Contact the Authors: “Tiger Tom®” Ehrhart and Chuck King

The following explanations, facts and plots provide supporting details for the article published in Tiger East/Alpines East Rootes Review and other marque newsletters.

The additional charts on this site illustrate some of the more significant variables we were able to quantify. Our intent is to show the more significant differences of the various variables we measured.

Our Appeal

We ran out of hot weather and our testing is incomplete. However, these tests have helped identify the key areas for improving cooling on a Tiger and Alpine as well. Building on the variety of information and experience gained, we can now focus on more specific objectives to improve cooling.

In the Summer of 2001, we are prepared to identify and quantify more specific improvements. We plan to test a variety of Fans/Radiators/Pulleys/Water pumps/Shrouds/Air restriction and ideas that you make available to us. The ideas can come any time. But we need the physical items for typically a couple of weeks in the heat of the summer so we can include them in our comparison test. We will do our best to coordinate testing with the availability of the components.

General Test Program Notes

1. Idle tests were run until engine temperature reached approximately 215 ° F, the point at which the fuel began to boil in the carburetor fuel bowl and affect the idle speed, AND/OR the temperature stabilized within one degree for three consecutive two minute measurement intervals.

Air Flow Enhancement

1. A Ford C9DZ-8600-A Maverick 6 cyl cut down to 14″ diameter was used for most of the testing. It is our opinion that the actual idle temperatures and times would have been lower and longer respectively throughout the tests if a more standard 15″ Maverick fan had been used. However the outcomes of the various tests clearly identify significant improvements even when using the 14″ fan.
2. An enclosed fan shroud fabricated from a Ford Taurus shroud was used for much of the testing in this test program while using a 14″ Maverick fan. Airflow testing shows an enclosed shroud does improve airflow through the radiator. Our enclosed shroud was not as deep (front to back) as a stock shroud. This provided an improved axial and radial position relationship with the fan blade over stock with respect to radiator/fan gap and blade tip and shroud edge. We also know that a 15″ fan can flow considerably more air than a 14″ fan. We ran out of hot weather and were not able to incorporate the enclosure principles into a stock shroud and test with a larger diameter 15″ fan. We are not providing data on this arrangement because the fabrication modifications of a stock shroud and performance measurements have not been completed.
3. Airflow testing of the Derale # 17015 fan indicated its performance was significantly superior to all other fans tested. Unfortunately we were unable to compare its performance at idle and interstate speeds because the hot weather left us. We know it performs better and recommended it accordingly. We plan to quantify its performance in the summer of 2001.
4. The sheet metal brace located across the lower front of the radiator obstructs approximately 10% of the radiator surface area, about three rows of tubes. We recommend it be removed. We have done some testing without this brace obstructing the radiator. Our best results are without this brace in place. The addition of additional bracing and a deflector at the base of the radiator to the bottom of the valance are believed to offer improved cooling. However, we have not done a comparison test at idle or interstate speeds to quantify the effect. We plan to do a comparison test in the summer of 2001.
5. Engine compartment venting: Using streamers to identify air flow at idle, we observed large amounts of hot air EXITING the engine compartment and reentering the front of the radiator from two distinct sources. The openings in front of the horns and the gap between the radiator and crossmember.
   At highway speed the openings in front of the horns adversely effect cooling because air is forced to ENTER the engine compartment. Consequently air expelled from the radiator is reduced because it must compete with the additional volume of air to exit an already restricted engine compartment. Blocking the opening in front of the horns is a valid old time Tiger cooling improvement that should be first on the “To do” list.

Plot interpretation

These plots are intended to demonstrate specific issues as explained by comments with each plot. Values and differences shown on the plots are for reference purposes only. They indicate significant difference(s) or interactions between a given variable or variables as measured. The reader should not attempt to extrapolate data for any reason from a plot. There are significant testing factors that must be factored into the meaning of the data that may not be apparent to the reader. For this reason, the reader is encouraged to contact the authors for additional explanations or detailed test data used to create the plots. Our interpretation is provided for each plot. Of course, you may have some of your own………but be careful.

