Are intake and exhaust valve stems different diameter?

I am asking because valve stem seals are sold separately.

 

Slightly yes, they also identify with different colours.

Why do you ask?

 

[QUOTE="Bishop84, post: 26725291, member: 172494Why do you ask?[/QUOTE]
intake: https://www.rockauto.com/en/moreinfo.php?pk=7488512&cc=1434686&pt=5800

exhaust: https://www.rockauto.com/en/moreinfo.php?pk=7488508&cc=1434686&pt=5800

they both list the same valve stem size (5.5 mm) but the dimensions of the seals is different. Why?

 

Never thought much of it haha. Just never mix up the colours.

I believe it has more to do with the cylinder head than the valve.

 

why?

 

Shape of the stem guide varying from intake to exhuast.

I'll have a 2GR cylinder head apart tomorrow, I'll try to remember to take a photo of the stems.

 

Would it be impossible then to fit the intake (narrower) over an exhaust valve (wider) by mistake?

 

I don't think they fit. I've never really tried. They appear visually very similar, but usually when doing valve seals I'm extra careful with part locations.

I believe the larger ones would just spin and it would be obvious when you try to reinstall the valve.

 

Why don't you ask the experts over at rock auto

 

maybe ask auto zone, first general question will be valve seals for 4wd or 2wd

 

After the auto vs manual question of course.