K-Series Vernier Pulley and Camshaft Belt Replacement
Discussion
antonio.cocchi said:
Is true that in case of belt replacement I have to do timing with dial gauge because marks is not enough to have the job done?
Thanks for the advice
Advice I've been given is generally 'yes'. I think the main reason being the crank pulley end.Thanks for the advice
From what I've read, unless you can guarantee the crank pulley is solidly located, which it isn't as standard, then the timing could go our by enough to cause issues.
This is the one job I'm nervous about doing myself as a result (not to mention not having the tools to do the timing).
Murph7355 said:
antonio.cocchi said:
Is true that in case of belt replacement I have to do timing with dial gauge because marks is not enough to have the job done?
Thanks for the advice
Advice I've been given is generally 'yes'. I think the main reason being the crank pulley end.Thanks for the advice
From what I've read, unless you can guarantee the crank pulley is solidly located, which it isn't as standard, then the timing could go our by enough to cause issues.
This is the one job I'm nervous about doing myself as a result (not to mention not having the tools to do the timing).
I thought: ehi, children game....
Then....
Edited by antonio.cocchi on Monday 18th January 07:35
I used this video as a guide when I did the belt on my MG ZS (1.8 16v non-vvc) - https://www.youtube.com/watch?v=WSmw_tmomeQ&ab...
I also used the workshop manual: https://www.vgkracing.com/k%20engine%20EU3.pdf - be sure to find the section that is correct for your engine.
In my case I used a cheap cam-locking tool and a big screwdriver to lock the flywheel.
I used a white paint pen to make easy to see marks on the crank pulley and be sure it was is the right place, but the screwdriver held the crank solid.
Although my pulleys were solid not vernier, they still needed to sit accurately, so in my view, as long as the marks lined up, I was happy. The critical element was getting the belt on correctly and tight in the right place. I took a few goes to get this right.
Once everything is together, you can turn the engine by hand on the crank bolt to test for resistance in the wrong place and make sure the marks line up after several rotations.
Go slow, go carefully, stop if you're not sure and ask questions and you'll be fine.
I also used the workshop manual: https://www.vgkracing.com/k%20engine%20EU3.pdf - be sure to find the section that is correct for your engine.
In my case I used a cheap cam-locking tool and a big screwdriver to lock the flywheel.
I used a white paint pen to make easy to see marks on the crank pulley and be sure it was is the right place, but the screwdriver held the crank solid.
Although my pulleys were solid not vernier, they still needed to sit accurately, so in my view, as long as the marks lined up, I was happy. The critical element was getting the belt on correctly and tight in the right place. I took a few goes to get this right.
Once everything is together, you can turn the engine by hand on the crank bolt to test for resistance in the wrong place and make sure the marks line up after several rotations.
Go slow, go carefully, stop if you're not sure and ask questions and you'll be fine.
That may work with stock cams, they don't have much duration or lift at TDC, for more extreme cams, an error of a few degrees on the bottom sprocket (that can have up to 8 degrees of slack) can mean valve piston contact even if the marks line up. You may be lucky, you may not. On a stock engines it’ll run 20 degrees out without issue , on an R500 5 degrees out and it’s goodnight Vienna for your engine.
On engines I build, I shim the cambelt sprocket so that it cannot move once fitted. This makes it an easier proposition.
Do it properly.
I always back off(retard) the inlet pulley by 5 degrees, back off (advance) the exhaust pulley by 5 degrees , then remove the belt, fit the new belt with the timing marks aligned and then check and set the cam timing using ‘lift at TDC’ to make sure it is set correctly,
Dave
On engines I build, I shim the cambelt sprocket so that it cannot move once fitted. This makes it an easier proposition.
Do it properly.
I always back off(retard) the inlet pulley by 5 degrees, back off (advance) the exhaust pulley by 5 degrees , then remove the belt, fit the new belt with the timing marks aligned and then check and set the cam timing using ‘lift at TDC’ to make sure it is set correctly,
Dave
Edited by DVandrews on Monday 25th January 11:35
DVandrews said:
That may work with stock cams, they don't have much duration or lift at TDC, for more extreme cams, an error of a few degrees on the bottom sprocket (that can have up to 8 degrees of slack) can mean valve piston contact even if the marks line up. You may be lucky, you may not. On a stock engines it’ll run 20 degrees out without issue , on an R500 5 degrees out and it’s goodnight Vienna for your engine.
On engines I build, I shim the cambelt sprocket so that it cannot move once fitted. This makes it an easier proposition.
Do it properly.
I always back off(retard) the inlet pulley by 5 degrees, back off (advance) the exhaust pulley by 5 degrees , then remove the belt, fit the new belt with the timing marks aligned and then check and set the cam timing using ‘lift at TDC’ to make sure it is set correctly,
Dave
The rule is, do what Dave says.On engines I build, I shim the cambelt sprocket so that it cannot move once fitted. This makes it an easier proposition.
Do it properly.
I always back off(retard) the inlet pulley by 5 degrees, back off (advance) the exhaust pulley by 5 degrees , then remove the belt, fit the new belt with the timing marks aligned and then check and set the cam timing using ‘lift at TDC’ to make sure it is set correctly,
Dave
Edited by DVandrews on Monday 25th January 11:35
Given all the research I thought I'd done, I had never read the 8 degree slack issue. They were only 135 cams, but still, I'd have been a lot more nervous if I had!
DVandrews said:
That may work with stock cams, they don't have much duration or lift at TDC, for more extreme cams, an error of a few degrees on the bottom sprocket (that can have up to 8 degrees of slack) can mean valve piston contact even if the marks line up. You may be lucky, you may not. On a stock engines it’ll run 20 degrees out without issue , on an R500 5 degrees out and it’s goodnight Vienna for your engine.
On engines I build, I shim the cambelt sprocket so that it cannot move once fitted. This makes it an easier proposition.
Do it properly.
I always back off(retard) the inlet pulley by 5 degrees, back off (advance) the exhaust pulley by 5 degrees , then remove the belt, fit the new belt with the timing marks aligned and then check and set the cam timing using ‘lift at TDC’ to make sure it is set correctly,
Dave
Thanks for take the time for answer (here and everywhere On engines I build, I shim the cambelt sprocket so that it cannot move once fitted. This makes it an easier proposition.
Do it properly.
I always back off(retard) the inlet pulley by 5 degrees, back off (advance) the exhaust pulley by 5 degrees , then remove the belt, fit the new belt with the timing marks aligned and then check and set the cam timing using ‘lift at TDC’ to make sure it is set correctly,
Dave
Edited by DVandrews on Monday 25th January 11:35
)Just another question, I try to check this with the previous owner, but he don't know and I cannot find the other owner.
What the reason to put vernier on a standard engine? Can I Guess there some upgrade on camshaft/head?
Thanks again
P.S. I have not take the pulley picture yet, hold on!
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