Hello all. I posted this problem and some follow-ups a couple of months back on another forum. I received all the standard answers/suggestions, but I ran that forum out of constructive answers. I think I need some inline 6 experts to think outside the box. I puchased a 65 Mustang last November for my wife. Car has 200 ci inline, and C4 automatic. The car has been a mechanical nightmare. I have addressed and fixed all concerns/problems except for one. The engine has a terrible vibration at idle in gear. It is noticable in park, but not anywhere near as extreme as in gear under load. Just to fill in the background. Timing was set to 12 degrees with timing light and vacuum disconnected. Idle was set to 500 rpm in gear. Both engine mounts have been replaced and are on correct sides. Transmission was removed and overhauled (due to knocking noise at front pump/torque converter area). Transmission was reinstalled with rebuilt/new torque converter, new flexplate and new mount. Distributor has been replaced with rebuilt one that I added a Pertronix Ignitor to. Ignition coil, distributor cap, rotor, plugs and plug wires have all been replaced. Autolite 1100 has been overhauled and reinstalled. I have had no issue setting carb. or timing. Timing cover was cracked, so I replaced with a good used one. I installed new timing chain with gears, new damper/balancer, new water pump and thermostat when I reassembled. I have no vacuum leaks. I have checked, double checked and triple checked. Fuel pump is new with new filter in canister. I don't know the history of this car or the engine. The engine has been apart, but I still have not figured out why. Somebody (who shouldn't have been working on cars) had the timing cover off (which they cracked), and the head/intake off. They painted them the wrong color along with the valve cover and air cleaner, before they reinstalled them. I know they also had the transmission out before I did, because alot of things were loose and poorly reinstalled. I don't believe the engine has been out of the car, because the oil pan does not appear to have been removed or re-painted. I know this is alot of info, but I'm at my wits end. Could something be internally bent or broken or wrong? I know it is a stretch, but could the crank be bent, the cam worn out, or something internal? I would like some suggestions before I remove the engine. Once I do that, I'm in for an overhaul. I'm in too deep now to guess anymore. The vibration is definitely in/from the engine. I can hold the chassis, transmission, exhaust, body and the rest of the drivetrain and not feel the vibration. Nothing is rubbing anything externally. Thanks for any/all help.
Engine Vibration
- Thread starter 67xl390
- Start date
8)
i think this is a big part of your problem. your idle speed should be higher in gear, closer to 650-700. i would also "power time" your engine rather than rely on the timing marks on the dampner. you do this by advancing the timing until you get detonation under acceleration, then back the timing off until the detonation stops.
i think this is a big part of your problem. your idle speed should be higher in gear, closer to 650-700. i would also "power time" your engine rather than rely on the timing marks on the dampner. you do this by advancing the timing until you get detonation under acceleration, then back the timing off until the detonation stops.
Rbohm, I understand where you are coming from. I don't have a vacuum reading. No vacuum gauge. I have hosed down every area with carb. cleaner where I could have a possible vacuum leak. No change to idle or running. I did replace the carb. adapter to intake gasket. The vibration really does not seem like running condition, like rough idle or misfiring. Idle is smooth. Does not fluctuate up or down. Engine does not shake or stumble. Vibration is physical. Hard to explain I guess.
2nd try...
sry for the extra questions... IDK so I'm asking
how did the piston tops look? any pitting?
how did the cyl walls look? all smooth?
does it still vibrate with more RPM/throttle? does it get worse with RPM/throttle? or does it stay consistant with RPM/throttle?
what about the mech fan?? take it off and try IDLE in park and Drive? watch the temp.... it should be enough time to figure out of the fan in unbalanced. give it throttle, does the vibration act the same?
if all else fails, take the block, assembled to a engine shop, and they should be able to rotationally balance the engine, or at least TEST if it's balanced before they tear it down. might be extra but would be worth to know if it was unblanced before you overhaul it...
I don't think a CAM would casue a big vibration, other than running lol, it's possible that you could have lost a lobe, take your oil pan off and you can see the cam shaft. rotate the engine to see the FULL duration of EACH lobe, intake and exhaust...
okay, all my idea's are spent... you have already thought of what I would have replaced and checked as basics, so I Don't Know at this point... Good luck and keep us updated.!!!
sry for the extra questions... IDK so I'm asking
how did the piston tops look? any pitting?
how did the cyl walls look? all smooth?
does it still vibrate with more RPM/throttle? does it get worse with RPM/throttle? or does it stay consistant with RPM/throttle?
what about the mech fan?? take it off and try IDLE in park and Drive? watch the temp.... it should be enough time to figure out of the fan in unbalanced. give it throttle, does the vibration act the same?
if all else fails, take the block, assembled to a engine shop, and they should be able to rotationally balance the engine, or at least TEST if it's balanced before they tear it down. might be extra but would be worth to know if it was unblanced before you overhaul it...
