Damm it's Hot !!

Dave123 · Posted: Sun Jul 10, 2011 6:24 pm Post subject: Damm it's Hot !!

Cooling issues with my 52 308. Initially when road testing with the rebuilt engine the temp gauge would run between 5/8 & 3/4. Changed the thermostat (180 degs) and installed the modern non-Hudson style along with the plug at the top of the goose neck as recommended.
I didn't trust The temp gauge in the car or the sending unit for that matter, so I installed an aftermarket gauge with a capillary line, which requires no current at all.
Then I took the radiator in to have it tested, Turns out it's fine.
Engine is rebuilt, no cracks into the coolant passages, also the coolant tube in the block looked to be in good shape.
Fired her up this afternoon with the new temp gauge and she idles at 200 degs,...funny at highway speeds the temp rises, but if you bring the engine speed down as in idling in neutral the temp drops?
Tomorrow will try removing the thermostat entirely, next step is to pull the water pump I guess

51hornet · Posted: Mon Jul 11, 2011 12:55 am Post subject: Re: Damm it's Hot !!

Ok so in the soft plug you drilled a hole? correct?

Before you pull anything what is the engine timing at? Hudson flat tops will run hot if the timing is off. Make sure you timing is correct. Check it with a vacuum gauge to make sure its correct for your altitude.

I have fixed many a hot running Hudson by checking and correcting the timing.

When you rebuilt the engine did you pop the freeze plugs and clean out the water jackets and you pulled the cooling tube did you run a block cleaning brush in and out of that?

Let me know how the timing check goes. Also do you have a 7Ib cap on the radiator and its fine?

The not cooling down while driving but cooling down while idling makes me think you need to check that timing.

Dave123 · Posted: Mon Jul 11, 2011 8:24 am Post subject: Re: Damm it's Hot !!

Soft plug has a hole.
I timed the engine as per my Hudson shop manual. Initially I used a timing light then road tested, accelerated hard in high gear at about 28 mph advancing the timing until a slight ping can be heard, then retard until the ping goes away.

The use of a vacuum gauge for timing I'm not familiar with, how does it work?

The shop that did the machine work on the engine replaced the frost plugs and boiled the block. I will contact them and question how thorough they were regarding cleaning the water passages etc.

New 7 lb radiator cap

51hornet · Posted: Mon Jul 11, 2011 12:00 pm Post subject: Re: Damm it's Hot !!

Lemme look up my vacuum gauge pdf and send to you.

Sounds like you did right thing on block cleaning. I like boiling out but I also use brushes as well.

Dave123 · Posted: Mon Jul 11, 2011 4:27 pm Post subject: Re: Damm it's Hot !!

Tried the ignition timing adjustment again, if anything I left it a bit advanced (still pings under load) although I didn't connect a vacuum gauge. In any case it still ran hot, 200 degs.

I removed the thermostat, which seemed to resolve the issue, at highway speeds it now runs too cool, 150 degs.

This to me indicates a faulty thermostat?, which I just bought.
Right away I noticed a huge increase in coolant flow through the radiator with the thermostat removed compared to a hot engine (with thermostat) with the rad cap off.

I guess the next step will be to source out an OEM Hudson thermostat.

On another note I'm not confident the vacuum retard for the distributor is functioning as it should. It seems like I have to run the engine timing quite retarded in order to stop the pinging. With a timing light it is about 2 degs before TDC, it sounds so much better with a bit more advance, 6 - 8 degs

51hornet · Posted: Mon Jul 11, 2011 6:21 pm Post subject: Re: Damm it's Hot !!

Also use a 160 degree not a 180.

Sounds like the vacuum pot is bad or the vacuum port is not putting out enough.

Put a vacuum gauge on it and see whats up.

Dave123 · Posted: Tue Jul 12, 2011 9:41 pm Post subject: Re: Damm it's Hot !!

How much movement should the vacuum pot on the distributor have?
Mine is working, removed from the distributor and connected to a vacuum pump, it has about 1/8" of travel...Doesn't seem like much travel

51hornet · Posted: Wed Jul 13, 2011 1:20 am Post subject: Re: Damm it's Hot !!

Yeah should be a little more than that.