Technical Timing, backfiring and overheating

A little background: I recently picked up a 47 chevy that has a 350. I was told it was a crate motor. Since I got it on the road at a stop the temp likes to creep up on it. It also diesels like a champ whenever I shut it off. When I hit it with a timing light the timing mark sits around the 12 o'clock position when the timing tab is around the 2 o'clock position. If I try rerarding the distributor it won't even start let alone run. I tried to convince myself that the wrong style balancer got installed. I went through and set cylinder 1 at TDC and sure enough the timing mark lined up on the tab where it is supposed to be but then again it wouldn't run until I advanced the timing to where the mark was around the 12 o'clock position.

I'm racking my brain and am truly at a loss. Also am I wrong to assume all 3 issues are related? Any ideas of what to check/adjust/change ect. would be greatly appreciated.

 

Timing chain problem? Maybe it jumped a tooth.

 

I pulled the timing cover and checked and the dots line up just like their supposed to at the beginning of the intake stroke on #1

 

Have a look at the distributor advance mechanism. If it checks out pull the dist. and check the gear for slippage on the shaft.

 

See that the ignition timing is advancing all the way up the RPM range. Somewhere in the mid 30s around 2500 RPM or so. This would be without vacuum advance. The base timing setting is only part of the story.

 

Just checked the gear on the distributor and it's brand new and the roll pin is still intact. Don't remember if I said it but it's a HEI distributor. The spring advance on the rotor seems to operate freely and as it should.

 

What vacuum advance are you running?
Ported or full manifold?

Use ported!
Set the timing correctly with the vacuum disconnected ( if you reconnect "full" manifold vacuum it will be too advanced at idle and when you shut off the engine)

 

It's a "damper", not a balancer. The 350 doesn't need any extra balancing..!

Since you have no clue what the ignition timing actually is...have you tried slowly "advancing" the timing, WITH the engine running ?

If the engine rpm increases, the timing might well be somewhat low, especially considering your overheating problem. Go ahead and increase the timing a little at a time, until the engine runs a little rough. Then back it down a little. Engine not running, start the engine. It should be a smooth start, no grunting, or hard spots in the rotation. If there is retard the timing, just a little.
Then drive the car, make sure that it doesn't "ping", or detonate under hard acceleration. If it does, back the timing down just a little more.

THEN...go buy yourself a "Top Dead Center" checking tool, and a timing tape the correct diameter for your damper.
Find the ACTUAL number one - Top Dead Center with the new tool. The with this new information attach the timing tape to the damper with the correct "0" in the correct location.
Now, you'll know what your timing actually is.
The above info is very simplified work for finding top dead center, the exact info can be found in most any cam catalog or YouTube video, if your aren't sure how to do it.

Mike

 

Lots of things seem like they should work, but they don't, and there's no way to know for sure unless it gets measured or tested. In this instance a timing light is required.

 

Gonna try to answer everything.

The vacuum advance is ported off the base of the carb.

When I had the heads off I double checked the timing mark using a video from the comp came YouTube site. The existing timing tab lines up perfectly with 0* on the tab being TDC on #1.

Once I have up on trying to time it with the light I did tune it by ear. It shake a little more than it probably should but there's a backfire when you hit the throttle. (See attached video)


https://youtube.com/shorts/6pTF1Y_r32A?feature=share


I'll go back through and see if there was anything I missed. I appreciate everyone's input, thank you guys for being awesome.

 

Double check:
1-8-4-3-6-5-7-2
Clockwise Rotation

 

You were right. I had 5 and 7 reversed at the plugs. The backfiring when I blip the throttle is gone. It's still shaking more than it should. The timing mark is still around the 12 o'clock position at idle with the vacuum to the distributor unplugged. If I try to retard it past that it won't run.

 

Manifold or carb vacuum leak???

 

Why not just advance the initial timing till it runs as good as it could? I haven't used a timing light in years. You could have the wrong balancer, wrong timing pointer...etc.

 

For the month or so that I've had the car running and driving it has been tuned by ear because I thought it had the wrong dampner installed. My concern is the overheating issue. While I'm moving it's fine but at a stop light it whatever the temp creeps up. I live in Vegas and we're only a month or so away from the temperatures being in the triple digits. If it's barely hanging on now the car will be undrivable soon. The cooling system should be big enough to handle a standard small block so I can't see it being that.

 

This will work if someone understands what they are doing and all the components and gee-gaws are working "as advertised". We don't know that. Most likely they are OK, but ...

