VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 still have overheating problems with my 34 chev

Hi there all,
thank you all for your input and advice.
yesterday I wanted to checked out the timing.
I removed the plugs and all were very sooty, I know where the idle screw is but am not sure how to adjust the mixture?

Next I checked the points, after reading the workshop manual.
they were within specification.

I then wanted to check the bell housing aperture and pointer timing with a timing light but then realised that I still had the sump removed, so will do that when I replace it today.
Thats the update so far.
any info on the mixture adjustment would be most helpful...

Peter

In addition to adjusting the mixture screw also check the air cleaner to be sure it is not restricted.Turning the mixture screw to the right should lean out the mixture and to the left enrich it. as you have black sooty plugs the mixture is too rich so leaning out will be necessary. With a little practice you will be able to tell from the sound of the engine when it is right.After adjusting the mixture you may also have to re-adjust the idle speed.

Just remember that adjusting the air dilution only affects the idle and low speed mixture. After ~15 mph the idle circuit is not functional.

so where is the mixture screw for adjustment? My carbie has a slow running screw that is easy to see and get to, but cant see any other screws. Is it on the btm of the carbie?
Peter

The idle adjustment is the only one on a W-1. All it does it increase the amount of dilution air as it is screwed out. That both reduces the flow of gas from the float bowl and richness of the mixture. As posted above it has no effect above ~15 mph.

So Peter, before you start ripping the radiator out and spending a bunch of $$$$$$ on rodding the tubes, power flushing, back flushing ect.

Sounds like you should check for the torque, done in correct sequence on the head bolts and NOT exceed the specifications. A leaking cylinder head gasket will cause overheating quickly.

Adjust the carburetor properly and get the engine running properly and too specifications.

Have enough water in the top radiator tank so that you can see into the top of the tank and with a light watch the coolent flow for bubbles. Bubbles can indicate a leaking cyl head gasket. There is also a liquid you can put into the water and if exhaust gases are present thru a leak, it will change the colour of the water.

Ask for the liquid at an auto parts seller or engine rebuilder or radiator shop ?

mike lynch

Hi there Mike,
thanks for the info.
I will try your suggestions
Peter

So infact Chipper, you are saying that my carbie has NO mixture adjustment? do I have to put up with sooty plugs and a super rich mixture?
Peter

The answer is probably no, you don't have to put up with the over rich mixture. It requires replacement of internal parts. Probably by someone that has experience or the exact specifications so they can make sure that all internal parts and metering holes are correct. If that carburetor can not be fixed, then replacement may be required.

Before any major carburetor repairs are considered, first make sure that the ignition system is up to snuff. Timing, weak spark, cold plugs are all potential causes of incomplete combustion which produces carbon instead of power. Low compression is also a contributing factor in incomplete combustion. Then there is restriction in the exhaust system.

hi there,
thanks Chipper for the suggestions.
The carbie is NOS from a later model, a 39 I think it says on the box.
I will start by checking the timing, now that the sump in back on.Then check the head-bolts and adjust the tappets and distributor if needed. If all are well, and the overheating still occurs, I will then move to the radiator and have it checked for blockage.
Will keep you updated in due course.
Peter

Update:
today I checked the timing via the pointer and ball bearing embedded in the flywheel.
It was well advanced.

I moved the distributor to rectify the situation and immediately the engine ran sweetly. It started on the first push of the button.

I then torqued the head bolts to 50 ft lbs and all bolts moved at least 1/2 a turn.
I read the workshop manual and it says to run the engine to heat up the system.

I then realised that I had not adjusted tappets on a 6 cylinder for over 18 years and had forgotten what is the procedure? so I stopped for the time being, and will have to find out what to do.

I seem to remember do number 1 when number six is closed, but that is a very distant memory......
any suggestions on the matter would be most appreciated.
BTW. it did not boil over immediately, but became hot because the vehicle was stationary.But did not boil.

Peter

To adjust the valves it is best done with the engine running. Make sure the engine is at operating temperature and set the idle as slow as you can keep it running. Identify the intake valves. Use a feeler gauge to set them so the gauge will go in but is hard to move except when there is no pressure on the gauge. When you have set the intake, change gauges and set the exhaust valves.

If you make an error let it be on the too loose side. Too tight could result in burning the valves.

The values to set the valves will be found in your repair manual.

