Friends,
I've finally installed the used Kastner A7 cam in my 1147 race engine and am
having trouble getting it timed correctly. When I set the #2 valve (intake
on #1 Cylinder) to open at 42 degrees, I cannot get the closing number
anywhere close. It's at 60 something on closing. Haven't even checked where
the #1 valve starts to open, as this seems so wrong.
Specs I received from FOT Aaron Johnson are below.
- Inlet opens 42 Inlet Closes 76
- Exhaust opens 76 Exhaust close 42
- Duration 293 Lift at valve .410
- Checking clearance at the camshaft is .013
- Rocker arm clearance is .020
Information I received from Kas himself is close to the above;
"That cam was done early on but it will work fine. The timing is Inlet 42-71
and the exhaust is 71-42. The cam has 293 degree duration and .410 lift at
the valve. As I remember the checking clearance is .013" and the running
clearance is .020"."
Kas also added, "Just for your information I believe that cam is done on a
factory billet meaning that the base circle is very close to the stock
diameter. Check to see if it is. If so, you can get a dynamite cam profile
put on that cam at Moon Equipment. You cannot E-mail them but phone and ask
for Bill Jenks and then tell him you want the A-10-A. This will go onto that
cam fine if it is the factory billet I used for lots of the camshafts. That
was the latest grind (54 - 90 and the gross lift is .517" )and it was
terrific but you do need high compression to deal with it."
Note the difference in closing measurements in the two sets of specs?
I know I have TDC on the crank set correctly. I'm seeing 42 degrees on the
degree wheel when the dial indicator on the top of the pushrod shows the
valve has opened .013 inch. The valve stays open like it should for most of
a rotation but is only at 60 something on the degree wheel when it has
closed to only being open .013 inch.
What am I missing / not understanding?
I already have the head installed, but I'm about ready to pull the cam out
and get a new one, or follow Kas's suggestion to send it out for a regrind.
I am running high compression with "pop-up" pistons. Something about this
cam just doesn't seem right, and adds to my suspicions about running a used
cam in this newly rebuilt engine. Hate to spend the money and time, but if I
have to do it, I might as well do it now.
Thoughts and opinions welcome...
Thanks,
"Jedi"
Joe Guinan
Fremont, NE
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http://www.fot-racing.com
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