VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 316 Timing From Scratch

Reviewed the shop manual, online articles, and previous posts but keep running up against incomplete or conflicting information.

I recently replaced the vacuum advance, fuel line and carburetor on the 316 engine of my '41 Special Deluxe. Of course, now it runs like crap - rough idle, dies on acceleration, etc.

When I resurrected her from 12 years of storage a year ago, I static timed the engine but may have just gotten lucky - fired up with 12-year-old gas in the tank. That's all been cleaned out now with new tank, new lines, new fuel pump, new carb. Up until I put in the new vacuum advance, she was running great. Even had her up to 60-65 mph and managed to blow a hole in the 80-year-old exhaust pipe (gotta replace that soon).

Right now, I have hand-turned the engine to where the timing pointer is directly on the flywheel BB and gaped the points to .018 per manual (plugs are gaped to .040). Octane selector is at 0.

Before I try to get lucky again, I figure I'd better check with the experts again on what my next steps should be. Turn the distributor so the points are open to max and lock it down? Turn the distributor to advance the timing or use the octane selector for that or some combination of the two? Note that I do not have a timing light so I will be doing it by ear.

Just trying to get the engine running smoothly again before sending all the shocks in for a rebuild and replacing the exhaust so I can get her on the road again.

BJ you can start with trying to adjust the timing by ear. If you think you want to drive up here I will help you.
Have you tried adding oil to the shock. I have some extra shocks I could let you use to send in to get rebuilt.

Added oil to the shocks, which worked for a while, but now it's all over my garage floor. Figure I may as well send all four in to Apple Hydraulics to get them rebuilt. I'm fine with it taking a couple weeks or so since I need to do the exhaust, brake light and some other stuff from underneath anyway - car is up on jack stands for now.

For the distributor, should I turn it so the points are wide open or closed while the timing pointer is dead on the BB for? Or should I advance the flywheel a little to one of the other marks? I figure I can fiddle with the timing a little by turning the distributor once I get it started and idling to the point it doesn't die on me, and then use the octane selector for a little more fine tuning as I've read.

Turn the distributor till the points just start to open, and have the octain on the center mark.

OK, sounds good. I'll start with that when I get back from work tomorrow. Thanks!

It didn't seem clear by your post but the point opening adjustment is done with the points on the top of the lobe, or widest opening.

Yep, I adjusted the gap with the points at their highest on the nearest lobe.

However, she's still not starting and I'm beginning to think that when I put the new vacuum advance in, I got the distributor turned when I reinstalled it. I seem to remember the rotor pointing to the 1 o'clock position at TDC as you're looking down at the distributor. Now it's pointing halfway between 4 and 5. Although, I wouldn't think that would matter as long as the firing order is correct (1,5,3,6,2,4).

I'm more curious about the BB on the flywheel. I assumed lining up the pointer with the BB is TDC on cylinder #1. But I recently read that lining up the BB could actually be 180 degrees off TDC, so it would have to go all the way around again to actually be at TDC. Is that true?

Based on the actual timing, yes it would matter.





Yes.

You need to have the rotor pointing to #1 after the intake valve has opened and closed and the BB at TDC. You can remove the valve cover to verify or remove the plug and while someone turns the engine by hand put your thumb over the plug hole. You should be able to fell the pressure from compression pushing on your thumb indicating it is on the compression stroke and coming up to TDC. Then note the distributor rotor location and if 180 out remove it and rotate 180 degrees and reinstall.

Yes, you need to make sure cylinder #1 is near the top of the compression stroke [/u]and[u] the rotor is pointing to the spark plug wire for that cylinder.

When I statically time an engine I use an ohmmeter to determine when the points open.

I set the octane selector to "0" and turn the engine so the pointer aligns with the ball on the flywheel and #1 very near the top of the compression stroke. That is 5 degrees before top dead center (BTDC).

Leave the ignition switch off. I then connect one lead from the ohmmeter to the electrical post on the distributor. I connect the other lead to a good ground on the engine. When the points are closed they meter should read very close to "0". When the points open the reading will go to the maximum resistance the meter will read which is the same reading when you turn the meter on but the leads are not connected.

I turn the distributor clockwise to make sure the points are closed (0 on the ohmmeter). Then turn the distributor counter-clockwise slowly while watching the ohmmeter. When the reading jumps to infinity. stop turning the distributor and tighten the mounting bolt.

The engine will fire at 5 degrees BTDC.

With the valve cover off and the timing ball at the mark, the two valves on #1 cylinder should have some play in the rockers, or clearance. At #6, one valve will be tight and the other probably has clearance.

If you want, you can move the wires around so that #1 is pointed to when the BB is at the pointer.