Peter
You had the right idea for doing valves not running, adjust the valves on the cylinder directly opposite where the rotor button is pointing.
Ray's idea of adjusting while the engine is running is just as good but it takes practice to get it right.
Tony

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Your now getting there, torque the cylinder head bolts to what they should be for 1/2 " ?? 75 pounds in the correct sequence. Take them to 65 pounds and then go around again to the final 75 foot pounds.

Peter have a look into the top of the radiator fill and see if your engine is producing exhaust gas bubbles into the water/antifreeze ? There should not be any bubbles.

One step at a time.

mike lynch

Mike:
I think that I am now making progress.
Prior to checking the timing, I removed all the plugs and they were very black and sooty, the mixture is too rich, maybe the timing change will make a difference now?

I mention this because if the head gasket was leaking oil into the water, you said that the plug would be super clean. This is obviously not my case (I hope).
So air is getting into the system somewhere?

I did notice bubbles in the radiator and previously had tightened the gland nut on the water pump, thinking that it was sucking air in at that point!

Peter

Air bubbles in the radiator and overheating can also indicate a cracked cylinder head.

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If the cylinder head is cracked it will allow water/antifreeze to seep into the piston area.

If the cylinder head gasket only is leaking , when running it will also allow exhaust gases to enter the water/antifreeze mixture and create bubbles in your water.

You need to figure out exactly what your problem is.

The timing & carb adjustment making the motor run smoother is a good step in the right direction as the motor is no longer boiling over. But the bubbles in the radiator water/antifreeze is not a good sign.

You will only have one clean plug if the motor is being run and car driven on roads, with one leaky cylinder having the water/antifreeze leak cleaning the plug. Are you getting steam out the tailpipe another tell tale sign of moisture from the motor. BUT....moisture will collect in the exhaust system when its been sitting for a while, so its not a first sign. If the motor has been heated up and ran for a while , there should not be any white steam out pipe.

mike

blue

if you don't have oil in your water and you don't have water in your oil,i would say your head is ok.
i would clean up your plugs or put new ones in and top off the water and drive the thing out on the road for a while and see how it doe's.
i don't know how you all got off on carb adjustment ect when the origanal problem was a hot running motor.
i'd quit messing with it and drive it.

jeff korner
southeast indiana

I believe that would be water into the combustion chamber...

You should pull the head and magnaflux the area around the valve seats. Many six cylinder heads will be found to be cracked at this location. It can be difficult to see with the naked eye but when the head gets hot they will open and allow hot gases to enter the water chamber.

Not to but in here...My '36 and me went through the same thing. I replaced the rad. did the timing thing. and double checked the slide on the vaccum advance octaine selector you know near the distributor...flushed with high pressure water both ways with rad. hoses off...used rust out rad. cleaner, etc...Boy was I suprised when I pulled the head to find that after setting up for a lot of years that the holes between the block and head were pluged with floating broke off chunks of rust! removed and presto cool as can be!!!

For it to heat up so quickly I would agree with the above. Timing, mixture, etc. would not cause it to heat up that fast. Either that or a cracked head, bad head gasket, etc.

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I think you would need a lot of water pressure , like what a pressure washer would put out, into the block to thru thermostat housing to attempt to flush the build up out.

mike lynch

Hi there Mike,
today I finished installing the oil filter system and it is working well, very simple to install BTW.

I also wrapped the first part of the the exhaust pipe from the manifold with impregnated wrap to retain the heat and keep the engine bay cooler.

Which now brings me to the original problem of overheating.
The adjustment of the timing now makes the car much easier to start and for a while it did not overheat as quickly as before.
I ran it for 5 mins and even with the electric cooling fan going it boiled and eventually stopped with the overflow tank spurting water over the distributor and shorting it out.

I am not sure which to do first.
strip out the radiator, a tricky 2 person job or remove the head to see if its cracked or has waterways blocked up?
There must be a simple explanation for the overheating and I would like to get to the bottom of it all!

I ordered new valve cover gaskets from the FS and discovered that the 2 that I originally ordered for a 34 were too narrow, and the casting marks inside and under the tappets indicated that the engine is at least a 35, are these 35 engines noted for overheating in any way?
I now know that my car has 35 running gear and a 34 Holden body.....
Just a thought.
Peter

Peter
Cork type Gaskets quite often shrink when they dry out with age so soak them for a few minutes in warm water may well bring them to correct size.

I would pull the radiator (even though it is a pain) first as you should have it fully cleaned when you do the head anyway.

Tony