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| cam timing https://ausmini.com/forums/viewtopic.php?f=5&t=25659 |
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| Author: | simon k [ Thu Dec 07, 2006 11:26 am ] |
| Post subject: | cam timing |
hiya all - I've just had a thought.... the few times I've put a cam into a motor, I've used a dial indicator and adjustable gears to get the cam timing where I want it, rather than just lining up the dots on the gears.... but I'm curious my question is: what are the symptoms of an incorrectly timed cam - specifically for a retarded cam - other than lower than expected power, might it overheat at high rpm in 4th gear (above 70kph)? what else? as an aside, I think the cam in my current motor may be over advanced a little, as it is louder than normal, and has a distinct crackle and the exhaust comes out of the pipe faster (more pressure) than I'd expect - making me think that the combustion is still happening/expanding as the valve opens - not a big deal - my real question is above |
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| Author: | drmini in aust [ Sun Dec 10, 2006 6:20 am ] |
| Post subject: | |
In general terms slight cam advance gives more torque, slight retard gives more top end. With most cams. But, going a whole tooth out is too far. That's 18* at crank. 
I've been told some timing chain sets were made with about 10* retard, for emission purposes. Another reason for checking cam timing during installation..... don't just line the dots up. 
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| Author: | Wombat [ Mon Dec 11, 2006 9:53 am ] |
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Where do you get the dial thingy ? what do they cost? are there different ones around and is one any better (ease of use etc) than another? |
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| Author: | drmini in aust [ Mon Dec 11, 2006 10:24 am ] |
| Post subject: | |
Got mine here- http://www.hareandforbes.com.au/sample_2/home.php Click on metal working catalog Mag base is $38 Dial gauge 2" dia, 0-1" travel (.001" steps) is$38. There is also a Metric one for the Imperially Challenged, but it does not have enough travel- only 10mm.
<edit> Of course, you can spend more on Bling ones elsewhere- eg buy Starrett, Moore and Wright, Mitutoyo etc- but for most things on a car the cheapies are fine. |
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| Author: | Wombat [ Mon Dec 11, 2006 12:56 pm ] |
| Post subject: | |
drmini in aust wrote: Got mine here- http://www.hareandforbes.com.au/sample_2/home.php
Click on metal working catalog Mag base is $38 Dial gauge 2" dia, 0-1" travel (.001" steps) is$38. There is also a Metric one for the Imperially Challenged, but it does not have enough travel- only 10mm. No I meant the big clock face dial thingy with degrees marked on it that goes on the crank pully to line up the timing - I have a magnetic dial gauge. |
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| Author: | drmini in aust [ Mon Dec 11, 2006 1:09 pm ] |
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Try a speed shop. 
That's where I got mine years ago, it's a Yankee one. Kent Cams sell them too. <edit> so do Crow Cams- http://www.crowcams.com.au/Products.shtml There is a drawing of one on the web somewhere, Benjamin just printed that and made his own. 
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| Author: | Wombat [ Mon Dec 11, 2006 2:06 pm ] |
| Post subject: | |
Thanks for the heads up - did a Google and found this 
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| Author: | DOZ [ Mon Dec 11, 2006 2:23 pm ] |
| Post subject: | |
Buy some spray glue from a craft shop ($??) and some 3mm MDF from Bunnings (about $3.00) Spray glue on MDF, add printed wheel, cut with jigsaw ($14.99) and drill hole, beauty mate. Daniel |
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| Author: | Wombat [ Mon Dec 11, 2006 2:41 pm ] |
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I printed it on A4 then ran it through the A3 enlarger photocopier and got it 41% bigger
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