Cam timing LT5

[creative sewer]

Need Help!! I've read everything I can on cam timing. Are there any pictures or DVD's out there? I can't get the connection between the TDC on the crank and the dial indicater on the cams. If I'm anywhere close to doing it right, I have 113 on the intake and 120 on the exhaust? It ran great but I'm going to have it ported and want to change it when I put it back together

[bdw18_123]

Have you read through the cam timing info put together by Mark Haibeck? You can download the PDF file from his website, here is the link:

http://www.zr1specialist.com/HAT%20W..._camshafts.htm

There are also lots of links to cam timing info in forum member Dynomite's "Solutions" thread (a sticky at the top of the "ZR-1 Technical Postings" section).
Link: http://www.zr1.net/forum/showthread.php?t=11619

Here is a cut-and-paste from it:

CAMSHAFT TIMING USING PINS
Camshaft timing http://www.zr1.net/forum/showthread.php?t=9813
Camshaft timing event picture http://www.zr1.net/forum/showpost.ph...5&postcount=16
Camshaft timing using pins http://www.zr1.net/forum/showpost.ph...7&postcount=66
Resetting timing chain tensioner http://www.zr1.net/forum/showpost.ph...1&postcount=18

CAMSHAFT TIMING USING DEGREE WHEEL
Top dead center TDC http://www.zr1.net/forum/showpost.ph...3&postcount=19
Marc Haibeck camshaft timing http://www.zr1.net/forum/showpost.ph...5&postcount=21
Camshaft timing details http://www.zr1.net/forum/showpost.ph...4&postcount=20
Camshaft timing optimum deg http://www.zr1.net/forum/showpost.ph...7&postcount=12
Degree wheel http://www.zr1.net/forum/showpost.ph...2&postcount=18
Setting up degree wheel http://www.zr1.net/forum/showpost.ph...41&postcount=7

[Dynomite]

Originally Posted by creative sewer

I can't get the connection between the TDC on the crank and the dial indicater on the cams. If I'm anywhere close to doing it right, I have 113 on the intake and 120 on the exhaust? It ran great but I'm going to have it ported and want to change it when I put it back together

I think you should look for maximum lifter depression 114 deg ATDC IN and 114 deg BTDC EX for a 90'-92' (both on number one cylinder drivers side front of engine).

The "connection" is the camshafts on number one cylinder should be at maximum camshaft lift (lifters depressed maximum) at 114 deg ATDC IN and 114 deg BTDC EX. The Pinning Method will get you close to these timing numbers. If you want different valve timing for ported engine, then use the degree wheel and a dial gauge on the lifters since the pins will not align with the holes in the camshafts exactly. The number one piston sees TDC every rotation and when you set the cams/lifters at maximum lift/depression 114 deg before and after TDC, that TDC becomes your exhaust stroke. The next TDC becomes your compression stroke.

I think there is a point on the cams (cams rotate once every two crankshaft rotations) that tell the injectors to inject fuel on the compression TDC and am thinking the plugs fire at both TDCs

What you want is equal lifter depression before and after max lifter depression noting the crankshaft rotation degrees (degree wheel set up on front of crankshaft pully) before and after max lift. For Intake example you might see equal lifter depression at 104 deg ATDC and 124 deg ATDC and splitting the difference would be 114 deg ATDC. You do the equal lifter depression "trick" because it is almost impossible to see max lifter depression using a dial gauge within say 5 deg either way as the cam lobe rotates over the flat.

Then there is the "trick" to tighten the camshaft bolts when you have the cams timed like you want without rotating the cam with respect to the venier plate during tightening of those camshaft bolts.

Here is a timing event picture provided by bdw18_123 in an associated post.