Duncan Jolly Posted June 23, 2004 Report Share Posted June 23, 2004 TR3a Overheating There have been a number of articles about TR3a’s overheating just lately. But what is the real cause and the right solution? I have been plagued with various overheating problems since owning my TR3a and all have been traced and rectified – from leaks, to blown head gasket, blocked rad and faulty water pump. I have successfully run the old girl for the past year with no problems. Now I have severe overheating again. All the common causes have been checked by me and a well known TR garage including cleaning and back flushing. Everything is OK. But I still overheat once in traffic. A bigger more powerful electric fan has been fitted, the bypass blocked off (original sleeved thermo has been removed) all to no avail. I have even butchered my grill to get more air in Once hot she will not cool until on the move again above 50mph. I am now devoid of ideas and cannot think of any logical reason for the overheating. Unless there is some new cause e.g. the spec of unleaded fuel changing in the past 6 months. I have been told of two other 3 owners with similar symptoms, so I suspect a common cause – but what is it and what is the solution? Quote Link to post Share on other sites
Dave Herrod Posted June 23, 2004 Report Share Posted June 23, 2004 Duncan, I am still trying to get my car in a state of tune that I'm happy with, but I have noticed that it is very sensitive to fuel quality and seems to pink far more with some fill-ups than with others. I do play around with the vernier retard on the distributor and have found that if I retard it so that she doesn't pink when pulling hard in a (too?) high gear the running temperature drops significantly. So, I would recommend that if you get any pinking at all, retard the ignition and see if the temp falls. Good Luck Dave Quote Link to post Share on other sites
clive Posted June 23, 2004 Report Share Posted June 23, 2004 Have you put the pieces of cardbopard in that emulate the shape of the TR2's front air duct? The TR3a had an overheating problem untill they added these as the air found it easier to by-pass the radiator rather than go through it. Quote Link to post Share on other sites
Duncan Jolly Posted June 24, 2004 Author Report Share Posted June 24, 2004 Thanks all, Yes I have the cardboard duckting in place. I do not get pinking but i have tried retarding by 2 deg and no discernable difference. She does run on a good deal after ignition off which i believe is a problem with unleaded. I do use Optimax. I have determined that the gauge is reading 10 deg high, however when she goes off the scale she boils over anyway so one does not need a gauge to judge that - and yes i have the correct pressure(new) cap. Going to fit new gauge anyway so I know whats what from the cockpit. cheers ps see you afloat Alec? Quote Link to post Share on other sites
james christie Posted June 24, 2004 Report Share Posted June 24, 2004 Hi Duncan, I have noticed that my 3a runs a little warmer now that she's unleaded, but certainly no overheating. Sounds like your problem is mechanical rahter than chemical I find that mine is very sensitive to the brew I use and even if we are lucky enough to have "98" octane everywhere here in France , the true octane varies enormously and I almost have to retune each time I fill up or she can sometimes pink quite alarmingly. Running on is an intermittent but frequent problem too Quote Link to post Share on other sites
Don Elliott Posted June 29, 2004 Report Share Posted June 29, 2004 Canada banned leaded petrol in 1990. Since then (over 82,000 miles) I have had to run with un-leaded. My TR3A gets hot but holds at 185 degrees when driving at 65 mph for long distances when the air temperature is about 20 degrees C. If the ambient air temperature is 35 C, the gauge will read up to the next line which is about 210 degrees F. I run a 50/50 antifreeze mix and water. Running with more water (less antifreeze) will give you better heat transfer and it will run cooler. You can also try "Water Wetter" which is quoted to improve the heat transfer rate. I never remove my radiator cap when the engine is hot. That's too dangerous. I rarely need to add water to the rad. I have never tracked down any conection between un-leaded and over-heating. And I never re-adjust my distributor setting. I run a 12" diameter 10-bladed Kenlow schrouded fan which I manually switch on when in traffic. If I see it up to the next line, I switch on the fan and in a minute or two the temperature is back down to 185 F. Don Elliott, Original Owner, 1958 TR3A, Montreal, Canada http://mysite.wanadoo-members.co.uk/trebor/don3a_big.JPG Quote Link to post Share on other sites
