slant 6 knock

-
pagilman

pagilman

Well-Known Member
Joined
Nov 19, 2005
Messages
790
Reaction score
5
Location
farmingtonPa SilverSpr FL
slant 6 knock My engine has been knocking since last summer, I only drive it on the weekends in the summer, if the roads are dry. I got it out today and have been waiting untill I had time to check the valve lash. But when i opened the hood the knocking sound sounded like it was coming from the bottom end. :cwm10: I pulled the plug wires one at a time and when I pull number 3 the noise stops. My question is can this be an exhaust leak? #3 is behind the carb and I can't get at the exhaust manifold to feel if it is leaking. ( high hopes). When I run the engine at about 1500 RPM the noise stops also. My question is do you guys think it is a rod or can it be a lifter needing adjusted or an exhaust leak? I have a 340 to put in but I was going to run the 6 this summer and put the 8 in this fall. Please help? thanks walt :salut:
 
Dam, it sounds like the rod. Pulling the plug wire, is the sure test. But, it sure wouldn't hurt to check the vavle lash.
 
I fired it up today amd drove it to town, when i started it, it quieted down after the oil got up and started to tap when i pulled out. It doesn't knock unless you are on the gas. Do you think it can be a sticking lifter? I would really like to drive it this summer with the /6. Thanks again for any help, walt.
 
I'm starting to have second thoughts about the wrist pin if it gets quieter after the oil pressure hits. If its a rod bearing you are on borrowed time if you drive it.
 
time to hammer it until it expires! It will prob knock for a while befoer anything really bad happens. 6poppers are incredible engines.
 
hell for how cheap slants are buy another one :notworth: as a fellow slantsixer :thumblef: i know aftermarket parts are expensive, but a starter motor is cheap. Good luck with everything man
 
Just a thought, hows the oil pressure ? Maybe the pump isnt up to it anymore. Maybe replace it with a high volume unit ? (not sure if anyone makes a hi vol pump for /6.)
 
If a 6 cyl "knocks" it's usually bad news, sorry to say anything in the valve train is usually a ticking/ slapping sound .
 
when mine started to tick i ignored it.. then it got worse. now im scrapping the whole car cuz the engine blew up.. it was a bearing failure.. 340mopar is right your on borrowed time if thats what it is.. and thats what it sounds like. but im no mechanic.
 
I back the boys up here, Sorry to say my friend...but those bottom end noises really suck. Your looking at piston down $$$. :wack: If it was your top end perhaps OK (valve, lifter), but as stated... pulling that plug wire says it all. :sad2:
 
when i got my dart with a slant six it threw a rod out the #5 but this is a common problem for slants to blow on #5, not really sure why, i would run this question at slantsix.org or slantsix.com, those guys are very helpfull and could probably hook you up with a new motor somewhat cheap
 
Hi
I have enough extra parts to build you a new /6 but it is all 65 parts. My sugestion do not even start it again 'till you do this to buy a little time, pull the pan and replace the rod bearings if the crank is not too bad clean it up a little with emery cloth.

I am in co. so shipping a motor would cost but I have extra rods.... I even have 2 sets of bearings.
 
thanks to all that have responded. i am taking it this saturday to a local guy who supposedly is the local guru on mopar engines and have him listen. i appreciate the offer for parts but before i would fix the six i would put my 340 in as I don't need the car accept for pleasure driving and was just hoping it was an exhaust leak. Pulling the plug wire would cause the cylinder not to fire,with less compression and quiet an exhaust leak???? Is this a possibility or just wishful thinking???????? thanks again to all!!!! your mopar brother WALT :salut:
 
Pagilman did you ever see the movie "Stripes" with Bill Murray. One of his lines was, blew up sir-blew up real good. Sorry to say but what you probably got there is a bad rod bearing getting ready to blow up "real good". :sad:
 
pagilman said:
thanks to all that have responded. i am taking it this saturday to a local guy who supposedly is the local guru on mopar engines and have him listen. i appreciate the offer for parts but before i would fix the six i would put my 340 in as I don't need the car accept for pleasure driving and was just hoping it was an exhaust leak. Pulling the plug wire would cause the cylinder not to fire,with less compression and quiet an exhaust leak???? Is this a possibility or just wishful thinking???????? thanks again to all!!!! your mopar brother WALT :salut:
Click to expand...

Another 60/40 call? Your right, pulling the plug wire will quiet your exhaust from that cylinder; but then again, pulling the plug wire means no power stoke which therefore puts less rock and roll on your piston pin, piston rod ect. I think ya know what I mean.....But, wishful thinking or hoping is not a bad thing. I will cross my fingers for ya, :prayer: and hope for the best. You will have to let us "all" know when you find out.
 
and /6s are known for exhaust leaks and broken manafolds so maybe 70/30 good luck
 
If ya need/want an entire slant 6 198 motor let me know , I have one rebuilt for racing, never used , Started and never even broke it in.... just laying around rusting away now. Cause I felt V8 Power :) Though I was planning to try n turbo this motor.
 
Clicking/ Tapping/ Rapping/ Slapping is usually top end noise but the bottom end can start this way, heavy knocking is botton end. Is the sound at engine speed or twice engine speed?? engine speed noises are engine problems from the piston down. Twice engine speed noises are the Camshaft and up. You can put A long screwdriver on different engine parts lower block, valve cover, exhaust manifold etc. and listen at the handle similar to a stethescope, the noise will be more obvious near the problem area. I have found bad Alt bearings and bad valves this way.
 
Eric_S68 said:
If ya need/want an entire slant 6 198 motor let me know , I have one rebuilt for racing, never used , Started and never even broke it in.... just laying around rusting away now. Cause I felt V8 Power :) Though I was planning to try n turbo this motor.
Click to expand...

:notworth:
still on the road and haven't had a chance to get a mopar guru to listen to my duster, but will post as soon as I can get home. Eric what do you want for the /6banger, walt
 
check the fuel pump, i put a new one on my 76 sport, it knocked. the sound came from the lower end. i used a steposcope to find it. just another place to look.
 
You must log in or register to reply here.
-

Back
Top