In general, the plots clearly show that there is no one fix for cooling a Tiger. Efficient cooling requires a balanced cooling system design related to water and air management. It is a common practice in the Tiger community to focus on radiators for improved cooling. Clearly, as evidenced from our results, radiators, high tech or Godzilla monster of any kind do not provide significant cooling improvement with out lots of airflow. Our studies support the need for improved airflow. Airflow is a complex process of interactions between the radiator, fan, shroud and overall body constraints. We have made strides in identifying key areas to improve and have noted them in this report.

Improved Tiger cooling can be expected over a stock cooling system when a variable shown on a plot that produced significant improvement is incorporated in a Tiger, but the magnitude may be different than that shown on the plot. Maximum cooling will be achieved when all the changes listed in the Summary of results are implemented.

Reminder

When evaluating your cars cooling performance, verify the temperature sending unit, instrument voltage regulator and gauge provide accurate results as a system before making decisions, bragging or complaining about effectiveness of your cooling system.

General Plot Notes

When reviewing the plots, keep the following in mind:

1. Many plots show only the upper portion of the temperature/time spectrum since the purpose is to only compare differences at the extremes (temperature and Time).
2. The test # provides traceability to detailed test data used to create plots.
3. Some plots have multiple variables with emphasis only on the most significant outcome. Remember, each test measurement evaluated only one variable. The reader should contact the authors if additional interpretation is desired.

• Stock VS Air Flow Enhancements
• Interstate Driving LOOP Better Performers
• Interstate Driving LOOP
• RADIATOR Comparison
• FAN Comparison
  Flexlite 1314 VS Maverick
• Open/Closed Hood & Increased Air Flow VS Radiator Change
• Radiators VS Increased Air Flow
• Water Pump Pulley
  Stock VS ’81 Fairmont 6 cyl.
• Radiator / Crossmember Gap
• Redline Water Wetter
• Electric Fan Comparison

Variables Tested

Radiators

• Stock
• Griffin Single row Aluminum, Single pass (1 1/4″)
• Fluidyne, Single Row,Triple Pass (2″)
• FX Single Three Row Single Pass (1 7/8″ )
• CX Core Four Row, Triple Pass (2″)
• CX Core, Four Row, SinglePass (2″)

Pumps

• Stock stamped steel paddle
• Milodon Hi Vol, #16230 (Fits Tiger but requires longer mounting bolts, causes fan to be closer to radiator than other pumps, inlet close to fan belt)
• Stewart Hi Vol Stage 1, #16103, Mfg. claims 41% incr. vol.

Pulleys

• Stock: 5 7/8″ Diameter
• About 1978 to 1982 Ford Fairmont 6 cyl: 5 3/16″  Diameter (Pump hub should be pressed on 1/8″ further than stock location. Pulley fits standard Ford 5/8″ shaft.. Pulley hole must be enlarged to 1″ if used on a stock Tiger water pump hub)

Stress cracks emanating from mounting holes on Tiger water pump pulley are becoming more common. The problem is acerbated by the addition of increased radial loads from alternators, air conditioning, etc. Reinforce the hub in this area or change to a Fairmont hub, which already has the proper reinforcement.

Shrouds

• Stock
• Custom, fully enclosed: Fabricated from “Junk Yard Dog” Ford Taurus by Chuck King

Fans: Electric

• 10″ dia, 4 blade, Summit equiv # SUM-G4910
• 12″ dia, 10 blade, Perma-Cool # PRM-19008
• Other “Junk Yard” specials (See airflow data)

Engine Driven
(After-market fans fit 5/8″ Ford water pump shaft. They require enlarging to 1″ if mounted on a stock Tiger water pump with a 1″ hub.)

Stock Alpine I-II & increased pitch

• Stock Alpine I-II & increased pitch
• Stock AlpineV & increased pitch
• Stock Tiger
• Flex-a-lite #414 14″ diameter
• Flex-a-lite #1314 14″ Diameter
• Imperial #221615 15″
• Diameter

Derale #17015 15″ Diameter


Maverick 6 cyl & increased pitch
• Ford C9DZ-8600-A Maverick 6 cyl. Cut down to 14″ diameter
• Ford C9DZ-8600-A Maverick 6 cyl with increased pitch

Temperature vs. Time

Interstate Driving LOOP Better Performers

Click on the image for a larger one

These were the best Interstate performers.

