To run with stat or not?

[motorclubaa]

Hi all
I am a member of the Marden Motor Club, a small village in the south east corner of England. The Club was donated a 1929 AA Recovery truck (it has a crane on the back) in the early '60s and has been running it ever since. The engine was changed not long after the acquisition, due to frost damage, for the smaller 14hp version This was extremely hard work, any hill was a nightmare crawling up in 1st or 2nd. So at last we had the original 24hp engine rebuilt at considerable expense and have been sorting this for the past couple of years.
The problem we have now is whether a thermostat should be installed in the pipe leading to the top of the radiator. We recently took the truck out with stat in and after a mile or so there was water and steam everywhere. So we took the stat out and all appears ok except that it runs rather cool, between 50 and 70 degrees C depending on the engine revs. I should have said that the rebuild included a nice new water pump. We have a piece of pipe with stat and a piece without stat, so it's a quick change! Also which way round should the stat be fitted? We guessed the steaming was due the the stat sticking, but in a saucepan it worked fine opening and closing nicely. One day I'll work out how to get a picture on here because the truck is pretty unique. By the way it was made here in England in Manchester, having checked all the numbers.
What happens in the States, do you run with thermostat or not??
Colin

[Stakebed]

I would leave it out, never had it originally.

[macswoods]

Welcome to the AA forum, nice to hear from new members. I a 29 Tudor with one, but my 29 AA does not both run OK. If you use the thermostat
try drilling a bypass hole in the side, have done it and it helped. All depends on the temperature in your area. There is a LOT of information on
this site and a bunch of great people. Mac.....

[AAholic]

I installed a t-stat in my '31 in part to restrict the flow in an effort to give the coolant a little more radiator time.
I've seen impellers that were modified allegedly for the same reason.
I can't say that it's made all that much difference though I haven't had any overheating issues to speak of.
The one thing that seems to make the biggest difference is a good (AA) radiator.

[1crosscut]

Hi Colin,

Welcome. It does seem as though you are running on the low side as temperature goes. As far as orientation of the thermostat generally the spring is on the engine side of the flow. Two down sides to a low operating temperature. Poor fuel economy and not getting the oil heated up enough to evaporate moisture and various contaminates out of the oil / engine. Since we are not into these old trucks for the fuel economy one needs just to be mindful of the moisture issue.
When you had the thermostat in and it was spewing water did you check the actual temperature of the water at that time? The reason I ask is quite often the radiators on the A's and AA's get over filled and water will come out making many think it is over heating when actually it is spitting water out from being too full. Make sure it is actually overheating by checking the water with a cheap meat thermometer. If it is not and is still spitting out water let it spit for a while and see if it settles in at a lower level. As long as the tubes are covered you will be fine.
We would enjoy seeing pictures of the truck. The pictures will have to be made smaller to be posted on this site. Here is how I do it:

Open your picture for editing. I use Microsoft Office Picture Manager.
Click on "Edit Pictures"
Click on "Resize"
In the Predefined width x height box select "Web - Large"
Click “ok”

Then "Save As" in a different file for posting. If you just save it your original picture will be changed so be careful of that. Once made smaller you can’t go back bigger.

Then at the bottom of the forum page click on the Attachments tab and then the Add files button and select your picture(s)

[KimVanOrder]

I havea '28 and have had troubles with over heating / steaming / spitting water. Here is what I found.

New radiator required after excessive radiator cleaning. ( Vinegar will clean everything out. Even what was plugging the holes) !!

New water pump impeller

No thermostat, let it run as cool as it wants.

Water / coolant. 50% antifreeze and two bottles of " Water Wetter " . The water wetter is what did the trick. Also water level is just barely over the top of the tubes in the radiator. It will find the level it needs. Don't over fill.

I drive it almost every day in the summers now with no more issues.

KVO

[motorclubaa]

Resize IMG_0872.jpg (136.07 KiB) Viewed 6343 times

Thanks for all your helpful replies. My mate and I have chatted this through and think we will run without stat, seems to be the safest thing to do, and try blanking off part of the radiator, with cardboard to start with until we are comfortable with engine operation. Apart from local runs our next big target is the annual London to Brighton run which is organised by our Heavy Vehicle Society on May 1st, this means a round trip for us of about 150 miles. The Truck has done this run several times over the years and we always look forward to it. The finish is on the seafront at Brighton, for those that don't know this around 50 miles from London.
The photo is a recent one, the white cable is charging the battery!
Colin

[macswoods]

Wow , sounds great. NICE looking truck ! Take some photos of your trip and post them .Us across the pond would like to see them. Mac..

[KimVanOrder]

Good; You don't need that stat. And I am very envious of you guys. Sound like a great drive. How fast will your truck run down the road?

KVO

[motorclubaa]

Hi,
Well after your good advices we took the truck out today for a run and covered some 65 miles with no problems at all. We ran without thermostat, BUT we covered around 40% of the radiator at the bottom, just with cardboard at this stage. It ran well, temperature when nice and hot around 80C and fairly steady. Up a long hill this might rise to 90C max, and down a longish hill it dropped to 60-65ish. Ambient temperature was around 7C so this is pretty cold by our standards, in fact just as we drove into Rye they had just had snow, a real surprise for southern UK these days.
The newly rebuilt engine makes a huge difference, it sales up an average hill no problem.
We visited a small harbour town on the south coast - Rye - stopped for a coffee, checked the engine out etc and drove home.
We appear to have a small problem with the timing slipping, the screw in the centre of the dizzy just loses it's grip and the timing slips maybe 30-40 degrees!! Any ideas for stopping this? I wondered about glueing wet'n'dry back to back and cutting a small 'washer', would this hold do you think?
Also we need to make the rad mask a bit more professional, perhaps also easily reduced in size for warmer weather, tatty cardboard doesn't really "cut the mustard". In the good old days a leather version would have been 'de rigeur'.
Colin

[KimVanOrder]

Just for jollies, try running it with nothing in front of the radiator. Let it run as cool as it wants to. I'd be very interested on how that works. ( I think it will be swell). As far as the slipping timing, Hum. you could try "Loctite". BUT, I would think getting spotlessly clean and then lock it down.

BTW If your talking about the 'cam' that opens the points that is slipping, they have a bunch of ridges on the bottom to grab into the shaft. Maybe time for a new one??

Good luck. We just got 14 " of snow last night.

KVO

[1crosscut]

Glad you had a good run with your truck. Sounds like it was a lot of fun. The temperatures with the cardboard on it sound pretty good. It would be great if it would run those temps with the cardboard removed. Since the ambient temperature was fairly cool for your drive you might be in good shape for general warm weather driving. How are you checking the temperature? Do you have a gauge installed? I use a dial meat thermometer placed directly into the water. When I started driving my truck I checked the temperature quite often until I got comfortable with how it ran. Now I just use it to help others figure out their temps.
Your idea of using the wet and dry sand paper to stop it from slipping is very out of the box thinking and it could possibly work. Go ahead and give it a try while you are waiting on the replacement cam and screw. It is pretty unusual to have timing move after it is set.