OM642 resealing timing case cover

[wwatu]

Hey.

I have some questions about the instructions in WIS, since this would be a pain to do again, I'd like to get it right first time, but some instructions are a bit unclear. I have also attached the said document to this post.

1. Pilot bushings - must not remain in cylinder block, yet under installation it says to replace them, meaning that I need to remove them from block and insert into timing case cover when installing? Would they be okay to reuse?
2. Tightening bottom screws first - as I understand I have to torque bolts from oil pan to spec first, then untighten them, insert centering sleeve, torque the timing cover bolts to spec and lastly torque the oil pan bolts to spec again? Wouldn't the fact that the timing cover moves after torquing the bottom bolts mess up the seal since the bottom bolts were already torqued down once?
3. Centering sleeve - Is it meant to be used with the front main seal in place or not? Since it says Install in the reverse order, then the first step would be to install the seal to the timing case cover. If with the seal, then would it be acceptable to just use the drive shaft pulley? Or is it meant to go in place of the seal and seal installed after.
4. Bolts replaced by steel screw/bolts - this is also quite confusing, as I can only see one part number for these bolts, which seems to be from aluminium. Would I need to replace only the timing cover or the oil pan bolts also with steel ones? Since they don't seem to be torque to yield bolts and only require 10nm torque it would seem to be okay to reuse, no?

If anyone has some input on these questions it would be much appreciated.

 

[wwatu]

4. So when checking with magnet, all of the bolts were attracted to it, so I guess this one is sorted, as they are steel insted, but does anyone have any info on the other points?

 

[Bellow]

In the absence of anyone with actual knowledge of this engine stepping forwards to help...

1. Pilot bushings - must not remain in cylinder block, yet under installation it says to replace them, meaning that I need to remove them from block and insert into timing case cover when installing? Would they be okay to reuse?

In my terminology I call them dowels - or hollow dowels. I'd leave them where the are assuming the timing case cover can be presented squarely on assembly. WIS kinda implies that that's not the case and that they can interfere with the sealant. In which case, better removed and remounted on the timing case cover. They are a PITA usually to remove, getting distorted in the process. If you go that route, be prepared to replace with new as distorted ones will cause grief. If you can present the timing case cover squarely though...

2. Tightening bottom screws first - as I understand I have to torque bolts from oil pan to spec first, then untighten them, insert centering sleeve, torque the timing cover bolts to spec and lastly torque the oil pan bolts to spec again? Wouldn't the fact that the timing cover moves after torquing the bottom bolts mess up the seal since the bottom bolts were already torqued down once?

I can't comment specifically. Does WIS intend the entire operation be done before the sealant sets? I think your method will be fine - unless someone disagrees...

3. Centering sleeve - Is it meant to be used with the front main seal in place or not? Since it says Install in the reverse order, then the first step would be to install the seal to the timing case cover. If with the seal, then would it be acceptable to just use the drive shaft pulley? Or is it meant to go in place of the seal and seal installed after.

I can't comment specifically. Hopefully someone with knowledge of this engine can and will.

4. Bolts replaced by steel screw/bolts - this is also quite confusing, as I can only see one part number for these bolts, which seems to be from aluminium. Would I need to replace only the timing cover or the oil pan bolts also with steel ones? Since they don't seem to be torque to yield bolts and only require 10nm torque it would seem to be okay to reuse, no?

You have that covered. Yes, reusable - just make sure they are clean.

 

[wwatu]

Thank you for sharing some information.

In my terminology I call them dowels - or hollow dowels. I'd leave them where the are assuming the timing case cover can be presented squarely on assembly. WIS kinda implies that that's not the case and that they can interfere with the sealant. In which case, better removed and remounted on the timing case cover. They are a PITA usually to remove, getting distorted in the process. If you go that route, be prepared to replace with new as distorted ones will cause grief. If you can present the timing case cover squarely though...

