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pace
07-04-2005, 11:21 AM
My TR3B overheats at highway speeds but not when I am tooling aroung town. Any suggestions?

Andy Blackley
07-04-2005, 11:27 AM
Sounds like a partially blocked radiator. Has it been back flushed lately? If not, try that first.

pace
07-04-2005, 11:39 AM
Radiator is about two years old. I have flushed and reflushed plus when I installed new piston sleeves and piston this winter, I cleaned all the rust out of the engine. I am stymied.

SeanTR3
07-04-2005, 12:03 PM
Is it possible that the thermostat is not opening?

Paul Johnson
07-04-2005, 12:10 PM
Yes, check the thermostat, and you might consider checking radiator flow as well, because new doesn't always equate to good. Hose off the bottom, and then with a hose in the top, see that the drain is as fast as what goes in.
Another possibility, though slim, is that the fan is on backwards, attempting to push the air forward into the radiator. At a stop or slow, it could work, but at speed the ram effect would counteract.
Good luck, and be sure to file a report when it's sorted out.

pace
07-04-2005, 12:18 PM
Paul, funy you should ask about the fan because I was just out checking to see if it was on backwards. How can you tell? I put a piece of paper on the front of the radiator and it stuck but I am not sure this is a good test. Can yo look at the fan and tell by some reference points such as which side should the round side of the blade be looking from the engine to the radiator?
I have good flow thru the radiator and have blocked off the bypass so all water goes thru the radiator. I have replaced the thermostate and I can tell when it opens by watching the temp guage when driving in the city.

Kurtis
07-04-2005, 12:38 PM
Pace,

When you say it overheats, what exactly do you mean? Does it actually boil over? Where does it run on the temperature gauge?

Try cheking the drain plug on the block. Open it up and see it coolant flow out freely. If it dosen't, you could have some blockage in the block itself.

Good luck!

pace
07-04-2005, 12:46 PM
My temp guage is in centigrades and when it starts to overheat, it goes to the second hash which I would guess is about 95-100 centigrades and then I pull off highway and drive slow until it cools back down. The plug on the side of the engine flow freely since I cleaned the inside of the block out this winter. I have not let it heat up to the point where it boils over. It will just sit and gurgle when I shut it off. Maybe I should just keep driving so I can see how hot it is going to get. I am waiting on a reply about the fan. That may be the problem.
Thanks for your input.

Mike

Paul Johnson
07-04-2005, 01:06 PM
[ QUOTE ]
How can you tell? I put a piece of paper on the front of the radiator and it stuck but I am not sure this is a good test. Can yo look at the fan and tell by some reference points such as which side should the round side of the blade be looking from the engine to the radiator?


[/ QUOTE ]

Sounds like a good test to me. You could also scotch tape the top of a piece of paper to the back side and see if the airflow pulls it away. Looking at my car for reference, from directly over the fan blade, the front of the blade is at the front left, and the blade rear is at the right rear.
Also, do you have the radiator shroud on? If not, then the air flow at speed could simply be floating around the sides of the radiator rather than through it.

Edited portion - forgot to mention to ensure ignition timing is correct. Ten or so degrees too high, or very low (after TDC) will make it run hot.

Kurtis
07-04-2005, 01:14 PM
There’s no way a sheet of paper would stick to the front of your radiator if the fan was turning backwards. I’d say your fan is installed correctly.

My TR4 has a centigrade thermostat as well, and typically hovers right at the second hash (the top of the “normal” range) during the summer at interstate highway speeds (65-70 mph). It drops closer to the midway point at lower speeds (50-55 mph). This mark (on my thermostat) corresponds to around 195F based on my measurements of the coolant temperature with a candy thermometer.

As long as it doesn’t get any higher than the outside mark on the middle band (and you don’t have any other overheating symptoms), I’d guess you’re operating within the upper normal limits.

pace
07-04-2005, 01:39 PM
Paul
Standing in front of the car looking down, you say the "front of the blade is at the front left". Are you referring to the edge that is closet to the radiator is on your left? If so, my is on backwards.

Let me know. I sure don't look forward to pulling the front end off in this heat. Thanks for your help.

Mike

Geo Hahn
07-04-2005, 06:38 PM
[ QUOTE ]
Another possibility, though slim, is that the fan is on backwards, attempting to push the air forward into the radiator...

[/ QUOTE ]

Even if you mount the fan 'backwards' it would still move air in the same direction. Think about it a bit... only way to change air flow is to reverse direction of rotation.

Guess you could say whichever way you mount a TR fan... they still suck.

vettedog72
07-04-2005, 06:50 PM
Change the thermostat. All new parts are not perfect. If the new thermostat is not the problem, then keep it as a spare.

Alan_Myers
07-04-2005, 09:40 PM
Hi,

Since your overheating is occuring at highway speed, I rather doubt it's the fan causing the problem. The fan serves little purpose over approx. 50 mph. The movement of the car is pushing air into the engine compartment and would likely overcome any reversed fan (which is impossible since it pulls air through the radiator either way it is mounted). I also doubt an auxiliary electric fan or a TR6-style plastic fan (8 blades) would help. These fixes are most effective for TRs that tend to overheat at idle and at slow speeds.

