V8 Balance Shaft

[tjmotter]

Sounds like a GREAT plan! Thanks!! I have a decent DeWalt boroscope that needs a workout

Todd

[tjmotter]

I got a really good look at the bearing with a side camera and it looks like new. This vehicle has 160K on it but has the drainhole so it looks like you are correct. With the drainage issue fixed, this bearing doesn't appear to wear out.

thx
Todd

[bobsepe]

V8 Counter Balance Shaft Replacement Work-Around

The trusty V8 with 251K began clucking like lose bolts in a can. At first, I thought the noise emanated from a serpentine idler pulley with a dry bearing, but no, it was the counterbalance shaft. The shaft sits between the two cylinder heads and deep inside the motor. The shaft has front and rear sealed bearing that are not lubricated by motor oil.

This noise went on about a week before I identified the problem. Unrepaired, the engine would self destruct due to the loss of timing. In this event, many owners are advised to junk the car as the cost to replace the counterbalance shaft is $6000 plus parts. The flat rate time for this job is 46 hours.

Counterbalance shaft (CBS) failure is a known problem allegedly caused by the accumulation of water in the CBS cavity. Volvo "resolved" the problem by drilling a weep hole in the CBS cavity adjacent to the rear bearing cap. This problem is a design failure by Yamaha. Placing sealed bearings in a hot motor rotating at 2500-6000 rpm is poor judgment.

In reality, the bear seal fails due to time and heat; the dry bearing begins to chirp. To keep the vehicle, I have to change the bearings or find a way to lubricate them. Typically, the rear bearing, between cylinders 7 and 8, is the first to fail.

Not anxious to remove the intake manifold, the Bank 1 exhaust manifold and cylinder head, I decided a work around was required. (Creativity is a wonderful thing.) Removing the intake manifold, fuel injector rail and other plumbing exposed the CBS cover. On the cover are two spark knock sensors. Upon removing both, I was able to peer through the opening into the chamber, which appeared dry and not crusty.

Conjecturing my 2006 V8 was one of the pre weep hole motors, I could fill the cavity with 90 weight gear lubricant to lubricate the ball bearings. Shortly after pumping a pint of 90W into the chamber, I observed a puddle on the floor. Yup, it had a weep hole. This wasn't going to work. Then, I reasoned, why not pump graphite lube with a consistency greater than honey into the chamber. Heat from the engine would cause it to flow, but ever so slowly. One tube of graphite grease later, I replaced the knock sensors and intake manifold.

The moment of truth, I hit the starter and the V8 roared, settled down to its 750 rpm idle and nary a chirp from the counter balance shaft. I had to use a stethoscope to detect a slight bearing noise from the CSB. Time spent, 4 hours.

Yes, a temporary fix good for 10K-15K miles; long enough to develop ambition to tear into the V8 on a cool Fall day as working in the 93° - 103°F summer heat is no fun. At that time, I might refresh the piston rings and bearings.

It is only possible to use this technique when the ball bearings have been destroyed, but are just dry. If the bearings have been ground into dust, they must be replaced. And I am developing a short cut method for that as well.

Questions; contact me at [email protected]

[bobsepe]

When counterbalance shaft bearings have NOT been destroyed...

[mcoluccio]

Hello everyone!
I'm the new owner of a 2008 xc90 v8 sport. I've owned a 2007 xc90 v8 for about 2 years and absolutely love it. So now I have two! I paid $2000 for it so I felt like it was a good deal. The car had regular maintenance at a Volvo dealership. He even had the oil changed and detailed at the dealership! The stack of receipts is as thick as a Stephen King novel...

Unfortunately, I think I may have the dreaded counterbalance issue. I put a stethoscope on the right side of the intake manifold and heard the very distinctive clank of the bearing gone bad. It's not as loud as most people have experienced but it's definitely audible to the naked ear. There's also a loud rattle sound when the engine is rev'd. not quite the sound of the bearing but more like pennys in a can kind of rattle... My engine serial is in the 6900's which I thought meant the car had the drain hole fix. Also, The engine was apparently never washed. I got a borescope coming Saturday to have a look at if the hole was actually drilled. I know another owner noticed that the indent for the hole was there but not drilled.

I did find a receipt from the Volvo dealership stating that they could not diagnose the noise. Instead, they gave an estimated $750 to just diagnose the issue. I'm actually pretty surprised that a dealer would not know this well-documented issue so it makes me wonder...