jean Posted June 29, 2004 Report Share Posted June 29, 2004 I think the running on problem is related to the engine RPM at the moment you switch off the ignition, at least this is what I experienced on my TR3A. In idle the engine normally turns at around 1k rpm and switching the ignition off, the engine will run on. Bringing the RPM back to 7 - 800 the engine will stop at once. As the throttle linkage is rather stiff I put the tip of the foot under the throttle pedal and slightly pull it back to lower the RPM before cutting the ignition, no run on Jean Quote Link to post Share on other sites
unclepete Posted June 29, 2004 Report Share Posted June 29, 2004 Duncan, you don't mention whether you run on unleaded with an addative or had your engine converted to unleaded. my leadhead 3a has a standard kenlow with a rheostat set to operate at 185deg and never misses a beat, even in traffic with 30 deg outside air - on standard unleaded with a Castrol lead and octane booster. One thing 2/3/3a/4 engines are prone to is airlocks - no ammount of replacing bits will sort this, i use clives tip to great success - open the heater valve - run the engine with the cap off - wait till the bubbles stop - turn off engine - top up if required and away you go - simple! its worth trying befre spending vast ammounts on pumps, head gaskets, adiators etc. peter Quote Link to post Share on other sites
svs451 Posted July 4, 2004 Report Share Posted July 4, 2004 Hi I have had similar problems over the years in the end the fix was to srip the engine and remove 40 years of rust and crud from the water jacket. Plus a new (not in line) recored rad and a ford fan which I made to fit on the back of the rad complete with a cowling so that it actually draws air through the rad!! Drop me a line if you want more details on the fan? Regards David Quote Link to post Share on other sites
Duncan Jolly Posted July 6, 2004 Author Report Share Posted July 6, 2004 Once again thanks all for your contributions. It certainly appears to a common topic this time of year. To answer some of the questions asked; I am running on unleaded. My engine was rebuilt 5K ago,with unleaded head and fast road cam. All the waterways were chemically cleaned. All carboard duckting is in place, a new pump is fitted, I have correct pressure cap. A new heavy duty elelctric fan has been fitted The Rad has been recently flushed with Rad flush and back flushed.I have also bled the system for air locks. There are no leaks, I have had it pressure tested, and the head gasket is OK The car actualy runs a dream if one ignors the temp gauge! Since my original post I have now fitted a replacement gauge that indicates that the original was reading 15deg F high, and has as yet not exceeded 200deg F. However I am still forcing water out of the overflow. A recent run to Gloucester she ran very well, but can you believe the new gauge did not go over 120deg F - not even normal temp yet I was "pressing on" as one does. However when I got home she pushed the ol hot stuff out and I had to put nearly a gallon back in today. .Bizare. The new gauge is now suspect I have decided that the old rad while passing water must be restricted by calcification. So my next move is to replace it with a thicker cored Rad. We will see how we get on... cheers all Duncan Quote Link to post Share on other sites
robgeev Posted July 6, 2004 Report Share Posted July 6, 2004 JUst bite the bullet and fit a new rad, since we fitted a new performance unit to Carl's, the damn thing almost makes ice! Pacet fan, 5 row fine pitch rad, Optimax+Castrol valvemaster or Millers octane booster. Also they go very well indeed. Timing-keep advancing untill it runs on, then back off untill it only does it after extreme abuse. Check vacumre advance retard in distributor is working correctly-advancing and returning smoothly. Good luck. Rob Quote Link to post Share on other sites
Guest mikemd Posted July 10, 2004 Report Share Posted July 10, 2004 Suggest you get a rad without the starting handle cutout, as this effectively reduces the available core by quite a large amount. Quote Link to post Share on other sites
Duncan Jolly Posted July 13, 2004 Author Report Share Posted July 13, 2004 New rad, sans starter hole goes in next week in time for Malvern. I like the sound of producing ice - now where did i put that bottle of malt? I will let you know how we do Cheers Quote Link to post Share on other sites
SirTK Posted July 15, 2004 Report Share Posted July 15, 2004 Much is made of the efficacy of the cardboard ducting panels so I really should have some, just in case. Is this a proprietory part or do I have to make them myself? Are there patterns available? Quote Link to post Share on other sites
