Troubleshooting a JAP Special

[cardan]

Love the oiling concept and the link with your dad. Keep up the good work!

Leon

[Rockburner]

Just a brief status report.

The sludge trap has been soaking in white spirit for a couple of weeks.



And, with some gentle encouragement....


All the little discs seem to be more or less sludge free and loose enough to rattle, just about.

So, its  all, i think, ready for reassembly once i get back from Latin America.

[Rockburner]

Gulp.... here we go....

Time to start the assembly!

First I checked the locating of the crank oil feed quill, which, for some reason, my Dad had left out of the engine when it was last buil!  How the big end was getting oil I have no idea.....
I only ordered this recently, I had no idea it was supposed to be there until I spotted it on the Speedway Service list of parts and wondered what it was....  If I hadn't lost the little seal from the timing cover and had to order new ones I'd never have known about this part.



I also checked the crank-shaft oil feed line was clear:


Yup!


I then set up the timing side crankcase on a few blocks so that it would sit easily, cleaned up the remaining lithium grease which was on the thrust washers on the crank shafts, fitted the bearing cage and rollers on that side, and dropped it into the case:


Fitting the bearings was a lot of "fun" - they're soaked in R30 and have a tendency to try to pop out when you're pushing the next one into the slot: this little so-and-so made a bid for freedom and I lost 10 minutes hunting for the git, eventually I DID find it on the floor, I think it somehow ended up under my shoe!


Second set of bearings all in:



I then cleaned up the case mating surfaces with Sika Wonder Wipes,



Then again with meths on a clean bit of cloth.

Just a fraction of the blue paper and wipes I went through....


The Threebond was a lot more fluid than I was expecting, and I lost a bit of time hunting for a nozzle amongst my other tubes of goo - unfortunately couldn't find anything to fit so I had to just dispense from the tube.
I think this was a little too much - but there wasn't a "huge" amount of overflow on the outside of the cases.



Note that on this side of the cases (the Timing side), there's a "wall" or "lip" on the inside of the mating faces - this provides a locating key for the other side and a partial "labyrinth" seal, it also means that hopefully there's a lot less chance of the Threebond getting into the inside of the cases if you apply it to this side of the cases (as opposed to the other half), well - that's my hypothesis anyway...

I fitted the other side of the cases, used the small bolts to hold it together and align them, then fitted the workshop legs and cleaned up the small amount of excess 3Bond that oozed out.  (the Wonder Wipes were very good for that).

The next step was to fit the output side crank seal - this is a modification to the original engine, I'm guessing from F500 racing, and I really ought to try to find another one at some point.
I 3Bonded one side of the gasket (the cases side) and fitted the ally seal mount.
Interestingly, the 3 holes are NOT in exactly 1/3rd circumference locations, the screws wouldn't screw down until I rotated the mount 1/3rd.  If I remember I may etch an "up" arrow into the ally just to make it easier next time.


Test-fitting of the timing wheel - as I was looking at the cases on the legs, and the wheel hanging on the wall I had a sudden panic that it wouldn't fit!!
But it does.


It's a nice tight fit on the output shaft splines.  I also like implementation of the fine-adjustment collar.


Woodruff key, splines, output cog and fixing nut, There's also a couple of large washers that fit over the nut which stop the cog sliding off.



I rummaged around in the box-o-bits but couldn't find another nut of the right size and thread to temporarily hold the splines on the shaft: this nut is the right size, but wrong thread, but it'll do for now just to stop the splines falling off.


I need to make up a pointer for the timing wheel: current thinking is to just use a bit of wire-coat-hanger and one of the mounting studs to hold it in place, can't see any problems with doing that, so will do that when I get to that point.

Next job will be the barrel studs (copa-slipped, and with a touch of grease on the rotating bits), barrel, with 3Bonded paper base gasket, quench the head gasket : Ooo - a heaty bit, watch out for fireworks!, and the head, rocker box, then timing gear..... should be fun!

[Rockburner]

Next stage.... the barrel.

These are the barrel studs.  The little discs above them go into the blind holes in the cases first to act as a "bump-stop" and (I think) to help against galvanic corrosion (or something)


Each one gets a small amount of copa-slip (One day that tub will run out, and I will be left hopelessly bereft!)


All in situ, and tightened down hard:


Cleaning up the excess copa-slip that was left


Ready for the piston: already have new rings and gudgeon pins.


The first bit is easy - piston and pin slid together nicely.


The circlips though were a bit of a fight to get in - but eventually I worked them in with a large pair of needle pliers (which is probably where that scratch on the piston came from. :roll: hey ho.


The second one was just as hard to get in.



Imprompto hook (from an old bungee net) bent up to keep the piston from flailing around.


Sika Wonder Wipes and meths again to get the base gasket surface clean


3Bond application, tried to put the minimum on this time, so just dabbed it on lightly and spread it out thin








The base gasket was fitted and more 3Bond lightly applied to the top surface of the gasket, then I checked the ring gaps: they just need to be "opposite" each other, and from memory, they shouldn't be directly on the "thrust" sides of the piston (ie, fore/aft), so I made sure they were lined up on each side of the piston:




Rather nice little ring-clamp from Dad's collection :


Much easier and lighter than some I've seen


And this is where I envy Zaphod Beeblebrox..... a 3rd hand would be helpful at this juncture.