Originally printed 9/78

Many Alpine and Tiger owners have expressed concern over inefficient heater ­defrosters. This problem is not so much one of design but of attention to details. Please note that none of the heater cores, except Tigers from #38200001 (Mark IA), are sealed in any way to the body at the blower air-intake aperture. Although this seal is shown for Tiger Mark IA on, it is often found to be missing. To obtain maximum efficiency from your system, the following items should be checked and adjusted, repaired or replaced as necessary:

1. Heater cores that have been subjected to radiator sealers, Stop Leak, Barrs Leak, and others generally become partially blocked across the bottom tubes. Flush or replace as needed.
2. Check the water control valve actuating cable. Be sure that the valve is opening fully. Adjust as necessary. See illustration.


Fig 1

Fig 1

3. Install cold weather (winter) thermostat. Minimum 185 F.
4. Seal the heater core to the blower air-intake aperture if your vehicle is not so fitted. Any medium dense foam or rubber strips or cut sheet (weather strip or typewriter pad) will work very well. The jute padding strip between the heater core cover and heater core side tanks must be left in place to prevent the holding stays on the under side of the cover from wearing a hole in the top of the core side tanks.
5. Inspect defroster hoses for tight fit (taped on) and freedom from kinks or crushed spots that would restrict flow.
6. Inspect all firewall plugs and seals. Where these are missing, duct (racer) tape works well if the proper plugs are not available. Also, a small strip of body sealer will help if the steering column seal is loose.
7. Inspect convertible (hood) top/hard-top to door glass for proper fit (seal). Adjust or replace as necessary.
8. Check the heater blower motor current draw. It should be less than ten amps.

Once having completed the preceding checklist, the heating system will be operating at its maximum efficiency.

As an added note, all Alpines and Tigers prior to series V Alpine and Mark IA Tiger have small vents between the crash pad and the dash face at the extreme outer edges. These should be sealed during cold weather. In addition, remove blower motor and inspect the inlet screen. Leaves and pine needles often collect there and block the air now.

by Phil Lindsay
Originally printed 3/80

Since my Tiger has to sit through commute-hour traffic snarls, I am always looking for ways to control overheating without resorting to obtrusive external modifications like hood louvers.

The stock Tiger hood latch is set up with a “safety catch” which holds the hood after the striker bolt has released. It has always seemed that when the Tiger was in hot weather, it would run a little cooler with the hood “propped open” in the safety position. This is especially true at slow speeds when the hot air gets trapped in the engine compartment.

I decided to attempt to improve on this “natural” Tiger cooling method. The additional cooling action occurs because hot air can escape out the small gap between the hood and the car body due to the safety catch. The size of the gap depends upon the dimensions of the safety catch mechanism and the stiffness of the spring that surrounds the hood striker bolt.

I have extended the length of the safety catch hook by approximately 1/2″. I fabricated the new hook from 1/16″ mild steel and brazed it onto the existing hook. Since the new hook is slightly longer than the stock hook, I had to provide a cut-out next to the striker plate for clearance when the hood is fully closed.

The coil spring on the hood striker provides the spring tension that holds the hood open in the safety catch setting. The stock spring is too weak to work with the modified safety catch, so it is necessary to install a stiffer replacement.

Remove the old spring by unscrewing the striker bolt and visit the local hardware store. The new spring should be stiff enough to hold the hood open in the safety catch position and yet be able to compress when the hood is in the fully closed position.

The final adjustment of the modified hood lock consists of adjusting the length of the striker bolt so that the hood remains firmly locked in the fully closed position. It is also important that the new, extended safety catch hook properly mates to its latch on the striker bolt assembly.

Finally, it is important that the safety catch release when the hood control is operated. There is a fair amount of trial and error work in order to make it all work. With this set-up, my hood opens far enough that hot air can escape from both the sides and back edges of the hood. When the hood is fully closed, there is no gap and everything appears “stock.”

by Phil Lindsay
Originally printed 3/80

When your Tiger is crawling along in slow traffic, the under hood temperatures can go out of sight. All of the engine cooling aids such as aluminum intake manifolds, header pipes and extra large radiators depend upon dumping their heat into the engine compartment. What’s needed is an under hood cooling system to remove this heat build-up when there is insufficient road speed to pull the hot air out of the bottom of the engine compartment.

