The Stovebolt Site Forums The Shop Area Engine Shop 1956 Chevy 235 Won't start after replacing rocker arms

Could use a little bit of help or for someone to point me in the right direction. I have a 56 Chevy 235 truck engine. Truck had sat for a number of years before I got it year ago. I replaced the coil, spark plugs, spark plug wires, battery, oil, and fuel pump. I also rebuilt the carb. Was able to get the engine running enough to drive it say 20 miles or so, while I started to work on other odds and ends on the truck.

The truck did have some white / blue smoke when it ran. While running the truck the other day with the valve cover off, I noticed that the rockers were not getting any oil. After a bit of investigation I found that it was the rocker arm, so I replaced that and followed the manual and set everything back up with #1 in TDC. To ensure that oil flowed I pulled the lifter cover and cleaned the oil tube that runs through it and pulled the distributor after marking the #1 plug on the cap and where the rotor was pointing to, so I could prime the system. I do have a rebuilt starter for it, but have not changed that out, since it was all working before.

Now that everything is put back together the engine will not fire. I have verified that the points and the spark plugs have spark and that the carb is getting fuel. Any thought or recommendations on what I should do next. Thanks in advanced!

If it is the original engine you may not have the valves adjusted correctly. You have to have some clearance between the rocker & valve stem to get it started. If it has an engine with hydraulic lifters the lifters may be stuck in the old position & not compensating for the change.
Make sure #1 plug is firing on the # 1 comp. stroke. If #6 valves are opening & closing as the engine turns then the pointing of the rotor should be to the #1 term in the cap.

George

Are you getting ANY spark at the plugs? Take one out, hook the plug wire back up, hold the plug body against some bare metal and have someone try to start the engine. If spark is blueish, put the plug back in and look elsewhere. If it is yellow or non existent find out why.

Elsewhere:
Is there gas in the carb throat when you pump the gas? If yes, look somewhere else. If no gas, find out why.

Somewhere else:
Is the spark occurring at the right time? Check your timing even though you marked the distributor before pulling it out. Once timing is right, crank the engine to #1 TDC (which is also #6 TDC). Both intake and exhaust valves (have a little slop between the rocker and valve stem) should be closed at TDC of #1 when on the top of the compression stroke. If they are tight you are on #6 compression stroke, so turn the engine one more complete turn. Now remove the distributor cap and make sure the rotor is pointing at #1 plug wire.

George types faster than me.

Watch the rotor while the engine is turning over to make sure that the distributor in all the way down to engage the gear on the camshaft.
If it is not down far enough to full engage, the cam gear will push the distributor gear up until the gears don't mesh and it will jump time. Sometimes the gears will settle back down and engage again, but it will be out of time.
Happened to me once. The design of these distributors are a little wonky and its easy for this to happen.

Thank you both. I have verified that I have spark on all plugs. It is more yellow than blue. I have a new condenser, points, coil, and ballast coming tomorrow.

I have verified #1 TDC, when the rockers have play and the #6 values are moving, at least I believe is the case. Maybe I need to add some play into the valves. I set them at .006 and .018. This has solid lifters.

I will check the carb. I had disconnected the fuel line at the carb to make sure I was getting fuel. This has the foot starter so without having a second person it is hard to see everything.

Thank you. Will post what I find.

52Carl. I do see the rotor turning. If it did jump time how do you suggest I remediate it. I just started getting these classics and learning as I go.

Another thing to worry about when it comes to getting the distributor in far enough is that it is possible (at least in GMC engines that use the same distributor) to get the distributor gear to mesh with the cam gear, but the tang at the bottom of the distributor shaft isn't in far enough to engage the oil pump properly. Happened to a friend's just overhauled 270 GMC. Had about 5 hours of use when oil pressure went to zero. He thought he got it shut off immediately, but an autopsy showed the need for another overbore, new pistons, new bearings, cutting the crankshaft again, etc. Detailed analysis showed "witness marks" on the very end of the distributor shaft and the oil pump shaft.

