Hi all,

Thanks for all the great posts and info on this site. It has been so helpful for a noob like me.

I just picked up a 1968 289 coupe and am having some problems with the motor.

I've changed - plugs,wires, rotor,cap,fuel filter,air filter, pvc.

In park... the car runs pretty good, however, when I shift in to drive or reverse she shakes like a steam locomotive.
I say steam locomotive, because that's what it sounds like. There is a poping sound from the right side. (she has headers and dual exhaust)

The shaking does subsides when I step on the gas and drive.

I've tried adjusting the idle to various level... 550 - 750 rpm... but she still shakes.

If I set her at the lower RPM setting 550-600 rpm, she will stall if I rev the motor too fast.

any ideas or advise?

thanks.

******NEW UPDATE******

Thanks for the compress tip..

I did the compression.

Cyl 1 barely registered any compression.
Cyl 2 I couldn't duplicate the same reading
Cyl 3 165
Cyl 4 150
Cyl 5 150
Cyl 6 145
Cyl 7 145
Cyl 8 135

I then pulled the valve cover off, and low and behold!
Cyl 1 - bend rod #1
Cyl 2 - The rocker #3 was off the notch on the spring... Which would explain why the reading was all over the place.

I pull rod 1 and 3 (counting from the front)off... The 3rd rod was straight.. and not problem.

Question 1 : is there a torque setting I should be tightening the rocker nut? An old timer machinic told me Half a turn when it's tight....

Got myself a new rod from an engine shop to replace rod 1, but when I went to tighten the nut all the way down on the rocker.... the rod is about 1/2 inch too short and does not rest on the bottom of the rocker at all.
I've double check the rod and it's the same length.... ..any advise?

 

sounds bad, it might just be U joins that are totally shot. get under the car and see if you can slide the drive shaft side to side, up and down, left and right, If yeah then they are bad.

If not then not sure what is causing it

Gun

 

twin exhaust ehh?

You mentioned that you recently changed cap, plug, and wires. Did you double check to make sure you didnt cross any up? (or maybe one popped off and your only running on 7). I've had a boot that came off and my would run like **** as soon as I put it into gear.

 

Hey good thinking
That might be it, when he said poping sound i was thinking metal on metal.

Gun

 

maybe u have a loose or broken motor mount

 

Double check your firing order.

 

Have you done a compression test??

 

Thanks for the compress tip..

I did the compression.

Cyl 1 barely registered any compression.
Cyl 2 I couldn't duplicate the same reading
Cyl 3 165
Cyl 4 150
Cyl 5 150
Cyl 6 145
Cyl 7 145
Cyl 8 135

I then pulled the valve cover off, and low and behold!
Cyl 1 - bend rod #1
Cyl 2 - The rocker #3 was off the notch on the spring... Which would explain why the reading was all over the place.

I pull rod 1 and 3 (counting from the front)off... The 3rd rod was straight.. and not problem.

Question 1 : is there a torque setting I should be tightening the rocker nut? An old timer machinic told me Half a turn when it's tight....

Got myself a new rod from an engine shop to replace rod 1, but when I went to tighten the nut all the way down on the rocker.... the rod is about 1/2 inch too short and does not rest on the bottom of the rocker at all.
I've double check the rod and it's the same length.... ..any advise?

 

Check to see if the rocker arm stud/s pulled out (up). The studs should all be the same height on all of the valves.

 

You're right... that one stud pulled up/ out.. I can see color change on the stud that tells me that about 1/2 inch of it was pulled up.

How do you get these back down? There's no hex base on these studs for me to get a grip to torque it down....


I am kind a tempted to just add a spacer or a nut under the current nut to make up the gap....