The Stovebolt Site Forums The Shop Area Engine Shop timing

I have a 1959 235 with hydraulic lifters, and have been having problems with overheating since the rebuilt engine was first started. Several things I seen here suggest that incorrect timing might be causing the overheating. But after searching on how to time my engine all I am is more confused.
Static timing to the ball, timing light to the ball, timing light to 5 degrees BTDC. Time to best vacuum reading. And which way does the distributor turn to advance timing? All I have on my flywheel is the ball, painted white. Right now I don't even see the ball using the timing light. By the way, the engine has 10 miles on it, new water pump (low mount short shaft), new radiator, hoses, thermostat, and yesterday it got hot enough that it blew the lid off of the overflow tank I put in!

Can someone help me out with this? It seems the more I look the confuseder I get!

Tim

What do you have for a radiator? How far is the fan from the radiator?
It takes a bright timing light to light up the ball on the flywheel since you can't get a straight on shot at it.
Can you drive the truck? How does it perform as is?

Setting initial advance to the highest idle speed in neutral, IME, is somewhat more advanced than the engine will like when in gear, but IDT that's your problem. If it has power and good idle quality, I suspect the air/water system before the engine.

Take a deep breath, exhale, lol. So below is a sun electric corporation tune up card. Looks like 59 gets 5 degrees before top dead center. Looks like the bb is tdc, the hash mark is 5 degrees. You turn the distributor counter clock wise to advance the timing.

Next question, are you confident the flywheel is a 59 flywheel?

Next, do a compression test. Should be consistent between all cylinders.

Now, let’s get you to a timing base line. Mark all the plug wires so you know which wire goes to which cylinder. Trace the number 1 plug wire to the distributor cap and put a vertical chalk line on the body of the distributor directly under the distributor cap tower for no.1 wire. Then pull all the plugs. Makes turning the motor over easier. Look at the bolt that is holding the octane selector plate down. The plate will have a center hash mark and there should be another hash mark on the distributor pad. See the photos of the octane selector plates. Essentially you want the plate to be centered on the pad hash mark. If it’s not, loosen the bolt and line up the center hash marks. Tighten the bolt.

Now, install a remote starter switch onto the solenoid. Put a finger or thumb over the no. 1 spark plug hole and begin to rotate the motor with the remote switch. One little bump at a time until you feel compression out of the no. 1 plug. Now, disconnect the battery and see if you can grab the fan belt and turn the motor clock wise until the bb is pretty close to the pointer. Now, get down with a light and see if you can find the 5 degree advance hash mark on the flywheel. Mark the hash mark on the flywheel with a paint marker or something. Bring the hash mark to the bb. Now, remove your distributor cap. Your rotor should be pointing at your chalk mark. If it’s not, loosen the screw on the octane selector plate/distributor clamp. Not the hold down bolt, the screw on the clamp. Turn the distributor until the rotor lines up with the chalk mark. Tighten the screw, install the cap, plugs and wires. You should be at 5 degrees btdc. Start the motor and check with a timing light.

While you are there, rev the motor a bit and make sure the vacuum advance is working. If the distributor does not move when you give it a quick rev, the diaphragm in the advance may be shot and you have a vacuum leak.

Finally, how cruddy is your distributor? If the distributor is shot, broken advance springs, or non working mechanical advance, this will also create issues with the timing and potentially the over heating. The photo of the distributor is one I rebuilt last year. When I got the point plate off I discovered that one of the springs broke off and jammed the advance weight so it could not move and no advance was occurring.

OK. The engine is a brand new rebuild. New distributor, points, condenser, rotor, cap, plugs, and wires. Compression is good in all cylinders, none more than 5# different. New starter, new radiator, new water pump and fan.

The truck starts up immediately, no problem, idles after the choke is off. I don't know how it should drive, but in fourth gear I could only get it up to 45. Keep in mind this is a 3800 (one ton) with the SM420 transmission and 5.14 rear end, so I don't expect it to be a speed demon! Although the last time I really drove it (in 1981) it would get up to 55, barely.

It has a foot starter, so no solenoid. I checked the timing when I was adjusting the valves, lined up with the BB.
I have adjusted the carb as well as I can, adjusting idle miz screw and idle speed. I pulled the thermostat and drilled a small hole in it to let any air pocket escape.

I thought there might be a problem with the radiator, or maybe junk in the block. The water in the radiator looked awfully rusty to me, so I drained the system, refilled with water, ran until warm, drained, refilled with radiator flush solution, ran for about half an hour, drained, filled with water, ran, drained and finally refilled with 50/50 water/antifreeze. Now the water in the radiator looks good, still a hint of rust but mostly green. I have a 160 thermostat installed.

I haven't measured the clearance between the fan and radiator, but I'll check that tomorrow. Also the size of the fan and pitch and number of blades.

"Mark the hash mark on the flywheel with a paint marker or something. Bring the hash mark to the bb." How? aren't they both on the flywheel? I don't know what year the flywheel is, it came with the engine so I assumed it was a 59. I know it is a 12 volt flywheel.

The reason I'm considering the timing is because I can't think of what else it could be. And at least if I KNOW the timeing is correct I can rule that out.

Right now I'm considering installing a 16" pusher electric fan in front of the radiator and removing the fan on the water pump. In case the problem is due to the low mounted fan. Although back in 1981 it didn't overheat (that I remember) and it had a 1962 235 with a low mount pump and fan.

I'm searching for anything that might solve this problem.

