crankcase won't part

I'm splitting the cases on a '68 motor and seem to be stuck at the point indicated by the arrow, which, based on a parts diagram, I think is a dowel, and not a broken stud. The dowel seems to be anchored in the drive side as tapping on it from the drive side drives the halves closer together. I am out of ideas other than soaking the general area in penetrating oil and applying the heat gun to the area again in the morning. I have been tapping on the drive side through the case mouth with a piece of wood as per the manual. Just wondering if anyone has any ideas.
Brendan

There are two slotted head screws that hold the cases it looks like one of them. If they realy won't move you will have to CAREFULLY drill the head off. As with everything else replacements are available. I can't remember which side head is on but manual should show it or someone here will know. There are 2 dowels but they can't be seen from the outside of the cases maybe some old jointting compound sticking things together to.

No, It's a dowel - on the earlier cases the hole in the RH case is blind drilled, so can't be seen from the outside.

If that's the sticking point get some heat on it - standard interrogation technique :wink:

A puller using 3x 1/4-20 studs in the primary mounting holes and a central bolt pushing on the crank will split the cases
assuming you only have the 2 dowels remaining...otherwise you will "split the cases" :roll:
#2 just the 3 studs and flat plate. screwing in the 3 nus will do the same.
2 small dowels continued from 1949 til the end of 20M3S. 200000 and up used the 2 tube/hollow dowels.
+1 heat

OH NO. I've been though this on my 1st Combat and it can take *horrific* efforts to part. The cause is the case halves have been engine drive torque-twisted distorted to blacksmith bind on the dowels. As already separated some as indicated then it ain't sealing goop glued together anymore but mechanically jammed. Maybe just maybe heating the TS case might expand its GRIP on the dowel but it didn't in my mean cases. I'd try to rig up a special "puller" on the DS crank and case. A plate to screw the three primary case bolts in to put pressure on crank against the TS case, then use stubby wood wedges enough to be able to get levers in the crack and try to pry a part micron by micron. Dowels stick into TS case about 3/8", so that much micron by micron till freed. The cases have over lapping lips so can't just pound in a normal wedge as it hit this lip to stop its entry. I'd such though how I'd do one ugh, next time. Put plate on the open top of case, fill with dried beans and jam in wooden tooth picks or wood wedges as ya can in the tiny seam gap then soak in water the hotter the better. So puller on crank, something swelling inside may give the extra force so that you can use levers, wood chisels, screw drivers, gasket scrappers etc to actually move apart micron by micron and not tear up the sealing surfaces. If that don't work, and it may not, as *horrific* means just that, relax and take to shop to bore out the dowel then cold weld another back in. Your report is only the second one after me that I've ever read anyone else encountering so don't expect the normal sensible methods suggested to help at'all. Once parted you need to figure out which way and how much the cases are twisted on dowels and remove a bit off both dowels so case can mate and be parted again. If ya can get them apart and remove crank then try to put back together you can run into exactly same fight to part again. DAMHIK. IIRC the engine/drive torque twists the DS CW so dowels will need those opposing surfaces relieved a few .000th's. Mine only took ~.003" off one side of each dowel, which I determined by inking dowel and mating cases again, UGH > with "horrific" efforts to part again but eventually got em back to normal effort to mate and part. Also expect the crank shaft is twisted bent too but that ain't what's binding up just likely cause. This ruined many nights and some weekends for me on such simple few minute normal task.

Heat and oil as mentioned above. Dave of course has a great idea using the end of the crank and a puller. If I were desperate, I would consider drilling a small hole so that I could get oil into that blind end while heating. Something like 5/32". It would be easy to repair with some JB Weld or similar later and shouldn't mess up the alignment. I would do this before I got to the point of prying on it but not before I convinced myself they were not coming apart without it.

Russ

I would set the cases on a wooden surface, (have a friend hold the cases steady), then take the largest flat-ended pin punch (new or carefully dressed) that will fit in that hole and give it several sharp raps with a medium ball peen hammer.

Like Dyno Dave discribed in his post I also made a case seperator it's just a round plate with three holes to match primary cover attatchment holes turned down three 1/2" all thread pieces to 1/4" x 20 thread on one end it works well although if I were to make it again I think I would just use 1/4 x 20 long bolts or all thread as it would be enough to separate the cases.

Thanks I wanted to verify that wasn't a screw or stud. I will try the puller and heat method.
Brendan

I have that cut-out from a magazine decoupage'd on my desk. I got the Commando at a time when I thought one would be out of reach for a while, and so when I got it, I felt like "I had arrived". Now, when I realized that I was able to make a puller from stuff I already had laying around, I really feel like I have arrived. I had a 1/4" steel plate that had been attached to some custom Triumph foot peg, and it already had 2 holes that matched with the inner primary cover threaded holes, so I only had to drill one hole, and I used 3 long 1/4X20 bolts.


Soaked the area in a little ATF/acetone cocktail for a few days, applied the heat



1/4 turns on the bolts one at a time, and success



Thanks so much for the tips. 20 years ago I would have been tempted to sneak a little screw driver blade or putty knife in there and tell myself it wouldn't hurt, but the puller method is way better. Sorry yours was so difficult to part Hobot, but I'm glad I didn't have to resort to the dried beans soaking in water method of expansion, or popcorn with the heat gun, etc.

Glad ya got er cleaved with one of my suggestions but you might not be home free yet. Exam closely the dowels for witness marks and once cases empty mate em again to see what might of hung em up as ordinarily they part pretty easy with just the sealant holding to break free. After I found Hylomar + thread I don't even strain the sealant gluing.

Good going.

I still think 1 or 2 sharp raps with a nice flat pin punch (wonder why they call them that?) would have popped it loose straight away.

GrandPaul, I tried that method, hitting from the opening in the drive side, but the first few strikes were met with a very solid feel so I stopped.
The dowel in the drive side case:

Clean and observe the dowel seat area for stress shift signs. Could just be rust swollen. Hope that's as tough as it gets bringing back to road life.

Make sure you use a dab of anti-seize going back together, for future ease...