Re: Plumcrazy & Greg Good Are a....
So, here's an update. (Long). Naturally, as soon as I get into middle of a Viper mod work gets the best of me
. That delayed me about 2 weeks but I finally got back to the build. So after installing the head on the driver's side, checking for push rod length ( there will be a detailed wite up on this for T&D rockers) it turns out I can use my existing 7.6" trend push rods.
I moved on to installing the passenger side lifters and head. However, I ran into a snag (literally) with the lifters. It turned out that 5 of the new lifters were binding while I tried to install them into the lifter bores. These 5 lifters would not fit any of the 10 bores on the passenger side and/or were just too tight which is not good. Long story short, Greg Good mailed me 5 new lifters and they went in like butter. They are the same lifters from the same batch. I suspect that the 5 suspect lifters either got nicked during shipping and/or I 'dropped' them in an oil container to soak. THANK Greg Good for the quick turnaround.
HOWEVER, before I bolted on the passenger head I had to resolve one item that was bugging me. That is the intake center line I calculated after installing the new cam. What bothered me about it is that I never got 109 degrees consistently. It varied between 109 and 114 at times. At first I chalked it up to my POS degree wheel (more on that later) and wrote it off. I also had a few tuners tell me not to worry about it because they "never degree my cams"
, "there's a little play in the timing chain, it's normal" or
"you're doing TDC wrong".
So I took Greg Good's advice, and procedure, and decided to double-check TDC and Center Line based on the #2 cylinder. This new camshaft has an advertised center line of 109 degrees. Being paranoid about this, I ordered a new cam degree kit. I ordered this
Heads Off Degree Kit from Power House. For the record, they make the Comp Cams kits.
Here's the procedure I used for finding TDC on the #2 Cylinder:
Step 1: Installed my degree wheel. Installed my dial indicator on the #2 piston and rotate the crank clockwise until the piston achieved maximum lift. At this point, I zero'd my dial indicator:
I also set my degree wheel to zero by moving the degree wheel to zero (TDC):
Step 2: I rotated the crank
counter-clockwise until the piston was down .100":
I then rotated the crank
clockwise .050" before zero (max lift):
At this point I looked at my degree wheel to get a reading which was 11.5 degrees BTDC:
Step 3: I rotated the engine clockwise until the dial indicator read .100" on the other side of TDC and came back up to .050" before zero (max lift):
At this point I looked at my degree wheel to get a reading which was 11 degrees:
Doing simple math 11.5 - 11 = .5. My wheel was off .5 degrees. I adjusted the wheel and repeated this procedure until I achieve 11.5 degrees on either side of TDC. At this point, the wheel/pointer was set correctly for TDC.
Now that TDC has been established, I need to check the center line of the intake lobe:
Step 1: I installed my dial indicator with an extension and perpendicular to the intake lifter on the #2 cylinder. I used the solid edge on top of the lifter:
Step 2: I rotated the engine clockwise until I achieved maximum lift on the dial indicator. At this point I zero'd my dial indicator.
Step 3: I rotated the engine
counter-clockwise until lifter was down .100". I then rotated the crank
clockwise until the dial indicator read .020" before zero (max lift):
I checked the degree wheel and got 87.5 degrees:
Step 4: I rotated the engine clockwise until the dial indicator reached zero and down to .020". I stopped on .020" and took a reading from the degree wheel which was 142.5 degrees:
Step 5: Using simple math to calculate centerline: 87.5 + 142.5 = 230/2 = 115 degrees.
My center line calculated at 115 degrees which means the cam is ******** by 6 degrees. I've performed this method, from scratch, at least a dozen times today and I consistently achieve 115 degrees.
This obviously confirmed my suspicion that something was off
. For the record, there's only one way to install this cam with the stock timing sprocket which is lining up the timing marks between the timing chain sprocket (6 o'clock position) and crank sprocket (12 o'clock position). The cam is drilled for one bolt and to fit the dowel hole on the timing chain sprocket.
So assuming I did this TDC and Center Line correctly I need to advance the cam 6 degrees to achieve 109 centerline. Greg has offered to take my sprocket and install an off-set bushing to achieve this. (he's the man).
But until I find out WHY this cam is ******** 6 degrees I will not rest. I'm thinking it's one of the following:
(1.) I screwed up somewhere.
(2.) The new cam has the dowel pin located in the wrong (********) position.
(3.) My stock cam was ******** 6 degrees (i never bothered to check the stock cam center line so I'll never know and I don't feel like swapping out the cams to check). But if this were true then my Viper would run like dog sh*t because 6 degrees is a lot.
As a sanity check, I measured the Intake valve opening at 7 degrees BTDC and the Exhaust Valve opening at 55 BBDC (per the cam spec card). I ended up with the Intake opening at 1 degree BTDC and the exhaust valve opening at 49 degrees BBDC. This seems to confirm the 6 degree anomaly.
I thought I'd post this to see if anyone can find what I did wrong and/or confirm my findings. I talked with/emailed Greg's ear off about this so I don't want to bother him anymore. It's amazing he's put up with me so far.