Engine case swap

[philstar]

My current 1600cc twinport engine case has bolts instead of studs to secure the oil sump plate—obviously, one has stripped and the engine is leaking oil, so it requires the engine removing and the case splitting to extract it and replace with the correct specification sump studs.

This engine has yet to be started for the first time, it has brand new cylinder heads, bearings, barrels, pistons, etc etc. The case itself doesn't look to be in great condition, and some of the sump bolts are wonky requiring modification to the sump plate holes. These sump bolts have been installed into sleeves, so it must be that some of the sleeves are wonky.

I have tried using silicon gaskets and higher quality sump plates / bonded washers however the bolts are slightly shorter than standard sump studs, so I don't have enough exposed thread to tighten anything with confidence.

I am considering replacing the case when I strip the engine to replace these sump bolts—it seems like a lot of work just to put everything back inside a compromised case.

Does anybody have any recommendations in terms of engine cases, or alternative options here?
Is there anything I need to be aware of when swapping engine cases?
Are there any worthwhile upgrades to do at this time, bearing in mind I set out to build a standard engine initially?

My main goal here is reliability, so I can use the bus without having to worry about the engine while I gradually upgrade/repair the rest of the components.

Thanks for any help—it's been a few years since I've been able to work on this bus but I'm trying to focus on it now to get it into a roadworthy state.

 

[mike202]

can't you just remove the bolts and re tap the case for over size studs?

like these https://www.justkampers.com/n0144781-oversized-stud-for-sump-drainer-plate-on-all-vw-beetle-t2-split-and-1600cc-t2-bay.html

sorry if I don't understand exactly why you want to change the whole engine case.

 

[philstar]

Thanks Mike,

I don't really want to swap the case, I just want peace of mind. The bolts—though they are the correct M6 diameter—look as though they are inside case inserts of some sort so I'm not sure I can remove these and re-tap for the over-side studs...

If they were all square I would just replace the bolts with standard studs after splitting the case, but because a couple of them are wonky I don't want to go through all this effort if I can't then guarantee the engine will hold oil.

It may be that I can get a dremel inside to cut the bolt heads off and then wind the remaining threads out without having to split the case, but again what's the point if I'm then left with wonky studs.

 

[mike202]

Ah I see, bolted from the inside down. I thought you meant bolts up throught the sump plate. Well if you think the holes are too far out of true maybe a new case is the only answer.

 

[philstar]

For those interested, I have some rotary cutting discs arriving tomorrow so I can try cutting the head of the bolt off. Here is a photo I took today after winding the stripped bolt up as far as possible until it hits the oil shield thingy:

Photo link

I considered cutting the thread off outside the engine but there will still be too much length on the bolt to extract it, so I need to cut it off right under the head. Luckily, there are washers that should protect the case.

 

[ozziedog]

Oh, I think you’ll find we’re all following this. Hopefully a kind result

Ozziedog,,,,,,,hopefully. :mrgreen:

 

[sparkywig]

Why don't you use thread inserts/helicoils?
Even if you have to go up a thread size it's surely easier than swapping your engine case.

 

[philstar]

There are already some form of thread inserts in there—I'm not sure what kind they are or what size, I'll get some closer photos when I manage to get the bolt(s) out.

I don't know much about thread inserts, a couple of these are slightly wonky but hopefully, they will hold oil with the proper equipment installed. If I can minimise any engineering work here I think that's the best route to avoid any metal deposits being left in the engine for its first hurrah...

 

[philstar]

Managed to cut the bolt off! I'll need to do an engine oil flush to get any contaminants out before I start it so I think I'll cut the other bolts off (apart from the one that holds down the oil shield), in the same way, to avoid having to do it in the future.

This should also solve my next job—getting the thread lengths correct. Currently, the bolts leave a mixture of 7.7mm–9mm exposed, which wasn't enough to install:

1. silicon gasket
2. oil filter
3. silicon gasket
4. sump plate
5. captive nut

How much thread should there be as standard? I've got a Bentley manual but it's been "borrowed" so I'll go and grab it back to avoid asking unnecessary questions...

I'll update my build thread as well

 

[philstar]

Now the bolt is removed, here is a blurry photo showing the insert—it looks like all the bolts have these:

Photo link

 

[gvee]

Doesn't like like that picture is publicly viewable, fella!
Might look fine on your screen but nowt loads here.

 

[philstar]

Thanks George—I've updated with links to my photos in google for now

 

[67panel]

A good tip is tap the original threads to BSF and fit studs

 

[ozziedog]

A good tip is tap the original threads to BSF and fit studs

Whereas the original stud fitter did it the other way around, as in tipped the tap

Ozziedog,,,,,,,,,,boom boom :mrgreen: I’ll get me coat :mrgreen:

 

[philstar]

OK I've had a couple of days on the bus, cut off the remaining bolts and replaced them will CSP sump studs, however, one of them is already a stepped stud, and another is really loose so it needs a thread insert.

I need to get this bus started, so I decided to go ahead and bolt the sump plate on with a couple of dodgy studs remaining and just have an oil catch pan underneath until I can fix it properly. I left the new studs at 12mm which is enough for the setup I wanted, but due to the shorter studs I have left in place I've had to skip the second silicon gasket for now.

Once the engine is properly run in I'll address this issue, but for now, the oil leak seems minimal...