I remember reading on some forum that someone found a loose bolt inside the upper intake manifold. He replaced the manifold and the noise was gone. I wonder if this may be the issue with mine. it had a similar sound to mine and it went away when he touched the "airflow valve??" I honestly don't remember the name of it. I've been trying to locate the forum post but I can't find it again. Does anyone here remember where that post is?

FYI, Some things replaced on the car recently are the bearings for the serpentine belt, the PS pump, alternator, and water pump.

2008_Volvo_XC90_V8_Sport.jpg

[bmdubya1198]

Nice, I love the passion red! Sounds like it may be the balance shaft bearing, but you’d probably have to take a video.
The good news is all the other stuff that should be done has been done already! Those pulleys will make a hell of a racket.

[bobsepe]

All Volvo V8s have a problem. It seems Yamaha built the engine and noticed it did run smoothly due to the 30° cylinder bank separation. The vibration problem was solved by fitting a counterbalance [CB] shaft in the valley between the cylinder banks. A sprocket and bearing were added on one end to engage the timing chain and a 2" roller bearing fitted on tail end.

The front bearing is lubricated by engine oil within the timing cover; the rear bearing is an external sealed roller bearing. This is a poor design, because roller bearings have a limited life. Somewhere after 135K miles the rear bearing fails and the CB wobbles within the outer bearing race making a racket sounding like piston slap. Eventually the CB breaks, the timing chain binds, cams freeze and valves collide with pistons rendering the engine scrap.

At 260K miles I noticed a piston slap sound and did the usual testing and concluded the CB rear bearing failed. Consulting the Volvo remove and repair manual, the repair procedure requires the engine-tyranny cradle to be lowered to the ground and slid out from beneath the vehicle. The next step is to remove the timing cover, bank 1 cylinder head to secure access to the CB cover plate and bearing cap. Replace the bearing ($30), install the cylinder head and position the timing chain correctly. Time: 43 hours plus gaskets and assorted hoses and parts.

Studying the problem, I devised a plan to replace the bearing without disassembling the engine. Removing the intake manifold provides access to the CB cover and rear bearing cap. Once removed, the old bearing could be slid off and the new bearing installed; a 6 hour job. I had to fabricate special tools to remove the access plate cover and bearing cap.

I used my torch to heat and bend a long 8mm box wrench to loosen and remove the access plate cover. One down and the bearing cap to go.

Yamaha used three T40 tamper proof fasteners to secure the bearing cap and not regular hex head fasteners. Space between the torx fastener and the head is tight; therefore, I fabricated a T-40 tool I could turn with a 1/4" swivel head hex ratchet while applying downward pressure.

I am uncertain how many inch pounds of torque I applied, but the tamper proof fasteners refused to break free. Heat was applied with an acetylene torch, but that did not help. I realized lock-tight was likely applied to the bolt treads and an impact wrench would be necessary to break the fasteners free. I noted it'd be impossible to use an impact wrench without removing BOTH heads to gain access to the torx fasteners with an impact tool. Knowing excessive torque would damage the recessed torx female fitting; the resultant damage would needlessly complicate the process.
Hex fasteners would have been possible to remove because the surface area is much greater and more pressure could be applied. Yamaha needlessly complicated the extradition.

Frustrated, I reluctantly reassembled the engine and decided this project must be postponed until the day time temperature regularly exceeded 60°F, or March 2021, as I work outside.

This otherwise straight forward repair has morphed into a major engine overhaul. As such, I may as well replace the pesky torque converter lock-up solenoid plus the transmission clutch pack whilst I've access to it.

If your bearing cap is not fastened with torx tamper proof bolts, you can do as I'd planned. If you want pictures of the tools, email me at [email protected]

You must not drive the vehicle in this condition because it will result in catestrophic damage to the motor. the following is a temporary work around..

