help with 3.4L engine noise; link to sound file

[jacktoad]

here is a link to the audio.video file:

http://smg.photobucket.com/albums/v91/raleigh5/?action=view&current=1992RodeoMotorSound.flv

i just don't have the experience to say what this noise is most likely to be...though it doesn't sound like the rod knocks i have heard on motorcycle engines. so....other bearings? piston slap? valves misadjusted? lifters shot? help

Stats:
newly replanted 3.4L(from a 94 camaro) in 1992 Rodeo
idle is at 1000rpm in video(i am working on that one)
timing is approx 16 DBTDC
increases when load placed on motor
almost disappears when lifting foot from throttle
ground wires are all grounded
oil level is alright( 10w-30; Fram filter...i know, i know)
starts right up, only problem being inconsistent idle
only driven maybe 6 - 7 miles... all under 40mph.
TBI from 4.3L matches bored Intake Manifold
Fuel injectors from 3.1L (4.3 injectors too many issues)
Occassional black,sooty exhaust.
Sound is very much like what an exhaust leak sounds like. but exhaust is joints are good.

--------------------
1992 Isuzu Rodeo 3.1L(now a 3.4L) V6 4x4

[Superdave]

are you sure all your spark plugs are in tight?


could be a leaky exhaust manifold gasket too...

[geoffinbc]

Souds l like rocker arms to me. You didn't adjust them right when you did the intake. One thing for sure is that is not a bottom end knock.

[ForcedFirebird]

I don't think my iron heads ever had exh mani gaskets, but the bolts liked to break - just from normal use.

[JohnnyReb]

Sounds like a exhaust leak

[jacktoad]

12/22/2007 update

thank you all for the replies and suggestions to my problem. here is where i am at the present time(XMas pun intended....lol).

all spark plugs are/were tight and their wires fully seated on the plug.

checked for exhaust leaks and still found none. new Felpro exhaust manifold gaskets were installed when i put this motor in the car. original config does not have gaskets.

once again set the valve lash. i did find that at least 2 rockers on the left side were too tight. originally, i had tightend all rockers(1:6 rollers) to 3/4 turn past the point of 0 lash(=no up/down movement of the pushrod). this 3/4 turn setting was apparently too much, as the car would not start. so, went back in and set rockers to between 1/2 and 3/4 turn beyond 0 lash. that is where they are now.

timing is now at 14 DBTDC and the motor idles just about 850rpm once it is warmed up.

drove car maybe 25 miles over the last week and the motor feels very healthy. has no hesitation and accelerates smoothly from all speeds(even hiway).

but..... the noise is still there. it is quieter. but it's still there. seemed to improve the most just after i adjusted the left side valves( i did this side 1st since it is the less time consuming).

my next steps are going to be a change in oil from 10w-30 to 10w-40. just to see if that makes any differnce at all.

i cannot start the motor now until i get a fuel return line from the dealer. it wont be there until after Christmas. i can take another sound video once i get the part.

question: is there a good way that i can at least narrow this down to being an engine noise? i ask this because i really manhandled the tranny in getting it mated back into the motor.

thanks again for any help and have a great Christmas everyone.

[geoffinbc]

There is no way 3/4 turn would not allow the engine to start. Even on coarse thread after market studs. It sounds to me like you you were not adjusting the rockers when the lifter was on the base circle or you tightened the nut too much before you added your preload. So you might have some rockers correct and some loose.

[davida1_hiwaay_net]

Nice video - that makes it so much easier to understand! This sounds JUST LIKE valvetrain noise.
You have the procedure right for the rocker adjustment. I have messed this up before. What I did wrong involved lifters that were not full of oil, and the fact that I had not done this in a while.
I could still turn the pushrods even after the lash had been reduced to 0, but it took a lot of effort. I thought "IF I can still turn them, it is TOO LOOSE" But all of us have different level of strength and such. After my adjustment this way, all lifters were fully compressed (plunger bottomed out) and then I went another 3/4 turn. I had all of the valves staying open. It would not start. I think you describe this condition!
The service manual may show a certain order in which to adjust the rockers, but to be safe I always do it the "old fashioned" way. I go cylinder by cylinder. Adjust the intake when the exhaust for that cylinder is fully open, and adjust the exhaust when the intake is fully open.
For each cylinder, bar the engine around until one rocker is fully actuated (valve open.) This will guarantee the other one for that cylinder is on the base circle of the cam. (valve fully closed)
Now rotate the engine until the one you just adjusted is fully open and adjust the other rocker for that cylinder.
This takes more time but it ensures that the adjustment will be done on base-circle.
After completing the adjustment, as a sanity-check, all the intake and all the exhaust rocker nuts should have approximately the same amount of thread showing above the nut.
This works for any engine, I use all the time in engines for which I can get no service info.
Your motor swap looks good in the video, quite a torque increase from the original motor, I bet!
I just thought about something - If the lifters are frozen and no longer will compress, it may be very difficult to make a valve adjustment. Also, if someone installed a set of "solid lifters" the valve adjustment procedure will involve a feeler-gauge meaurement at the rocker tip and valve stem. (If they even make dolid lifters for this engine?)
Bottom line, the sound in the video is the sound of loose rocker arms. In my opinion; I can't hear anything that sounds like a transmission noise.
Later,
David