There are several ways to do the trick, ranging from the obvious hood louvers to exotic exhaust fan systems. Since I try to keep my Tiger stock in outward appearance, I choose to provide cooling ports without the addition of hood or fender louvers. With the aid of a chassis punch (the cup and die type used in the electronics industry), I made a series of 1 1/4″ diameter holes in the wheel well area.

Although a hole saw would also work, the limited access might be a problem unless the engine compartment was stripped clean. The chassis punch provides a very smooth edged hole that will work well with a rubber grommet plug. The diameter of the hole should match the grommet size. I was able to locate grommet plugs with a 1 9/32″ diameter so I selected a hole punch with a 1 1/4″ diameter. Obviously, if you don’t drive your Tiger much in the rain, you don’t need the plugs. I use the plugs only during the heavy rainy season (November – April).

The number and location of the cooling ports probably isn’t important as long as the hot air can escape. I have approximately 16 holes on each wheel well and in order to avoid weakening the wheel well, I spaced the holes at least an inch apart.

Try not to place the holes directly in line with the electrical connections on the generator voltage regulator or starter solenoid. After using this set-up for over 2 years, I am convinced it works.

Lots of hot air can be felt around the front wheel wells when the Tiger idles. I doubt that the ports are effective at highway speeds due to the air turbulence created by the tires. Although the wheel well cooling ports are easy to do and don’t change the stock appearance of the car (at least from the exterior), the approach is a bit messy and may not appeal to everybody.

The punch and rubber grommets may be obtained from the following:

Punch: Model 730 Round Radio Chassis
Greenlee Tool Company
2136 12th Street
Rockford, IL 61101

Grommet Plugs: 1 3/4″ diameter
AA Rubber and Plastics
2960 25th St.
San Francisco, CA 94110
415-826-3740

Model 963 Rubber Grommet Plug
Atlantic India Rubber Company
571 West Polk St.
Chicago, IL 60607

Call or write for current price and availability information.

The venerable Joseph Lucas Ltd. has done it to us again. The infamous 4TR regulator used on the Series V Alpine has been changed from a three (3) terminal unit (Figure 1) to a newer four (4) terminal unit (Figure 2). Both units are electrically the same as far as use in the Series V is concerned. Just reconnect wires as shown in figure 4. DO NOT connect any wires to the + terminal of the four (4) terminal unit when using this unit in a Series V. As a safety precaution be sure power is off i.e., no voltage is present at the wires to be connected to the regulator. To be sure, you should disconnect the battery.

from CAT

Most of those numbers we have published for Tiger radiator hoses are good, but there is one number that is not. Do not, repeat, do not order Dayco No. 71016 for use as a lower hose. It’s too small in diameter.

Numbers for hoses that do work are as follows:

All will require some cutting to fit and, as you can see, the upper is an easy match.

by Kent Williams (CAT)

Ford makes a 6-bladed metal fan that is the same diameter as the stock 4-bladed unit. That fan is PN C9DZ-8600-A. The bolt pattern and hole size are correct, but the center hole must be drilled out to 1″ diameter.

Before installing, spin the fan to see that it clears the rack housing. I had to remove a small amount from each blade by grinding. Check balance carefully. I have used this blade for several years and have had no overheating at idle or low speeds here in the Texas heat.

Editors note: Only the rear corner that interferes with the rack needs to be removed, not the whole blade length.

by Phil Lindsay

In my experience, the stock Tiger cooling system provides adequate cooling of reasonably stock engines under most driving conditions. Notable exceptions are freeway snarls and slow hill climbing on hot days (especially when behind a Winnebago). Obviously, both of these exceptions occur when the airflow through the radiator is primarily due to the fan, since the “Ram” airflow is minimal due to the low car speed.

The stock Tiger was equipped with a conventional shallow-pitch 4 bladed metal fan. Much has been written on the advantages of replacing the stock fan with a high performance fiberglass unit.

