The Stovebolt.com Forums Home | FAQ | Gallery | Tech Tips | Events | Features | Search
Whatcha doing now?
What did you get done on your Bolt today? - 2021 and later
The original thread is still in tact and we have 14 pages already for this time frame. A "mini-Project Journal" if you will.

Stovebolt driving report
Started by Cletis in 2012 - 36 pages and going strong!

Who uses their truck as a truck - 2021 and later

Re-started this thread. Three pages and counting.

Bolters in the Side Lot
are planning get togethers and what not. See who's near you.

Stay busy; keep warm!
Share your enthusiam.
Searching the Site

Get info about how to search the entire Stovebolt site here. To do a search for just the forums, get those details in the IT Shortbus fourm.
2023 Old Truck Calendars
First one
Nothing like old trucks working

2023 Stovebolt Calendars

Check for details!


Who's Online Now
21 members (FAST55, 2ManyTrucks, Gdads51, buoymaker, 55shaker, 3 invisible), 231 guests, and 3 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums59
Topics128,341
Posts1,054,260
Members46,615
Most Online1,229
Jan 21st, 2020
Step-by-step instructions for pictures in the forums
Previous Thread
Next Thread
Print Thread
#1304748 Tue Mar 26 2019 07:12 PM
Joined: Dec 2008
Posts: 1,840
P
panic Offline OP
'Bolter
I've been asked "I have the valve opening & closing points of a cam, but how do I calculate the intake and exhaust centerlines, and the LSA or lobe center angle?"
Using the McGurk #18 data:

For the intake lobe: (intake closing - intake opening) / 2, then add 90 degrees
Example for 10-55 timing: 55 - 10 = 45, divide by 2 = 22.5, add 90 = 112.5 degrees ATDC

For the exhaust lobe: (exhaust opening - exhaust closing) / 2, then add 90 degrees
Example for 72-32 timing: 72 - 32 = 40, divide by 2 = 20, add 90 = 110 degrees BTDC

LSA: (intake CL + exhaust CL) / 2
112.5 + 110 = 222.5 / 2 = 111.25 degrees

I just wrote an Excel spreadsheet that calculates this automatically from your input, e-mail me for a free copy: jdiamond (at) optonline.net

panic #1304857 Wed Mar 27 2019 01:55 PM
Joined: Jan 2013
Posts: 1,685
S
'Bolter
Good school Panic, only thing missing is how to determine cam advance ground into the cam.


1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
https://www.youtube.com/watch?v=Bli...n05i04t1aokgm4p04jiwgffwhyyih5xbk0h00410
1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration
panic #1304861 Wed Mar 27 2019 02:08 PM
Joined: Feb 2000
Posts: 4,593
J
'Bolter
Use this site, https://www.blocklayer.com/degree-wheeleng.aspx to build your custom degree wheel. Just add the data from the cam card, and you have a degree wheel just for that cam!

panic #1304871 Wed Mar 27 2019 03:22 PM
Joined: Feb 2004
Posts: 25,699
H
Kettle Custodian (pot stirrer)
Thanks, Joe! Added to my "favorites" list!

BTW- - - -has anybody else thought about drilling and tapping the snout of a stovebolt cam and using a harmonic balancer installer to push the timing gear on?
Jerry



"It is better to be silent and be thought a fool than to speak and eliminate all doubt!"
Abraham Lincoln

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!

There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self.
Ernest Hemingway

Love your enemies and drive 'em nuts!
panic #1304889 Wed Mar 27 2019 05:10 PM
Joined: Dec 2008
Posts: 1,840
P
panic Offline OP
'Bolter
Typically the suggested (or already selected) intake lobe center is 4 degrees advanced from the CL.
More advance closes up the intake valve-to-piston clearance, more retard closes up the exhaust-valve-to-piston clearance.
Overlap and LSA are constants (at least, in single cam engines!).


Moderated by  Justhorsenround, KCMongo 

Link Copied to Clipboard
Home | FAQ | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Powered by UBB.threads™ PHP Forum Software 7.7.5