Setting the valve timing

[Dean0]

What would be your thoughts on moving it to the advanced position ? What effect does advancing the cams have ?

x2

 

[warp9.9]

Cheers mate, same here mate...


after the chain tensioner is set and engine rotated 4 times and crank timing mark set at TDC the cam timing marks are retarded by approximately ½ a tooth, I then bump the crank slightly forward clockwise so as the cam alignment tool/fixture slips back into place, the crank timing mark is then positioned ATDC by a ½ a tooth… If I deliberately and jump a tooth, the crank timing mark is then positioned BTDC by ½ a tooth on the crank sprocket.

Is the chain, gears, or guides new or are you reusing the originals?

 

[Dean0]

Is the chain, gears, or guides new or are you reusing the originals?

I am reusing the the originals... from memory the cam chain measured 137mm over 23 links... the cam sprockets show no sign of wear, the crank sprocket looks good but I have not removed it for inspection... nor have the guides been physically inspected as I have not removed the clutch cover, although I have confirmed the cam tensioner pawl sits on the 16th tooth every time I release it... the cam tensioner gauge tool does indicate the need for the spacer when setting the tensioner.

 

[Dean0]

Went with retarded as it was closer to the mark than if I went to the advanced.

with my set up the distance of the dot on the crank in relation to the mark on the crank casing when retarded is approximately the same distance as advanced.

 

[warp9.9]

I am reusing the the originals... from memory the cam chain measured 132mm over 23 links... the cam sprockets show no sign of wear, the crank sprocket looks good but I have not removed it for inspection... nor have the guides been physically inspected as I have not removed the clutch cover, although I have confirmed the cam tensioner pawl sits on the 16th tooth every time I release it... the cam tensioner gauge tool does indicate the need for the spacer when setting the tensioner.

Ok its not bad reusing the parts especially since they are not worn out. Let me get a cup of coffee and think a little and I will give my reasons for setting it the way you have it verses setting it the half tooth different. I am a amateur so I am sure a highly qualified man like @Neville Lush who would have many many times the experience and skill that I have.

 

[Dean0]

Cheer Scott, I find your take on all things rocket very interesting, you've helped me out before now...

 

[warp9.9]

Cheer Scott, I find your take on all things rocket very interesting, you've helped me out before now...

No dude I do not know what I am doing but usually between people on the site that I pay attention to I learn from then well I try to get a bunch of heads together to sort it out. Like I am going to get dressed and go down to the barn and see how much rotational movement you can get between the cam gears and the cams with the two 6 mm bolts in (see how much one could shift the gear with the bolts in if any) Right now it looks to me like you delayed the intake cam timing which seems to be moving the opening event from 12 BTDC to say 3 BTDC Just using the half crank tooth which is 9.47 degrees of crank movement.I have to run some ratio figures to see how much it rotates the cam gears. anyway it moves the opening event and the closing event of the intake cam from 28 ABDC to 37 ABDC leaving less of a compressing stroke left. See where I am going here? the draw stroke is the same it just starts later and the compression stroke is less.

Someone like Nev would just know this answer not have to try to reason and figure out what happens from the change.

Ok I found a cam gear down stairs 38 teeth so a half tooth on the crank 9.47 = 4.73 degrees of cam movement so instead of 12 BTDC were talking 7.26 degrees on the intake side. I should also note I measured about a .025 or .64 mm clearance between the cam bolts and the holes in the gears.

 

[dragonjocky]

I've never torn into this motor "yet", so my comment shoild be taken with a grain of salt. However, I have completed a built on my V2 and there was great discussion about the timing chains aand stretch. In the end we discovered it was not stretch in the chain that was an issue for timing, but the wear (not visible by idol inspection) on the timing gear that was causing timing issues. I would perform a measurement diagnosis of the gear before reusing it, or simply replace it and know your at spec.

Did my motor build at 37000 miles

 

[warp9.9]

I've never torn into this motor "yet", so my comment shoild be taken with a grain of salt. However, I have completed a built on my V2 and there was great discussion about the timing chains aand stretch. In the end we discovered it was not stretch in the chain that was an issue for timing, but the wear (not visible by idol inspection) on the timing gear that was causing timing issues. I would perform a measurement diagnosis of the gear before reusing it, or simply replace it and know your at spec.

Did my motor build at 37000 miles

Yes some wear can not be visibly detected which is why Triumph points out what wear to visually look for as wear and how to measure the chain. Still human error can creep in plus we have to take in mind tolerance on the manufactured parts all of them including bolts tolerance can work for you but it can also work against you. I seen this on a couple cam chains and noted they were made in different countries.

 

[Pedro]

I would check the timming marks with a degree wheel and a dead stop. To find TDC. I still think you have slack in the chain.