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Post by Rockalicious on Mar 6, 2022 22:53:34 GMT
Does anyone have a recommendation for a TDC tool and feeler gauge?
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Post by greenandgold on Mar 7, 2022 3:59:42 GMT
Guess it all depends what you what to do and in what state of assembly the engine is in. If you plan to time an engine with the head off, the set like the one shown in the first pic is what you want. A mag base and a dial indicator. Lots of other uses for this set up too, such as measuring run out of rotating parts, using as a depth stop, checking surface flatness, etc. I'd personally opt for a simpler magnetic base, one without the fine adjustment nob/hardware on the rod; the stuff gets in the way, can get loose and you'll rarely use the adjustment anyway--more annoying than useful. Here's an example: www.mscdirect.com/product/details/76444009 If the heads are installed, you can encounter set up challenges contorting a mag base to support an indicator while trying to pass its spindle thru a plug hole. The magnetic mount has to have a solid, stable mounting point, which is sometimes hard to find on an assembled installed engine. (Aluminum heads aren't magnetic) And spindle/plunger extensions will most likely be needed to gain the necessary length. FYI, there isn’t a standard on indicator spindle threads. Some are metric, some not, with differing threads diameters and pitch. If you plan to find TDC and then time an engine with the heads installed, something along the lines of the second pic, a dial indicator with the correct plug hole adapter, is usually easier/quicker to use and fits into more confined spaces. The plug hole adapter provides a very solid, stable mounting point. If you plan to time an engine where the plug hole isn’t at a right angle to the up and down rotation of the piston (think early ski doo singles/twin fans for instance) an indicator roller tip can help minimize plunger jamming. {Search “indicator roller tip”) You would also need the offset measurement timing spec. If the offset spec isn’t available, then using this type of set up to time the engine isn’t possible without knowing some trig related engine stats. There is a third style. Uses a dial indicator with very long spindle extensions. The indicator is held in place with an adjustable arm fixture allowing the indicator to be positioned at various angles. The fixture takes the place of a mag base. Not inexpensive. Here’s a pic www.toolsource.com/cylinder-bore-gauges-c-614_264/timing-gage-set-2cycle-small-engines-1-in-range-p-76183.htmlSome plug locations/fin layouts are easier than others to use this type on. Space can get tight and clearances a challenge, particularly on installed engines. Good luck |
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Post by tompriebe on Mar 7, 2022 23:18:35 GMT
I actually use a spark plug for a base. Cut off the ground electrode, break out the porcelain, drill and tap a hole for a set screw through the plug. If you are lazy, wrap electrical tape around any plunger style shaft, and friction fit it in the naked spark plug.
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Post by tompriebe on Mar 10, 2022 1:52:52 GMT
Maybe that wasn't useful?
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Post by greenandgold on Mar 10, 2022 2:42:20 GMT
I liked it. On my list of things to do when the temps in the shop hit 60 is to try to knock the center out of a spark plug. I do need a 12 or 10mm adapter for a bike and have a few used plugs in the bin. Pretty sure I could come up with uses for home made 14mm or 18mm hollow threaded adapters too. Thanks for the idea.
When just trying to find tdc in order to stuff a rope into the cylinder to stop a piston/crank from rotating to remove a clutch bolt, I’ll just stick a piece of welding rod into the plug hole and watch it. Keeps the rope from getting caught in a port. Probably not so useful if you’re setting points…..
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Post by Rockalicious on Mar 10, 2022 22:22:55 GMT
Great amount of info! Many thanks eh.
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Post by olyman on Mar 11, 2022 21:12:36 GMT
Good ideas boys. A long time ago I picked up a super cheap dial from princess auto, and pretty much only use it for doing timing. It came with a mag base and you can rig up just about anything to hold it iin place. I like doing that with the head off if I can, but if not I try to make it as vertical as possible so I can use the direct #'s because I don't trust mine any other way
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Post by tompriebe on Mar 12, 2022 1:34:48 GMT
I know that the angled plugs are a pita. My big stripped 18mm plug is always interesting. That's why I like the friction fit electric tape method for TDC. You can find TDC, rotate the dial, retract it a little bit and re-zero, and not worry too much about the angle of the plunger vs. the dome of the piston.
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