24VChevy said:
For the initial testing I was running a Smarty tune and F1 injectors only. Truck runs clean and strong (12.1 @112 mph) at the 1000 ft mark.
With the valve fully open (dial indicator on top) I have lots of pistion to valve clearance. I could open the valve another .100' with no contact. On the first run I bent I/E on #4 E on #4. The second run I bent about eight in total.
I am thinking about installing the stock valve springs and running them for now. At what point does the stock springs become the limiting factor for boost and rpm?
Thanks
This engine has totaly stock internals, stock headgasket, stock pistions just a different cam/springs for hard parts.
At maximum lift is not where you have any chance of valve to piston clearance problems. The biggest problem is at overlap
10 ,
5 and
0 degrees before
TDC on the exhaust valve , remember the piston is chasing the exhaust valve and
0, 5 , 10 degrees after
TDC on the intake where the intake valve is chasing the piston down.
In a diesel the events are short, and on stock cams the ramps are slow and lazy. When you go with a good performance cam the ramps are quickened up to achieve maximum window to more air thru with out increasing seat timing excessively and killing cranking pressure .
Ok, I always use a degree wheel and do it the way I have been taught, and if you have a degree wheel , there are many web sights that give you a step by step way to degree a cam in and check piston to valve
But if you are like most Hot Rodders , both diesel and gas , you don’t have one and probably don’t have any plans to get one eather , so you can use this method at you own risk, but this will get you in the
ballpark to see if you need to go and invest in a degree wheel
First you will need to find a true
TDC,
To do this take number one injector out and using a dial indicator mounted on the head and use a long enough probe to reach the top of the piston. make a mark on you timing cover in the center
Next rotate the motor
slowly, watch as the piston comes up all the way and stops, this is when the dial stops moving, and the piston dwells at the top ,
set you dial on zero
Next rotate the engine any left; let the piston move down until the dial reads a given amount, I use .
100
Mark the balancer with a mark corresponding to the mark on the cover, then rotated it the other direction till the same
.100 down and make a similar mark.
Measure half way between the two marks and you have
TDC scribe a line
By Multiplying the radius of the dampener by 3.14 pi and dividing by 360 you get .038 of a inch equals a degree so measure so measure .190 for 5 degrees either side of
TDC and .380 either side for 10 degrees . mark all four of these with a line on the balancer.
Now with you lash nuts loose and the
lash at zero, role the motor thru until you see the exhaust closing on one when you reach the first mark, or
10 BTC stop put the dial indicator on the valve spring retainer, set to zero , then with a t-handle allen head wrench add lash until it stops , this is zero or when the valve hits the piston, you need a minimum or .
050 on a 24 valve race motor now measure the 5 degree mark and next the
TDC , do the same for the intake valve.