GAH!  First attempt and the friggin bottom ring managed to slip out after the ring-clamp had slid away!


But, after a couple more attempts (it was a bit of a fight to get the rings into the bore!)
Yay!


Up


And down she goes!


The piston moves nice and freely in the bore, must remember to drip a little oil in there just to help it slide before I do the head gasket.
I pushed the barrel down and wiped up the worst of the 3Bond excess


Then stuck the head on so I could pull the barrel down tight and let the 3Bond go off properly in compression.
Here's the head sitting on the top of the studs so you can kinda see how the studs work.
The upper part of the stud assembly is free to rotate so it pulls the head down onto the barrel.  With studs like this, you can remove the entire barrel and rockerbox assembly without having to split it all up (should you want to)



However: doing up the studs is a long process because you can only rotate the stud with a spanner about 1/3 of a turn each iteration..... so I broke out my new secret weapons....


Wera Joker spanners: they're good.


You can flick the spanner back and forth like a ratchet spanner:   Took a few tries before I really got the hang of it, they do tend to drop away unless you use your other hand just to keep them aligned on the nut correctly, but by f~ck do they speed up something like this!  The studs go into the head by about an inch (approximately) on a relatively fine thread, so  it's a LOT of 1/3 turns to do - the Joker cut the time down I'd estimate by at a half, if not more.  I was pressed for time while I was doing this last bit as well, so I was very grateful for having the Jokers! (I can't seem to put an Amazon url into here - so just search for "Wera Joker Self-Setting Spanner"  I have a set of 4, each one covers a smallish range of sizes.)


I left the head tightened down so the 3Bond has time to go off and the base gasket should be all set by the next time I get into the workshop.



Coming up!

Fire! Heat! Water! Imminent probability RB burns himself!

[Rex]

Nice going.
Probably an optical illusion, but is that piston circlip fully seated in it's groove all round?
I've been caught out before where the supplier fitted round section circlips in a square section piston groove, and they didn't seat well.

[Rockburner]

Nice going.
Probably an optical illusion, but is that piston circlip fully seated in it's groove all round?
I've been caught out before where the supplier fitted round section circlips in a square section piston groove, and they didn't seat well.

It is yes, i had to look 3 times though...

[Rockburner]

I think things are going well... (and a lot faster now the weather is warming up!)

So - last night I got another couple of hours in the shed and....

Dribbled a bit of oil into the cylinder to help the initial ring seal and checking of compression


I got the engine spinning a bit by hand and then wiped most of the excess that had gathered at the top of the barrel.

Then it was time for some heat!


The last time I tried quenching copper it was some brake-line crush seals and I massively over-did it and turned them into slag....
So this time I played the heat over the gasket until I had a glow chasing the heat around the ring, then chucked it straight into the water


I only did one side, mainly because I really did NOT want to over-heat the thing and warp it out of shape, so, we'll see how it goes.  If it starts blowing very quickly... at least I now know how to get at it.

Shiny side up!


Buttoned up again.


I did try rotating the engine with my thumb stuck over the plug hole..... and there's definitely compression there!  Whether there's enough compression only time will tell....

So - time to assemble the rocker box:
All the bits:


First I cleaned up the threads for the rocker adjusters:


Stuck the cap-heads on the valve stems : (This is exactly the sort of thing I would forget if I hadn't put ALL the parts into little trays of associated parts, as seen above, I would highly recommend this practise if you're doing a job like this).


The exhaust rocker had a little bit of corrosion on it's shaft, (phnarr), so I gave the shaft a little polish (ooer!).  The inlet seemed fine.




Assembly of the rocker shaft with all their annoying little roller pins in situ:


I dribbled a little bit of oil into the roller-pin bearing assemblies to get them started, they definitely felt dry when I was first checking their movement.

As described earlier in the thread: the Rocker box assembly is done by pushing the bearing liner for the outboard (push-rod-side) as far out as it will go, fitting the top-cover of the box, then donig up tight ONLY the inboard screws, so the inboard bearling line is locked in place, and the outboard liner is "just" moveable ... then screwing the outer cover on, and the bosses on the inside of the outer cover then push the rocker arm into the box: pushing the outboard liner into the box just enough.  This means the rocker arm "end-play" is automatically controlled and is hopefully minimised.  I may actually re-do this process with a lot more photos next time I'm in the shed just to make sure I've done it right....

First thing to go on is the lower halves of the valve-covers.


I had to spend a bit of time trying to figure out where the washers on the bolts that hold the rocker box to the head (only 2 of em!) were supposed to go.  I didn't make an exact note of this when I disassembled the bike (d'oh!) but I think I worked it out eventually.  The complication is that there's also a bracket fitted above the rocker box that attaches to a head-steady which bolts to the bike's frame at the headstock, so I was trying to figure out if there should be a washer under the bracket, or 2 above....  I'm pretty sure there's no washer under the rocker box, it mates directly to the top of the head.

And that is where I ran out of time for the evening.  :roll:

I'm currently pondering the idea of trying to seal the valve gear with the 3Bond - it's not designed to be sealed (it's a shale-track engine, weeping oil all over the place is a design feature), so it's a problematic process at best.  Especially since I may well be placing and removing things repeatedly....

Food for thought over the weekend anyway.

NEXT TIME:  Rocker box fitting and TIMING! (well, hopefully!)