cam chain tension

[pggg]

Prom, so "C" is the point of least resistance between any given 2 compression strokes? So therefore the point 180 deg opposite on the timing plate can also be used?

[pggg]

So if the plugs are removed when tightening the camchain, then the crank position should make no difference?

[rover]

You are getting off the track. Read Randy's reply again. The "C" mark is where all the cams put no pressure on the timing chain. As each lobe pushes against the valve to open it, the chain is under tension. When the valve starts to close, the pressure comes in the other direction. At the "C" mark, there is no pressure from either direction (four sets of valves), and the spring loaded adjuster can remove the most of the slack in the chain. The tension on the chain has NOTHING to do with the pressure in the cylinders. The only reason it is recommended to remove the spark plugs is to make it easier to rotate the engine.

[prometheus578]

Thanks Rover. Yes, Randy was correct. Many thanks for clearing that up for me.
I bumped into two old Yama mechs today, and they confirmed the bit about the point of least valve compression.
Sorry, Pggg. My comments about the pistons and compression were just an expression of my addled brain slowly trying, step by step, to theorize and figure things out by myself... till the voices of experience step in and slap me back to reality.
Next time that I ask a dumb question, I'll just sit back for a while and wait for the more experienced heads to reply, instead of boldly blundering myself into buffoonerey!

"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Stephen Hawking

[pggg]

Heaps of spring pressure at the "C" mark Rov.

[GNEPIG]

.. buffoonerey makes for good entertainment

if you never ask you may never know

[Ken Talbot]

Originally posted by prometheus578

Next time that I ask a dumb question, I'll just sit back for a while and wait for the more experienced heads to reply, instead of boldly blundering myself into buffoonerey!

Now that would be no fun! Did you ever see one of my posts about using a molasses mixture for removing rust from the inside of a fuel tank?

[pggg]

I'm sticking to my 1st answer - the "C" can be at TDC or BDC or everywhere else in between with valves closed, opened, or spinning in cartwheels and still make no difference. The chain always locks tight at any position. Garyc, just don't let off the strain or go backwards.(forwards)

[prometheus578]

Yeah, Ken.... I read that one about the molasses. But I decided that I'd try the one with the arm and hammer washing soda first. Only prob is, I can't find the stuff. I've done science experiments with my boys and understand the electrolysis and transference of metals, just need to find the washing soda. NoGo from Lowes and Home Despot. Any thoughts?
As for the "C" mark again. Provided that one is certain that there is no slack anywhere in the chain, I suppose that the tension could be adjusted at any position. But there is really no way of knowing that for sure.
The "C" mark ensures that you have the least possable pressure on the cam lobes, so that there is no chance of them moving on their own, and putting a little slack in the chain on the at the rearward side, or between the cams at the bridge area.
Pggg...I'm sure you've seen... when adjusting cams or whatever, that the valve spring's pressure can turn the cams on their own if the chain isn't tight. I would have reached that conclusion(or maybe not!) given enough time, but just got sidetracked by my piston compression theory.
I'm slow... but I get there in the end. (usually with the help of others)

[xj11john]

Just suppose ....

Suppose someone didnt read this old thread or their manual closely and didnt go clock-wise on the crank and lined up the "C" by going counter-clockwise? What would happen.

Don't ask me how I know, but I may have done this.
I adjusted it yesterday and it still seems a bit (alot) noisey top end.

Thanks in advance.

[randy]

If you line up the "C" going counterclockwise, then the chain slack will be on the side opposite of the tensioner.

So, do it again going clockwise.

[xj11john]

Thanks Randy!

That's got to be it, I was going to re-do it if I didnt get a responce soon, But that was really Fast!

Thanks Again,

You guys rock! (as said here quite often).

John

[remccool]

Going back a post or 2, I would have to guess that the cam and crank gears are a 2 to1 ratio, being a 4 stroke engine with 2 cylinders firing at the same time (1&4, 2&3), if you stop the pistons half way up, they will all be half way up (or half way down), all of the valves will be closed, and the crankshaft will be in that position twice for each of the cams to sync right and open the valves when they are needed to be opened (makes more sense in my head than when I type it). Just thought I'd throw that into the conversation....

[Ken Talbot]

Careful, John. If you're turning the crank the correct way, you'll have trouble if you overshoot the alignment mark even a little bit if you just tweak ti to alignment without going another full revolution to hit the mark. The slightest turn the wrong way puts tension on the side where the adjuster rubs, and it defeats the action of the adjusting spring.

[xj11john]

Ken,

I was wondering if the first time I turned it counter-clockwise would it then throw the mark off? I would'nt think so since it should just be the chain moving backward across the guides.

Thanks for eveyones comments.