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FE Power Forums => FE Technical Forum => Topic started by: Urgefor on July 09, 2024, 01:47:20 PM

Title: Valve stem heights
Post by: Urgefor on July 09, 2024, 01:47:20 PM
Long story short I had some larger valves put into a set of 6090G heads awhile back.  I'm finally ready to get them installed but noticed what appeared to be differing valve stem heights upon closer inspection. A straight edge and feeler gauge says all of the exhaust valve stems are .007 to .008 lower than the intake valve stems.  Spring closed height is within the specs I gave the machinist. In retrospect, I probably should have given one specific install height to avoid any confusion. I made the assumption the machinist would make them all the same height but within the range I gave. Live and learn I guess.

This isn't a race engine.  Maybe classified as street/strip but in reality mostly street.  Thoughts?
Title: Re: Valve stem heights
Post by: frnkeore on July 09, 2024, 02:50:54 PM
That is not enough to worry about.
Title: Re: Valve stem heights
Post by: pbf777 on July 09, 2024, 04:02:35 PM
     There can be many different reasons for varying valve stem tip heights and not necessarily being a negative indictment of the workmanship by the machine shop.  And as stated previously, the sum your encountering shouldn't present a problem.   :)

     Scott. 
Title: Re: Valve stem heights
Post by: Ford428CJ on July 11, 2024, 03:19:27 PM
Long story short I had some larger valves put into a set of 6090G heads awhile back.  I'm finally ready to get them installed but noticed what appeared to be differing valve stem heights upon closer inspection. A straight edge and feeler gauge says all of the exhaust valve stems are .007 to .008 lower than the intake valve stems.  Spring closed height is within the specs I gave the machinist. In retrospect, I probably should have given one specific install height to avoid any confusion. I made the assumption the machinist would make them all the same height but within the range I gave. Live and learn I guess.

This isn't a race engine.  Maybe classified as street/strip but in reality mostly street.  Thoughts?

 Even from the Factory… FE’s came that way. A little shorter on the exhaust valve than the intake valve. I’m sure the reason why, was because the exhaust valve is hotter than the intake side. Little more spring pressure.
Title: Re: Valve stem heights
Post by: pbf777 on July 11, 2024, 04:04:19 PM
Even from the Factory… FE’s came that way. A little shorter on the exhaust valve than the intake valve. I’m sure the reason why, was because the exhaust valve is hotter than the intake side. Little more spring pressure.

     I was under the impression that it was done because the exhaust valve and seat faces were expected to erode faster than that of the intake side and hence provide a bit more time before servicing might be required.   :-\

     Scott.
Title: Re: Valve stem heights
Post by: Ford428CJ on July 11, 2024, 06:27:38 PM
Even from the Factory… FE’s came that way. A little shorter on the exhaust valve than the intake valve. I’m sure the reason why, was because the exhaust valve is hotter than the intake side. Little more spring pressure.

     I was under the impression that it was done because the exhaust valve and seat faces were expected to erode faster than that of the intake side and hence provide a bit more time before servicing might be required.   :-\

     Scott.

  Sure, all heat related stuff….