ZeeOSix

If you study the chart I showed in Post #20 against the GM procedure, you'd see that's not true, and every rocker that's torqued down while following the GM procedure has zero spring pressure on the rocker arm.

ls1 Statesman

With any rocker setup with intake and exhaust on a single shaft they must be torqued while both valves are closed, with GM setup this isn't an issue.

gMAG

iTrader: (1)

I stand corrected. Sorry for my confusion.
Still, the YT's are a single/common shaft type design, and I would still follow the directions for my setup, which calls for tdc on each individual cyl while adjusting both int & ex.

ZeeOSix

Ahhh, yes ... this is true.

On a side note - if anyone doesn't believe the GM procedure works for the independent GM rocker setup, after all the rocker arms are torqued down, put the motor in the condition the procedure calls out. You will see that you are able to rattle the lifters for those valves that are supposed to be un-loaded during the tightening sequence.

ZeeOSix

No biggie ... I had to make up that chart when I replace the springs on my LS6 so I could see what was going on with the GM tightening sequence.

one fast zo6

iTrader: (490)

good info

gMAG

iTrader: (1)

When you get older, you develop CRS (can't remember s#$t).
At least we all increased our post counts.

gMAG

iTrader: (1)

I thought that this info would be helpful.
Moderator "JOSEPH" sent this to me as a reply to my question about finding TDC #1. on the LS1
Being old-school, I was used to lining up the dots on crank & camshaft gears, then setting rockers for #1. Following this procedure, I couldn't figure out why the valves on #1 were not completely closed. I thought that the vendor had sent the wrong cam, or that there was an error with the cam grind.

As follows.....Thanks, Joseph!
.................................
Glenn,

I'm glad you found my info helpful, not many people know the valve events for all 8 cylinders and when they happen. You would naturally assume with the dots aligned it would be the firing position of cylinder #1, when its actually the start of the intake stroke as far as the piston/intake valve is concerned. With the dots aligned cylinder #6 is the one to set preload/lash/ or for installing rockers.

Each 90* (720* / 8cyl = 90*) on the crankshaft gear is another cylinder firing, while each 45* (360* / 8cyl = 45*) on the camshaft gear is another cylinder firing. Having the timing cover off helps to watch the sequence.

Here's a copy/paste of a manuscript I'm working on that may help also:


Quote:
Originally Posted by Joseph
LSX Firing Order 1, 8, 7, 2, 6, 5, 4, 3

TDC Cyl. #1) Camshaft dot at 12:00 / Crankshaft dot at 12:00
TDC Cyl. #8) Camshaft dot at 1:30 / Crankshaft dot at 3:00
TDC Cyl. #7) Camshaft dot at 3:00 / Crankshaft dot at 6:00
TDC Cyl. #2) Camshaft dot at 4:30 / Crankshaft dot at 9:00
TDC Cyl. #6) Camshaft dot at 6:00 / Crankshaft dot at 12:00
TDC Cyl. #5) Camshaft dot at 7:30 / Crankshaft dot at 3:00
TDC Cyl. #4) Camshaft dot at 9:00 / Crankshaft dot at 6:00
TDC Cyl. #3) Camshaft dot at 10:30 / Crankshaft dot at 9:00

If you have that and the timing cover off you don't even half to measure how far you turned the engine over, just line up the dots to the correct orientation and install.

Thanks,
Joseph

ZeeOSix

The chart I posted in Post #20 shows clearly how once Cyl #1 is at TDC at the end of compression stroke (which is the same as TDC on the beginning of the power stroke), then each 90 degree rotation of the crank puts the next cylinder in the firing order at TDC on the compression stoke. This is useful if working on the engine when the cam end is not exposed for viewing.

gMAG - good info you passed along also if using the cam turns and marks as the indicator. Cam turns once for every 2 turns of the crank, so using the cam makes it every 45 degrees instead of 90 degrees of the crank to get the next cyl in the firing order on TDC.

gMAG

iTrader: (1)

The context of that day was to locate just TDC #1. After this was accomplished, the remainder of the firing order/valve positions fell into place.

wildcamaro

iTrader: (15)

Just to chime in to any earlier post but my 98 camaro service calls for blue loctite on the rocker bolts...you could in all likely get away without it but I always go **** on engine building...

Spoolin_Notch

iTrader: (8)

Thanks for posting this!

gMAG

iTrader: (1)

You're welcome, & thanks to Joseph!
I find it very direct. Each of us knows what the cam & crank setup look like.

ZeeOSix

2002 Corvette Factory Service Manual mentions nothing about Loctite on the rocker bolts. Guess GM changed their procedure along the way.

TexasVortexx

iTrader: (31)

Nice thread, will help with re-installing my Harlan Sharps

slammedc5

iTrader: (1)

Aloha,
I'm not saying what's rite or wrong, just saying thousands of folks have just tightened to 22 ft , rotate and recheck. Rotate and check just to make sure they all got torqued. Speed shops people I know and myself included. The ls1s have NON adjustable valve trains. Torque the rocker, and the lifter will pump up when car is started.

Just last week I installed my mayhem cam. Dot to dot, I tightened. Then just for **** and giggles, I turned the crank to 5 other positions, I checked all rockers everytime. The torque was 22 ftlbs everytime. My project turned out cherry again.

I'm not going to jump in and debate, just saying, the "set it and forget" method has worked just fine for thousands of projects.

joecar

This only works if the engine is rotated an odd number of times between bolt torquing...

if the engine is rotated an even number of times, then some of the bolts will be at 22 ftlb and others will be at less than 22 ftlb...

I think this is why some people experience a few rockers coming loose.

vettenuts

iTrader: (4)

Harlan's use a common shaft for a single cylinder and you must rotate each piston to TDC firing stroke to install these rockers. Don't follow the GM procedure for Harlans.

vettenuts

iTrader: (4)

If you tighten a bolt to 22 lb-ft and then re-check it, it will never appear to change. When tightening, you are measuring running torque. When you re-check, unless you loosen the bolt, you are checking static torque which will always be higher than the running torque. As a result, unless the bolt has radically loosened, the torque will appear to not have changed especially if using a preset clicker type of torque wrench.

Hope that makes sense.

TexasVortexx

iTrader: (31)

Yes correct. I came here to relearn TDC.