Will my corvette run with the crank and cam timing incorrect?

Question

I replaced the camshaft in my 87 corvette and timed the cam gear in the 6 oclock postion and the crank in the 12 oclock position. After putting the distributor in i noticed the number one rotor position is off by about 90 degrees while at TDC. This concerned me so i checked the manual and it says to time both gears in the 12 oclock position. I feel like i found the correct TDC now with the rotor pointing to my new number one spark plug wire but am waiting to start it because of the initial error in the timing. Can i get away with leaving the timing the way it is as long as i make the new firing order by repositioning the spark plug wires? Will the valves bend or will the valvetrain follow the correct path? By initially being 180 degrees off i think if i turned the crank 360 they would both be at the 12 oclock postition and my new TDC.

This is a lot of great advice i was afraid i was going to have to start all over again. I must have pulled the distributor while not at TDC. By the sounds of it i was able to accomplish correct cam timing even though i was 180 degrees off on the cam. With that, can i turn the oil pump with a screwdriver to where i want it? I wanna get the rotor to point to the original # 1 on the firing order so i'll have some peace of mind the computer will function properly.

Answer 1

All you did was put the camshaft in 180 degrees wrong. To get the vette running all you have to do is pull No. 1 sparkplug and tap motor over until you feel compression at the plug hole ,then put the engine timing mark on the top dead center (0°) mark pull the distributor and put it in the right way with the rotor pointing to #1 plug wire as shown by your manual. Some times the distributor will not go all the way down because the oil pump drive is not lined up,in that case just bump the motor over until it drops all the way. the last thing to do is turn the motor over until you have it back to 0° TDC to recheck that the distributor is in correctly. Start the motor and set the timing

Answer 2

Did you originally take the distributor out "before" you had tdc? If so, it is the oil pump shaft that is out of position. It is easily overlooked, but the engine needs to be at top dead center before pulling the distributor. That way, the pump is in the right position when going back in.

With both the cam and crank marks in the right position, you need to move the oil pump shaft to the right position to line up the distributor with the slot in the oil pump shaft. That's if you want to get it back to where number one "should be"...

Valve timing seems right now, if I read you right (you did turn the camshaft before loading the valves, didn't you?)...moving plug wires around may correct the rotor problem, but it will no longer be "by the book".

**Additional**: Yes Mike, all you should have to do is put the engine at tdc again, pull the distributor, "note exactly where the slot on the distributor is when you pull it, and move the shaft on the oil pump the right amount to put number one wire where it should be...the other guy(s) were right, the valve timing was on the intake stroke with the engine one revolution off...

Answer 3

You are correct! If it the cam is 180 off, it will automatally correct itself when the crank rotates 360.

The distributor has to be matched to the cam position, and think you have it in backward, why not just pull it out again and turn it 180, rather than put it together wrong. It may run with the wires rotated 180, but will you be able to live with what you have done. Won't you sit up at night thinking about going out to the garage to make it right?

Answer 4

Hmmmm.......
Well, if you know you have the crank/cam timing correct, is it possible you simply need to rotate the disrtibutor drive two or three teeth to get the rotor to point in the right direction?

Or, are you saying you NEVER took the distributor out??
and the timing is off???Then after sliding the cam into position you probbably bumped the drive gear on the distributor a little.

Pull the distributor, and realign it. It's not going to change ANYTHING reguarding valve timing.
While it's out, you may want to prime the oil system anyway.

Answer 5

yea....it was done to my fiance's chevelle on a 327 stroker motor...but you need to reset the timing regardless. make sure you do it the right way first time around....
crank the motor over by hand because they might not stay in time....
what's your valve clearance? you could bend them if compression is high...
watch your computer system too because it might not recognize what you have done with the wires...

ok...he is over my shoulder telling me all this...sorry if it's out of order or confusing!!! LOL...he also said that there are a few variables that are missing....why you had to change the camshaft, was it replaced over a lost lobe, what type of motor and oil was used. He says on a new motor, he wouldn't start because of the computer, old motor...ok....if it's 180 degrees out, you have to fix that....is it a stock cam? regular stock bottom end? did it blow lobes?
you can get hold of him through my [e-mail]....he has a 76 stringray vette

Answer 6

yes you could move the distributor or adjust the way the wires are on the cap and the car should run and run fine.

You also could paint a car with a roller and house paint.

It's not the right way but it will work

Answer 7

I wouldn't want to take a chance and I wouldn't want to replace all the parts that could break. Why not bite the bullet and time them correctly and be done with it and enjoy the ride?

Answer 8

no your valves will be opening out of order with the firing. You will need to fix it. Might be very costly to let it go.