Testarossa Exhaust valve stem seals; with or without?

Good questions. I wonder also if the valve and/or valve guide materials and/or clearances changed as well.

Regardless, little oil will typically be lost on the exhaust side. I do not recall ever seeing folks complain about valve seals leaking (intake or exhaust).

Good questions. I could only speculate. As you note, retrofitting seals may cause lubrication problems.

 

The TR SPCs are very misleading about this -- the picture shows a valve stem oil seal (item 12) only on the intake valve, but the quantity in the table is 48 (so all valves get a seal). My guess is that early euro F113A TR (K-Jet without Lambda) might have been designed like 512BBi (intake valve seals only) as this is what the TR WSM also shows (page B25), but, a US F113A040 TR (KE-Jet with Lambda) needs an exhaust valve oil seal (to prevent oil entering the cats and mucking up the O2 sensor/reading) -- and then, in later TR SPC covering both KE-Jet with Lambda and KE-Jet without Lambda, they left the quantity as 48 without updating the picture.

 

Are you saying that your 1986 TR is a F113A engine and you've got it apart now? If so, did/does it only have intake valve seals?

One thing that surprised me is that, in the online 1985 TR SPC, they don't have separate entries for a euro (quantity 24) and a US (quantity 48) -- it just says quantity 48 (like the later TR SPC). Since the TR WSM doesn't show exhaust valve seals (and the TR WSM is the F113A engine), I have to think that it was their intent to not use them on the F113A at one time, but why it wasn't also shown in the early TR SPC seems odd?

 

I never have seen a flat 12 4 valve engine without seal on the outlet valves

 

Interesting that that 512TR WSM? cross-section still does not show an exhaust valve seal, but the figure in the 512TR SPC does show valve seals on both the intake and exhaust valve (and quantity 48):
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