vintage advantage racing valve spring set, cb77

hillhudson · Post by **hillhudson** » Sat Feb 26, 2011 9:57 pm

hey all, i just received a set of these vintage advantage racing valve springs and seats along with different sized shims. the package says "install @ 1.380 to 1.420in" can anyone help me out on decoding this measurement ? plus in what cases would i want to use the valve spring shims the set came with ?

any and all help is very appreciated.

-hill hudson
portland oregon

G-Man · Post by **G-Man** » Sun Feb 27, 2011 3:26 am

Hill

The height of the spring once installed on the valve. That's why they supplied shims...

The idea is to get the springs to the same length and therefore force on the valve seat. Depending upon how much the seats have been cut, the length of valve stem protruding into the head will be different.

Cheers

G

hillhudson · Post by **hillhudson** » Sun Feb 27, 2011 2:28 pm

oh okay i see, so the idea is to just make sure they're all the same length. so their is similar compression in both cylinders ?

G-Man · Post by **G-Man** » Sun Feb 27, 2011 2:49 pm

Hill

Not so much the compression in the cylinders, just to get the spring tension matched across all of the valves.

Cheers

G

hillhudson · Post by **hillhudson** » Mon Feb 28, 2011 1:51 pm

thanx g-man!,

teazer · Post by **teazer** » Wed Mar 02, 2011 12:19 am

The easy way to check installed height is to fit teh valves caps and cotters, but use either a light spring from the hardware store or an inner spring only. That will hold everything in place so you can measure the height from the spring seat to the lower surface of the cap.

Shim as required to get the specified height and therefore the right spring pressure.

I tend to recess (pocket) the valves slightly and always need shims. I had my machinist make up a batch covering a range of sizes and was about to get some more made, but if Les B or Orient Express has them that would probably be cheaper and quicker.

hillhudson · Post by **hillhudson** » Wed Mar 02, 2011 12:28 am

awesome, hey thanks teazer!

i'm going to eventually be putting together a short video on the entire rebuild process, i have always wanted to see a video of people going through one of my favorite bikes so i figure i should just make one myself.