Actually they were quite easy to remove and no harm done, I think I can reuse them, but the question rather is should I. Because when the dowels are in place I don't think there is enough clearance from the bottom to make a good seal. Because with dowels in place I can't really bring the cover to the corner diagonally to push equally down on front and bottom. Since there can't be much movement vertically which means the cover would just push the bottom sealant away I think. Is this what you meant by presenting squarely? In the WIS document for newer 642 models, like 222, it states that the dowel pins should be just removed, which makes sense when upper oil pan is not removed just for that same reason. If the upper oil pan would be removed there would be no issues to have the pins since the bottom isn't making a contact, but then again if it were removed I couldn't tighten lower screws first, so a lot of confusion about this particular step. Maybe do a test fit with sealant applied just to bottom to see how much, if any is pushed away?

I can't comment specifically. Does WIS intend the entire operation be done before the sealant sets? I think your method will be fine - unless someone disagrees...

I guess so, since it is in one step. But my main concern with this would be if there is some movement after initially torquing down bottom bolts and releasing them to torque down other bolts then wouldn't that mess up the seal?

I can't comment specifically. Hopefully someone with knowledge of this engine can and will.

I think that it is supposed to go inside the seal for mainly installing it, so I guess the balancer would be okay to use just for centering the timing cover. In this link there is a diagram that shows the usage: https://eng.jtc.com.tw/product/?mode=data&id=5453&top=2

 

[wwatu]

I can't seem to edit my previous post so I'll make another reply. I think I've pieced it together. In the document I've attached in the first post, the word Replace in step 15 must be incorrect, it should say Remove instead, since there are wrong wordings in other WIS documents also, I think that must be the case. I have read through the same process for multiple models which I have also attached to this post for anyone interested.

What I found:

• For every other model it states clearly to dispose of the bushings for the same reason I thought previously, when installed with upper oil pan in place they would just push the sealant away.
• Only for model 222 the sealing ring is installed just before installing harmonic balancer. For every other model, it is installed before inserting centering sleeve. Since the tool is same for every model, I think this too is error for model 222 and the centering sleeve goes inside the seal.
• In the document 642 in model 166, 292 it says introduce pilot bushings, then tighten all screw/bolts, when clearly it means the centering sleeve, so the wrong wording seems to be quite common.
• Some models call to first tighten bottom bolts, some for lower bolts below bushings before loosening and inserting centering sleeve, so I guess this is dependent on the specific model and timing case cover design, so I guess I'll have to trust the document for my model on this.

So, after all this, correct procedure to my understanding is this:

1. Install new seal in cover
2. Remove dowels/pilot bushings(unless upper oil pan is also removed)
3. Insert timing cover, tighten whichever bolts your specific document asks for first
4. Loosen those bolts
5. Insert centering sleeve(it should be okay to use harmonic balancer for this, just maybe some bolts might not be accessible with it in place, but those could just be hand tightened and torqued after removing the balancer when other bolts are torqued, because I'd imagine the cover wouldn't be able to move at that point)
6. Tighten other bolts and then those same bolts again

Still, if anyone has done this I'd be happy to get an input. Also how much of a groove on harmonic balancer shaft would be okay to use, the old seal didn't leak but there seems to be a slight groove.

 

[Bellow]

Thank you for sharing some information.


Actually they were quite easy to remove and no harm done, I think I can reuse them, but the question rather is should I. Because when the dowels are in place I don't think there is enough clearance from the bottom to make a good seal. Because with dowels in place I can't really bring the cover to the corner diagonally to push equally down on front and bottom. Since there can't be much movement vertically which means the cover would just push the bottom sealant away I think. Is this what you meant by presenting squarely?

By 'presenting squarely' I mean as if the engine was out of the car on a stand and you could just walk straight up to it, cover in hand and plapp it on. As opposed to the usual wriggling it into place.
As before, I lack specific knowledge of this engine but suspect it is as per my smart engine and on it proper sealing is only possible by sandwiching the timing cover between the cyl head and sump pan (or girdle plate). Any attempt to slide the cover in scrapes the sealant off. Without being in the same room as your engine I cannot advise - other than trust your own instinct.

