Opti installed wrong
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Registered User
Joined: Jan 2007
Posts: 29
From: Hoffman Estates
Re: Opti installed wrong
No you are totally wrong on this point!
With a stock lift cam .... the LT1 is a NON interference motor. You can place any stock piston at TDC, and with the timing chain off, you can rotate the cam sprocket and fully open both the exhaust and intake valves without coming anywhere near interference!
If you did mis-assemble the timing chain ...... your stock LT1 motor will crank just fine.
After you assembled the timing chain, you did crank over the engine by hand a couple of times, (at least!), and watched the two (2) timing dots on the cam and crank sprockets ..... re-align several times at the 12 o'clock and 6 o'clock positions, right???
With a stock lift cam .... the LT1 is a NON interference motor. You can place any stock piston at TDC, and with the timing chain off, you can rotate the cam sprocket and fully open both the exhaust and intake valves without coming anywhere near interference! If you did mis-assemble the timing chain ...... your stock LT1 motor will crank just fine.After you assembled the timing chain, you did crank over the engine by hand a couple of times, (at least!), and watched the two (2) timing dots on the cam and crank sprockets ..... re-align several times at the 12 o'clock and 6 o'clock positions, right???
heres what im seeing.. at TDC on 1 both valves are closed, as i turn the engine 1 revolution 6 goes is at tdc and valves are closed.. if the cam was out of time with the crank wouldnt i see something out of the ordinary? the valves open correctly to me as far as piston movement goes.. Im out of town at the moment and I cant check anything...
Registered User
Joined: Jun 2000
Posts: 857
From: Washington, Michigan USA
Re: Opti installed wrong
yea i rotated it at least one time.. the dots did line up... man im really hoping that opti is on wrong..
heres what im seeing.. at TDC on 1 both valves are closed, as i turn the engine 1 revolution 6 goes is at tdc and valves are closed.. if the cam was out of time with the crank wouldnt i see something out of the ordinary? the valves open correctly to me as far as piston movement goes.. Im out of town at the moment and I cant check anything...
heres what im seeing.. at TDC on 1 both valves are closed, as i turn the engine 1 revolution 6 goes is at tdc and valves are closed.. if the cam was out of time with the crank wouldnt i see something out of the ordinary? the valves open correctly to me as far as piston movement goes.. Im out of town at the moment and I cant check anything...
You are to be congratulated! Yes indeed the valve opening and closing sequence you describe above, appears to indicate that your VALVE timing is okay. Kudo's for putting the timing CHAIN on correctly.
Your only hope now is that there IS a problem with the way the Opti was installed to the cam, to account for your observed problem with ignition timing.
When you get back in town and can pull off your Optispark cap, DO the test Shoebox and Speedygonzales told you to do in posts #2 and #3 ........... and let us know what you find.
Also, when you try and start this motor as it now sits ........ do you hear a "popping" back through the exhaust system, which would CONFIRM that the spark plug is firing while the exhaust valve is open???
And finally, double check to see you have the plug wires correctly installed on the optispark cap. Do ALL cylinders appear to fire with the exhaust valve open, or just two or four??
Last edited by 97 6SPEED Z; Aug 3, 2011 at 09:43 AM.
Thread Starter
Registered User
Joined: Jan 2007
Posts: 29
From: Hoffman Estates
Re: Opti installed wrong
So I want to thank everybody for their help, it turns out the pin on the cam was not in the correct spot on the opti, when I removed it the pin was positioned in the recessed hole for the bolts of the cam. I installed it correctly and she fired right away..
Thanks everyone again.
Thanks everyone again.
Registered User
Joined: Jul 2002
Posts: 1,942
From: Kissimmee, Fl, USA
Re: Opti installed wrong
So I want to thank everybody for their help, it turns out the pin on the cam was not in the correct spot on the opti, when I removed it the pin was positioned in the recessed hole for the bolts of the cam. I installed it correctly and she fired right away..
Thanks everyone again.
Thanks everyone again.
Registered User
Joined: Jun 2000
Posts: 857
From: Washington, Michigan USA
Re: Opti installed wrong
So I want to thank everybody for their help, it turns out the pin on the cam was not in the correct spot on the opti, when I removed it the pin was positioned in the recessed hole for the bolts of the cam. I installed it correctly and she fired right away..
Thanks everyone again.
Thanks everyone again.
Glad you got it fixed.
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