V8 Balance Shaft

[bobsepe]

Oh yeah, if you think you can drop a junkyard V8 engine into your car without first replacing the countershaft bearings, you are fooling yourself.

[bmdubya1198]

Oh yeah, if you think you can drop a junkyard V8 engine into your car without first replacing the countershaft bearings, you are fooling yourself.

I always say, if you're going to replace the engine, always do everything possible while it's out. Especially when you have an engine that has a notorious problem, take care of it while you have the easy access.
My aunt just ran into this with her 4.0L SOHC Explorer. Those engines are known for timing chain issues, and the shop that replaced the engine (due to failed chain guides) dropped a used engine in. 6 months later, it just jumped timing due to the guide or tensioner failing... again. For a shop, it's just stupid to do this job without redoing the chains/guides/tensioners.

[Roger_850T]

If I picked up another V8, (which I'm thinking of,) I'd consider pulling the engine to fix everything that needed to be fixed. Of course the valve cover gaskets, and timing cover gaskets, and crank seal. It'd be easier to do the rear main seal, too. Replace all the hoses, too. But would I do the balance shaft bearings? Hmm, good question. A 2005 with the original bearing? Yes, and drill the hole. A 2008? Not sure. I'd try to see if I can do it without pulling the cylinder head - I wouldn't want to pull the cylinder head unless there was a good reason to, and I'm contemplating whether replacing the balance shaft bearing just on mileage is a good enough reason.

Does anyone know if the balance shaft bearing can be done without pulling the cylinder head? I suspect not, but wondering anyone has been able to do it.

Roger

[bmdubya1198]

I can't say I've heard of anyone doing it that way. I'll have to look around, because now I'm curious.

[bobsepe]

I spent considerable effort to made special tools to remove the counterbalance bearing shaft cover so I could replace the end bearing without removing bank 1 (1-3-5-7) cylinder head. It is not possible because the factory security fasteners are highly torqued. The CBS was installed prior to the installation of both cylinder heads. The fasteners beneath the bank 2 cylinder head can only be removed with long nose industrial vice grips once the bank 1 cylinder head has been removed. Once removed, I threw the fasteners as far as I could and replaced them with hex fasteners so I could service the bearing down the road without removing a cylinder head. I suggest you do the same. Beware you must remove the cam shafts and the 2 timing chains.

If you do not plan to remove the timing chain cover, which you should reseal because it leaks like a sieve. You'll need to remove the cam shafts to access the head bolts. When you tip the head, the valve pushers may fall out. Each is a different size and must return to it's original position otherwise you'll burn out the valves because you've changed the clearances. The cam shafts are hollow and break easily. I learned this the hard way and had to purchase a replacement exhaust camshaft.

You must retime the whole engine, banks 1 & 2 plus the master chain with the crank. Hint, place the crank on the timing mark before disassembly.

You really should NOT attempt to service the CBS without dropping the engine to the ground. You'll save time and aggravation by doing so.

Only after dropping it to the ground can the angle gear housing be refilled with gear oil. After 150K miles, it is almost dry. That's your next failure point.

Plan to install new brake pads and struts. Under stand that the struts on the V8 are taller than the struts used on the 5 and 6 cylinder models. This is to provide additional clearance between the tire and the bottom of the strut.
I've made videos on how to do all of this.. Budget two weeks to do this service. Once person can do it all, but helps makes it easier.

bob [email protected]

[bypass]

Good Evening Everyone,

Im currently taking the task for repairing the balance shaft bearing that exploded on the 2005 xc90 v8. I have everything currently broken down thanks to the wonderful instructions from OP and VIDA, but i am faced with a few issues for re-assembly that have put that brakes on my work.

1st. The Balance shaft is a bit worse for wear, since it spun inside the bearing while it was seized. I had a machine shop do their best with the damaged the contact surface where the replacement bearing is supposed to sit and level everything out, but realistically i would prefer to replace it if possible. I tried reaching out to Tasca but they said the back order for it was 7 to 13 weeks!

2nd, I cant locate ANY of the special tools to assemble the balance shaft back. I Looked on Tascas website as well as visiting my local volvo and they are telling me they are discontinued (i also asked to borrow if possible, the dealer said not unless my car is coming through their service center). I cannot find T9997025 ,T9997245,T9997246 at all, though a colleague of mine said i can just use a hammer and socket to set the bearing? He told me though that T9997248 is needed, since that is the only way to properly set the bearing clearance on the balance shaft.

So long story short, does anyone know where i can get these tools, especially T9997245? Also, if anyone has a source on a readily available balance shaft.

Thanks in advance!!

[bobsepe]

Hope you got this fixed.. I've a spare, slightly used, counterbalance shaft plus a bearing. I was able to accomplish the job without special tools.
Bob
[email protected]

[bypass]

Hi Bob,

I sent you a PM

[Roger_850T]

Hi bypass,

When I did this, I did not have either 9997025, 9997245 or 9997246.

7245 is only used for pulling out the balance shaft with the old bearings on it, when you don't care about the load going through the bearings because you're going to replace them. I used an appropriately sized bolt and some spacers, and a fabricated 7246 (see below)

For 7246 I fabricated a standoff with a piece of 3/8" steel and some bolts, and then just used a different, appropriately sized bolt in lieu of 9997245 to pull the balance shaft out. (I did transfer the locations of the bolt holes from the block to the steel to align the bolt holes, using the bracket that I removed from the engine.)

I do have 7247 and 7248.

7247 primarily ensures that you are pressing on the outer race when you press the shaft in. It's helpful, not critical, especially if you have a collection of press collars to use. An appropriately sized socket will also work fine.

I agree that 7248 mostly sets the clearance - also, in some of the operations, it ensures you are pressing on the outer race when you are putting it in, not on the inner race, so you don't damage the new bearing. I also have some pretty good dimensions for it. (I just sent them to someone on Facebook recently - was that you?) I can send you the dimensions if you want to try and fabricate it.


For 7025, it's primary function is also to ensure that you are only pressing on the inner race when you press the bearing on to the shaft. Any convenient socket of the right dimensions should suffice, which is what I did.


I bought several of the tools from a place in Europe. https://www.carparts-pros.com/ If you enter 9997248 in the part number box, it still comes up. I Bought 9997196, 9997247, 9997248, and 9997279 from them, in 2019 it was 119.10 Euro for the parts, plus 89 Euro for shipping. I just checked, it looks like the prices have gone up a bit from then. They also have 9997245.

Good luck! Let us know how else we can help!

Roger

[bobsepe]

I have a used, but very serviceable counterbalance shaft. This one is slightly scuffed.

Bob Sepe
919-417-5019
[email protected]
Dec 2, 2023