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Valve guide question
https://ausmini.com/forums/viewtopic.php?f=5&t=35141
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Author:  mini-dunger [ Sat Aug 25, 2007 12:52 am ]
Post subject:  Valve guide question

Hi guys just a quick one, what way do the valve guides press in/out ? I spent this week making a nice press and I want to try it out and my rocker bushes and conrod bushes havent rocked up yet.


Does anyone know whats up with karcraft? they have been unreachable all week.

oh, Thanks everyone

Author:  drmini in aust [ Sat Aug 25, 2007 7:10 am ]
Post subject: 

Always press valve guides downwards, into the chamber. When fitting new I oil the hole first.
I use a punch made from an Unbrako shoulder bolt, turned down to fit in the guide. To press in to the right depth I have a bush that I slip onto it.

Note if it's a smallbore head the 1275 guides are too long- take 3mm off the pointy end before fitting, or they will obstruct the port and can even jam the valve.
I've not seen the short smallbore guides sold for years now.

Author:  mini-dunger [ Sat Aug 25, 2007 11:15 am ]
Post subject: 

I thought the guides were all the same? I am using 1100s valves so should I be looking for any ones in particular? or just "mini" ones? Either way milling them down and re bullet nosing them again is no big deal. The depth that then need to be pushed in would be written some where in a manual shouldnt it?

Thanks Kev

Author:  drmini in aust [ Sat Aug 25, 2007 12:53 pm ]
Post subject: 

mini-dunger wrote:
I thought the guides were all the same? I am using 1100s valves so should I be looking for any ones in particular? or just "mini" ones? Either way milling them down and re bullet nosing them again is no big deal. The depth that then need to be pushed in would be written some where in a manual shouldnt it?

Thanks Kev

On a smallbore 998 head the guides are 15.5mm above the spring seats (I just measured a mint 998 Clubby one).
On a 940 (ie 1100S) head they are about 14mm above the spring seats.
Note these spring seats are different depth to a smallbore.
As you are using 1100S valves, (which are 2mm longer stems) in a smallbore head, I would leave the top of guides 16 or 17mm above spring seats, and leave them stock length- they should be OK.

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