In the GMC engine, the gears start to mesh about 4/10" before the tang engages the oil pump. Probably similar in the Chevy engine. Below is a drawing I did of the engagement that I measured on the 270.

I know you don't have this problem. I'm just saying it is something to watch out for while inserting the distributor.

Getting gas to the carb inlet does not guaranty it gets into the throat. Look down the throat & work the throttle to see if gas is getting into the throat. You could shoot a little either in it & see if it will start.
If you have any valve clearance at all it should run. You can readjust the valves when you warm it up a bit.
You can use a large screw driver or pry bar to turn it over from under the hood. Hook it behind the shaft & pry down on the lever on top of the starter switch.

George

Tell me how you verified tdc, and how you installed the distributor.

Dragsix, I verified tbc on #1 by aligning the pointer to the first mark right of the ball on the flywheel, then I visually looked for the piston via the spark plug hole. I then rocked the crankshaft back and forth to verify that the valves on #1 were not moving and that #6 was. For the distributor, with #1 at TDC and had the rotor pointing to the negative wire post on the distributor and inserted it until the octane selector was flush with the block. This caused the rotor to move to the 5 o'clock position where the #1 spark plug wire attached.

Bill, I saw that as well with the oil pump. I am pretty sure I got that in the slot, but need to verify.

George, I have put either in the throat of the carb with no luck.

Assuming you do have good spark at the plugs, and the timing is correct, I think this is fuel related. Make sure there is gas getting into the throat of the carb when you work the throttle. I had an issue with my carb rebuild (my error) where I forgot to install the tiny check balls correctly, plus I had forgot to replace the accelerator pump. It ran "ok" but something was missing when I accelerated. I also had whiteish smoke. My accelerator pump was stuck in the carb and it almost looked like it was a pressed fitting. Come to find out you need to pry it out of there with needle nose and install a new one. Again, this was my rookie error.

Just a few things to try as you are getting fuel to the carb, and you are getting some sort of spark.

Had a little bit of time. Changed the ignition ballast, still getting 12+ volts out of each side. Wonder if it is bad as well. Also changed the rotor and the spark seemed to get a bit better and the engine seemed to get a bit further along. Also checked to make sure I was getting gas in the throat and I am. When I get a bit more time going to pull distributor and change points and condenser. Thank you for all your ideas and help.

Close the points and check both sides of the ballast resistor again with the key on. One should read 12v while the other should read 8v to 9v. The coil + should read that same 8-9 volts and the coil - should read zero volts.

If you have spark, why would you change points and condenser?
Check to see if you are still at TDC on the compression stroke of the number one cylinder, and that the rotor is still pointing at the #1 position on the distributor cap.

With the points open you will get the 12 volts at both terms. on the resister. With the points closed you should get about 8 or 9 volts at the term that goes to the dist. pos. term.. When the starter is cranking you should get about 10 volts at the coil pos. from the bypass from the starter switch.

Here is what I would do just to assure myself I am at tdc for starting. First, use the bb as the standard. Trace your No. 1 plug wire from the plug to the cap. Put a vertical chalk or paint mark on the body of the distributor directly under the center of the no. 1 plug wire tower on the cap.

Next, remove the plugs, and rotate the motor by hand until you feel compression coming out of the number one spark plug hole. Now slowly rotate a little more and line up the bb with the pointer.

Next, wipe the distributor pad and octane selector clean. Find the hash mark on the pad, and the 0 mark on the selector. Loosen the bolt and line them up. Tighten the bolt down.

Take off the cap. You want the rotor pointing exactly at the chalk mark you made earlier. If it’s not, loosen the screw and adjust it to get to the mark. That is close enough to get started, but if you want to get closer, look at the point rubbing block and see if it’s on the highest point of the lobe. Make a minor correction if required. Now, reset the point gap. I might consider replacing the condenser.

With that accomplished, I would feel pretty confident that the distributor is correctly set for an initial start up.

It was the distributor that was not timed. I thought I had it back the way it was, but was wrong. The mark on the distributor worked, and now it is back running. Will let it get warm and reset the valve lashes now. Thank you all for helping this wanna be mechanic!!!

Always good to hear a success.