- This topic has 100 replies, 10 voices, and was last updated 9 years, 1 month ago by
.
-
Topic
-
EDIT: Read post: http://ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/41968-86-volvo-740-turbo-vibration-and-noise-issues?start=70#83381
Greetings all the way from Norway!
I have an issue with my 1986 Volvo 740 Turbo Intercooler that I can’t find any solution to. When driving past 60 km/h the car start to vibrate. I have had my car to a couple of different workshops, but none have managed to get it fixed.
Thought I could mention some technical specs about the car.
Engine – B230ET (134kW, turbocharged)
Injection system – Bosch Motronic ML 1.0
Gearbox – M46 (manual 4-speed + electric activated overdrive)
Rear axle – 1031 (torsen differential)Here is a runthrough of what I’ve done so far:
* Replaced every bushing on the car.
* Replaced engine mounts and gearbox mount.
* Replaced bushing and bearing for the driveshaft.
* Replaced the gearbox with one driven approx. 100.000km
* Replaced the differential and had the rear axle at the Volvo dealer to check for slack. Found well within tolerance.
* New tyres and rebalanced them.
* Changed wheel bearings.
* Changed rubber coupling (hardy coupling) between the gearbox and driveshaft.There have been vibrations since I bought the car 10 months ago. It is a common problem that the bushing for the driveshaft goes bad (which causes vibrations), so I didn’t really see that as a problem. After changing it I also realized that the driveshaft had a loose piece inside it that were impossible to remove. I then bought a used driveshaft. The vibrations were now less intensive, but very noticeble. I then replaced much of the things mentioned above, without any luck. Had it at a workshop to get the issue sorted out, the driveshaft were then replaced again with another used one. Got the car back as “fixed”, but there were still vibrations. Turned out the workshop installed it wrong (splines mismatched the balance markings. I corrected that, now the vibrations are almost gone, but are still there. Doesn’t look like any workshop know how to fix a RWD car anymore. None have equipment to measure angles etc.
Any suggestions on what to do here? This have been bugging me for a long time and won’t give up until it is fixed!
– Frank
-
Replies
-
What about the old DIY drive shaft balancing trick with two screw type clamps you move around until the vibration is gone? I’ve never tried this but it might be fun to test.
My car, a Japanese make AWD turbo car, will vibrate at speeds between 55 & 65 mph in 5th gear. How much or even if this vibration occurs depends on the tires I am running. As you might expect, the more expensive the tire the better the car likes it.
Yes, I’ve heard about that DIY trick. The dealership told me to do it. Have the car running and put a screwdriver to the drive shaft to find out the point where it would jump. Then put on a clamp at that spot and move it around. Personally I don’t feel comfortable being under the car when it is running. Especially when it needs to be at higher speeds. I’d rather leave the balancing to a professional with proper equipment.
I’ve had a breakthrough now! The workshop that did the mandatory technical inspection on my car also had a look at the vibration issue, as mentioned. They told me that if they were to troubleshoot it, they would have to try it spline for spline until the vibration is gone. Yesterday I pulled it off and rotated it 180 degrees and put it back together. Guess what… The vibration is now gone!
At least the speed related vibration… Now I noticed another parallel problem. The extra vibration and noise during load is still there. I did some testing and noticed that it only occurs between 1500-2000 RPM. Doesn’t matter which gear I’m in.
I’ve read on dedicated Volvo forums that tuning the engine I have (B230ET) isn’t a very good thing. Increased boost pressure will cause catastrophic failure for the engine, or deformed (bent) rods for the pistons. Since I have low compression in one cylinder, and the car have evidence of being tuned, I find this theory very possible.
As a side note. The turbocharger is supposed to output 0,53 bar g. If turned up, already at 0,8 bar g the engine is in the danger zone of damage. The rods are weak (9mm thick), and the next generation engines (B230FT or B230FK) got thicker rods (13mm thick).
I actually want it to be stock, but using an untouched ECU will cause the engine to cut out when the boost is at its highest. Apparently the 0,2 bar extra boost is enough to cause issues with the original chip. It simply doesn’t deliver enough fuel I suspect, since it is “out of range”. So I’m not going to add more boost, I’m actually going to lower it so I can use a stock ECU.
Haven’t changed the ECU yet, as I probably need to go to a workshop to get the turbo pressure adjusted correctly.
