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TR2/3/3A Timing TR3A and Overheating

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David_Reaka

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I am new to the BCF. I have recently installed the Pertronix Flame Thrower Electronic Distributor and coil to my '59 TR3A. My query relates to the Static timing. According to an article by Ken Gillanders, static timing was the more accurate option than strobe (with the original distributor). Furthermore, he suggests 8deg advance rather than the 4deg factory suggestion. When I first installed the new electronic version last summer, I noticed the engine ran better at the 8deg (strobe used). I have the car running but would prefer to know the timing is correct. How does one perform a static timing check with the electronic distributor? I have "overheating" and want to eliminate all possible causes. In dealing with the overheating, I have recently installed the upgraded water pump (Moss) as well as the original bellows thermostat. Radiator is OK and flushed the system with Prestone product 4 times!! I have also replaced all the hoses and the connecting pipe. I have not checked the accuracy of the temperature sender unit nor the temperature gauge's accuracy. BTW car was overheating before any of the above work. I am awaiting a reply from "Pertronix"...Any comments will be greatly appreciated. Thank you, David
 
Does it have an origianl or replacement grill in it? Unless they have fixed the problem, the replacement grills have smaller holes in them and don't let as much air through as the original ones. Also the prestone flush might not be enough. It may be better to take the radiator to a shop to have it cleaned out, or there may be 50 years or crud and buildup in the block iself keeping it from circulating all through the system. Try opening up the drain cock in the side of the block and see if you get any coolant coming out, if so how clean is it?
 
Any further description of when it overheats?

Years ago, my Dad's TR3A would consistently overheat on the freeway. Tried all sorts of things, but the problem was finally traced to the carb jets & needles being worn. Setting the mixture by the book (at idle) would result in it being way lean at high speed cruise, hence the overheating.

I had a similar problem with my TR3A, that proved to be caused because the radiator tubes were no longer in good thermal contact with the fins. It flowed just fine, the radiator shop gave it a clean bill of health; until I asked them to test it for thermal efficiency. After the recore, no problems at all.

For the timing, I recommend doing a "road test". Advance the timing until you can just barely make the engine knock (when hot) by lugging it in 4th gear (eg floor the throttle at 30 mph in 4th gear). Personally, I like to back off 2 degrees (one division on the vernier) from that point, just for a little extra insurance.

Have you checked that both the vacuum and centrifugal advance mechanisms are working?

If it isn't getting hot enough to boil, then it's definitely worth checking the gauge for accuracy. The original gauges frequently read high, especially if the engine has been overheated. Note that the original gauge is mechanical, it does not have a separate sender unit. The bit that screws into the thermostat housing is part of the gauge; there is actually a very small bore tube that runs through the spiral wire. Even a small crack in that tube will let the vapor escape and ruin the gauge.
 
Thanks for the prompt replies. Regarding the "vernier", the new distributor does not have one. Rad is ~12 years old. The car hasn't been used much since it was installed (< 1000 miles). I have had the car 25 years and it has always overheated - sometimes with coolant boiling out the overflow. Coolant floods out the Rad drain cock but is not nearly as enthusiastic in exiting the block. Coolant is clean at the block. Overheating occurs when weather is warm and engine is under "load". On the flat it will slowly creep past 185 (halfway between 185 and 207.5 - next gradation). Then as load is increased eg. hill it will hover just beyond 207.5 and continue to rise if engine is turned off at that point. Randall your comments about the carbs are interesting. That was going to be my winter project - rebuilding them. I will comment more when I hear back from Pertronix. David
 
I predict that Pertronix will tell you to set the timing "in the conventional manner".
 
David_Reaka said:
the original bellows thermostat.
Click to expand...
Might be worth checking that it is opening fully. The bellows thermostat relies on ether inside the bellows to expand and push it open; it's possible that some of the either has leaked out over the years and the thermostat no longer opens as it should.

Triumph later modified the design with a restriction in the bypass line and an ordinary wax pellet type thermostat (without the sleeve to block off the bypass). Many of us have chosen a similar path, either by converting to a TR4 thermostat housing (with the restriction) or adding a restriction ourselves.

I ran a pipe tap into the fitting on the water pump, so I could install a pipe plug with a 3/16" hole drilled in it. In addition, I drill a 3/16" hole in the thermostat backing plate (so some water always circulates through the radiator). Others have found that a copper pipe cap (3/4" I think, not sure) will fit snugly into the bypass hose, and drill a hole in that.
 
