Bad vibrations...

[Ski 61701]

Ok, now it sounds like you are narrowing things down. If you have a vacuum gauge hook it up to a good vacuum source, probably where you plug your pcv valve hose to. See how the needle fluctuates. Im sure there are charts on the web that will show you if you have X for vacuum look at timing, leaky valves worn rings etc. You might be on the way to figuring this out. Kudos to you for sticking it out and trying to solve the problem.

 

[Ski 61701]

Just had another thought, have you looked at your left front motor mount? Maybe its toast and thats whats causing you grief. Usually can check with car on the ground driveshaft installed and car in gear have driver start to brake torque while you look at the mount to see if its separating

 

[PP1RT]

Pull the valve covers and observe your rockers when running. Readjust rockers.

Is it possible it is valves not sealing?

Or not opening?

 

[Ski 61701]

https://www.motor.com/magazine-summary/mastering-the-basics-reading-a-vacuum-gauge/

 

[Dave145]

The heads are super coked up. The pushrods don't spin on half the cylinders till higher rpms. We tried to adjust the valves earlier (done cold to .012 and .024). Made the car run quieter...wonder if they are off because everything was so grimy? With the vacuum gauge hooked to the PCV hose, I get a solid 20" at idle and 15" in gear. When I hook the gauge to the tree off of cylinder #7, I get 20" at idle, at between 13-15 in gear (needle swings like Tarzan).

After replacing the coil, the car is MUCH smoother above 50mph (on the speedo). Still vibrates at 30-45 pretty bad. This happens with the trans in gear and in park.

The mounts are all rock solid. The rubber is pliable and not cracked.

 

[PP1RT]

Compression test?

 

[Ski 61701]

If its as bad as you say with gunk build up, and you've tightened valves up, they might not be seating properly now. Id loosen them up to at least factory specs, and like pp1rt mentioned do a compression check. Your valve faces / seats might be really out of whack after sitting for all of those years in the wonderful Midwest humidity.

 

[oldbee]

Just for giggles try removing the fan?

 

[Dave145]

I tried running it yesterday with all the belts off and that didn't change the vibration at all. I'll be de-gunking the heads and resetting the valves. Hopefully that works and if not I'll try the compression test.

 

[jim ritchie]

All advice given would usually resolve a vibration that accures at different speeds like you have and would have been from trans back to drive line, suspension,shocks,wheels or tires,but now you have narrowed it down to engine -transmission. It sounded earlier like engine ran smooth(maybe not)but if engine is stock,and seemed to run OK,look at torque convertor,flex plate next.This has gone full route and too bad you had to change so many parts ,but usually it should be fixed by now.Hope it is finally near the end.

 

[Dave145]

I've got the car back together and currently dumped seafoam into the oil to try and free things up. For what it's worth, prior to reinstalling the driveshaft, the vibration seemed to die down a bit as the foam was going through the system. I'm not expecting a miracle, but there's no way the converter is bad on a 73k mile car, and the flex plate did not seem to have any cracks or loose bolts.

Crossing fingers get that this thing is finally almost done.

 

[Dave L]

I've been reading your post.Maybe your stuck on your vibration being a suspension problem.You said earlier that your poly runs smooth now it not. I would look at a tune up, you may have a bad wire or a plug giving your headache

 

[Dave145]

Well followers, I have decided I am not worthy of being part of this club due to my financial standings. I have never seen a car need so very many parts replaced just to drive.

It still vibrates. No change at all. Knocks your brain loose 40-50 and again at 80. Surges at any constant speed. Now knocks because 10* of timing and 87 octane apparently don't get along.

Looks like only way to fix this turd is to manifest money out of air. Motor? Trans? Driveshaft? All three? Hey why not. After all, it doesn't matter that I've wasted all summer on this thing.

I know I shouldn't be this frustrated but I am. I never knew I'd need a charity fund to fix a single car. I'm not new to old vehicles as I own 5 in various States of completion. I'm not new to mopars, as I have a (now wrecked) '76 Dart.

I have no ideas left at this point. Besides checking the same thing over and over and over again, pretty sure everyone is.

Thanks for the help, but I quit.

 

[PP1RT]

You just need a fresh set of eyes on the car. Frustration sets in and a guy cant think straight. Find someone to help you out. I know there are a bunch of mopar guys in WI. Get some beer and cheese curds and you'll have more help than you know what to do with!!

 

[oldbee]

Usually the way it works out is something simple that everyone completely overlooked. The problem is there and solvable. I can almost guarantee it. Everyone is pulling for ya, and then comes the head scratching from "why didn't I think of that"!!!

 

[PP1RT]

And its a bitch tryin to troubleshoot without seeing and hearing the vehicle

 

[Thunderlugs]

Well followers, I have decided I am not worthy of being part of this club due to my financial standings. I have never seen a car need so very many parts replaced just to drive.

It still vibrates. No change at all. Knocks your brain loose 40-50 and again at 80. Surges at any constant speed. Now knocks because 10* of timing and 87 octane apparently don't get along.

Looks like only way to fix this turd is to manifest money out of air. Motor? Trans? Driveshaft? All three? Hey why not. After all, it doesn't matter that I've wasted all summer on this thing.

I know I shouldn't be this frustrated but I am. I never knew I'd need a charity fund to fix a single car. I'm not new to old vehicles as I own 5 in various States of completion. I'm not new to mopars, as I have a (now wrecked) '76 Dart.

I have no ideas left at this point. Besides checking the same thing over and over and over again, pretty sure everyone is.

Thanks for the help, but I quit.

DAVE.... You need a break no doubt! Just step back, Take some time away from this project, reload with with a clear head and retackle the project down the road ! Everyone on this site will be here to help out You have No Worries there! You can always stop by for a conversation. You know where to find me!
Thunder

 

[miller]

I know I shouldn't be this frustrated but I am.

I know you must be, and don't blame you one bit. But, also fully agree with the guys! Time to take a step back. Time to get a breath, forget it, for awhile...who knows, that light bulb might come on! It's something...just have to figure it out.
Hat's off to ya, man. You've given it a good run. Good luck, whatever you decide!

 

[jim ritchie]

If it helps,,most of us have had a problem that just can't be found easy ,,,and believe me after 70 years,,,there have been many problems,,,and also have had no money to just take it to someone and have them change parts until they find it! As all have said ,,take a break,,,sometimes the journey is rough but super sweet rewards when you do find it !As a club ,this is the best in the world for classic B body mopars,but also hard to solve problems ONLINE,,,I think I can speak for most members that have followed this site,,WISH WE WERE THERE TO HELP YOU IN PERSON !!

 

[Centerline]

After going through this thread again I think there is one thing mentioned that may point to the problem.

You said the previous owner(s) story on the car was a bit murky and that some questionable work had been done which needed to be corrected. I strongly suspect that some kind of work done to the engine/trans created a balance problem or a part has broken which is causing it. One thing comes to mind is a broken vane in the torque converter. It would not be evident at low rpm but would definitely show up under load or at higher rpm. ... just a thought.

The engine/trans is where you need to concentrate your efforts from here on. With luck it will probably wind up being more labor on your part than expense but you may need to pull the engine and trans for a minor rebuild to fix this. If the vibration is as bad as you say, its more than likely damaging internal parts of both so disassembly and inspection would be a prudent course especially if its all gunked up like you said.

With luck it will be something simple like the wrong flex plate or bad dampner.