The shaft sits between the two cylinder heads and deep inside the motor. The shaft has front and rear sealed bearing that are not lubricated by motor oil. Unrepaired, the engine will self destruct due to the loss of timing. In this event, many owners are advised to junk the car as the cost to replace the counterbalance shaft is $6000 plus parts. The flat rate time for this job is 46 hours. Some shops can do it in as little as 2 days. But you have to remove the heads, replace the head gaskets, etc. The engine-tramsmission cradle has to be dropped to the floor and slid out from beneath the vehicle so you can remove the heads to gain access to the counterbalance shaft. You also have to remove the front timing chain cover. If you choose to put a used motor in this vehicle, you must first install a new counterbalance shaft tail bearing. (It's $30.) Otherwise you'll be back in the same place in a year or two. There are no two ways about it, if you intend to keep this vehicle, you've got to remove the heads. I plan to implement a lubrication strategy for the replacement bearing so I never have to do this again. BTW, I've 2 of these vehicles.
*******************************************************
Counterbalance shaft (CBS) failure is a known problem allegedly caused by the accumulation of water in the CBS cavity (This is not true!). Volvo "resolved" the problem by drilling a weep hole in the CBS cavity adjacent to the rear bearing cap. This problem is a design failure by Yamaha. Placing sealed bearings in a hot motor rotating at 2500-6000 rpm is poor judgment.

In reality, the bearing seal fails due to time and heat; the dry bearing begins to chirp. To keep the vehicle, I have to change the bearings or find a way to lubricate them. Typically, the rear bearing, between cylinders 7 and 8, is the first to fail.

I decided a work around was required. Remove the intake manifold, fuel injector rail and other plumbing exposed the CBS cover. On the cover are two spark knock sensors. Upon removing both, I was able to peer through the opening into the chamber, which were dry and not crusty.

I pumped graphite lube into the chamber using a grease gun and a needle adapter. Heat from the engine will cause the lube to flow, but ever so slowly. One tube of graphite grease later, I replaced the knock sensors and intake manifold.

I hit the starter and the V8 roared, settled down to its 750 rpm idle and nary a chirp from the counter balance shaft. I had to use a stethoscope to detect a slight bearing noise from the CSB. Time spent, 4 hours.

Yes, a temporary fix good for 10K-15K miles. It is only possible to use this technique when the roller bearings have not been destroyed, but are just dry. If the bearings have been ground into dust, the bearing must be replaced.

If you care to talk about this, email me at [email protected]

Good luck.

[Hermarcel]

I remember reading on some forum that someone found a loose bolt inside the upper intake manifold. He replaced the manifold and the noise was gone. I wonder if this may be the issue with mine. it had a similar sound to mine and it went away when he touched the "airflow valve??" I honestly don't remember the name of it. I've been trying to locate the forum post but I can't find it again. Does anyone here remember where that post is?

https://www.swedespeed.com/threads/the- ... st-2221853
https://www.swedespeed.com/threads/knoc ... st-6139114

[mcoluccio]

I remember reading on some forum that someone found a loose bolt inside the upper intake manifold. He replaced the manifold and the noise was gone. I wonder if this may be the issue with mine. it had a similar sound to mine and it went away when he touched the "airflow valve??" I honestly don't remember the name of it. I've been trying to locate the forum post but I can't find it again. Does anyone here remember where that post is?

https://www.swedespeed.com/threads/the- ... st-2221853
https://www.swedespeed.com/threads/knoc ... st-6139114

That's it, Thank you!

[mcoluccio]

All Volvo V8s have a problem. It seems Yamaha built the engine and noticed it did run smoothly due to the 30° cylinder bank separation. The vibration problem was solved by fitting a counterbalance [CB] shaft in the valley between the cylinder banks. A sprocket and bearing were added on one end to engage the timing chain and a 2" roller bearing fitted on tail end.

The front bearing is lubricated by engine oil within the timing cover; the rear bearing is an external sealed roller bearing. This is a poor design, because roller bearings have a limited life. Somewhere after 135K miles the rear bearing fails and the CB wobbles within the outer bearing race making a racket sounding like piston slap. Eventually the CB breaks, the timing chain binds, cams freeze and valves collide with pistons rendering the engine scrap.

At 260K miles I noticed a piston slap sound and did the usual testing and concluded the CB rear bearing failed. Consulting the Volvo remove and repair manual, the repair procedure requires the engine-tyranny cradle to be lowered to the ground and slid out from beneath the vehicle. The next step is to remove the timing cover, bank 1 cylinder head to secure access to the CB cover plate and bearing cap. Replace the bearing ($30), install the cylinder head and position the timing chain correctly. Time: 43 hours plus gaskets and assorted hoses and parts.

Studying the problem, I devised a plan to replace the bearing without disassembling the engine. Removing the intake manifold provides access to the CB cover and rear bearing cap. Once removed, the old bearing could be slid off and the new bearing installed; a 6 hour job. I had to fabricate special tools to remove the access plate cover and bearing cap.

