scott123007
Well-Known Member
Specifically and most importantly, you never rock a fixed dowel into place. You rock the object onto the fixed dowel.
Boogered the valve inspection
- Thread starter rbmgf7
- Start date
The reason I did what I did is because of my explanation below and why I don't see Yamaha's process any different.
I work in a manufacturing facility where we do exactly this: fasten two parts together and bore them to within tight tolerances.
For the sake of explaining, I'll relate our process at work with names of cylinder head parts.
We press the majority of the dowels surface into the cap so it retains in the cap for two reasons:
1. The cap has an open hole so it can be accessed from the outside (and, well duh, there's a fastener going through it). Hence, if my occurrence were to happen, they can pull the cap off, press out the dowel, and try again (which it does happen on seldom occasion). If you press the majority of the dowel into the cylinder head and something boogers up, how are you going to get it out? From an at-home perspective we can remedy something but in an assembly line, this can't be tolerated. I know it seems ironic that I ask how to fix my problem when we have these problems at work. Well, our dowels, caps, and cylinders heads are MUCH beefier so if a dowel is crushed, the other parts remain unscathed.
2. The cap is separated during another assembly process so if you leave the dowel in the cap, this alleviates damaging the dowels since people are working around the cylinder head. You're at risk if you have people assembling around thin walled dowels.
I'm not saying anyone is wrong but I can't understand the logic if the majority of the dowel is in the cap or the head (unless you're looking at it from a manufacturing assembly perspective). Flip the parts. Imagine, in a theoretical sense, mating the head to the caps; the caps being stationary and you're able to maneuver the head. It's not different.
It just eludes me because there wasn't any resistance; it fasted with 7 ft-lbs down to the mating surface. The dowels are also tapered on the ends.
Oh well, chalk one up for the weird cases of "when service maintenance goes wrong".
I work in a manufacturing facility where we do exactly this: fasten two parts together and bore them to within tight tolerances.
For the sake of explaining, I'll relate our process at work with names of cylinder head parts.
We press the majority of the dowels surface into the cap so it retains in the cap for two reasons:
1. The cap has an open hole so it can be accessed from the outside (and, well duh, there's a fastener going through it). Hence, if my occurrence were to happen, they can pull the cap off, press out the dowel, and try again (which it does happen on seldom occasion). If you press the majority of the dowel into the cylinder head and something boogers up, how are you going to get it out? From an at-home perspective we can remedy something but in an assembly line, this can't be tolerated. I know it seems ironic that I ask how to fix my problem when we have these problems at work. Well, our dowels, caps, and cylinders heads are MUCH beefier so if a dowel is crushed, the other parts remain unscathed.
2. The cap is separated during another assembly process so if you leave the dowel in the cap, this alleviates damaging the dowels since people are working around the cylinder head. You're at risk if you have people assembling around thin walled dowels.
I'm not saying anyone is wrong but I can't understand the logic if the majority of the dowel is in the cap or the head (unless you're looking at it from a manufacturing assembly perspective). Flip the parts. Imagine, in a theoretical sense, mating the head to the caps; the caps being stationary and you're able to maneuver the head. It's not different.
It just eludes me because there wasn't any resistance; it fasted with 7 ft-lbs down to the mating surface. The dowels are also tapered on the ends.
Oh well, chalk one up for the weird cases of "when service maintenance goes wrong".
scott123007
Well-Known Member
Well, that is where it IS different, Ray. There is way more rocking movement AND leverage by the object with a fixed dowel in it, than the object it is attaching to. That is why the object with the dowel in it already, should be the stationary one. Besides, these dowels are not pressed in place. A careful twist with your fingers (or sometimes pliers) will remove them.TeneRay said:
In many applications which require the use of dowels, it really is six of one, half a dozen of the other how they go together because they are just for alignment and do not have to be rocked in to place under tension, but some cam caps are under tension when being assembled and that is when it is critical to rock the cap onto the dowel, not rock the cap with a fixed dowel, into the head.