Need some advice from the engine guru's out there. I had to replace the lifters on a 454 and while at it I did the pushrods and installed a set of Comp Cams Roller tip rockers - not full rockers but just the roller tip.

- Valves were adjusted using the exhaust opening - adjust intake and intake closing - adjust the exhaust + 1/2 turn.

- When you crank the engine the beast for at least the first 10 cranks or so, bucks like either the battery is low or the timing is super advanced or the valves are too tight.

- However, it will start and it idles very smooth. Connecting a vacuum gauge to manifold vacuum, it is pulling 19-20" and is almost rock solid. I believe if valves were hanging open the vacuum guage would be flopping around 4-5 points each time a tight one is hit. Is this correct?

- When I reinstalled the distributor I brought the #1 piston to TDC compression stroke (felt compression in the plug hole and then lined up the rotor pointing to the #1 tower in the distributor.

However, the engine still seems to act as if it is too advanced. I have to set the static timing to about 4-5 degrees on the pointer to get the thing to crank somewhat smoothly. I found the idle was better or smoother at 4-5" than 8-10 on the pointer.

My questions are : Do these symptoms suggest valve adjust or timing advance because I screwed something up or what? Thanks

 

any chance you got the spark plugs wired one off in sequence, in other words you didnt pick the correct tower

 

Thanks for the idea. Would not the engine run pretty rough with the firing order 1 off?

 

If it idles fine I doubt that your firing order is 1 off.
Just a wild guess from a newbie but i would think that your distributor might be one tooth off when you installed it again.

Or, here's another wild guess, could you have set the TDC on the exhaust stroke iso the compression stroke?

But then again, lots of people here that know a lot more then me.

If something doesn't work, undo what you did last.
Obviously has nothing to do with replacing lifters or rockers so take the distributor back out, redo TDC and install again.

 

sounds like my small block-was out one tooth --I would check that again--let us know how you make out--

 

The 1 tooth off makes sense. I think 1 tooth is worth about 20 degrees in timing which would put it way...... advanced and buck like hell. That may be why I need to "retard" the timing down to 4 degrees or so instead of the usual 10-12 initial timing. I will check this tonight or tomorrow and let you know. Thanks for the suggestion. Jim