of the knock and going away when in gear sounds like a flexplate, but the trans has obvious issue's also. ("in and out of gear")
 
Ok, you gave me a hint right there; the engine seemed to get stuck.
-A long time ago I had a 318Dart904. It was eating the thrust bearing. I could hear the tell tale clunk sound. Circumstances prevented me from fixing it. Eventually the convertor/flexplate assy was able to move far enough forward that the bolts could snag on the back of the block. Like you, I hit the key a couple of times and away it went. When I finally got to it, the bolts had chewed part way through the rear cam plug as well as "grooving" the block.Of course the crank thrust surface, and the bearing face,were toast.
I have a hunch this may be your problem too. Now go check that endplay.See post5

-As to the ticking;I suspect its related to that endplay as well. It could be that when the crank moves to the rear it smacks the thrust bearing on the front, and then when it moves to the front it drags the convertor bolts into the back of the block. So you get the clunk and the tap; randomly at idle, in neutral, due to the nature of the firing pulses.
-When you put it in gear, the TC and pump put a load on the crank, and if the thrust was towards the rear, everything would be quiet.
-Then again, the bolts could just be loose, as others have said.Doesnt speak to the clunk tho.
-So get under it already,lol
 
random ticking under load, torque convertor bolts. wifes minivan, perfect example. tightened them up with some locktite..faggetabout em! Heck, my wifes suburban would drop in and out of gear, was a plugged filter. Yeah, Im the guy that ends up fixing them.....I got a slant trans, come and get it. Im in Tustin, bring a sixer of Guiness.
 
Knowing the statistical cause of death in the slant 6, It's going to poke the #5 rod through the left side of the block. Statistics prove nothing. Could just as easily be the neck on the torque converter that drives the front pump is cracked. A separated piece of that neck cant get away / go anywhere but it can move around a little changing the sound produced. In the few examples I've ran across I could feel it in the floor pan under my feet.
 
AJ/FormS said:
Ok, you gave me a hint right there; the engine seemed to get stuck.
-A long time ago I had a 318Dart904. It was eating the thrust bearing. I could hear the tell tale clunk sound. Circumstances prevented me from fixing it. Eventually the convertor/flexplate assy was able to move far enough forward that the bolts could snag on the back of the block. Like you, I hit the key a couple of times and away it went. When I finally got to it, the bolts had chewed part way through the rear cam plug as well as "grooving" the block.Of course the crank thrust surface, and the bearing face,were toast.
I have a hunch this may be your problem too. Now go check that endplay.See post5

-As to the ticking;I suspect its related to that endplay as well. It could be that when the crank moves to the rear it smacks the thrust bearing on the front, and then when it moves to the front it drags the convertor bolts into the back of the block. So you get the clunk and the tap; randomly at idle, in neutral, due to the nature of the firing pulses.
-When you put it in gear, the TC and pump put a load on the crank, and if the thrust was towards the rear, everything would be quiet.
-Then again, the bolts could just be loose, as others have said.Doesnt speak to the clunk tho.
-So get under it already,lol
Click to expand...

Thanks for that info. Yes next day off I'm on it.
 
Okay guys... I think I want to "V8" my Duster. I have an 89 Ramcharger with a 360 tbi. Can I remove all the smog crap, replace Tbi with carb and put in my Duster? The engine moves the Ramcharger like a scalded dog, and since the Duster is at least a half ton lighter, it should really move. Too big a hassle? Or worth it?
Thanks!
 
So, you want to hop up your car, eh? Welcome to the club.
-Putting that TBI360 in there will be dynomite. Worth it? Heckyah. Trouble? heckyah.Cheap? hecknoh.
-This would be an excellent project.Right up there with your first kiss.
-The only things you will need, in addition to the doner, are; time,money,tools,some skills,knowledge,and perseverance/dedication. Of these,by far the most important,is the last. If you believe you are up to it, the rest will come.
-FABO can help in the knowledge dept.,and encourage you in trying times.
 
Slant6power said:
Okay guys... I think I want to "V8" my Duster. I have an 89 Ramcharger with a 360 tbi. Can I remove all the smog crap, replace Tbi with carb and put in my Duster? The engine moves the Ramcharger like a scalded dog, and since the Duster is at least a half ton lighter, it should really move. Too big a hassle? Or worth it?
Thanks!
Click to expand...

My personal experiences: 360 ,the Duster.Do the research here, before you even loosen a nut. Start a separate thread, keep notes, ask lots of questions/take your time. My 2 pesos.
 
why not just drop the entire 360 drivetrain with computer, smog and all in the Duster? then maybe start weening off the smog. Itll run great, decent mileage and wont stink up the drive through. youll only need to figure a return line to the tank and an external EFI fuel pump.
 
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