2G HORRIBLE knocking when engine warms up

[edmaxx]

today i worked on my talon i have been rebuilding for the past couple months, fixed my boost leaks. i have a CAS sensor to eleminate my crank and cam position sensors, when i got it running pretty good (still looking for leaks) it had no knocking noise, pulled my spark plugs to see if they were getting gas, they were, put it back together.... started it up and clack! clack! clack! sounds like its coming from the bottom end.

any ideas?

 

[TJCTalon]

Rod knock???

Sounds like you already know what it is. Only way to tell is drop the pan. Youve been doing regulare oil changes correct?

 

[edmaxx]

i actually just got this engine in the car and got it running, dang, how do i check?

 

[bluzvr4]

u can check the oil and see if theres any metal in it

 

[edmaxx]

so pretty much i need to drop the oil pan no matter what?
what causes rod knock?
why does it only do it when its warmed up?

 

[jimbob_843]

Rod knock most comonly occurs when the rod bearing has excessive wear which in turn will cause it to spin (spun phrase) within the rod end. In most cases it ruins the rod and crank but stop it before it can. Drain oil look for metal flakes in oil and filter. If they are present then drop pan and pull the rod caps and inspect.

 

[TJCTalon]

So take off your downpipe, and take off all those bolts holding on the oil pan. It will probably be stuck on there pretty good if its never been off. Try not to do too much damage prying it off. Also when you drain the oil, make sure the pan your draining it in is clean, that way you can see any metal flakes in there.

And please refrain from starting and running the car until you find out whats wrong. It will only make it worse. Goodluck

 

[JusMX141]

Sound anything like this?

<iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/lpzff1Rm-Gg" frameborder="0" allowfullscreen></iframe>

If so, you're S.O.L.

 

[edmaxx]

so i did my timing again just to make sure nothing sliped and i was crushing valves, i noticed that when my spark plugs were out the noise didnt happen?

side note- ya it sounded alot like that, but when i put the plug on cylinder 3 it didnt make the noise at all, but on any other cylinder it did????

im pretty lost right now, this would be my first engine rebuild and i wouldnt be suprised if i did something wrong, but three days ago the car ran fine, then one day it decided to no rev past 3000 rpm, then it was fine today, then this weird noise later in the night???? what the hell

 

[edmaxx]

so my engine is making an awful knocking noise that sounds like its coming from the crank, but it only does it if all cylinder 1,2, and 4 spark plugs are in, or just one in any of those cylinders (doing this while there is no spark and cranking the engine with the starter?). the engine runs, but sounds like something is just rattling around in my engine all over the place, stalled once with a loud metal on metal hit and i stopping cranking it!

 

[3kgt2nv]

no spark plug nothing for the piston to push against to knock since it cant make compression. You have most likely spun at least 1 if not more of your rod berrings.

 

[3kgt2nv]

or you could have snapped a rod.

pull the pan and have a look see

 

[edmaxx]

thats what i was thing, dang, so i drop the pan and chack? if so pull the head and pistons, replace rod bearings, and throw it all back together?

 

[3kgt2nv]

I would pull the pan and look first. Then decide the best course of action

 

[Tyeler18]

thats what i was thing, dang, so i drop the pan and chack? if so pull the head and pistons, replace rod bearings, and throw it all back together?

Best case scenario, yes.

 

[edmaxx]

Word, thanks guys, ill just have to drop the pan and see whats up, if you have any other ideas throw em' out, ill post back and tell you what i see/can tell.

 

[rlacasse1]

Best case scenario, just replacing the rod bearings. But, more than likely, you are "el screwedo" as our friends to the south would say.

 

[edmaxx]

why do you say this?

 

[rlacasse1]

Because it sounds like you have been running it a bit trying to figure out what is wrong. And the more you run it with shot bearings the more damage you will do to both the rods and crank. If you get a light knock and just shut off the engine sometime you can get away with replacing just the rod bearings, cheap and easy. But if you run it, then you have to rip the engine apart because you have to replace the damaged rods and crank.

 

[DSMTyson]

Because it sounds like you have been running it a bit trying to figure out what is wrong. And the more you run it with shot bearings the more damage you will do to both the rods and crank. If you get a light knock and just shut off the engine sometime you can get away with replacing just the rod bearings, cheap and easy. But if you run it, then you have to rip the engine apart because you have to replace the damaged rods and crank.

Haha you are more than likely screwed! Sorry

 

[etay89]

love the enthusiasm guys -_-

at any rate, drop the oil pan. if there's giant chunks of metal in there (when i say giant, i mean easily noticeable), then chances are your rods are trashed.

from this point on, you got 3 options
a) get a new DSM
b) get a used engine somewhere else (you may have damaged the head. it's unlikely but still a possibility)
c) rebuild the engine.

good luck dude

 

[Absit]

If you do rebuild, note the crank may need to be cut, many DSMers just replace it because of theoretical the loss of strength.

 

[edmaxx]

well there were some nice chunks in there (awesome), so im pulling the engine tomorrow... i took it all apart and its ready to go. thanks for all the help, i guess i did something wrong in the rebuild. what should i upgrade to in a crank, while im doing this again?

 

[Absit]

OEM is fine for 99.999999% of us.

 

[edmaxx]

alright ill just stick with OEM, cheaper anyways. any better piston rods that are pretty cheap?