Keep in mind these timing parameters were set when gas was much lower octane. I understand wanting to get it close to book on initial start but you'll probably find your engine runs smoother and has more power if you time by ear once the engine is running. I time my '38 to fastest/smoothest idle warm & lock it down. If minor adjustment is needed I use the octane selector.

I fully agree with Tiny. I haven't used a timing light in decades even in freshly rebuilt engines. The old shade tree method always works.

Thanks everyone for all the great advice, especially about taking the valve cover off. I think I can get her timed now once I fix the BROKEN ROCKER ARM!

I'm thinking that was the start of all my problems with the poor running - not the carb or timing or anything else. Took the valve cover off and noticed one of the rocker arms for #6 cylinder is broken.

Do/should I replace the whole assembly or can I replace just the broken arm? Is there anything to know about this repair? Checked the advanced service manual. It shows illustrations and mentions the super-duper metal they're made from ("armasteel") but doesn't seem to mention how to replace a broken one.

You can just replace one but you will want to the shaft for wear and the rocker arm where they contact the valves. I do have extra rocker arms. You will have to remove the rockers and shaft as an assembly.

I agree with Dens. How much you replace will be determined by the amount of wear on the shafts and rocker arms. I am having the tips of the rocker arms for my '37 ground to remove the slight wear pattern caused by the tip of the valve stem. The shafts and bushings in the rocker arms have minimal wear.

Your rocker arms were used for many years (41 to 53). There are actually 4 different rocker arms in the assembly.

OK, Dens41, I'll follow up with you, since you're only a few miles away. I'll be around either Saturday or Sunday this weekend, depending on when my older brother and I go up to work on my mother's house (building her a master bath, laundry room and master bedroom). If you can, I need a new rocker arm and a little advice on how to go about replacing the arm. I was kind of hoping to go through this whole restore process without having to do any major engine work but it looks like that was just a pipe dream.

And the exhaust, shock rebuild, etc. will have to wait until I make sure I have a running engine to actually power the car. First things first.

When replacing the rocker arm you will want to try to determine what caused it to break. Check for bent push rod and/or stuck valve.

Thanks, Steve! I went out and looked at it again this morning and see that the rod under the broken rocker is sitting lower than all the other rods. I also cannot pull it out so, at the least, I assume it's bent. Gonna have to remove the intake manifold and see what other problems I've got.

This thread has morphed from Timing from Scratch to finding/diagnosing the real cause of a rough-running engine.

Years ago there was an article in G&D about several ways to time the old Chevrolet engines. Gene may have been the author of the article but I don't remember now.

Mike Buller may have a means and know how to search that article out or someone at the G&D publication or HQ may do so.

It was an interesting article and would probably be of benefit in the instant thread.

Best,

Charlie

Hopefully someone will post/repost that like. It would be a great help once I get to that point again.

Would backfiring have caused a bent push rod and broken lifter, or would that have been a symptom?

Just wondering as it started having what sounded like fuel starvation issues last fall - backfiring pretty badly, loss of power. Remembered I'd never replaced the fuel line so I did that and it seemed to work for a while but not 100%. Wondering if one of those gunshot-loud backfires might have rammed the rod up so hard it caused the damage.

Most likely the problem started with a sticky valve caused by running some with old gas. Had similar problem on a friends 49 Buick that was not driven enough to keep fresh gas in it, he does not use ethanol. Also have the heads off a GMC pickup at the farm where I work part time, the problem was a miss on 1 cylinder that had a bent exhaust valve that stuck open and hit a piston. He has gas in barrels on the farm that don’t get used fast enough.

BJ you shouldn’t have to take the manifold off, but may have to take the side cover off to get the side cover off to get the push rod out.

Got the side cover off - no small feat with the engine still in the car.

Discovered the push rod is not bent at all - thought it was because I felt the resistance of the magnetized end on the lifter. Checked all of the other rods and lifters and everything moves freely and seems fine. Maybe it was just time for that rocker arm to break?

After I got it home about a year ago, I drained all of the old gas and replaced the tank. I've got a new tank, fuel lines, fuel pump and carb. Before this happened, I had burned about a tankful of clean non-ethanol gas through it. Could the valves still be working through their stickiness from the old gas? What other problems do I need to check for, or will replacing the rocker arm be sufficient?

If the push rod was not bent I think you may be ok just replacing the rocker arm. If you don’t have the side cover gasket you can get them at Arnold’s or O’Riliey’s.

If you're going to be around tomorrow afternoon - after 2 or 3 - I can run up to your place and get a rocker arm from you. It's the second from the back of the engine (#6 cylinder). Not sure if that's exhaust or intake. I've read somewhere that intake and exhaust rocker arms are different, but, like I said, I've read conflicting information.

I know The Filling Station sells them but if one of the auto parts stores happens to have the gaskets in stock, all the better.