Engine Knock, Opinions Before I Go In

[Mac Stew]

Valve springs looked good visually and seemed ok when turning the engine by hand but I won't be able to rule it out completely until I look at them while its running. I was also thinking about the possibility of a warn lobe on the cam, I know it can cause some of the symptoms I am having. Tonight I am going to take a closer look at how much each valve is opening when I turn it by hand and then if I have time to make a mess and someone to help I will get them to crank it and take a look at it under power, I think its really the only way I am going to track this down.

 

[plymouth67]

Does it miss while running...if it's not missing then I doubt it's a collapsed lifter. Could be a valve hanging up in the guide....had that happen before. Find the one hanging up and pour some tranny fluid on it and it should shut it up.

 

[Darthomas]

Broken spring normally results in major engine miss/shake.
Rx:
Seafoam in oil and the patience of Job.
If it's a lifter that's sticky, it will eventually free up.

 

[Mac Stew]

I don't actually think its missing, its not shaking, I didn't clearly hear a miss when it was running but I was more focused on the knock. I have a buddy coming over on Tuesday and he is gonna crank it for me while I look at it, should be able to locate it then. In the meantime while I was by myself I rotated the engine by hand and checked the travel on the valves, see if I could clearly see one not opening all the way and although I didn't measure them they all looked good. I also did a quick compression check, I haven't done one since I bought the car and was curious to see what I was working with in general, it was done cold because I didn't want to run it long enough to warm it up until I figure out what the knock is, results are attached in a pic, issue in #2? I did it at the beginning and again at the end and got the same reading both times. I will have to do it at temp once its fixed.

 

[Mike67]

Instead of cutting up valve covers either go to harbor freight and buy you a stethoscope or take an old broom handle and place it on each exhaust port while pressing your ear to the other end. You will very easily be able to identify which cylinder is causing you issues.
Darthomas is right about the sea foam, that stuff is pretty amazing for cleaning gunk out....certainly wouldn't hurt it.

 

[miller]

Yeah, #2 is low...I'd put a eyeball on it. If you still have the covers off, any chance one of the pushrods for #2 is bent? And, take a look at the tappets, where the pushrod end sits in the tappet 'cup'. With both tappets bottomed on the cam lobes, the tappet piston (cup), should be slightly pushed down, .010-.020 down from the retainer. Push on the rocker arms, to see if either tappet piston is hung. Of course, look at the cam lobes for wear.
Previous motor I fooled with had over half the pushrods bent, but on top of that, cam lobes looked okay, but many of the tappets had bad wear at the contact surfaces.

 

[mopar_man]

Hard to tell in the pic but did anybody have the rocker back bones off and got all the rockers mixed up and just put them back on not knowing that the intake and exhaust rockers are different ? If they are on wrong , the push rod is pushed to the side and can hang up or even be slowed down during the engine running .

 

[72Fourspeed]

If you have a timing light, shine it on the valvetrain. The strobe effect will let you see things that you wouldn' t otherwise. I once caught a bad lobe this way.

 

[Daves69]

Listening to a video is hard to determine. Did you isolate the knock sound area. Run it and try the broom/stethoscope deal per pri. Pull a plug wire one at a time listen for changes.
Out of the box, automatic? Loose TC bolt?

 

[Dako]

My money's on a bad / collapsed lifter...

If the motor 'runs fine' but is making that tapping sound, it's likely a lifter.

 

[oldbee]

Mac- just lay finger/s on each rocker while running,you'll feel where the noise is coming from. If a lifter collapsed you'll feel the noise and on that rocker try pushing down harder & see if noise quiets down.

 

[Rick Carson]

Engine looks very clean inside,not a sludge problem like I was leaning towards myself.We used to drain the oil and not the filter, then install 3 qts of "f"type trans fluid,very high detergent. Fire it up and let it idle,not raising the rpm at all.after about 10 minutes it would start ticking and banging and missing and then it would smooth out and you might have one little tick and the rpm would actually rise a little.Then shut it down and and change the oil and filter,restart and it would tick 2 or 3 times and then purr like a kitten.

 

[Rick Carson]

hey bud,you got this car for sale on kijiji ?

 

[Mac Stew]

Hey guys, quick update. Before my buddy came over on Tuesday I wanted to find the cylinder making the noise so I decided to pull each wire while its running to see if the noise stopped. Noise was coming from the passenger side so I started with #2 that had the low compression and when I pulled it the engine shut off. I thought that was weird seeing as a V8 can run with one or two cylinders not firing, it may shake and struggle but haven't had one shut down right away like that so I plugged it back in, started it up again and pulled #4, no change, plugged it back in and pulled #6, no change. Went through them all and found out that its only running on 4 cylinders. 1, 4, 6, and 7 weren't firing at all, remember I have never driven this car, I wouldn't be able to tell by the power missing or gas millage and the engine was running smooth and didn't sound like it was missing because it was running half the engine, every other cylinder in the firing order was firing correctly and it was smooth because of that. I remembered hearing this a while ago from a buddy that had the same issue and it was the carb as one side of the carb feeds 1, 4, 6, and 7. I took the carb off and did a quick clean on it, I couldn't do a full rebuild as I didn't have the rebuild kit and gaskets but I cleaned out the idle screws and passages and when I put it back all the cylinders fired and the noise was gone. So long story short it was the carb, guess a lesson in KISS, keep it simple stupid, I should have pulled each wire first and seen which was causing the noise and caught this a long time ago.

Once I got it running I went to pull it out and it wouldn't go into gear, it has been sitting since, I have been so busy with work and with family I haven't had a chance to look at it and by my schedule now it may be a bit before I can get underneath and check why its not going into gear.

Yes Rick it is listed on Kijiji as I don't have the time to fix it and enjoy it right now. With my work schedule, my 2 year old daughter and my wife being 7 months pregnant I just don't have the time this car deserves. I am not going to give it away and if I don't get a decent offer from someone who will take care of it I'm definitely going to keep it and fix it over time. I know that if I sell it I will be kicking myself in a couple years when my schedule hopefully gets a little lighter, I will probably be looking to buy another Mopar so storing it and working on it slowly may be the best thing. I listed it to see if there was any interest but will most likely keep it as it is a solid car, frame, floors, suspension, interior and body (minus paint) are all great, little mechanical work and its good to go so it will be tough to sell.

 

[HT413]

Something you might try... with valvecovers on and engine running, use a screw driver as a stethoscope. Put the handle firmly against your ear and tip against the valve cover over each rocker. Might help you pin point the noise.

 

[Mac Stew]

Got an email from someone looking to come see the car and I couldn't do it, I can't sell it, took the ad down. I'm going to keep it and fix it up, may take a bit of time but it will be on the road at some point.

 

[polywideblock]

 

[Rick Carson]

Well the best of luck to ya either way. Especially with the new edition in a couple of months.Family first, but mopars and friends a close second.

 

[SlinktRR]

so you are saying that cleaning the carb allowed it to start running on all 8? Please confirm because that doesn't sound right, I may have misread your post.