marvmul Posted July 15, 2004 Report Share Posted July 15, 2004 Much is made of the efficacy of the cardboard ducting panels so I really should have some Absolutely correct : when the ducting is in place, without gaps between the radiator and the ducting, the fan is only needed when the car is stationary, even in hot wether. Quote Link to post Share on other sites
Dave Herrod Posted July 15, 2004 Report Share Posted July 15, 2004 Does anyone have a pattern or dimensions for this ducting? I have heard reports that the cardboard doesn't last too well (strange really considering its location!) and would like to try making something out of aluminium sheet. My car doesn't have the ducting at the moment and I do have to use the fan below about 40mph. I can't find any fixing details in the various manuals that I have. Can anyone help? Dave Quote Link to post Share on other sites
Don Elliott Posted July 15, 2004 Report Share Posted July 15, 2004 There is nothing in the manuals about the air deflector ducts, because when the TR3A was introduced, these cardboard air ducts were not part of the regular production. All TR3A's produced between September 1957 through to about July 1958 were not equipped with them. My TR3A was built on Feb 14, 1958 and when I bought it brand new in May, 1958, there was no air duct on it. The TR2 and TR3 had metalwork to direct and force all the air through the radiator. But with the wider TR3A grille and no air ducting, the air followed the laws of nature and aerodynamics and took the easiest path after entering the grille, The cooling air just flowed around and over the top of the radiator. There was nothing to force the air through the radiator which, if you think about it, forms a serious resistace to air flow with all those tiny spaces between the fins and water tubes. So when it got hot in the summer of 1958, TR3A customer/owners complained to their S-T dealers in hot areas of the world who then reported the problem to the factory. To correct the problem, I can visualise about 10 designers and engineers in Coventry brainstorming this urgent problem till the early hours of the morning. It had to be cheap. It had to be quickly and easily shipped to and installed by dealers at low cost. And it had to last past the 3000 miles warrantee period. But they work and are essential. They are available from any TR3A parts supplier for a few pounds. They come it three pieces and are held together with metal rivets like the ones you would find holding a file of papers together in a filing cabinet. You know - the brass ones with the ears that you fold out after putting the air duct parts together. I put mine in new in 1990 and painted them body colour like they should be. About 4 times during the last 14 summers of driving my TR3A, I re-sprayed them again. They still look like new after more than 82,000 miles. Don't waste your time trying to make your own. They come cheaper than what you will waste in time trying to collect the information, make them, etc. Don Elliot, Original Owner, 1958 TR3A, Montreal, Canada http://www.zen21606.zen.co.uk/Forum%20Gallery/don3a2_big.jpg TR Register member since 1987 Quote Link to post Share on other sites
marvmul Posted July 15, 2004 Report Share Posted July 15, 2004 I've seen nice radiator ductings made out of aluminium sheet. Like Don says, new cardboard one's are cheap, and I think you can't buy aluminium one's of the shelf. You have to make a template in cardboard, and than have it made in aluminium sheet by someone who has a sheet metal folding and cutting device(a roofer...). Be sure that the aluminium ducting doesn't rest against the core of the radiator. Perhaps you can buy aluminium ducting from Revington? Quote Link to post Share on other sites
Guest chris jameson Posted July 16, 2004 Report Share Posted July 16, 2004 Duncan, You didn't mention whether the overheating problem came on suddenly, or gradually became worse over a period of time.... I went through the overheating thing with my 3A rebuild, and after replacing the water pump a couple of times, having the rad rebuilt, fitting a six bladed fan and fitting the ducting, the thing runs at quite a moderate temperature (currently about 165 F in the Australian winter, with OAT of 16C). I don't know what the Optimax mix is like over there, but I find my car runs very poorly with Optimax...I avoid it like the plague. Have you tried running some of that gunk (can't recall the name) through the carbs which cleans the combustion chambers (and produces lots of smoke - don't do it outside the window)? Perhaps you have a bit of a carbon buildup, which could explain the running on. I agree with Jean, however...mine runs on if I have the idle at 1000 rpm, and the problem goes away at 800 or so. Grasping at straws, but you seem to have covered all the probable causes... Cheers, Chris Quote Link to post Share on other sites