I used my torch to heat and bend a long 8mm box wrench to loosen and remove the access plate cover. One down and the bearing cap to go.

Yamaha used three T40 tamper proof fasteners to secure the bearing cap and not regular hex head fasteners. Space between the torx fastener and the head is tight; therefore, I fabricated a T-40 tool I could turn with a 1/4" swivel head hex ratchet while applying downward pressure.

I am uncertain how many inch pounds of torque I applied, but the tamper proof fasteners refused to break free. Heat was applied with an acetylene torch, but that did not help. I realized lock-tight was likely applied to the bolt treads and an impact wrench would be necessary to break the fasteners free. I noted it'd be impossible to use an impact wrench without removing BOTH heads to gain access to the torx fasteners with an impact tool. Knowing excessive torque would damage the recessed torx female fitting; the resultant damage would needlessly complicate the process.
Hex fasteners would have been possible to remove because the surface area is much greater and more pressure could be applied. Yamaha needlessly complicated the extradition.

Frustrated, I reluctantly reassembled the engine and decided this project must be postponed until the day time temperature regularly exceeded 60°F, or March 2021, as I work outside.

This otherwise straight forward repair has morphed into a major engine overhaul. As such, I may as well replace the pesky torque converter lock-up solenoid plus the transmission clutch pack whilst I've access to it.

If your bearing cap is not fastened with torx tamper proof bolts, you can do as I'd planned. If you want pictures of the tools, email me at [email protected]

You must not drive the vehicle in this condition because it will result in catestrophic damage to the motor. the following is a temporary work around..

The shaft sits between the two cylinder heads and deep inside the motor. The shaft has front and rear sealed bearing that are not lubricated by motor oil. Unrepaired, the engine will self destruct due to the loss of timing. In this event, many owners are advised to junk the car as the cost to replace the counterbalance shaft is $6000 plus parts. The flat rate time for this job is 46 hours. Some shops can do it in as little as 2 days. But you have to remove the heads, replace the head gaskets, etc. The engine-tramsmission cradle has to be dropped to the floor and slid out from beneath the vehicle so you can remove the heads to gain access to the counterbalance shaft. You also have to remove the front timing chain cover. If you choose to put a used motor in this vehicle, you must first install a new counterbalance shaft tail bearing. (It's $30.) Otherwise you'll be back in the same place in a year or two. There are no two ways about it, if you intend to keep this vehicle, you've got to remove the heads. I plan to implement a lubrication strategy for the replacement bearing so I never have to do this again. BTW, I've 2 of these vehicles.
*******************************************************
Counterbalance shaft (CBS) failure is a known problem allegedly caused by the accumulation of water in the CBS cavity (This is not true!). Volvo "resolved" the problem by drilling a weep hole in the CBS cavity adjacent to the rear bearing cap. This problem is a design failure by Yamaha. Placing sealed bearings in a hot motor rotating at 2500-6000 rpm is poor judgment.

In reality, the bearing seal fails due to time and heat; the dry bearing begins to chirp. To keep the vehicle, I have to change the bearings or find a way to lubricate them. Typically, the rear bearing, between cylinders 7 and 8, is the first to fail.

I decided a work around was required. Remove the intake manifold, fuel injector rail and other plumbing exposed the CBS cover. On the cover are two spark knock sensors. Upon removing both, I was able to peer through the opening into the chamber, which were dry and not crusty.

I pumped graphite lube into the chamber using a grease gun and a needle adapter. Heat from the engine will cause the lube to flow, but ever so slowly. One tube of graphite grease later, I replaced the knock sensors and intake manifold.

I hit the starter and the V8 roared, settled down to its 750 rpm idle and nary a chirp from the counter balance shaft. I had to use a stethoscope to detect a slight bearing noise from the CSB. Time spent, 4 hours.

Yes, a temporary fix good for 10K-15K miles. It is only possible to use this technique when the roller bearings have not been destroyed, but are just dry. If the bearings have been ground into dust, the bearing must be replaced.

If you care to talk about this, email me at [email protected]

Good luck.

Thank you so much for the info! I'm really interested to know if your method for fixing the CB bearing ends up working for you. Does having loctite on those bolts make it impossible to use your method?

I was not looking forward to removing one of the heads. I'll definitely contact you for some photos of the custom tools. Did Volvo move from using the tamper-proof torx bolts to another type of fastener at some point?

From what I can hear I have both issues with this car. The intake damper flap loose bolt and CB bearing!