Tim

I think the root of your issue may be in your last paragraph. Low mounted fan! Unless the fan is centered on the radiator you loose cooling efficiency. You can try installing a radiator shroud which will draw more air or do the supplemental electric fan route.🛠

Try another new thermostat. Half of the ones we get now are defective. When does it overheat? On the highway, idle slow speed, right away or after you run awhile. I don't think timing or fuel mixture is the problem. Be shure there is no shipping packing on the new radiator blocking the flow of coolant.
George

I went out this morning and took some measurements.

From the tip of the fan blade to the center of the fan is 8". It has four blades.

From the center of the fan to the top of the fins (NOT the top of the radiator) is 13".

From the leading edge of the fan to the face of the radiator fins is 1 1/4".

Maybe the fan is too far away from the radiator? Maybe I need spacers? I don't know how far from the radiator the fans should be.

I didn't measure the pitch of the fan blades.

Tim

What type of fan do you have? If it is a flex fan, make sure that it is not a reverse direction fan.
1 1/4" is too far away in my opinion, especially since your fan extends significantly below the bottom of the radiator. When the fan extends below the radiator, it will draw air from below the radiator rather than through it.
I have seen trucks set up like yours work jut fine, but they did not have a 1 1/2 inch gap between fan and radiator. I recommend a 1/2 inch gap.

Carl

I was thinking of about a 1/2" gap between the fan and the radiator. With a spacer that thick can I just use steel tubes from the lumber yard? I can't remember what they are called, but solid steel used as bushings. I'm sure they have some the correct ID for the bolts that hold the fan. Or do I need to get a special spacer from the parts store?

I think I will try moving the fan closer to the radiator, and see if that makes any difference. Then check out the timing. Then install an electric fan in front of the radiator. I don't know if I can have both the water pump fan and the electric at the same time.

Tim

Ready made spacers are available at the parts stores in various sizes. Water pump relocation plate? Fan shroud. Pusher electric fan is mounted in front of the radiator so no interference with the regular fan.🛠

My 59’ 235’ in my 52’ 3100 was originally a long shaft with the radiator mounted in front of the fan support. Although I did not drive it on the road for more than a few miles, I did run it several times up to temperature (180 degrees) without it overheating. I have since changed it over, by installing the relocation plate with the original 216 water pump, then relocating the radiator back to its original location. A project I highly recommend.

However, after reading the above post it sounds like you are very frustrated and somewhat all over the place without really ruling out possible issues. I have been there and feel you pain.

You originally started this thread questioning the timing. Dragsix posted an excellent procedure on timing the 235. You have to eliminate some of the possibilities, and that’s a great place to start. Besides it doesn’t cost you anything. That’s where I would start.

OK. I went out yesterday and redid the timing. Started engine and let it warm up until it idled without any choke. Disconnected vacuum advance line. Checked point gap. Started the engine and put the timing light on the flywheel and couldn't even see the ball (which I had painted white). Messed around and got the pointer right in the middle of the ball at idle. The engine smoothed out, idled well, and seemed good. Today I'm going to recheck the lidle mix screw on the carb, then take it out for a short drive and see how it does.
I also started to remove fan to install spacer, and realized that there isn't enough room to do so without pulling radiator, so that is not happening now. I did check air flow through the radiator by putting a smoke bomb (left over from 4th) in front of the radiator while the engine was idling, and the fan sucked the smoke through, so at least there is some good air flow.
We'll see how it goes.

Tim

Your motor needs 5 degrees before tdc so you are actually running the motor 5 degrees off the factory setting. The bb is tdc. Find the hash mark or use a dial back light and get to 5 btdc before you readjust the carb. Also, did you check the vacuum advance for operation? If you look at the factory shop manual (See Keith hardy's On line Manuals if you dont have one) you will see that the hash mark is the first radial line clockwise from the bb. You need to get this motor to a factory baseline first and foremost. Then you can tinker with adjustments from the factory specifications.

Drag, I think he has it right, check the pic. BB here is 5 degrees advanced.

I could be wrong of course, but according to the 59 shop manual and the sun tune up chart, its the hash mark on a 59 wheel, clockwise from the bb.

http://chevy.oldcarmanualproject.com/shop/1959_60/59sms0704.htm

See Note 1B.

Good call Drag, I guess it depends on what flywheel he has. Confusing on how they did things back then, I guess they never considered parts moving around like they do these days. Thanks for your clarification. So this one then::
Steve

I agree, it is confusing which is why i asked Bluesman earlier whether he knew, one way or the other, whether he had a 59 flywheel. Frankly, if he does not have a 59 flywheel, the timing is suspect without actually being able to identify true tdc. This may be a good opportunity to sort the differences out. When I get home tonight, I will look at my flywheels and see if I can match up casting numbers with years and then take photos of the marks. I only have one or two not still bolted to a motor but let me look and see what I have. I don't know myself what all of the marks and the meanings are on some of the flywheels. Might be a good time to sort that out, maybe make a tech bulletin out of it.

Here is a post/thread with info on the variances and oddities of 216/235/261 timing marks on flywheels.

I get what you are writing about. I used to have math anxiety. After my brain had time to develop, math became very easy. Then i decided to learn Stovebolt mechanics and had to deal with Timing Anxiety. It will become clear by following the advice here.

I'm not sure what year flywheel I have, it came with the engine, and when I had it off the engine I didn't look for anything but the ball. I don't think I even knew there were supposed to be other marks on it.

Having said that, I think I have the timing right now. It starts easily, runs smooth, idles fine at low RPM, and didn't over heat when I took it out for a drive yesterday.

I guess what I really need to do is turn the engine by hand a bit at a time and try to find other marks on the flywheel. That's the only way I can think to be sure of what I have.

But at least it's running good now!

Tim