In the WIS document for newer 642 models, like 222, it states that the dowel pins should be just removed, which makes sense when upper oil pan is not removed just for that same reason. If the upper oil pan would be removed there would be no issues to have the pins since the bottom isn't making a contact, but then again if it were removed I couldn't tighten lower screws first, so a lot of confusion about this particular step. Maybe do a test fit with sealant applied just to bottom to see how much, if any is pushed away?

I'm surprised the dowels came out without a fight - but that was the desired result so all OK.

I guess so, since it is in one step. But my main concern with this would be if there is some movement after initially torquing down bottom bolts and releasing them to torque down other bolts then wouldn't that mess up the seal?

See earlier comment.

I think that it is supposed to go inside the seal for mainly installing it, so I guess the balancer would be okay to use just for centering the timing cover. In this link there is a diagram that shows the usage: https://eng.jtc.com.tw/product/?mode=data&id=5453&top=2

I think it just shoulders up to the seal and lets you use the bolt to push into place. Neat, but I can't see why the new seal can't just be drifted in with a hammer - unless tight for space. I don't see that tool as a protector of the seal's sealing lip.The lip isn't endangered until fitting the balancer.

Re the wear in the balance (separate post) - there are repair sleeves for that available for some engines. Have a look on Rock Auto as I think I've seen them there for American engines. Your car was likely sold in the USA so RA should have parts for it - including said sleeve if one exists for this engine. I cannot say if the wear on yours is acceptable or not.

I was hoping others with real knowledge of this engine and the work you are undertaking would step forward and help. Where are they?

 

[wwatu]

By 'presenting squarely' I mean as if the engine was out of the car on a stand and you could just walk straight up to it, cover in hand and plapp it on. As opposed to the usual wriggling it into place.
As before, I lack specific knowledge of this engine but suspect it is as per my smart engine and on it proper sealing is only possible by sandwiching the timing cover between the cyl head and sump pan (or girdle plate). Any attempt to slide the cover in scrapes the sealant off. Without being in the same room as your engine I cannot advise - other than trust your own instinct.

Yeah, that's why I believe the wording is wrong in the document and I need to remove the dowels, with them gone I see no problem inserting the cover correctly.

I think it just shoulders up to the seal and lets you use the bolt to push into place. Neat, but I can't see why the new seal can't just be drifted in with a hammer - unless tight for space. I don't see that tool as a protector of the seal's sealing lip.The lip isn't endangered until fitting the balancer.

Exactly, In this context though it is needed to center the timing cover because the dowel pins are removed, balancer should be fine for this job also, I checked and it doesn't even stay on the way on any bolts so.

Re the wear in the balance (separate post) - there are repair sleeves for that available for some engines. Have a look on Rock Auto as I think I've seen them there for American engines. Your car was likely sold in the USA so RA should have parts for it - including said sleeve if one exists for this engine. I cannot say if the wear on yours is acceptable or not.

Actually I'm from Estonia, and aware of the speedi sleeve option, but the price for it isn't worth it, 30€ for the sleeve and 110€ for new corteco balancer. I'm just wondering what the acceptable wear would be, when measuring, the groove seems to be 0,1mm less than rest of the shaft, so 0,05mm wear on the sealing surface. Other than that it doesn't feel sharp or didn't leak before taking apart or anything.

 

[Bellow]

Actually I'm from Estonia, and aware of the speedi sleeve option, but the price for it isn't worth it, 30€ for the sleeve and 110€ for new corteco balancer. I'm just wondering what the acceptable wear would be, when measuring, the groove seems to be 0,1mm less than rest of the shaft, so 0,05mm wear on the sealing surface. Other than that it doesn't feel sharp or didn't leak before taking apart or anything.

To avoid the 'sleeve' I'd look at smoothing down the affected section with emery paper and, if there is still any discernible lip, install the seal slightly short ie, not fully home (but not by more than say 2mm max) - with the intention of having the new seal's lip run on a slightly different, slightly better part of the balancer spigot. So long as there is still enough of the seal's outer surface engaged with the casing to hold it securely that is.