Welcome to the party, David! As you've already noticed, questions here get answered post-haste.

And we like pictures!

:cheers:
Mickey
 
Aloha David,

Here is a procedure to statically set up initial timing with your Pertronix. It has been compiled from several sources and with help from fellow BCF members.

TR Ignition Timing

Ignition timing is a poorly understood, very important and a frequently done wrong part of a tune up. While most distributors are designed to be timed with a strobe or an electronic timing light and running, the TR distributor is designed to be timed with a static light and with the engine stopped. If a Triumph 2 or 3 is timed with a strobe while running all you will get for your trouble is a poor running engine with badly retarded ignition timing.

Procedure with stock contact breaker point ignition system:
1. Remove the coil to distributor low-tension lead at the distributor, usually located in the distributor base and next to the cylinder head. Connect a static light (any 12 volt lamp) between the distributor terminal and a convenient hot lead (the battery will do).
2. Using either the crank or by pulling the fan, move the pulley around in a clockwise direction as viewed from the front. Place the hole drilled in the rear half of the pulley 3/8” to the left of the timing pointer. The timing pointer is attached to the timing chain cover, just off to the right of the centerline as viewed from the front of the car. DO NOT turn the pulley in a counter clockwise direction, as the crankshaft motion is not directly transmitted to the camshaft due to the timing chain tensioner. The fan must be moved in a smooth and continuous movement clockwise to the correct location.
3. Loosen the clamp at the base of the distributor and very slowly turn the distributor in a counter clockwise direction until the static light just comes on and then clockwise until it just goes out. This is the exact point of ignition and it is possible that the light may come on as you tighten the clamp, making it necessary to readjust until the light just goes out. Then reconnect the low-tension lead and you are ready to go. 3/8” measured on the circumference of the crankshaft is about 8deg, which is more initial timing advance than the factory recommends, the engine however seem to run more effectively at 8deg than 4deg of advance. Original: Ken Gillanders, January 1985. Transcribed by: David Templeton, June 29, 2002

Procedure with Pertronix electronic ignition
1. Set the TDC hole in the fan pulley as described above.
2. Fully connect the Pertronix module, coil, etc.; then connect a test light as follows: remove the black wire off the coil, and connect your test lamp from the black wire (negative ground cars) and a 12V source. With the key on (power to the coil & Pertronix), the test light will be on when the Pertronix is "on" (equivalent to points closed) and the light will be off when the Pertronix is "off" (equivalent to points open). The test lamp will only require about 90 mA to power and shouldn't cause significant heating of the module. Adjust the distributor as described above. Rather than running back and forth to the ignition switch to limit the "on" time of the Pertronix module... I simply unplug its red wire which is connected to my coil (+) terminal. CAUTION when the Pertronix is powered, around 4 Amps is flowing continuously through the module and if it overheats can burn out. Pertronix tech support says that "too long" is about 5 minutes. To be safe, try to limit yourself to 3 minute. In normal running the duty cycle is reduced so overheating is not a problem. Provided by Randall (TR3Driver) and Doug Lawson from British Car Forum
 
Oh, one more thought : Is the cardboard air deflector installed inside the front apron? The factory didn't install these on the early TR3As, but recommended that they be retrofitted. The deflector helps route air through the radiator, instead of letting it flow around the sides and top (where it does little for engine cooling).
 
Hey David.

As a fellow TR3A owner who had a chronic overheating problem for DECADES, I advise you to install an electric fan. The SPAL is the fan of choice here. I went with the SPAL fan and have, so far, been very happy with the results.
 
Hi Randall
Any photos of the modifications you described in this post? With those mods, do you run a regular thermostat and not the bellows type? Installing my water pump this week so this is timely for me.

Pat
 
Sorry, Pat, I didn't think to take any photos. But others (Geo Hahn I think) have posted photos of the pipe cap, in recent other threads. And yes, the point is to run a regular thermostat instead of the bellows type. Actually, my TR3A did OK with a regular thermostat and no restriction, but it had several other mods (10 psi cap, Modine core, electric fan, etc)

IMO the various fan modifications are only useful if your overheating problem is at low speeds (like stop and go traffic). For anything over about 30 mph continuous, the "ram air" effect should be plenty; and the fan is pretty well useless over 45 mph. It just doesn't move enough air to even begin to keep up with the higher heat output at higher speeds.

