trying tp split very difficult cases

[mark from florida]

Trying to split my cases on the ct 70 motor prepping for the big bore kit. watched and rewatched Kirby videos. thanks Kirby,have all screws out and cannot get this sucker to come apart. thought possibly center gasket was overlapping outside cases so I cut it back to flush. beat on it with mallet. nothing. thinkin about possibly heating it up. will this damage anything? plans are to replace crank and trans with 4 speed and manual clutch.have all new gaskets and seals.also found stripped screw on access cover to flywheel. any sggestions to getting that sucker out.possibly will need to source a new one.one more dumb question. I want to powder motor black. can I assemble then powder or do all cases separate? poss paint center of motor with spray paint the just powder outer cases?thanks again to all the gurus.

 

[lukelaw1]

Photos would defiantly help to confirm everything is apart to correctly split the cases.

You shouldn't have to use heat and I wouldn't aluminum/zinc go from a solid metal to gelatinous pile of metal without warning, granted that's around 800 degrees for zinc and 1200 degrees for aluminum.

You should powder coat pieces separately, if assembled, electrostatic powder coating will creep into the motor and get all over the internals. Also in powder coating the powder has to be baked, sometimes at temps up to 450 degrees so make sure you don't have any gaskets or seals installed. The other important thing is having the painter mask off all the areas you don't want powder coated. I wouldn't want any powder on the inside of the motor cases, inside of covers, inside threaded holes, bearing and gasket areas. This will cover you in case paint prep isn't up to standards and paint would happen to peel/flake off inside the motor.

 

[69ST]

Make sure all of the case screws are out. It's surprisingly easy to find one "hiding" in plain sight. A well-baked & ossified gasket can hold the case halves together very convincingly. FYI, there's not as much adhesion as you might think. What you're dealing with is a lot of acreage, combined with a pair of straight/warpage-free case halves...essentially composite construction. I could see the cases remaining "glued" together well enough to withstand 200lbs+...if that could be applied without damaging anything. But, just break the bond anywhere along the perimeter and that strength will vanish. A wood dowel placed inside the spigot (bore opening) and small mallet will break the bond without scarring metal. In an extreme situation, a thin blade can be tapped into the gap...only above the outsides of the motor mounts...and you'd better know what you're doing.

As for powdercoating engine parts...high-risk proposition. How are you going to keep everything but the outside surfaces of the cases & covers 100% free of overspray? That's a lot of masking, what are you going to use as masking tape, that will withstand 400F curing heat? You could get by with having the flywheel cover & outer clutch cover done; those can be masked well enough by laying them, gasket side down, as the powder is applied. The case halves could be masked and painted. IMNSHO, the only viable finishes for an engine are paint, or bare aluminum...as-cast, or polished. There are just too many potential pitfalls with PC and the outer covers are easy to repaint, at any time.

 

[kirrbby]

Make sure all of the case screws are out. It's surprisingly easy to find one "hiding" in plain sight. A well-baked & ossified gasket can hold the case halves together very convincingly. FYI, there's not as much adhesion as you might think. What you're dealing with is a lot of acreage, combined with a pair of straight/warpage-free case halves...essentially composite construction. I could see the cases remaining "glued" together well enough to withstand 200lbs+...if that could be applied without damaging anything. But, just break the bond anywhere along the perimeter and that strength will vanish. A wood dowel placed inside the spigot (bore opening) and small mallet will break the bond without scarring metal. In an extreme situation, a thin blade can be tapped into the gap...only above the outsides of the motor mounts...and you'd better know what you're doing.

As for powdercoating engine parts...high-risk proposition. How are you going to keep everything but the outside surfaces of the cases & covers 100% free of overspray? That's a lot of masking, what are you going to use as masking tape, that will withstand 400F curing heat? You could get by with having the flywheel cover & outer clutch cover done; those can be masked well enough by laying them, gasket side down, as the powder is applied. The case halves could be masked and painted. IMNSHO, the only viable finishes for an engine are paint, or bare aluminum...as-cast, or polished. There are just too many potential pitfalls with PC and the outer covers are easy to repaint, at any time.

Driving in a razor knife blade is a trick that I've never heard before...and I love it. Soo much better than any advice I may have given you for what to try next. IMO, it almost a surefire method. racerx is the master.
As SOON as it cracks apart, toss the blade and grab your mallet again. If it doesn't crack open, leave the blade in there to help push, and grab your mallet again...or wood dowel, and continue the tapping and whacking.

 

[69ST]

Driving in a razor knife blade is a trick that I've never heard before...and I love it. Soo much better than any advice I may have given you for what to try next. IMO, it almost a surefire method. racerx is the master.
As SOON as it cracks apart, toss the blade and grab your mallet again. If it doesn't crack open, leave the blade in there to help push, and grab your mallet again...or wood dowel, and continue the tapping and whacking.

View attachment 64389 View attachment 64390 View attachment 64391

You've become quite the illustrator in your old age, kirb...well done, sir!

 

[mark from florida]

thanks you guys. took another stab at it with the razor blade. worked like a charm. all it took was just a little help.seemed like it popped open. thanks again. now to take cases to work and clean them real good in parts washer.probably will paint inner cases with pj1 case paint then powder outer cases and top end.whats your opinions on using steel takagawa head gasket?v2 head.