| From | Message |
dakota curt
Dodge Dakota
JOIN HERE
3/27/2005
10:48:16
|
 Subject: 3.9 clacking noise
IP: Logged
Message:
I have a 1990 dakota with the 3.9 v-6. It has 317,000 miles on the original engine. Over the past 50,000 miles or so a distinctive clacking noise has developed in the engine. I have replaced the timing chain,lifters and pushrods. This did not help. This past weekend I needed to drop the oil pan to replace leaking gasket and while the pan was off I replaced the rod and main bearings along with new oil pump. I pushed and pulled on the connecting rods and noticed no wrist pin play in piston boss. I put everything back together and started up the engine. Same noise as allways with no improvement. I know this engine has alot of miles but it still runs great. Compression is good and even between cylinders. Oil consumption is less than 1/2 quart between changes (3000 miles). Power is good as new. The noise does seem to quite down a little when the engine is warm. It almost sounds like a diesel. Could this be piston slap and if so is there anything to help? Also How can I tell if the rocker arms have worn where they pivot on the rocker shaft. They look good but there are no specs. in my service manual stating what size hole should be on the rocker arms. This noise sounds valve train related but I am stumped. Sorry to be so long winded. Any thoughts will be welcomed.
p.s. The rod and main journals were miked and plastigauged. All tolerances were within spec.
Thanks, Curt
|
david hughes
Dodge Dakota
JOIN HERE
3/27/2005
15:05:25
|  RE: 3.9 clacking noise
IP: Logged
Message:
check the vac. controled flap value on the exhaust manifold.
|
vern
Dodge Dakota
JOIN HERE
3/27/2005
16:42:23
| RE: 3.9 clacking noise
IP: Logged
Message:
my first dak 87 had this noise,diesel like sound,
i never found what was causing this, but i thought the noise was the rockers and shafts causing this and/or possible the valves slapping close,once the rpms got 1500-2000 the noise was less or just seemed that way
there should be .050-.080 of preload on the lifters when the rockers and shafts are tighten down,if you do,nt have this the lifter plunger maybe coming up against the retainer lock to hard causing this noise,if this is the case thats not good the lock could brake causing the lifter to come apart
with this said
i drove mine for 2yrs with this noise and no ill effects[i still have the truck and the noise is still there]but now its a yardtruck/parts
|
Dakota Curt
Dodge Dakota
JOIN HERE
3/28/2005
07:51:19
| RE: 3.9 clacking noise
IP: Logged
Message:
I would also like to state that the oil pressure is good. 1/2 scale on gauge at idle and 3/4 scale at 2000 rpm. This has never changed since truck was new.
Thanks
|
93dak4x4
Dodge Dakota
JOIN HERE
3/28/2005
21:10:53
| RE: 3.9 clacking noise
IP: Logged
Message:
with that many miles, if i were you i would probably just replace the rockers as well, you already did the hard work with the lifters and pushrods. while you are at it you could upgrade to 1.7's and increase your power a bit. but if you like the truck and plan to keep it, i would do it.
|
BYRAMCVFF
Dodge Dakota
JOIN HERE
3/29/2005
11:55:59
| RE: 3.9 clacking noise
IP: Logged
Message:
I HAVE SAME NOISE ON 91 5SPD.I WAS TOLD IT IS COMPRESSOR BEARINGS.HAVENT HAD TIME TO CHECK.BUT MY TRUCK DOES MAKE A RATTLE SOUND AFTER IT WARMS UP.
|
Dakota curt
Dodge Dakota
JOIN HERE
3/29/2005
13:16:47
| RE: 3.9 clacking noise
IP: Logged
Message:
This sound is coming from the engine. It is worse when it is cold and quites down some as the engine warms up. It is most noticeable at idle and deceleration. It quites down under light acceleration. I am thinking piston slap but removing spark plug wires one at a time makes no difference in the sound. I have experienced piston slap before and usually removing spark plug wires will quite the noise on the problem cylinder. I even tried killing two cylinders at a time with no difference in sound. The rockers are really loose fitting on the rocker shafts but this maybe normal. I am not that familiar with the chrysler rocker shaft set up. The rocker shafts appear to not be worn where the rocker arms make contact. Can any tell me how to check the actual rocker arms to see if they are in spec.?
|
Relf
Dodge Dakota
JOIN HERE
3/29/2005
15:17:11
|  RE: 3.9 clacking noise
IP: Logged
Message:
Have you thought about the timing chain? Those things loosen up as you add milage. Go to speedtweaks.com to learn more about it. I think you click on "upgrades" or something like that. Relf.
|
Relf
Dodge Dakota
JOIN HERE
3/29/2005
15:18:25
| RE: 3.9 clacking noise
IP: Logged
Message:
Oh, you've replaced it. Sorry.
|
DDWI
Dodge Dakota
JOIN HERE
3/30/2005
21:57:30
|  RE: 3.9 clacking noise
IP: Logged
Message:
You CAN'T use new lifters on a used cam and vice versa also. The bottom of the lifters wears concave, and the cam lobe wears also, especially at 300K. Putting a new flat lifter on a worn cam lobe puts the entire compressed valve spring pressure on an area the size of a pencil point... and eats up those new lifters you put in pronto.
|
Dakota Curt
Dodge Dakota
JOIN HERE
4/01/2005
17:02:17
| RE: 3.9 clacking noise
IP: Logged
Message:
Thanks for the reply but this engine has roller type lifters which according to the service manual it is ok to use new lifters with an old camshaft. Is this information wrong
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
