Is anyone still using clay to verify P/V clearance?

General engine tech -- Drag Racing to Circle Track

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cjperformance
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Re:

Post by cjperformance » Tue May 08, 2018 6:09 pm

dwilliams wrote:
Tue May 08, 2018 5:48 pm
statsystems wrote:
Thu May 03, 2018 1:12 pm
Clay is the only way to do it.
10-4. Clay doesn't just tell you how much, it can also tell you if the piston maker put the reliefs in the right spot... and with today's "improved" heads, the valves aren't necessarily where the piston maker might have expected them... That's not even getting into changes in the valve angles.
So true, i have clayed pistons with a large dish top and found that the typical area that a valve would contact has miles of clearance but is almost touching in one tiny area at the inside edge of the squish band. This would also have been found with the dial indicator method but would have been very difficult to pick with solder.
Craig.

steve316
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Re: Is anyone still using clay to verify P/V clearance?

Post by steve316 » Tue May 08, 2018 7:53 pm

I have used lite spring method sense 2004; if I don't have the needed clearance I use clay to locate the problem area.

geraldtson
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Re: Is anyone still using clay to verify P/V clearance?

Post by geraldtson » Tue May 08, 2018 9:47 pm

Plumbers putty works good for me with light coat of oil on putty and valves. Have done the spring- indicator deal before. It was something good to have learned but i don't use it anymore.

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Re: Is anyone still using clay to verify P/V clearance?

Post by pamotorman » Wed May 09, 2018 8:31 pm

i just used a light spring and set the engine at 10 degrees BTDC with the correct lash set. i slipped feeler gauge of the thickness of the clearance i wanted between the rocker tip and valve stem tip and if the valve did not hit the piston i knew i had the clearance i wanted.

engineguyBill
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Re: Is anyone still using clay to verify P/V clearance?

Post by engineguyBill » Wed May 09, 2018 11:30 pm

pamotorman wrote:
Wed May 09, 2018 8:31 pm
i just used a light spring and set the engine at 10 degrees BTDC with the correct lash set. i slipped feeler gauge of the thickness of the clearance i wanted between the rocker tip and valve stem tip and if the valve did not hit the piston i knew i had the clearance i wanted.
When using the light spring/dial indicator/degree wheel method, the measurements should be checked at several locations at least 20 degrees BEFORE and 20 degrees AFTER TDC in order to get valid results. A lot happens in this area as the valves are chasing the piston . . . . . . .
Bill

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ASE Master Certified Engine Machinist (+ two otherASE Master Certifications)
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