I don't think a CAM would casue a big vibration, other than running lol, it's possible that you could have lost a lobe, take your oil pan off and you can see the cam shaft. rotate the engine to see the FULL duration of EACH lobe, intake and exhaust...
okay, all my idea's are spent... you have already thought of what I would have replaced and checked as basics, so I Don't Know at this point... Good luck and keep us updated.!!!
MPGmustang, Thanks for the suggestions/help. I appreciate it. I have not tried without the fan. Could be possibility. With engine rpm raised to about 1000, vibration is gone. Throttle is responsive and as I said, vibration is not a misfire type shudder/shaking. It is harmonic. If I grab the oil pan with engine running and in gear, I can feel the vibration. Holding anything else yields no vibration. I have not had the cylinder head off, so I don't know the condition of the pistons or cylinder walls. Previous owner/repair person had head/intake off at some point. I am more worried today that there is an internal engine issue. The exhaust manifold that is on the engine is from 1960/1961 Falcon according to the stamping number. I blew this off as installed by somebody to replace original cracked/damaged one, but now I figured out yesterday that the oil pan is also from an older engine possibly same 1960/1961 Falcon. The drain plug is at the rear of the sump, not the side like all the 200 ci pan pictures I have seen. I only found 1 photo online of my pan, and the photo claimed it was the pan from a 1960 Falcon with a 144 ci? According to the stamping numbers, the block is original as well as the head/intake, but everything else is becoming highly suspect of being cobbled together.
Gene Fiore
Famous Member
I'm with MPGMustang on maybe a fan issue? Try removing ALL belts and start it up to see if you still have the vibration. Keep us updated.
Is the oil pan straight or is there a dent or dents?
I wonder if it has an aftermarket cam...
My engine has a horrible harmonic 'thump' on lower RPM settings... it just comes naturally they way it runs when RPM is low... nothing wrong with it and once I reach 800rpm it smooths out.
if it was an unbalanced engine it would just get worse continually and literally SHAKE itself to death... but this vibration IMO is not harmonic... like when my presure plate was un-balanced, it got worse with higher RPM... dangerously worse.
these are opinions, and in mo mean are meant to be fact... I think... I don't know.
My engine has a horrible harmonic 'thump' on lower RPM settings... it just comes naturally they way it runs when RPM is low... nothing wrong with it and once I reach 800rpm it smooths out.
if it was an unbalanced engine it would just get worse continually and literally SHAKE itself to death... but this vibration IMO is not harmonic... like when my presure plate was un-balanced, it got worse with higher RPM... dangerously worse.
these are opinions, and in mo mean are meant to be fact... I think... I don't know.
67,
This is in response to you and Stu also.
Think about a missing/broken piston skirt/loss or gain of compression on one or two cyls;
a plug gap accidently bumped closed; worn cam lobe--mentioned already.
Its possible you have a partially or severely blocked exhaust port/header branch. One more important possiblity is a bent connecting rod from fluid or whatever being trapped above the piston at some time. I've seen these examples before, even on diesels. Many a muscle car had bent rods from carwash water entering hood scoops,etc.
You might also want to look for missing material from crank/rods/pistons,but not likely. Look at rods to see if placed in wrong cyl,installed backwards, caps mixed up---.
Hope this helps. Good luck.
Gary
This is in response to you and Stu also.
Think about a missing/broken piston skirt/loss or gain of compression on one or two cyls;
a plug gap accidently bumped closed; worn cam lobe--mentioned already.
Its possible you have a partially or severely blocked exhaust port/header branch. One more important possiblity is a bent connecting rod from fluid or whatever being trapped above the piston at some time. I've seen these examples before, even on diesels. Many a muscle car had bent rods from carwash water entering hood scoops,etc.
You might also want to look for missing material from crank/rods/pistons,but not likely. Look at rods to see if placed in wrong cyl,installed backwards, caps mixed up---.
Hope this helps. Good luck.
Gary
Thanks again to everybody. Everybody thinking outside the box. It's great. The oil pan does not have any dents in it. I did check this out when I had the transmission knocking problem. Thought the crank was hitting the inside of the pan. It is not. The aftermarket cam is a possibliity, but wouldn't a cam be more lopey than vibrating? I can turn the idle up, but then it hits into gear too hard, and when the idle comes down in gear, the vibration is still as noticable, even if the in gear rpm is 800-900. I don't think the engine is internally unbalanced as much as I think something is wrong/broken/incorrectly assembled internally. I agree that if it was internally unbalanced, the vibration would get more violent and noticable the higher the rpm went. I did do a compression test. All cylinders checked out from 145 to 160 psi. All within 10 percent of each other. I removed the new set of plugs over the weekend, and installed another new set after checking the gap on all of them. What really has me stumped is that the engine runs fantastic, has great throttle response and is smooth in park and while driving. The vibration is only present in gear at idle. Can anybody think of anything internally that could have been installed incorrectly or damaged that could cause this, but yet not present itself as a noise or knocking or something other than vibration? Like I said, somebody unqualified had this engine apart before and I still have not figured out why, which makes me wonder if I am chasing my tail and should just start tearing it apart from the top down. Is there anything in the valve train that could be the source without being noisy? Should I pull the valve cover and take the valvetrain apart to look at anything, or is my problem probably in the bottom end? I am not giving up on this car, because my wife loves it. I just don't want to needlessly pull the engine out and overhaul it. It is cold in the midwest without any heated garage! Thanks again.
