|
Re: Degree a cam without a degree wheel?
[Re: sixpackgut]
#923505
02/08/11 06:20 PM
02/08/11 06:20 PM
|
Joined: Dec 2008
Posts: 1,200
UK
602heavy
pro stock
|
pro stock
Joined: Dec 2008
Posts: 1,200
UK
|
Quote:
when you hear noises  .
 .................correct.
|
|
|
Re: Degree a cam without a degree wheel?
[Re: ZIPPY]
#923506
02/08/11 06:42 PM
02/08/11 06:42 PM
|
Joined: Jul 2010
Posts: 3,502
SOUTH JERSEY
HEMIFRED
master
|
master
Joined: Jul 2010
Posts: 3,502
SOUTH JERSEY
|
Quote:
In college I was taught the "Isky split overlap method" for those situations where nothing is available, no tools and no specs, and you have no choice but to make do.
It isn't really accurate, it's only slightly better than nothing, I don't like it, but the procedure does exist if somebody would like try it.
I used that method many times. with another hint we would place a straight edge on the tops of the lifters. when they dead even you had zero degrees.once you had that changes then could be made with offset bushings
Quote:
CHECKING VALVE OVERLAP WITHOUT DEGREE WHEEL OR DIAL INDICATOR
When installing a camshaft, or when an occasion arises where it is necessary to make a check on valve timing and no appropriate instruments are available, the recommended Isky procedure is as follows:
Insert the camshaft and mesh the timing gears on the stock marks. Do not as yet install the timing gear cover.
Adjust the valve lash of the intake and exhaust valves of the No. 1 cylinder.
Using a long wrench or lever, turn the engine over in the normal running direction. Use enough leverage to get an even, steady movement instead of a jerky motion. Rotate until the intake and exhaust valves of No. 1 cylinder are in the overlap position (both valves opened slightly). Stop exactly on T.D.C., which is marked on the harmonic damper.
Now loosen and back off the rocker arm adjusting screws until the intake and exhaust valves are just barely closed. Lock the adjustment screws so that the intake and exhaust valves are at exactly zero clearance.
Now turn the engine over exactly one revolution of the crankshaft to T.D.C. on the harmonic damper. You are now at T.D.C. on the compression or firing stroke.
Take Notice! Now there is a large space between the rockers and valve stem tips. The space indicates the actual amount the valves were open at T.D.C. of the overlap period (less valve lash, of course).
We will measure this gap space by probing with common feeler gauges of various thicknesses combined until we determine the gap space. After computing the gap, record the figures for both intake and exhaust in your notebook. If the amount of gap on intake and exhaust is exactly the same, you have a perfect split overlap. AN EXAMPLE USING AN RPM 300 CAM
Advanced Cam Position: If your intake happens to come out with .100 gap, and the exhaust with say .080 gap, your cam is in an advanced position. In this position, the came will produce more low-speed power or torque. However, there might be a slight loss of power at high RPM.
Retarded Cam Position: If, on the other hand, the intake came out with .080 gap, and the exhaust at .100, your cam is in a retarded position. In this position, there will be some loss in low-speed torque and power, and probably some subsequent gain in high-speed power.
Split Overlap: If the intake and exhaust gap read out exactly even, or within .005 of each other, you have a split overlap. Generally speaking, all racing cams run best in the split overlap position. While there are exceptions to this rule, it is usually best for overall performance.
home of the
Sox and Martin Hemi Duster
|
|
|
Re: Degree a cam without a degree wheel?
[Re: sixpackgut]
#923509
02/08/11 07:23 PM
02/08/11 07:23 PM
|
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
|
master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
|
Quote:
how about this, with the motor in the car, line it up dot to dot, and move the cam around till you get the most compression. all you need is a compression tester and probably a battery charger
Doing just that was the advice back in the day.
Wayback when, Iskys tech man T.Willie, stated " The object is to set the cam at the position producing maximum cranking compression pressure." He admitted it may not be as effective as using a Dyno, but with cams 300* duration and under its very effective. He does further state that going past 8* can cause those funnny sounds that both you and 602 refer to.
In that article it shows him getting the cam dialed in with a degree wheel and the Final; 4th step he uses a simple compression tester for the final adjustment.
Step 4 read like this.
4. The Optimum position for the camshaft will result in the highest cranking compression as read on a simple compression tester. 
|
|
|
Re: Degree a cam without a degree wheel?
[Re: Sport440]
#923510
02/08/11 07:55 PM
02/08/11 07:55 PM
|
Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
Quote:
how about this, with the motor in the car, line it up dot to dot, and move the cam around till you get the most compression. all you need is a compression tester and probably a battery charger
Doing just that was the advice back in the day.
Wayback when, Iskys tech man T.Willie, stated " The object is to set the cam at the position producing maximum cranking compression pressure." He admitted it may not be as effective as using a Dyno, but with cams 300* duration and under its very effective. He does further state that going past 8* can cause those funnny sounds that both you and 602 refer to.
In that article it shows him getting the cam dialed in with a degree wheel and the Final; 4th step he uses a simple compression tester for the final adjustment.
Step 4 read like this.
4. The Optimum position for the camshaft will result in the highest cranking compression as read on a simple compression tester.
In using this manner how would you determine the 8*
cause you dont have a degree wheel... and like said
the more advanced you go the higher the cranking
pressure till the funny noise.... thats alright I'll
just stick with the degree wheel
|
|
|
Re: Degree a cam without a degree wheel?
[Re: MR_P_BODY]
#923511
02/08/11 08:10 PM
02/08/11 08:10 PM
|
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
|
master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
|
Mike without a degree wheel he wouldnt know where 8* is. Isky tech man T. Willie was using a degree wheel. I wasnt advocating this method just showing sixpack gut that it was given as advice by no other then a Cam manufacteres Tech guy at one time.
IMO, with Iskys tech T,Willies advice. Every cam would be installed 8* advanced because cranking comp does goe up closing the intake valve sooner ABDC. Thats not what our bigger race cams always needs or wants. But remember , T, Willie stated it was for cams 300* and under, I take its thats advertised so those are typically street type cams.
Im sticking with the degree method also, but with a minumum of 4* advance. Thats also pretty much the standards with Comp cams too. mike
|
|
|
Re: Degree a cam without a degree wheel?
[Re: emarine01]
#923512
02/08/11 08:16 PM
02/08/11 08:16 PM
|
Joined: Dec 2009
Posts: 1,074
detroit, mi
POS Dakota
super stock
|
super stock
Joined: Dec 2009
Posts: 1,074
detroit, mi
|
Quote:
Cant someone close by just lend this fella a degree wheel 
All he has to do now is enlarge/print the wheel pictured above and glue it to a pie tin if he wanted to be cheap. It will work.
It's a deFree wheel!!!!
|
|
|
|
|
........at what point would you stop advancing centreline?
But I know he knows half a dozen racers within one hour from his place 
