Valve Guide Clearance

T

Truckphone

Member
Is there any downside to having the clearance very small? I've read on here that smaller the better with the Briggs racing oil thats very thin. Thanks Ale.
 
Not really they tend too open up pretty quick .
Oil viscosity really has little to do with it . They slide in easy and spin easy . Proper lubrication initally is most important.
 
Truckphone said:
Is there any downside to having the clearance very small? I've read on here that smaller the better with the Briggs racing oil thats very thin. Thanks Ale.
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.001" IN & .0015 EX. That'll get you close and be on the safe side.
In my opinion, tighter is better, but as mentioned, the exhaust clearance can cause you problems as the exhaust valve carries a lot of heat while the intake side always has a fresh charge of cold fuel to keep its dimensions the same.
Now, how are you measuring your clearance? Dial bore gauges in this dimension are extremely expensive.
You can use pin gauges, just make sure that your bore is straight (ie no taper, etc.) if you are using a hone to final size the guides.


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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
www.youtube.com
34 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
CarlsonMotorsports said:
.001" IN & .0015 EX. That'll get you close and be on the safe side.
In my opinion, tighter is better, but as mentioned, the exhaust clearance can cause you problems as the exhaust valve carries a lot of heat while the intake side always has a fresh charge of cold fuel to keep its dimensions the same.
Now, how are you measuring your clearance? Dial bore gauges in this dimension are extremely expensive.
You can use pin gauges, just make sure that your bore is straight (ie no taper, etc.) if you are using a hone to final size the guides.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
www.youtube.com
34 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
Click to expand...
I was planning on reamers then honing to size. Trial and error until the stem fits and then wiggle and measure with an indicator?
 
Truckphone said:
I was planning on reamers then honing to size. Trial and error until the stem fits and then wiggle and measure with an indicator?
Click to expand...
Be careful with reamers . The briggs reamers are too big too start . If you have access to various sizes thats good . Otherwise honing would be my suggestion .
The few I had shop done by c-f seemed loose .
 
flattop1 said:
Be careful with reamers . The briggs reamers are too big too start . If you have access to various sizes thats good . Otherwise honing would be my suggestion .
The few I had shop done by c-f seemed loose .
Click to expand...
I'm not gonna buy the Briggs tools, I figured cheap reamers won't get too hurt sizing brass guides. I can get .22 , .23 , .24 reamers for cheap.
 
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