CXFA Balance shaft installation

[reidman]

Thanks DXX, I've just checked, mine are still in the block with no crank, so I couldn't take your approach without removal. However, I can see that when I rotate the block, the heavy side drops downwards and is consistent with the images and thoughts above. I figure then, for re-assembly with the crank, I need to find a way to prevent the weighted side of the balance shaft from spinning back around when the block is upside down to get things set up as I suspect they need to be. and timing.

 

[reidman]

Or as I have just realsied...assemble with piston 1 at BDC, ensuring the shafts have spun downwards. Simpler and should do it I reckon.

 

[DXX]

You could weigh each piston / rod / BE bearing cap / bolts individually, I suspect they will be almost identical.
Fairly safe to assume that the crankshaft is perfectly balanced.

 

[reidman]

Thanks DXX, please correct me if you think I am wrong, but my understanding is the shafts aren't there to aid the balance of the crank traditionally and as you say, it should be perfectly balanced anyway in that respect. The shafts are to negate second-order imbalances created from the piston movements not being perfectly opposed to one another when rotating, a situation that exists in all inline 4s apparently. In these engines, they have attempted to engineer out this effect with the weighted shafts.

 

[DXX]

Correct but the discussion earlier was regarding dynamic balancing, that would also be used to correct minor discrepancies in piston / rod assembly weights in my opinion.
If you know that each piston / rod ass’y is equal it’s one more thing to discount if you have an issue later.

 

[reidman]

Just to expand my knowledge DXX, what do you do if they are different? Thanks

 

[DXX]

Just to expand my knowledge DXX, what do you do if they are different? Thanks

In an engineering workshop environment there would be a determined tolerance and material would be shaved from the rod.
I’m not recommending you do that, just suggesting that it’s a very easy check to make prior to an engine build.
You just need a good electronic kitchen scale.

 

[reidman]

Brilliant, thank you. I will do that out of curiosity to see if there are any differences in the piston assembly weights. It would be good to know they're all spot on...hopefully! after all this effort.

 

[reidman]

Or as I have just realsied...assemble with piston 1 at BDC, ensuring the shafts have spun downwards. Simpler and should do it I reckon.

Yeah... just realised...don't do this! It puts you 180 degrees out on the balance shafts and it clashes on 2. Crank goes in at 90 degrees past tdc or bdc. My assumption about installing at bdc, which would put the balance shaft 180 degrees around was wrong! As they spin twice per crank rev. All looks good now.

 

[bshortman]

Hi guys, jumping on this thread as I also seem to be in the same situation!

My CXEB engine (yes, THAT engine) is currently sitting in a workshop after some TLC and a cylinder re-bore. It sounds like the last piece of the puzzle is setting up this oil pump balance shaft.

I’m unfortunately not mechanically minded, I was just told “the oil pump balance shaft setting up tool is all we need now to get your engine put back together” and they are struggling to source one. And like the OP, Google searches are not much help either.

How are you guys getting on with your rebuilds?

Thank you in advance

 

[DXX]

Hi guys, jumping on this thread as I also seem to be in the same situation!

My CXEB engine (yes, THAT engine) is currently sitting in a workshop after some TLC and a cylinder re-bore. It sounds like the last piece of the puzzle is setting up this oil pump balance shaft.

I’m unfortunately not mechanically minded, I was just told “the oil pump balance shaft setting up tool is all we need now to get your engine put back together” and they are struggling to source one. And like the OP, Google searches are not much help either.

How are you guys getting on with your rebuilds?

Thank you in advance

If you have your engine in a professional workshop and they didn’t reference mark the gear train when dismantling I hope things work out as this is absolute basic requirement when overhauling machinery and any time served engineer / mechanic should know that.

 

[bshortman]

If you have your engine in a professional workshop and they didn’t reference mark the gear train when dismantling I hope things work out as this is absolute basic requirement when overhauling machinery and any time served engineer / mechanic should know that.

Im hoping that they have!

 

[DXX]

I’m unfortunately not mechanically minded, I was just told “the oil pump balance shaft setting up tool is all we need now to get your engine put back together” and they are struggling to source one. And like the OP, Google searches are not much help either.

I don’t have access to the CXFA manual but the balance shaft locking tool for my CFCA is part # T10255 and is widely available, I suspect it is the same tool for your CXFA but obviously you would need to confirm, a quick phone call to VW Parts Dept will tell you.
Don’t buy from VW, far cheaper alternative suppliers.

 

[DXX]

I’m not sure if your repair workshop is following the VW engine manual but if your CXFA is the same as the CFCA there are many parts that require renewal when removing and refitting the balancer shaft module, mainly fasteners but also the intermediate gear assembly if the balancer shaft module has been renewed. The intermediate gear teeth has a coating from new that wears off when running to allow the correct backlash.

 

[reidman]

Hi guys, jumping on this thread as I also seem to be in the same situation!

My CXEB engine (yes, THAT engine) is currently sitting in a workshop after some TLC and a cylinder re-bore. It sounds like the last piece of the puzzle is setting up this oil pump balance shaft.

I’m unfortunately not mechanically minded, I was just told “the oil pump balance shaft setting up tool is all we need now to get your engine put back together” and they are struggling to source one. And like the OP, Google searches are not much help either.

How are you guys getting on with your rebuilds?

Thank you in advance

Hi Bshortman, I don't think there is a tool! I never found one

 

[bshortman]

Hi Bshortman, I don't think there is a tool! I never found one

Thought this would be the case! Has yours been running ok since you put it back together?

 

[bluezie]

Hi Bshortman, I don't think there is a tool! I never found one

Looking at my parts fiches, the balance shafts on the diesel engine are not shown as separate parts to the block. It appears the base block includes them and a crankshaft.
Could be a bit like the old 2.5 5 cylinder engine, where the entire gear chest is part of the engine with no spare parts available, or set up data. Effectively, if a gear wears out, it's a new engine. (or a doner engine, or a machine shop to make parts.)

 

[bshortman]

Good grief. VW really did us dirty with this one didn’t they

 

[reidman]

Thought this would be the case! Has yours been running ok since you put it back together?

Fine so far...fingers crossed!

 

[bshortman]

Fine so far...fingers crossed!

My local garage has informed me the engine is due back with them next week! I'll get as much detail from them as possible about how they did the fix and post on here