Dowel question

[kevino]

One dowel fell out as I was pulling things apart.  The other was sorta glued into the head and I sorts mangled it getting it out.   Don't imagine it will cause problems if I reuse it?   The BBK kit did not come with spares.    

[90GTVert]

That's not bad. I would try to put it over a bolt or rod and it may go back to shape pretty well. Then I'd order a couple of spares to keep around for next time.


BTW; if anyone else is seeing no pic... I clicked the pic icon and could see it on the hosting site.

[snaker]

An assortment of these concrete anchors can be handy for this sort of thing.
Lots of different shapes.
I like this one for the smooth gripper edges.
You might have to tweak a bit to fit.

[GrumpyUnk]

That's not bad. I have seen a lot worse. If only one end is distorted, you can install that into the 'fixed' position carefully, and then as you install the cylinder or head, that portion will be round and install as normal. There is no load or difference in function if the parts are kept in alignment, as alignment is all the ferrules do. They are there to make sure the components are aligned to the machined position and the oil passage around the cylinder stud is not impeded due to being offset.
I have used small-nose pilers to bend these little things back to 'close enough' to fit, as local resources are slim and of course I had/have no spares.
tom

[kevino]

I used an old drill and plastic hammer to tap the dowel into relative straightness. SO I have 6 dowels. Two go where the cylinder mates to the body. Two go where the cam assembly meets the cylinder. SO where to the last two go?

[GrumpyUnk]

AFAIK, only 4 dowels were used. Two on each mating surface. If you look at the lower surface of the engine, there is an oil outlet on the upper left near the upper left stud. Oil comes out that hole, travels across via a passage cut into the bottom of the cylinder(visible in the picture above at the close right corner). The oil then goes around the stud, up to the bottom of the cylinder head and then to the rocker arms, etc. I do not think one of the ferrules goes on that stud, so bottom would be close left and far right facing the front of the engine.
There are pictures in engine manuals for the 139QMB. I think the ferrules go into the lower left and upper right top of the cylinder, then the head is slid down the studs onto the ferrules. The images in the PDF I have show those positions, at least one ferrule, but I think there were two on every engine I worked on.
tom

If you are working w/o a manual, you should poke around looking for one on site or online. You need the manual for the torque spec for the cylinder stud nuts, at least.
I have no idea where I found the manual I have. Titled: 139QMB_Engine_Manual.PDF

[kevino]

I have the Haynes Manual for Chinese 50cc motors. But it doesn't tell me where the six tubes should go.

[kevino]

I found where the two dowels are supposed to go. Working late into the night and sweating like I'm in New Orleans, I didn't see where they were supposed to go. But they're all in now.