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Old 12-05-2005, 05:39 PM
SedanMan SedanMan is offline
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Default 1,000 lashes

Given that we all have to use solid lifters, how often do you check/adjust your valve lash?

I don't think that adjusting valve lash is any kind of competition secret so I'll go ahead and ask......any tricks to doing it, especially on GM engines? (different firing order than the ones allowed for the Fords)

Do you adjust them hot or cold?
Turn the engine over using the crank bolt or a starter switch?
How do you know if the cam is in the right position? (marks on the damper or just watch the valves?)

I guess it's like changing your oil. You can't do it too often, there's a rule of thumb for how often you do it (although everyone has a different thumb), and it shouldn't be ignored forever.
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Old 12-06-2005, 11:35 AM
Rheacerdave
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Info for Ford's would be appreciated, too.
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Old 12-06-2005, 11:44 AM
jimwheeler jimwheeler is offline
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I adjust mine hot, turning over with starter. Bump until they are fully closed, adjust, move on. With the valve stud girdle that they just legalized, I don't adjust very often. The stud girdle has tall adjusters that are clamped between two pieces. You adjust then tighten the bars around the adjusters.
Every couple of races I pop the valve covers and do a random check. If I find one out of adjustment I do them all.
wheel
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Old 12-08-2005, 06:35 AM
BMiller
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I adjust them hot once, let them cool, then check them cool. That way I have a correlation between hot and cold and can adjust them cold in the future and avoid the hassles with dealing with hot parts. Usually after every weekend I check them.
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Old 12-08-2005, 06:57 AM
jimwheeler jimwheeler is offline
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Quote:
Originally Posted by BMiller
I adjust them hot once, let them cool, then check them cool. That way I have a correlation between hot and cold and can adjust them cold in the future and avoid the hassles with dealing with hot parts. Usually after every weekend I check them.
Bill,
Good idea, I'll try that.
wheel
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Old 12-08-2005, 08:18 AM
Dawson Motorsports
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years ago I found an article in Circle Track magazine, it was written buy Randy Dorton. It explains his procedure for adjusting valves[cold]. I'll see if I can find it, and post it here. It's worked every time. Like Jim, we spot check and adjust accordingly.
Chuck
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Old 12-08-2005, 09:27 AM
SedanMan SedanMan is offline
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Quote:
Originally Posted by BMiller
I adjust them hot once, let them cool, then check them cool. That way I have a correlation between hot and cold and can adjust them cold in the future and avoid the hassles with dealing with hot parts. Usually after every weekend I check them.
Sounds like a good idea. What correlation did you find between hot and cold and was this on a Ford or GM engine?

I spoke to my engine builder once about what he would recommend for lash amounts and he gave me some cold numbers. He also told me that in his experience he didn't find much difference between hot and cold (maybe because everything in the valve train is steel and it all grows somewhat proportionally, although one would think that the valve would get longer at a greater rate than the rocker arm stud because the valve gets much hotter).
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Old 12-08-2005, 09:38 AM
BMiller
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The correlation changes depending on valves, cam, lifters, head design etc. Remember the heads are cast iron - at least they are supposed to be . Also the cam manufacturer will recommend a delta from their hot to get to initial cold but I found that to not be very accurate (but works fine for initial start-up / break-in).
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Old 12-08-2005, 10:46 AM
SedanMan SedanMan is offline
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Sorry, I was asking what correlation you found on your engine, not just a general question. That's why I was asking if you had a Ford or GM engine. Of course if this info is considered a secret then I'll respect that.

I can imagine that stainless valves change more in length when heated than alloy steel, but I think most are SS. Also, I think a cam with a more aggressive ramp would like less lash, but I'm assuming most of our semi-spec engines have roughly the same lash attributes. Again, it was just a curiosity and of course I'd have to do my own homework on my setup.
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  #10  
Old 12-10-2005, 01:36 PM
SedanMan SedanMan is offline
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Quote:
Originally Posted by Dawson Motorsports
years ago I found an article in Circle Track magazine, it was written buy Randy Dorton. It explains his procedure for adjusting valves[cold]. I'll see if I can find it, and post it here. It's worked every time. Like Jim, we spot check and adjust accordingly.
Chuck
Chuck, any luck with finding the article? If it makes the job easier then I'm all for it. I figure the easier the job is the more often it'll get done.

Thanks.
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