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Location:
Brisbane
Registered:
October 2002
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valve sealing question
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Tue, 25 November 2003 10:47
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i have just got myself a spare 18RG head, i have lapped in the valves, and when i put the valves back in and pour water into the chambers to check for full sealing, it still leaks, no 2 leaks all out in about 30 mins but 1,3,4 only have about 1/2 left after 1.5 hours, will this small leakage affect compressions.
i have checked al the vaves with bearing blue and it comes up fine
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Location:
Brisbane
Registered:
February 2003
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Re: valve sealing question
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Tue, 25 November 2003 14:38
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this is with spring pressure?
you might need an engine shop to re-grind the valve seats and faces - should be a standard 3-angle job with a polish afterwards?
seeing as it's not in an engine you might as well give it refresh: valve seats, minor porting/polish, cleanup gasket surface, cleanup the spark-plug threads, etc)
charles.
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Location:
tallahassee FL usOFa
Registered:
May 2002
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Re: valve sealing question
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Tue, 25 November 2003 16:57
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water, with its surface tension(ever float a razor blade?), oughta stay FOREVER(except for evaporation) even with poor valve seats.
with springs installed and gasoline/petrol poured down the ports there should still be ZERO seepage with any newly ground/lapped valves.
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Location:
Canberra
Registered:
December 2002
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Re: valve sealing question
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Tue, 25 November 2003 23:28
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Have you got a picture of the valve because it sounds pretty bad. Also you do have the springs and collets in etc dont you silly question i know.
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Location:
Brisbane
Registered:
October 2002
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Re: valve sealing question
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Wed, 26 November 2003 07:55
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no i dont have the springs in cause i dont have the tool, i have lapped them in with the rough paste then the smooth paste and checked with bearing blue and it has a very good sealing area (2mm+) on each valve.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: valve sealing question
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Wed, 26 November 2003 08:01
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they may not seal perfectly with no springs, but at rpm, with spring pressure (around 40-80lbs!!) they should seal okay. try the leak test with springs installed and see what happens.. should have buggerall leakage then.
when i was doing the CC'ing of my chambers, i cbf putting springs on, so put a light smear of grease to seal them, otherwise they'd leak. once springs were installed, no leakage..
Cya, Stewart
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Location:
tallahassee FL usOFa
Registered:
May 2002
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Re: valve sealing question
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Wed, 26 November 2003 16:28
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"very good sealing area (2mm+)"
Wider is NOT better!! Toyota 4AGE spec is 1 -1.4mm
the seat does 2 things, seal and transfer heat(especially the exhaust), and you need the opposite seat widths for each so there has got to be a compromise. wide transfers better, but narrow seals better and is necessary to cut through & crush out the carbon deposits without going for stronger springs.
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Location:
Brisbane
Registered:
October 2002
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Re: valve sealing question
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Thu, 27 November 2003 09:37
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i re did the intakes last night and i did the bearing blue test and the are very good, just have to do the exh now
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