Andrew Smith Posted July 16, 2004 Report Share Posted July 16, 2004 Hi Duncan I asked similar questions to you some time back after the engine rebuild on my 3A in November 03. My engine was rebuilt to 89mm with a lead-free head and suffered from intermittent overheating and air locks. Given that the rad, pump, hoses and waterways are all ok, these are the measures that worked for me and are offered as general advice: 1. Dump the thermostat: I was running with the original bellows fitted and I've still got a number of these new and boxed! 2. Cut out the centre mechanical parts from a modern wax type thermostat and fit it: this then acts as a restrictor and backs up the water allowing it to cool in the rad. Without it, the water would just pass through the rad limiting cooling affect. 3. Fit a restrictor in the bye-pass hose; otherwise the water will just circulate and "bye-pass" the rad for the most part. Without the restrictor there is a chance of creating local hotspots in the engine with consequent results! 4. For the restrictor, I used a washer with a 1/4" hole (GHF314 from Moss is ideal) or you could use a 10p piece and drill it with either 1/8th or 1/4". You will need to use a second jubilee clip behind the washer to keep it in place and prevent it slipping down the hose under pressure. Ensure the washer/coin is fitted hard against the bye-pass housing outlet inside the hose. 5. Use Shell Opitmax with Castrol Valve Master Plus, this reduces run-on in my case. 6. Fit a Kenlow or similar. I fitted a 13" Kenlow Blower 2000 Series (13/B); this works a treat and fits neatly on the rad and is supported by the internal lip on the apron. 7. Definitely fit the rad ducting, this is often overlooked as discussed in other posts: it's a must. 8. Finally, ensure the correct rad cap is fitted: 4psi with the correct length neck otherwise water will just deposit itself under your car via the overflow tube. At one stage I was considering fitting the TR4 expansion bottle, but haven't ruled this out entirely. With all these measures in place my 3A now runs at 170-180f with outside temps up in the mid-eighties and only in heavy traffic does the Kenlow need to come on now. I've set this at 185f. Hope some of this of use. Good luck Cheers Andrew Quote Link to post Share on other sites
jonlar Posted July 16, 2004 Report Share Posted July 16, 2004 Have you tried running some of that gunk (can't recall the name) through the carbs which cleans the combustion chambers (and produces lots of smoke - don't do it outside the window)? In UK, many years ago, you could buy a Redex applicator, which was the the same size as other instruments, and you could adjust the amount of Redex used. If you suspected sticky valves or or build ups, you were recommended to bleed neat Redex (proprietary upper cylinder lubricant) directly into the carb (air cleaner removed), which did solve some problems, but a total smog of white to light blue smoke would envelope everything in a better than James Bond style smokescreen. Quote Link to post Share on other sites
Duncan Jolly Posted July 16, 2004 Author Report Share Posted July 16, 2004 Chris, now if i lived in Aus I would have serious problems, if only because I don't do heat myself, give me a nice cool North European day anytime. The problems seriously maifested themselves after an engine re build with a fast road cam, + new HS6 carbs and needles. Once set up to get max umph she stared to get hot. I have backed advance of a bit, but do not wish to do so any more or reduce valve clearance as I will not get the benefit of the cam etc. I am keeping fingers crossed that new Rad will do it. The run on is a symptom of unleaded fuel. I have heard of anti run on valves that let air into the carb once teh ignition is off to weaken the mix but have not heard of anyone with one fitted? Oh the joys of classic motoring Duncan Quote Link to post Share on other sites
Andrew Smith Posted July 16, 2004 Report Share Posted July 16, 2004 (edited) Regards Andrew Edited May 26, 2007 by Andrew Smith Quote Link to post Share on other sites
robgeev Posted July 16, 2004 Report Share Posted July 16, 2004 Duncan I always thought it was courteous to at least acknowledge advice or help when offered, even if it was thought to be **** or missing the point. Regards Andrew Andrew, perhaps Duncan doesn't feel the conversation has ended? Rob. Quote Link to post Share on other sites
Andrew Smith Posted July 16, 2004 Report Share Posted July 16, 2004 Hi Rob Maybe, but then I'm always accused of being a bit "previous" by the "one that knows"! If that's the case Duncan, then my apologies to you sir for being discourteous. I'm off to Boston tomorrow on holiday, so there will no replies or posts from me after 6am until Sunday 1 August. Phew! All the best Andrew Quote Link to post Share on other sites
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