If you have checked the radiator as described above, also is it the type with the hole in the middle so a hand crank can be used to start the engine? If it has the hole, it's about 20% less efficient than the radiator without the hole. The only fix is to have it re-cored without the hole, or replace it with a repro or used radiator without the hole. I've heard of people adding tubes to TR radiators, during a rebuild, to help them be more effective. And, there are expensive aluminum radiators available that would likely improve effectiveness quite a bit.

Here are some other ideas.

1. Check that the gauge and sending unit are accurate. Best way to do this is to test them in a pot of water on the stove, with an accurate thermometer to compare. Alternatively, switch them out for good ones. It is entirely possible the car is not overheating, the gauges are simply inaccurate. Alternatively, some folks have had good success using those "non-contact" therometers, such as is sold by Radio Shack ($50-60, I think) or racer suppliers ($300 - $700 and up, but a much higher temp range and more accurate).

2. Radiator shrouds are missing, replace them, they are critical to most TRs, direct the air to the radiator, rather than letting it pass around the radiator.

3. Wrong type of thermostat. Try to get one of the "sleeved" thermostats. Moss is selling reproductions for under $40, but they seem to be out of stock right now. TRF may have some, but price seems to be a lot higher, around $70. These prices are ridiculous for a t'stat, but TRs (and some other LBCs) use an older, special type that blocks the radiator bypass when they open. These t'stats are either specially made or modified, and that's why they are so expensive.

A more modern, "standard" or sleeveless t'stat will allow a lot of water to go through the bypass even when the engine is fully warmed up, instead of through the radiator. The bypass returns coolant to the engine without being properly cooled.

All the available sleeved t'stats seem to be 160F or "Summer" rated. That's okay, it really doesn't matter except in the Winter if the car is running *too* cool to make the heater effective (like it's very effective to begin with).

An alternative if you must use a modern, sleevless t'stat is to partially block the bypass hose. This can be done by inserting a tight fitting plug in one end of the hose, perhaps with a 1/4" hole drilled to allow *some* water to pass, then reinstall the hose as normal. In conjunction with this, it might be necessary to drill some small holes in the t'stat flange will allow a bit of water to pass while the engine is warming up (might already have a bypass of this type). It's not a good idea to run a TR motor without *any* t'stat in place. It will almost always overheat. Racers used to heat the t'stats until they were wide open, then jam them in that position, so that there was still some restriction in there.

Yet another alternative, if you want to try to run without a thermostat entirely, is to put a restrictor sleeve in place of the t'stat. These are hard to find, but occasionally show up on eBay and elsewhere. The car will warm up slower with one of these in place, and might actually run too cool if the car is not driven hard.

4. Check that the carbs aren't running too lean. This can cause the engine to run hotter than usual, particularly at speed on the freeway.

5. Check the radiator cap and/or install an overflow bottle. On your car the cap should be 4 lb. rated (as dictated by the heater core, which can't handle higher pressure) and probably 1" tall. Sometimes the neck on the radiator is replaced and most newer ones are 3/4" tall. In this case, you'd need a 4 lb., 3/4" cap. If you don't have a heater installed, you could get a TR4 cap, 7 lb., which would give a bit better cooling.

The original style cap has a rubber seal only on the bottom. When system pressure gets high, this allows coolant to simply escape out the draiin, onto the ground.

Modern rad caps often have two seals, one on the bottom, the other just inside the cap to seal at the top flange, as well. These can be used with a catch bottle, which is kept about 1/3 full when cold, and will actually allow any coolant pushed out while driving and caught in the overflow bottle to be drawn back into the radiator, once the engine is shut off and the system begins to cool. This helps keep air out of the system and the radiator topped up.

6. Install an improved type of water pump. Ken Gillanders at British Frame & Engine sells these in the U.S. Might be able to special order through Moss (Moss Europe sells them). More expensive than the originals, but have 6 curved impellors that help the coolant move better and are less prone to cavitation at higher rpms, when compared to the original straight, 4-bladed water pump fitted to the cars. If you have a good water pump, you can just get the impellor and press it on after removing the old one. The entire upgraded pump costs about $170.

7. Use a coolant mix which is 25% anti-freeze and 75% distilled water. Most directions suggest 50/50, but that will have less cooling effect.

8. Add Redline "Water Wetter" to the cooling system. It helps reduce temps overall.

9. I hate to suggest it, but you mention doing some engine rebuilding lately. How was the block cleaned out? If not done carefully and thoroughly, it's possible that some flakes of rust got stirred up and have now found their way into one or the other passages. Of course, I hope this isn't the case! The fact that cooling is effective at lower rpms seems to indicate that the system is circulating and *not* plugged in any way.

10. Are there any engine modifications? Higher compression will make an engine run hotter and put more demand on the cooling system. Headers will increase underhood temps, when compared to stock, cast exhaust manifolds, and can lead to cooling problems. To reduce this have mild steel headers ceramic-coated, while stainless headers can be wrapped.

