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jhow66 · 06-13-2005, 06:24 PM

Hey Yukon how much lift does the new cam have? Sounds like your spring retainer is hitting the telfon seals at full lift. Most of the time when you install this kind of valve seal the valve guides must be machined. Just used a cam in my son's (orangeuavol) BB 408 that had .538 lift on exhaust side that cleared with regular seals and stock springs. When you are replacing the seals that are broke here is a way to check to see if you have enough clearance:
1--install valve retainer and keepers (valve spring off).
2--hold valve on seat and measure from under lowest part of retainer to top of valve guide with seal installed.
3--Take this figure (as an example say .505) and subtract the cam lift (say .498 as an example). This shows that you only have .007 clearance (not enough).
4-- Someone will know what the clearance should be, so chime in.
5--Don't put it back together until you check this clearance as this is what is breaking your seals (and probably bending your push rods.
Hope this helps.

06-13-2005, 06:24 PM	#49
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	Hey Yukon how much lift does the new cam have? Sounds like your spring retainer is hitting the telfon seals at full lift. Most of the time when you install this kind of valve seal the valve guides must be machined. Just used a cam in my son's (orangeuavol) BB 408 that had .538 lift on exhaust side that cleared with regular seals and stock springs. When you are replacing the seals that are broke here is a way to check to see if you have enough clearance: 1--install valve retainer and keepers (valve spring off). 2--hold valve on seat and measure from under lowest part of retainer to top of valve guide with seal installed. 3--Take this figure (as an example say .505) and subtract the cam lift (say .498 as an example). This shows that you only have .007 clearance (not enough). 4-- Someone will know what the clearance should be, so chime in. 5--Don't put it back together until you check this clearance as this is what is breaking your seals (and probably bending your push rods. Hope this helps. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer Last edited by jhow66; 06-13-2005 at 06:25 PM.