[34blazer]

quote*(If they even make solid lifters for this engine?)


the 660 uses the same .842 dia lifters as a sbc. well almost, you have to find lifters that use the same pushrod diameter cup as the factory.*in a nutshell* theres more options but its not worth gettin into unless someone wants to know. i have a solid cam with HOWARD'S solid lifters. they laser cut a small oiling hole in the bottom for added lubrication. its like a .020 hole to keep the oiling system from loosing pressure.

back to topic

[Joseph Upson]

Sounds like an exhaust leak to me although it's a hard call when considering rocker noise. Have you checked for a loose EGR valve or bad EGR gasket? I didn't note where its location is but that can do it.

[davida1_hiwaay_net]

You can have an asistant hold a folded towel over the tailpipe and put backpressure on the exhaust system. If the it's an exhaust leak, the sound will change dramatically. It will go from a ticking to a blowing sound.
It's an old trick someone showed me years ago!

[deancass2000]

Things I have found in the past associated with a noise like this are:

1) Rocker arms or lifters, I've had lifters stuck in the lifter bore and with each rotation of the cam lobe it would hit the lifter and make this noise.

2) Exhaust gasket leak

3) Loose flywheel bolts on automatic trans.

4) An accessory drive (altenator, water pump etc) making the noise.

I would unhook the serpentine belt, just to make sure it's not the obvious like an alternator or something similar making the noise, easy enough to check. I would then check the flywheel to torque converter bolts and make sure they are tight. Then, you could pour a little transmission fluid into the intake or carb or whatever you have for fuel delivery, this will help identify an exhaust leak, if you have one...the white smoke will be obvious from the area of the exhaust leak. If after that you still haven't found it, I would pull the valve covers and focusing on the area where the noise is loudest, I would "loosen" each rocker to see if the noise changes, if it changes on the one you lossen you have found it.......I have found problems using this dianosis in the past and have actually uncovered problems in all of these areas using these techniques.... good luck!

[jacktoad]

update on 12/31/2007:

thank you to all who have offered up advice and suggestions to help me locate this problem. using your posts, i've tried to go through and eliminate some things from being the cause of the engine noise.

here is where things stand right now:
the motor still has the tapping/clacking sound when accelerating. it occurs mostly when accelerating hard or when stabbing the gas pedal while idling. if the rpm's are built up gradually the noise is barely noticeable.

after doing some internet lookups/reading on hydraulic lifters, i do believe that i need new lifters. a couple looked pretty beat/collapsed when i put this motor back together(i just didn't recognize this condition). similar to the ones in the following picture.



here is a link to video/audio that i took this morning. the noise is not very audible in this clip. it is VERY noticeable when accelerating(ask my wife, she has started calling me Jed Clampet).

http://smg.photobucket.com/albums/v91/raleigh5/?action=view&current=1992RodeoMotor12312007.flv

Here is a list of things i did since last post:

this rodeo has 5 speed manual.

removed serpentine belt and started motor.....no change in noise.

blocked exhaust at the tailpipe while engine was running-> only made the engine want to stall and the tapping sound of motor seemed to get louder.

exhaust leak sound is pretty much gone after replacing the left side exhaust manifold gasket. the removed gasket looked alright.

removed the EGR vlave and cleaned and tested it. seems to operate as it should. there is no gasket between the mating surface of this and the intake manifold.

valves have been adjusted to 3/4 turn after 0 lash. used the method adjustment suggested by David where each valve is set when its partner is fully actuated. adjusting nuts(In/Ex) are all approx same location on their stud. motor starts right up.... initially, i had taken the non-start condition to be due to too much preload. wrong...it was several things, including timing, IAC setting and probably some fouled plugs. my bad. btw, i actually prefer this method of adjusting the valves.

thanks once again for your help.

Happy New Year!

[davida1_hiwaay_net]

Glad you're making progress! Before spending a lot of money on lifters, you can dismantle them and clean the pieces. See the following picture for what the pieces should look like after cleaning. Mine were WORSE than the ones shown in that picture!
David

http://68.209.87.173/89_LeSabre/lifter_1.jpg

[geoffinbc]

Yea you can clean them but it is not worth the effort. You can get a whole new set for cheep and be sure they you wont have to take the engine apart again.

The only thing I would caution against is off shore lifters. But from a reputable company.