I recently replaced the original fan with a 12" Hayden electric on the TR3, but only because I was having trouble in extended traffic jams in 90+ weather. Most days it never even comes on during my usual commute to work.

Yet another point : some of the reproduction water pumps have much smaller impellers than the originals. Haven't had the problem myself, but I've heard that they can cause overheating problems. It's also possible (tho not very likely) for the vanes to erode away; so if nothing else works, it might be worth inspecting the water pump impeller.
 
Dave,I have always prefered a dynamic timimg light for accuracey and dont see why this would cause motor to be retarded,unless using the static,no vacuum setting,which you mentioned would be a problem.
I like that a dynamic light because it lets you check the advance throughout the range.
Is the the desired advance curve available to compare readings with a light so that advance ,either mechanical or vacuum ,or the combination of both can be checked at idle and redline,or max advance?

Still reading on what little info I have on the stock dist.
Thanks
Tom
 
I have recently been experiencing an more pronounced over heating issue. My car has done the typical over heating when the outside temp. is high and I'm idle ling or going slow for some period of time. However recently have seen temps. driving that are climbing. from what I've read here I have to wonder if flushing my block might be a good idea. I remember in an older post Randall or someone describing a process that was used to get as much junk as possible out of the block. can anyone help me with that.
 
TFB said:
Dave,I have always prefered a dynamic timimg light for accuracey and dont see why this would cause motor to be retarded,
Click to expand...
The problem is that the original centrifugal advance curve starts below idle rpm, but only the "no advance" (aka "static") timing figure is given. If you look at the workshop manual, you'll see "initial" centrifugal advance given as 0-2 degrees at 200 rpm. Although the book isn't particularly clear on the point, I believe those numbers are given in terms of advance and rpm at the distributor, which of course turns half the speed of the crankshaft. So in crankshaft terms, that is 0-4 degrees advance, at 400 rpm.

Since idle speed is higher than that (mine doesn't like to idle below about 800 rpm indicated), there can be an appreciable amount of centrifugal advance present when timing with a light.

(On a side note, I believe the low initial advance rpm, combined with the low static advance, was to help ensure the engine could not "kick back" when starting with the hand crank.)

The numbers are available in various places, but of course first you have to identify which distributor (and which vacuum advance) you have. There were several different distributors installed by the factory, plus of course many replacements have been done with some other model of distributor. (Did you know that a MG Midget distributor will fit and run? :laugh: )

Here is some partial information that I gathered from various sources:
Centrifugal advance and plots
Vacuum advance numbers

Then of course, the next question is whether those numbers actually mean anything today. I'd guess that there are relatively few TRactor motors that are totally stock (who can resist those oversize liners when doing a rebuild), and of course the fuel we have today is quite a bit different as well. The book says "Premium fuel of 95 octane (research method) or higher must be used" ... where are you going to buy that? This is why I feel that the "road test" method is much better.
 
ekamm said:
I remember in an older post Randall or someone describing a process that was used to get as much junk as possible out of the block. can anyone help me with that.
Click to expand...
That was probably me. What I did was to drain as much coolant as I could into a bucket (for proper disposal later), then open both drains (radiator and engine block), remove the upper radiator hose, remove the heater valve (actually just a plug on my engine since I don't have a heater) and install a garden hose-to-NPT adapter into the heater valve hole. If you have a heater, you may want to disconnect or cap the return line on the LH side of the engine.

Then I connected the garden hose and let it run full force. Once the water ran clear, I used an ordinary blow gun to blow shots of 150 psi shop air in through the drain valves. It knocked an amazing amount of stuff loose from inside the radiator and engine block.

I have in the past gone as far as removing the liners and taking a wire brush to the inside of the block, but this method was much easier and seemed to get the desired results. I probably should repeat it, though, as it's been a year and the coolant has turned brownish again.

Note that, although the driver's handbook implies that antifreeze is only needed in freezing weather, it should actually be used year-round. The anti-freeze also contains corrosion inhibitors, that prevent the thermostat housing and radiator joints from being eaten away by electrolytic (dissimilar metal) corrosion. Since the inhibitors work even when the engins is not running, and they do wear out over time, the coolant should be changed every 2 years (or as recommended by the antifreeze maker, seems like Prestone is now recommending 5 years even for their "green" coolant) even if you don't drive the car.

Purely for entertainment, here's a shot of what happens when the coolant doesn't get changed for 30 years:

DSCF0013.jpg
 
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