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timing chain tensioner and guide ???s


clutchdust

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i'm curious if this looks weird to any of you. i replaced the chain guides while i was this far into the motor and according to a response to an earlier question, i tried to set the curved guide (the one above the tensioner) as close to the center of the block as i could. however, when i did that, i couldn't get the chain on the sprockets. i don't know if it's just because it's a cheap knock-off but i had to take a dremel and oblong the upper bolt slot for the bolt to align with the hole. then i put as much pressure against the chain as i could by hand while tightening down the bolts.

182100_1648-med.jpg

182100_1646-med.jpg

also, is the clipped link considered the "bright" link as referernced in my haynes manual? is there really a better manual than this one anyway? they're speaking too much 'english' and i'm having a hard time translating. :oops:

182100_1647-med.jpg

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Ok, a couple of things here.

 

Firstly, your engine isn't on top dead centre. To get everything aligned properly, you must start with the engine in this position. I can tell its off because of the position of the keyways on the crant aren't pointing straight upwards relative to the engine block.

 

To get the chain tensioner shoe and curved chain guide in proper position, you're almost there. Loosen the top and bottom bolts on the curved chain guide. Use your left hand and push to the right the whole guide from the middle until you have achieved a lovely radius that takes out that kink you seem to have just around the tensioner shoe. Then snug the bolts so that the curved chain guide stays in that position until your torque the bolts up later.

 

Check the position of the cam. Take off the chain and the camshaft sprocket. The camshaft locating pin that fits into the cam sprocket should be at the top looking from the front of the engine, similar in orientation to the keyways on the crank.

 

I can see the 'bright' links on your chain. The distance between these links are not the same , so the 'short' side of the chain is the side that you'll be needing to work with. The little sprocket on the crank has a spot or timing mark on it, so long as it was put on the right way around. Put the chain on so that one of your bright links or link plate is directly over the 'spot' on the crank spocket. The short side of the chain runs up along the straight chain guide so now the second bright link plate will sit on the right side of the camshaft sprocket, usually two complete links sitting on the cam sprocket. The first link plate only half sits on the cam sprocket. I did not count this one, so its two complete link plates on the sprocket...understand?

 

With a fresh chain, set your timing on the camshaft sprocket to number one unless you have a different camshaft that requires you to set it up via the timing card specs.

 

There are heaps of articles on this site that can help you out with stuff like this. Search, read and then read some more.

 

One thing about engine building is to never be in a hurry. Not to be unkind, if you haven't got the time nor patience perhaps you should be paying someone else to be doing it for you. Inexperience is another thing and the way to learn is to have a go and that's always a good place to start.

 

Good luck.

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Also you have the joiner clip on the wrong way, I.E, the open part of the joiner should be on the trailing end when the chain movies,

Chain move clockwise, the open bit on the clip should be on the left,

You learn these thing when you miles away from home and you chain on your motorbike comes off because the joiner clip was put on the wrong way

 

another way to think off it, is the part with the most mass (on the joiner clip), should be at the froward part,

 

Nigel

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thanks guys. i shouldn't be surprised you guys caught that it wasn't at TDC, just surprised that it was the first post! i was going to put a disclaimer that this was a mock-up photo just to see how things lined up, but y'all caught me.

as far as the chain is concerned, i plead ignorance to that one. the link is the way it was when i took it off. i haven't disassembled it or anything. i've been suspicious that someone rebuilt this motor previously and maybe i was right.

i do admit i'm struggling to understand exactly how to work the cam and ignition timing. not quite as idiot-proof as my SBC to be sure. i'll search out some info on the site. the haynes book is the suck.

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BTW, while i'm at it, i'm thinking of making a small bracket that bolts across the tensioner block and opposite chain guide that has a small block between the two halves of the chain. the idea is that should i decide to do a cam swap later on, the block won't allow the tensioner to pop out of place and just less concern in general should i ever need to pull the cam sprocket off. thoughts?

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Just broke out the "How to Rebuild" book (I find it much more helpful than the Haynes manual). The idea is to adjust the slack side chain guide 'tangent' to the chain. It means aligned with, or as ozconnection pointed out, so it doesn't kink and has a nice smooth curving radius.

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BTW, while i'm at it, i'm thinking of making a small bracket that bolts across the tensioner block and opposite chain guide that has a small block between the two halves of the chain. the idea is that should i decide to do a cam swap later on, the block won't allow the tensioner to pop out of place and just less concern in general should i ever need to pull the cam sprocket off. thoughts?

 

I play with my cam timing quite a lot, so I take the cam sprocket off and reposition it to suit my application all the time. For me, the easiest thing to use is the 'good ol wooden chock'. Mine is quite small so its easy to drop the camshaft sprocket into the guts of the head once the camshaft sprocket bolt is removed. I then roll the chain over the sprocket and pull it back up to put the bolt back in etc.

 

The chock measures 18mms thick,

Measures 68mm's aolng the top edge,

measures 35mm's along the bottom edge,

and is 88mms tall.

There is a right angle from the top right down.

 

I like this although a shoe stopper would work and is still available from Kameari, so you decide. My tool took 5 minutes to make and cost virtually nothing.

 

To get the chock out , just turn the crank slightly when everything is ready and out it comes. To jam it in, I use the handle of a hammer upside down. A few firm taps are all that's needed.

 

Cheers. :cool:

wooden chock_thumb.jpg

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on a previous 240 that i just did some head work on, i just stuffed a piece of 3/4 heater hose down there. it worked fine but i'm just thinking as long as i have the front cover off it would be real easy to do. my only concern is how much whip do you think is in that chain when it's running? i don't know what it would be like with the guides but if you ever saw a SBC chain run without the chain cover it would freak you out.

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