Project Fix the Rod Knock, can we do it? Lets talk

[A_Harman]

Originally Posted By: TechnoLoGs
Proposing that, if I commit to buy tools and take the time and step-by-step document the process, that BITOG would commit to helping me look at the rod and bearings, and ultimately have this be my first real, actual, engine work project.

I am uploading a video of the last time this ran, I am letting it cool now, but since this engine has been pushed/tested its luck enough, I now want to let it sit until I can remedy the problem, not pour Lucas in there and hope it fixes it, it is abundantly clear that it will not. I put it in there to get home as I had to take the S10 to get the old engine. No room in the F150.

It appears to stall out when hot, a la overheat. Surely the one superhot cylinder with the bad rod is to thank for that. No blown gaskets, no smokes, no drops, no residues.

You can hear it in the video, and I made some commentary. It now rests.

?



Part of being a good engine builder is knowing what parts NOT to use. Take the engine apart and buy or borrow the proper measuring tools and measure everything to be comfortable that the engine can be rebuilt to service specs. If the crank journals are blued or a cylinder wall is cracked, trash the parts and look for better components to build on. If you have the luxury of time to build your own shortblock from individual components, it would be a valuable experience, but laborious and fraught with endless details. If you have to get the truck back in service, buy a professionally remanufactured shortblock with a good warranty, and do the top-end assembly yourself.

 

[TechnoLoGs]

 

[Rickey]

First I have seen some other things make "similar" noises.
First in mind is loose torque converter bolts, this actually happened to me once.
A harmonic balancer with a loose outer ring can also make some noises that "might" be mistaken for rod bearing knock. A loose piston wristpin will sometimes make a "double knock" sound.
A loose piston/cylinder fitment will knock more under acceleration and usually become quieter when hot.
Disabling spark plugs one at a time may be useful in figuring which cylinder is the offender.

If the problem is narrowed down to a particular rod bearing, use 400, then 1000 grit sandpaper and a shoestring to polish the rod journal. If the bearing has spun in the rod, a junkyard piston/rod assembly with good rings can be used if necessary.
If the crank needs appreciable polishing a 1 or 2 thousandth undersize bearing may be in order.

It may be that the oil sender is interlocked to the fuel pump and causes the stalling.

Good luck Sir, let us know how it turns out.

Rickey.

 

[Fleetmon]

I don't mean any disrespect by my question but did you ask " how to take off the oil pan"? If so, I don't think you're ready to get into the guts of an engine or as A_Harmon mentions, determining good parts from bad. What was wrong with the old engine?

Replacing the engine with a 350 sounds real cool UNTIL things start going wrong.....like exhaust, accessory brackets for alternators and stuff, wiring harnesses, and etc.....you can get in way over your head and wallet real quick and still end up with a dead truck.

Probably the best thing to do at this point is remove the engine oil pan, identify the bad rod and snap a picture or two for people in here to look at and try to decide via a picture which way would be the best way to go....realizing of course that any band-aid fix may only last a day, a week, or a month or so.

I'm certainly not trying to be the naysayer here but I would rather be brutally honest with you rather than you spending your money on a dead mule that no amount of money, time, tears, or sweat will bring back to life.

Rickey has some good points and maybe it's not a catstrophic failure...it's up to you to find out and make the decision.

 

[TechnoLoGs]

Rickey and Fleetmon I am loving the advice. Shall I take off a spark plug from the distributor and see if I hear knocking noises, to rule out "rod knock," is that how that goes?

The engine seemed.. to pull strongly, but it stalled more than it used to. s a result, I have left it to cool. I think there is one messed-up cylinder; though the bolts could have been put back on in such a hurry.

If only those bolts were easy to get at.

Quote:
What was wrong with the old engine?


The old engine actually never did get back timed correctly, but the smke was more indicative of head hasket problems, or even cracked water jacket. It had been spewing out of a certain part of a block.

This was the old engine, that never did get timed right. Maybe that is all it needed but idk..

**This engine below is now no longer in the engine bay, rather the back, just sitting there. I strongly suspected head issues on it (the old engine.) In hindsight, it never got timed right, but made some kind of "sand shaking" sound when driving. This one did, too, until back timed, and some suspect it may not be rightly timed? The stalls... it bogs down at lights, but there are no smokes. It is downright weird, actually.

The old engine, when I was at the light, I had to floor it and smoke covered the roadway and I had NO power and it sounded like shaking sand. I pulled it into the AAMCO, where it stalled and at that time I looked for the new engine. Then, that engine went in.. ur in ate ing a river of oil exactly the same as taking oil jug and slowly pouring it onto the ground from dipstick housing. Even now, the dipstick on there is jammed in, but it doesnt leak...

I will video the diagnostic of cylinder-by-cylinder on what is in there. I will let it cool, so I dont push the envelope too much.. I already chanced it driving it today.



^^ I have BRAND NEW Starter (that one you heard died,) motor mounts and radiator with a lifetime warranty from the components int he above video (less than two weeks ago.) I also have BRAND NEW coil, distributor cap and rotor, fuel filter, no more Check Engine light (it is totally not lighting on the new engine, a good thing) and more, I sort of forget.. some sort of module on the back of the distribur is brand new too.

