schnellttz06

I have a Lingenfelter GT7 cam that I had in my old motor and now I am building a new engine and it has probably 30,000 hard miles on it but It still looks good however with some signs of wear. I do have brand new Lunati high rev lifters though. I called Lingenfelter and got the cam card info, the intake is supposed to open at -16.9 and close at 45.1. However I get -22 and 45. The lobe sep is specd at 121 and Im assuming the centerline is 121 as well.

I have an adjustable timing set and I tried to adjust it to make it work, but if I get one side perfect the other side will be off and vice versa.

Could my cam be worn and that's why I don't see 16.9 @ .050 lift and instead I don't get it until 22, yet the 45 on the closing side seems to be fine?

I appreciate any advice...

zzcamaro00

Make sure your no.1 cylinder is at absolute tdc using your dial gauge indicator that you should be using. then your timing marks should line up at either:crank at 12 o clock and cam at 6 or 12 o clock position. i personally like lining them at at crank at 12 o clock and cam at 6 clock. once you have true TDC make sure your wire pointer is pointed at 0 degrees on the timing wheel. they make detailed instructions how to do it. http://www.ebay.com/itm/How-to-Rebuild-GM-LS-Series-Engines-LS1-LS6-Generation-III-IV-5-3-5-7-6-0-/380684070486?pt=Motors_Car_Truck_Parts_Accessories&hash=item58a289ee56&vxp=mtr

this booked details it pretty well. helped out a lot, and if you got the comp cams kit, it came with instructions as well. keep in mind that there are different methods for doing this.


now to your question, if the cam was worn enough to make the valve events open at different degrees than specified than both numbers would have to be off. not just the opening number. make sure they gave you the correct cam card.

schnellttz06

Yeah, I have that book. I used the dial indicator to get TDC so I know that's good. I guess I will have to call lingenfelter back up and verify the cam specs. I just thought that there would be more wear on the opening side of the cam then the closing side and that may have caused my issue.

Thanks.

zzcamaro00

im not an expert on how a cam would wear out, but when i do see worn cam lobes, its worn all the way around. when the cam begins to open the valve the pressure on the cam lobe goes up as it reaches maximum lift and then goes back down on the closing side of course, maybe the lobe profile is different from one side to the other idk.

schnellttz06

I talked to lingenfelter again and they said I must have the wrong data but they didnt have it readily available so they are supposed to contact me back with the correct specs. I guess I will just install it with the dots if I cant get a straight answer, shame I just got this nice cam degree kit and not able to use it.

RonSSNova

iTrader: (3)

Well, you are using it!
Sounds like you have the wrong cam specs.
Normally, one would degree in the intake centerline and call it good. Checking opening and closing points verifys the lobe is ground how they said it was ground.

Roller cams don't typically wear out. They either stay good, or fail.

Was there ever a cam card for that cam? Could be a top secret grind.......

Ron

zzcamaro00

well.....do you wanna sell it?lol

schnellttz06

Ok, Well they finally got the cam card to me. It was working fine on the old motor so I know it hasnt failed. This is the first time I ever degreed a cam so maybe Im doing something wrong.

The guage goes on the first lifter on the driver side right? I do have a LSA tensioner on the timing chain, I wonder if that is having an affect on it.

LPE part #: L210095297
Engine(s): GM Gen III & IV V8 engines except Displacement On Demand (DOD) & camshaft phaser applications
Firing order: 1-8-7-2-6-5-4-3 (per standard GM V8 cylinder numbering)
Intake Exhaust
Valve adjustment: HYD HYD
Lobe lift (inches): 0.326 0.321
Valve lift (inches): 0.554 0.546 with 1.7 rocker ratio
Valve lift (inches): 0.587 0.578 with 1.8 rocker ratio
Duration @ 0.006": 261 282
Duration @ 0.050": 208 230
Lobe Separation Angle (LSA):
Degrees of advance:
Valve timing @ 0.050" tappet lift: Opening Closing
Intake -16.9 BTDC 45.1 ABDC
Overlap angle -22.7
Exhaust 56.2 BBDC -5.8 ATDC
These specs are with cam installed at: 121.0 intake center line 121.0 exhaust center line
Recommended installation angle: 121 (intake center line angle)

schnellttz06

Ok, well I figured out what I was doing wrong. My readings were off because I zeroed the gauge at TDC but I didnt realize the lobe was already lifting on the intake side slightly. I zeroed it before TDC where it was obvious it wasnt on a lobe, then it all degreed perfectly just like the cam card specified.

zzcamaro00

there ya go. i did that the first time. you need to measure from the base circle of the cam not measure from TDC

JPH

iTrader: (2)

I would advance the cam alot.