Two simple things you can try.
First try to isolate it to one cylender by removing each spark plug wire one at a time and noting the results. Takes about 5 min. but you must use a tool for this as you could get shocked.
Second, saw this in another post here, remove all the belts to eliminate any vibs coming from auxilery equipment.
Good luck.
First try to isolate it to one cylender by removing each spark plug wire one at a time and noting the results. Takes about 5 min. but you must use a tool for this as you could get shocked.
Second, saw this in another post here, remove all the belts to eliminate any vibs coming from auxilery equipment.
Good luck.
67,
Another thing I forgot to mention: you could have carbon build-up on an intake valve or seat area making breathing restriction.
You could still obtain compression reading and maybe fair idle. At higher speeds power would be down but roughness maynot be evident.
In addition to shorting-out plugs you could have someone do a power/balance test to possibly isolate trouble.
Good luck. Keep us posted.
Gary
Another thing I forgot to mention: you could have carbon build-up on an intake valve or seat area making breathing restriction.
You could still obtain compression reading and maybe fair idle. At higher speeds power would be down but roughness maynot be evident.
In addition to shorting-out plugs you could have someone do a power/balance test to possibly isolate trouble.
Good luck. Keep us posted.
Gary
chessterd5
Famous Member
hello, have u pulled the belt(s) yet? THERE'S A POSSIBILITY U HAVE A BEARING OR BUSHING GOING OUT IN AN ALTINATER OR POWER STEERING PUMP. It doesn't nessacarily have to squeal or make noise to be bad. Had any charging problems. If it has power steering try cranking it all the way one way then the other to see if the vibration gets worse. If u pull the belts & it goes away then reinstall 1 belt at a time till it returns. Then BEING VERY CAREFUL!!!!!! while the engines running use a long screwdriver as a stethescope by placing it on each of the accessories & holding it to your ear & follow the vibration till it gets the most intense. you'll know it will be bouncing in your ear! If u still can't find it in the accessories & you think it maybe internal then u can place the screwdriver on top of the valvecover above each cylinder one by one till you find the hole with the problem. One other possibility is oscilateing or vibrateing exhaust piping. check for broken loose or missing hangers. New car manufacturers put wieghts on their exhaust systems for this very type of reason.I hope this helps, thank you.
Ok, time for an update. Before that though, thanks to everyone that stepped up with more suggestions. Unfortunately, I am in the same situation I was in. The weather almost hit 40 degrees today, so I went outside to work on the car. I ran the car until it was warmed up and the choke was off. I then ran it without the belt on (no power steering, no a/c). Vibration the same. I then reinstalled the belt. I removed the front exhaust pipe from the manifold, thinking that the exhaust front pipe has been made to match the '60-'61 manifold and it is under more tension than it probably should be when bolted up, and maybe the exhaust was amplifying something. No luck. Vibration same with open exhaust. I even looked at vacuum leaks again. None. I took the valve cover off and ran the engine with the valve cover off. All rocker arms moving and valves all opening and closing. All valves seem to be opening and closed an even amount from what I can tell by visually watching valves. Pushrods and rocker arms seem to be moving up and down straight if that makes sense. Seems to be no bent pushrods or broken rocker arms. Rocker arm shaft tight. I ran the engine removing one spark plug wire at a time, and each cylinder started to misfire without plug wire and then smoothed out when reinstalling wire. I am finally at my wits end, and have no more guesses, adjustments or parts I can replace. The next logical step that I can figure is to start disassembling the top end of the engine. If anybody has anything else to suggest before I do, then please let me know. Thanks again to everybody.
2 X what 69.5 Mav said: "... Mechanic's stethoscopes..."
louder when cold, when hot? on high revs? (neutral & in gear did not change it I seem to remember?).
use a hose or solid rod (hose may B more safe - 1) to manipulate, 2) if heated or thrown around) if cheep like me.
I saw no indication of U locating a general area (did I miss it?) of the sound & this may help B4 going to alot of expense in time/$ 4 diagnosis. U will need to craw around/underneath/left/right/frnt/back...
Keep talkin...
Luck to ya!
louder when cold, when hot? on high revs? (neutral & in gear did not change it I seem to remember?).
use a hose or solid rod (hose may B more safe - 1) to manipulate, 2) if heated or thrown around) if cheep like me.
I saw no indication of U locating a general area (did I miss it?) of the sound & this may help B4 going to alot of expense in time/$ 4 diagnosis. U will need to craw around/underneath/left/right/frnt/back...
Keep talkin...
Luck to ya!
thesameguy
Famous Member
Did you ever run the motor on a stand? Perhaps there is nothing wrong with the motor, but something screwy in the transmission!