Crankcase oil sump plate holes - poor repair

[ADP91]

Hello all,

I bought my A10 motor that I am using from my project as rebuilt by the previous owner. Overall the rebuild looks good, but the crankcase sump plate wasn't installed at the time (just covered with some cardboard and tape). I didn't think much of it until I purchased a new SRM billet aluminum oil sump cover and tried to install it. No matter which way I rotated the plate I could not get the bolt holes to align. Upon closer inspection it appears one of the bolt holes was either repaired or damaged and is no longer in correct alignment with the other three holes. It also appears that there is a hole in the threads of the 'repaired' hole.

Photo #1 - shows the misalignment of the hole (top right).

Can anyone advise on what the best course of action is? Options I have so far are:

a) Disassemble the engine and have it professionally repaired.
b) Replace the crankcase with a better set (I currently have a set of cases).
c) Modify the sump plate to match the alignment of the holes in the crankcase (would the hole in the threads cause oil leaks?).

I appreciate any insight!
-Angus

[route 66]

That's a shame.In my humble opinion that is a very poor repair and I can't see it doing anything other than leaking oil.Especially once its up to temperature. Split the cases and have it repaired properly would be my advice.

[Sakura]

If that's the standard of workmanship of the previous "repairer" I would start again, checking everything as you go. Not worth risking a major blow up.

[coater87]

 If the rest of the rebuild looks good, I am modifying that SRM sump plate.

 If the gasket surface is flat, an off-set mounting hole will not cause a leak.

 If you have any doubts about the quality of the machining or parts used in the rebuild, thats a different story.

Lee

[BSA_54A10]

If it is just the one that does not line up then you have 2 options
1) modify the sump plate
2) thread some alloy rod and screw it tight into the hole then drill & tap for the sud in the right place

[Swarfcut]

  Angus.  With the engine already out of the bike a full tear down and professional repair makes sense. However if the crank has any endfloat above spec, that will need addressing and so as substituting a better set of crankcase castings involves the same set up procedure, this may be a cheaper option.

  There appears a witness mark on the flywheel. Methinks the oil pick up pipe is tight against the crank, again another reason to strip down for clarity. The pipe normally protrudes down through that hole in the gauze, which acts to filter out  debris and prevent it entering the return side of the pump. That pick up pipe  looks to be completely awry.

  With the engine apart, inspection of components and thorough cleaning of oilways and crank sludge trap takes away a lot of the mental anguish about a possible future expensive failure, always a worry on an unknown build.

 Swarfy.

[RDfella]

That lug looks seriously iffy - to me it looks like it has been cut out and another piece stuck in with epoxy metal or similar.
I hate making work, but I'd pull those crankcase halves apart for a better inspection. It could then be built up with weld.
Those stud holes becoming stripped and then ruined by DIY attempts at reclamation are fairly common.

[groily]

Darn sight easier to deal with it now than down the line, surely?

[RichardL]

I’m going to post some links to my repair for a similar issue as I dig them up.

https://www.a7a10.net/forum/index.php?topic=14370.msg119450#msg119450

Richard L.

Edit: https://www.a7a10.net/forum/index.php?topic=14794.msg124066#msg124066

[ADP91]

Thank you for the advice everyone. It seems like the best course is to the split the cases and have it repaired.

The other case half I have is in great shape. Would there be any downside to just swapping the one case half? Wonder if the machining would match well enough or if the surfaces would have to be machined to match.

Thanks,
Angus

[RDfella]

Don't even consider swapping one half unless it is unrepairable. You'll probably need to line-bore the crank main bearings, the camshaft bushes and also hope the register on the two halves is a snug fit. Welding up that lug is so much less hassle.

[BSA_54A10]

Thank you for the advice everyone. It seems like the best course is to the split the cases and have it repaired.

The other case half I have is in great shape. Would there be any downside to just swapping the one case half? Wonder if the machining would match well enough or if the surfaces would have to be machined to match.

Thanks,
Angus

It is a casting so it can be built up with welding rods
If you are sure you want to do the full removal / replace bit.
Cut the bad bit out with the cases assembled
Make up a backing plate from steel at least 1/16" thick
Clamp it behind the spot where you want to build up
Build up a new corner, remove the steel backing plate ( molten aluminium will not stick to steel ) .
Machine /file the cases flat
drill new hole
tap hole
flush out cases
This is not a load bearing stud and is only there to clamp the sump plate yight enough to stop the oil leaking.
I hink a few here have lost sight of that.
Alternative method is to drill & tap a hole in some aluminium square or hexagional bar stock
Remove the bad repair and tack the new piece in place then do full welds both sides .
 

[ADP91]

Don't even consider swapping one half unless it is unrepairable. You'll probably need to line-bore the crank main bearings, the camshaft bushes and also hope the register on the two halves is a snug fit. Welding up that lug is so much less hassle.

Okay good to know. Didn't think about the other machine work that would be involved. Thanks

[ADP91]

**UPDATE**

Finally got around to stripping the motor down to cases.

Here are some photos of the previous "repair". Seems like they did not following the correct procedure for adding weld to the cast aluminum. Getting it fixed in the coming weeks and I will post updates.

Also I have a question for the group, should I remove the crank roller bearing prior to any machine work? If metal dust gets in there I imagine it could be difficult to clean properly.

Thanks

[muskrat]

G'day Angus.
Yes I would remove the bearing. Heat the case in the oven (wait till SWMBO is out) to 150C or so and it will fall out. same for putting it back in, put bearing in the freezer first.
Cheers