 

[TechnoLoGs]

This is all in Norristown PA, btw.

 

[Fleetmon]

IF it's just a bad rod bearing and IF the crank is good and IF you're up to the task, you may have all the parts you need to patch it from the old engine....then again, it may be something really simple and easy per Rickey. Pulling plug wires one at a time is a good way to diagnose a problem as he described....times a'wastin....get to it and see what you got.

If you determine it is a rod, you may have to lift the engine a bit to get the pan off but it should be doable....just take your time so your're not breaking anything else while you're fixing it.

Maybe 'Bama can give you a hand but if it were me, I'd stay away from the 350 idea unitl you have the time and money to do it right.

Good luck!

 

[TechnoLoGs]

OK, I took a wire off at the distributor cap. This was the result.



Quote:
Maybe 'Bama can give you a hand but if it were me, I'd stay away from the 350 idea unitl you have the time and money to do it right.


Man.. I really hope Bama rematerializes because the way he was talking, he has done this maybe about 100 times. He even told me he could get these engines for like $300, $350 down where he was from but that is all the way down in.. Bama...

He got all the Good Ol' Boy tricks. Ready to put the two engines side-by-side, take the one in there apart, see what we see, new bearings, new gaskets, maybe timing chain.. [censored], where is he!!!

 

[Fleetmon]

(shhh...you'll have to whisper it to me since I can't get any video on this work computer!)

 

[Rickey]

Pull the plug wire at the plug to avoid cross firing.

 

[TechnoLoGs]

And will this engine fit my truck? http://www.ebay.com/itm/1994-chevy-v6-4-...983&vxp=mtr

 

[itguy08]

Originally Posted By: TechnoLoGs

And, itguy08: I believe the OP sender unit is not functioning. Unless you believe it to be accurate?


First thing I would do is get a new sender or oil pressure gague to see if you have good oil pressure. If not, you could fix the rod knock and it will be right back unless you address the lack of oil pressure. And if it has no oil pressure, it's definitely a bunk engine.

That would be my first step - make sure oil pressure is up to snuff and if it is address the knocking noise. No oil pressure will definitely cause knocking and will trash the engine.

 

[Rickey]

Pull one plug wire check, replace the wire. Repeat with different wires until you have found a plug wire that stops the knocking, or ran out of wires to check. If you have a well insulated way of gripping the wire you can replace/remove while the engine is running to confirm noise.
Revving the engine a little with the wire on and off may be helpful in diagnosing the noise.

Remove only one wire at a time and replace before removing others to avoid mixups.

 

[Rickey]

"That would be my first step - make sure oil pressure is up to snuff and if it is address the knocking noise. No oil pressure will definitely cause knocking and will trash the engine."



A bad rod bearing can cause low oil pressure.
it's somewhat of a "chicken and egg" thing.

 

[Rickey]

For an insulated spark plug removal tool a DRY stick of wood or length of plastic pipe and some electricians tape can be used with a little imagination.

Yes;I've done this the "poor boy" way many times in the past.

 

[Rickey]

Originally Posted By: Rickey
Pull the plug wire at the plug to avoid cross firing.


Clarification:

Pull the plug wire ONLY at the spark plug to avoid cross firing.
don't pull at the distributor as crossfiring can result.

 

[itguy08]

Originally Posted By: Rickey
"That would be my first step - make sure oil pressure is up to snuff and if it is address the knocking noise. No oil pressure will definitely cause knocking and will trash the engine."



A bad rod bearing can cause low oil pressure.
it's somewhat of a "chicken and egg" thing.


True but looking at his video he's not getting any pressure (or not enough to make the sensor move) so I'd think you would at least get 1-5 PSI even with bum bearings.

 

[Rickey]

Originally Posted By: itguy08
Originally Posted By: Rickey
"That would be my first step - make sure oil pressure is up to snuff and if it is address the knocking noise. No oil pressure will definitely cause knocking and will trash the engine."



A bad rod bearing can cause low oil pressure.
it's somewhat of a "chicken and egg" thing.


True but looking at his video he's not getting any pressure (or not enough to make the sensor move) so I'd think you would at least get 1-5 PSI even with bum bearings.


I have got to wonder if this vehicle has a "true" oil pressure gauge or one of those all or none "idiot gauges"
If its the all or none type then one or a few psi would read zero probably.

 

[Fleetmon]

probably the best way to tell would be to look down the oil filler hole and see if "stuff" looks like it's getting oil....by now, if it's not, everything is probably pretty dry. If it has a baffle, remove a valve cover and spin it over.

Even a couple of psi is going to lube the top end.....no oil on top means a manual gauge in the sender hole to qualify zero oil pressure. I agree that even if a rod bearing or two is complete toast it's still going to have SOME pressure.

On 350's, if run low on oil and they spin a cam bearing, you lose top end oil pressure and oil pressure flow for the sender (and fuel pump signal), correct? Is this 4.3 designed the same way?

 

[stephen9666]

Originally Posted By: itguy08
No oil pressure will tend to do that. Watch the oil pressure gague - it's not registering and blinking.


Good eye. In the video it clearly shows no oil pressure.

Now, in theory it could be a sending unit problem, but it sure is suspicious...