340 is knocking

-
daves66valiant

daves66valiant

68 Dart 340/727:66 Signet Vert 340/5spd: 68 D100
Joined
Nov 24, 2005
Messages
3,151
Reaction score
1,071
Location
SoCal
:pale:

The 340 I just installed recently is tapping on the passenger side much louder than I would like to hear. I still knock at operating temperature and with a stethoscope I can hear ticking throughout with valve cover on. I can't pinpoint it. I thought it was normal in the begining (denial I'm sure) but now it is a little louder. I don't want to wipe out my cam. The cam was broken in by the engine builder on a dyno. I'm worderding if it is something with the valvetrain or an exhaust leak since I just put on new headers. BTW the driver's side sounds good.

One note. I removed the passenger side header to replace the oil filter adapter plate gasket and the header gasket was torn a little. I reused it anyways. So, I am really hoping that this is the problem. With my luck it is the valvetrain.

Question:
What should I be checking and looking for when I pull the valve cover? What issues may be causing this and how to fix it? Was the initial setup for the hydralic lifters off. They are non-adjustible steel Comp Cam flat tappet rockers if that helps.

Dave
 
Being the header hater that I am, I suggest you hunt an exhaust leak with the stethoscope or just a piece of tubing before pulling the valve cover.
Good luck
 
I would start with a new header gasket although you wouldn't think you would hear it thru a stethoscope. To isolate valvetrain noise in the past I just run the motor with the valve cover off and use a hammer handle and load each rocker sideways and on top until I find the rocker.


Chuck
 
?one/is this the same valve train that was on mtr on dyno ??
?two/if yes and you DID not change or loosen valve train I would look at did you put on valve covers new after dyno ?? some valve covers are very low for some valve train rocker arms...
Good Luck !!
 
My best case scenario is the gasket change. So I'll be getting a new set tomorrow. Any suggestions for good gaskets for tti headers. Aluminum vs Copper vs metallic/fiber

I have not changed anything except to put headers on. This is only the second time I've fired up the motor. They are the Mopar Performance Chrome valve covers.
 
340Dart said:
I use Remflex gaskets. You will never buy any thing else once you try them. I tried them all. These seal and no retorquing of bolts.

www.remflex.com

Fred B
Click to expand...

Ditto Remflex, By the way I found the cylinder head paint under the header flange was blackened from leaking, it was obivous it had issues.
 
heard a couple other talk about remflex. just ordered some.

Any other thoughts on the valvetrain as the cause? bump
 
Can you hear the noise from within the car? If so take the car out for a ride. An exhaust leak will stop making noise as soon as you take your foot off the gas. If the noise goes away every time you take your foot off the gas then its an exhaust leak.
 
If you decide to pull the valve cover, check the rocker shaft hold down bolts and see if any are loose or broken. It happens sometimes.
 
I had a MP cam and lifter kit that had a bad lifter from the get-go. It wouldn`t pump up and was tapping like an Irish dancer. It was no problem identifying the lifter as loud as it was. It did had me worried at first though. I finally replaced it and the tap went away. If it`s a rod bearing you can pull a spark plug wire off a cylinder one at a time and see if the tap abates some. Pulling the plug wire will usually quiet the cylinder that`s the culprit whether it`s the rod, a wristpin, or something in the valvetrain like a bad lifter. Does it make more noise when the engine`s cold or hot?
 
was getting louder as it was warming up more.
 
daves66valiant said:
was getting louder as it was warming up more.
Click to expand...

I think we can rule out the idea of an exhaust leak, as they usually disappear or quite significantly as the motor warms(materials expand and contract with heat and cold). What is the oil pressure readings as all of this is going on? What does the gauge read when its warmed up?

With the noise intensifying after being warmed up, the thinning of the oil seems to be aggitating the noise. This could be a noisy rocker(loose hold down) or maybe the oiling holes on the shafts are facing the wrong direction? A lifter may be noisier if the oil thins, but I have always had them quiet sown with warmth.

On the bottom end, the intensified noise when warm could be a signature of a rod bearing issue. Again, what is the oil pressure when warm? I had a bad wrist pin in a motor once that had symptoms similar to what you have described.

All and all, valvetrain or rotating assembly, the thinning of oil with a warm engine is playing a part in whatever this is.
 
Thanks for the info again. My suspicion is something in the valvetrain.

So what does it mean if the oil pressure goes up or down with the ticking? Something not getting oiled properly I presume. My knowledge is still pretty basic so this is all learn as I go. Thanks. The gremlin hunting continues another day.
 
Oil pressure fluctuation could indicate a rod bearing issue. Pull the oil filter off and cut it open. Examine the pleats for any bearing material. On a fresh rebuild, there may be some fine metallic particles but there should not be any bearing material.
 
With it getting loader when it gets warm, I'm guessing a rod bearing. This is just a guess.


340mopar I used the Percys too. My right side header would leak after a few months. Went though 2 sets. The remflex eliminated it. They were a good gasket but would not stop the leak.

Fred B
 
id check the rockers first, seeing as i have seen this on a motor me and my dads friend put a set of eddy heads on. the pushrods were 3/8's race stuff from the 80's and not the 5/16's like the holes were drilled for i think. so they were binding up, and when he thought he had the rockers adjusted properly, they were bound up and chattering.
co
id replace the header gasket, and pull the valve cover off and give them a look. its usually the simple things that will mess you up is what ive noticed.

hope this helps!
 
When the motor was rebuilt they should have replaced the rod bearings. I will have to call them. I don't know if they are FederalMogul or Clevite bearings.

To replace them would be a bitchh. Would I be able to do this repair without pulling the engine? I worked so hard getting everything into the car to have this Bullshit happen. Fucck me. This is very irritating at this point in the game. Just goes to show nothing ever turns out perfect the first time. Will wait and see what it is.

Thanks again.
 
70 cold 60 warm and it's steady. I'll check it again after the weekend and when I put the new header gaskets on. At least I'll have that part eliminated
 
daves66valiant said:
70 cold 60 warm and it's steady. I'll check it again after the weekend and when I put the new header gaskets on. At least I'll have that part eliminated
Click to expand...

That oil pressure sounds almost too good to be a bad rod bearing. Have you pulled the plug wire off the suspect cylinder while it`s running to see if the knock abates? I`d give that a try first, if the sound persist at the same level than maybe you can look elsewhere, perhaps a collapsed lifter or even a loose rocker lock nut.
 
You must log in or register to reply here.
-

Back
Top