One fiberglass fan, which has been used, is the MODEL 214 Green-Bladed Fan made by Flex-A-Lite Corporation, Tacoma, Washington. This fan moves almost twice as much as the stock fan at idle, engine speeds and 70% more at cruising speeds (3000 RPM).

Flex-A-Lite has developed a stainless steel bladed fan with even higher capacity than the fiberglass-bladed fan. Compared to the fiberglass fan, the new stainless steel fan, MODEL 1314, flows 25% more air at idle and 20% more at 3000 RPM.

Since everyone knows that “you don’t get something for nothing.” It’s therefore worth pointing out the disadvantages of this “Super-Fan.” Other than requiring slightly more engine power, the problem is proper clearance between the front of the fan and the radiator, as well as the back of the fan and the upper radiator hose. If you have a stock radiator (2″ thickness), there really is no problem because the fan can be spaced away from the water hub with flat washers to clear the hose. In this case, the fan hub hole (7/8″ diameter) pump does not have to be enlarged to 1″ diameter since the washers will space the fan away from the water pump hub.

Those with “Fat Core” (2-3/4″ thickness) aren’t so lucky! In order for proper clearance between the back of the radiator and front of the fan, it is necessary to carefully ream out the 7/8″ fan hub hole to 1″ so it will fit over the water pump hub. With the fan located against the water pump hub, be sure there is sufficient clearance with the upper radiator hose, especially if the vacuum advance distributor mechanism is in the way.

The Gates MODEL 20686 upper radiator hose can be cut so that there is clearance. Once properly installed, the MODEL 1314 Fan has provided a significant improvement in cooling for a number of “Hot Tigers.”

by Gary Durborow

I would like to tell you about a few do’s and don’ts that I have to explain almost daily to customers at the shop. Each is carried out easily and, although it may cost you more initially, can save you tenfold later.

1. When you change the engine oil, change the oil filter.

   This is rather important. After all, you change the oil to remove the dirt and contamination that has accumulated in the engine, right? Well then, the oil that is contained in the oil filter does not drain with the rest of the crankcase fluid. It stays in the filter. When the filter is left on, you are effectively putting a quart of dirty oil back into the sump. The five or six dollars you spend for a filter is easily offset by the decrease in engine wear experienced with clean oil.

2. When the ignition breaker points are replaced, also replace the condenser.

   Believe it or not, a condenser becomes accustomed to a given set of points. The two parts wear almost equally. The job of the condenser is to regulate the amount and polarity of voltage entering the point set. If you’ve ever noticed a small tip forming on one breaker face of the points, this is a sign of condenser problems. That tip is actually metal from the opposite face and is moved from one side to the other due to incorrect polarity. This is also a good reason not to file the point faces. When you remove the build-up, you actually are widening the gap because the metal is missing from the opposing side.

3. Don’t leave the thermostat out.

   Too many times when the thermostat is suspect, it is removed and not replaced with another. The idea behind the thermostat is to regulate the temperature of the engine coolant. In order to do this, it governs the speed at which the coolant is supplied to and from the radiator. Without the thermostat in place, this cannot be accomplished. The coolant will be moved only by the water pump and by natural convection. At idle, the coolant hardly moves, and at higher speeds it moves too fast. This allows far too much in the way of temperature variation. As it is, the coolant is kept at about plus or minus 10 degrees of the thermostat rating. Without a thermostat this can vary much more either way, and operating an engine too cold can be as harmful as running it too hot.

4. Always use antifreeze year-round.

   This is especially important on engines with aluminum cylinder heads, as an Alpine has. Antifreeze is not only meant to keep from freezing in winter, but also to dissipate heat in summer. Plain water cannot come close to the same effectiveness. Antifreeze also contains additives to help fight corrosion in the system. This corrosion can be extremely detrimental to aluminum. The cylinder head can be eaten away to the point that it can be used only as a boat anchor. With antifreeze selling for about $6 per gallon, and a good used cylinder head going for about $100, it’s not hard to see the savings. By the way, not all brands of antifreeze are compatible with aluminum. Not all of those, which are compatible say so on the container either. To be sure, stick to using one of the popular brand-name types.

So, you see, spending a small amount of extra time, effort and cash now can spare you a major headache later.