11. Adding an oil cooler might help. If you do, be sure there is a thermostat installed in the lines leading to it, as well. Otherwise, an oil cooler can overcool, which is almost as bad as overheating the oil.

12. How many miles are on the engine since it was rebuilt? It's not uncommon for the rings to take a while to bed in, which might make the engine run a little hotter due to increased friction. That's one reason to take it a little easy while a fresh rebuild is breaking in.

Let us know what you find out.

Cheers!

Alan Myers
San Jose, Calif.
'62 TR4 CT17602L

Paul Johnson
07-04-2005, 09:53 PM
[ QUOTE ]
Paul
Standing in front of the car looking down, you say the "front of the blade is at the front left". Are you referring to the edge that is closet to the radiator is on your left? If so, my is on backwards.


[/ QUOTE ]
I was standing behind the blade, but looking down, so I guess we're looking at the same thing.

Couple folk suggest it doesn't matter which way the fan is, and I usually defer to these comments, but I'm not so sure this time. First, I know for certain that we used to get in trouble with Minis because of exactly this issue. Second, and perhaps there is a pilot out there to help us, isn't it the case with variable pitch props that you completely reverse the pitch to enhance braking? You guys have my curiosity up now, but if I'm wrong it won't be the first lifelong truth that has been shattered for me, and I'll still sleep at night.

Bill
07-05-2005, 10:44 AM
I'll tell my cooling story just to make you feel better.
My 59 TR3 has a TR4 engine so the cooling problems are the same. Mine was always overheating in the summer. I live in Florida so that is most of the time. I had changed the car to rack and pinion steering so I had to change the fan to an electric which I put on the lowest setting. In order to fix it I had the radiator re cored and the engine flushed and cleaned. I took the tempature adjuster out of the fan and it runs all the time. I also installed a second "pusher" fan with a controller that comes on about 195 degrees. All of this cost about $500 and it still ran hot. I finally bought a $6.99 thermometer and stuck it in the filler neck, I found out my temp gauge was 20 degrees off.
Knowing this I can say the car always ran fine.
My advice is to spend the $6.99 first.

Dave Russell
07-05-2005, 11:59 AM
[ QUOTE ]
[ QUOTE ]

Couple folk suggest it doesn't matter which way the fan is, and I usually defer to these comments, but I'm not so sure this time. ---- isn't it the case with variable pitch props that you completely reverse the pitch to enhance braking?

[/ QUOTE ]
It usually DOES matter which way the fan is mounted. True that it will move air in the same direction when mounted either way. However, the blade contour is non symetrical to optimize flow for one direction & it will be less efficient if mounted backward. Yes - The actual pitch has to be reversed to obtain braking. Something that is impossible to do on an automotive fan.
D

Geo Hahn
07-05-2005, 12:27 PM
Agreed -- there is a correct front & back to almost any fan, whether a fancy curved airfoil or those fairly basic paddles on a TR. My point (as Dave noted) was that you would not change the direction of airflow if you reverse the fan... perhaps a somewhat counter intuitive notion.

I would start by verifying the real temp then reviewing all the basics outlined here (timing, rad shroud, blocked rad or passages, etc.) as yours is not the normal over-heating pattern.

pace
07-05-2005, 01:02 PM
I want to thank everyone for all the suggestions and leads you have given me to solve the overheating problem. It is truly a wonderful feeling to know you have a place to go when you have a problem. If and when I solve the problem, I will let you know. Again, thanks.

Mike Pace

bobh
07-05-2005, 07:26 PM
Another possibility is that the engine is running lean at speed. You can install an air/fuel ratio meter to monitor the ratio.
In addition to the suggestions for increasing the cooling capacity and performance. You may want to consider an oil cooler. One of my looooong term projects is a 1951 Ford pickup. The truck uses the famous Ford Flathead engine. In one of the old books I've read the author said that the oil in a flathead is responsible for 40% of the engine cooling. The TR3 engine is a little more modern than the flathead so the amount of cooling supplied by the oil should be somewhat less. But it still does contribute. Adding an oil cooler should help.
By the way, B&M has a series of transmission cooler they market as "Super Coolers". One of the designs is almost identical in size to the coolers sold in the popular TR kits. The B&M cooler is polished and sells for around $50. We put one on my brothers TR250 this spring when the old one sprang a leak. Other than having to buy a few fittings (NPT to hose barb) it was an easy swap. Before we ordered the B&M unit I checked with B&M about the pressure. They said their Super Coolers are OK for use as oil coolers. Infact the oil cooler kit they sell uses one of their supercoolers.

Radford
07-05-2005, 07:39 PM
[ QUOTE ]
I finally bought a $6.99 thermometer and stuck it in the filler neck, I found out my temp gauge was 20 degrees off.
Knowing this I can say the car always ran fine.
My advice is to spend the $6.99 first.

[/ QUOTE ]

Start with the simple things...this is awesome advice.