Process of elimination & methodical troubleshooting always beats guessing and throwing parts at it, especially for anybody trying to help remotely sight unseen.

I will say getting the plug wires in correct firing order should help considerable with all the Unpleasantness.

 

The plug wires was a new issue. I just finished putting everything back together yesterday morning from pulling the heads and got those 2 mixed up.

 

Regarding your over heating, do you have a fan shroud?

 

Yes. It's got a 16 inch electric fan set up as a puller. It's tight to the front of the radiator core

 

Have you checked the timing with or without the vacuum connected?

 

Vacuum disconnected and the port plugged

 

Put a clutch fan and a single points distributor on with a resister and Delco coil.. I would remove the vacuum advance and give it the initial it wants.. Stop trying to force the factory suggested timing and just give the motor what it wants.. Make sure you have a 160 Stant-Superstat thermostat. Those pill thermostats are known for causing those temperature issues you are having..

 

I don't have room for a clutch fan between the radiator and water pump. I do like the idea of going back to a standard distributor and coil setup though. I'm currently running a 180* thermistor so that would definitely give me more wiggle room as well

 

My feeling is if it’s over heating at idle with a 180 thermostat, it will still do it with a 160. So separating issues here, how have you verified it is actually overheating? Just watching the gauge shoot up? Does it bubble out the overflow? Pick up an inexpensive laser thermometer and verify it and the temps you’re seeing on the gauge.
I replaced an alternator because I was too lazy to look for my meter and the OEM volt gauge was stuck on 12v at the time.

 

I have separate sensors for the gauge and the fan. The fan comes on at 180 which is what the gauge reads when it comes on. I do have an IR thermometer at work. I'll bring it home tonight just to verify though.

 

I would try to get it back to a manual fan. This would eliminate a lot of issues that come with electric fans.. That alternator is working hard keeping that engine cool. Something the electric system in this car was never designed to do..

The nice thing with the points is you can instantly have one of the best electronic ignitions by using the distributor to trigger a CD box. If you run into trouble, just switch it back to points only..

I like my cars to be as simple as possible..

Yesterday the red Gen light came on in my el Camino. It turned out to be a bad connection at the voltage regulator. I had it all fixed by the time my wife came out of the super market.. This car is so simple, it has a Gen, Temp and Oil light.. If I would of had a gauge it would of been a while before catching it. The ultimate is having both light and gauge. I would like to have a tach though..
When I got home, I cleaned it all up and soldered all the joints then I used harness tape, hit it with the heat gun and all is well...

 

I agree I'm all for simple. As far as the electrical system there's nothing original left though. I rewired the whole car with a painless style universal harness. Next time I'll get some measurements to see about going back to a manual fan. If for no other reason my first job or if high school was at a radiator a/c shop and I saw more than a few cars come in because the plastic fasteners that go through the core of the radiator ended up sawing their way through a tube or two with enough vibration and time. This electric fan was already installed on the radiator when I bought the car so I just decided to run with it for now.

 

The issue here is that engine and under hood area was designed to have continuous ventilation like a manual clutch fan would give.. Having the electric fan shut down then try to over come the extra heat with an electric fan that moves a tenth of what the clutch fan could move is the issue.. I would really look into this because having the temps climb in stop n go traffic is usually an issue of weak under-hood air flow.. There are narrow clutch fans today, I would look into them or moving the radiator out a little..

Having the fan come on at 180 might be too far for the electric fan to over come. I would try a 160 thermostat, I like the Stant Super-Stat get it for 160. This would be the first thing I would try.. Then if no good, change the sensor to 160 if changing the system back to mechanical isn't in the cards for you right now.
Some people run these washers with different center openings instead of a thermostat.. This slows the water speed down to allow the air to cool it..

 

If it is good while driving,,,,it is getting good circulation.
At normal speed,,,,you don’t even need a fan,,,,,if the engine is right and getting good flow .
At stand still,,,,,,you are not getting enough air movement over the cores .
Could be radiator,,,,,,could be shroud,,,,,just not getting air exchange from radiator .
I reread your post,,,,,,,it has an electric fan,,,,,mounted to the front of the radiator,,,,,setup as a puller.
Shouldn’t that be pushing ?
If it is on the front,,,,,,it needs to blow through the cores .

Is this a new radiator,,,,of just a good old one ?
That makes a huge difference sometime .

Tommy

 

It's a brand new radiator and you're right it's a pusher set up, I mistyped it.