Anyhow, I’m out of ideas when it comes to the slight vibration and noise that occur at 1500-2000 rpm. The workshop that looked at it said everything is fine in the drive train, so it has to be the engine. Most likely the cylinder with bad compression causes imbalance that is transferred throughout the car. The vibration and noise goes away if I put the car in neutral or push in the clutch pedal.
I can also head a very faint metallic knocking sound from the engine. The mechanic that looked at the car say it might be one or more bad bearings inside the engine. Not a big issue at the moment, but will get worse. So I’m going to send the car away to get the engine overhauled after the winter.
I spoke with a mechanic regarding the flywheel in my car. I showed him a picture of how it looks like. His response was that he had never seen anything like it. Judging by how it looks, he thinks the source of the vibration is the flywheel. He said it have at some point had a lot of heat that have hardened the metal unevenly, making the surface brittle and uneven. That it is now slightly bent, not a 100% flat anymore. Does this sound like a possible cause?
I’m not a mechanic. I know that it does occur friction when engaging and disengaging the clutch, so I thought it was normal wear. The mechanic said that it should not occur THAT much friction during normal use. This flywheel he said show sign of very serious abuse and should be machined and rebalanced, or changed completely. Guess the flywheel needs attention at the engine overhaul.
Here is a picture of the flywheel:
[URL=http://s1218.photobucket.com/user/frankbilder/media/20130726_211239_zps7db3ae3a.jpg.html][IMG]http://i1218.photobucket.com/albums/dd414/frankbilder/20130726_211239_zps7db3ae3a.jpg[/IMG][/URL]
That fly wheel is cooked. Yes that could be a vibration source.
It is connected to the engine and if unbalanced will transmit that
unbalance/vibration to what it touches.I would price a new one. What
did the clutch look like? You may want a new clutch also.The clutch disc, pressure plate and thrust bearing is brand new. Changed everything when I changed the gearbox the last time. I took off the flywheel to change the seal behind it. Used new bolts and specified thread locker when I bolted it on again. Also used a calibrated torque wrench applied to the correct setting, and torqued it in a star pattern.
I changed the clutch disc and thrust bearing two years ago when I bought the car. The reason I changed everything this soon was because I got a grinding/whining noise when engaging the clutch. Changing everything (again) solved that issue.
I can mention that the clutch disc that was on the car when I bought it were usable, but was heavily worn. The springs in the disc were cracked to pieces and rattled.
I’ve been reading some more on this issue and have concluded with that I have what is called “clutch chatter”. When engaging the clutch, the car will shake a lot. Especially around 1500 rpm. This can also occur when changing to higher gears as well, not just when starting off in 1st. When driving I can feel slight vibration between 1500-2000rpm, which also causes noise in the back. A low frequency rumbling sound, like a propeller plane. The vibration is felt throughout the car, but mostly noticeable in the floor and steering wheel. Not felt as much in the seat as it did before when I had speed related vibration caused by the drive shaft.
Since the flywheel is very toasty, I guess it is the problem. In the pictures small surface cracking can be seen as well. It have visible symptoms that would cause these issues I’m experiencing.
Ordered a new flywheel from Volvo, as well as new bolts and center bearing for the gearbox axle. Going to get it changed with the engine overhaul. Been driving with this for two years now, so guess it will hold a few more months.
Nothing new has happened, yet. Thought I’d give a small update anyway on the current progress.
I’ve been in contact with a workshop to get an overhaul on the engine. I’m currently waiting to get a price estimate on the job, should get it tomorrow. They wanted to check out if it is possible to get a replacement engine for the car. I also want to get a full tune-up on the injection system, as it is currently running a rich fuel mixture. The turbo also output too much boost. The ECU also have a tuning chip installed, which I don’t want since it is illegal.
Hopefully the engine will be replaced/overhauled shortly after Easter. 🙂
[quote=”samaron” post=94233]Nothing new has happened, yet. Thought I’d give a small update anyway on the current progress.
I’ve been in contact with a workshop to get an overhaul on the engine. I’m currently waiting to get a price estimate on the job, should get it tomorrow. They wanted to check out if it is possible to get a replacement engine for the car. I also want to get a full tune-up on the injection system, as it is currently running a rich fuel mixture. The turbo also output too much boost. The ECU also have a tuning chip installed, which I don’t want since it is illegal.
Hopefully the engine will be replaced/overhauled shortly after Easter. :)[/quote]
Thanks for keeping us up to date. 🙂
- You must be logged in to reply to this topic.