Category Archives: Tech Tips

M1 – Installing an Additional Gauge

by Stu Brennan

If you’re like me, and you want to know as much as possible about what’s happening with the systems in your car, then you have probably considered adding an extra gauge. I wanted to add a voltmeter, but where should it go? I didn’t want to hang it under the dashboard. I already had an ammeter, so the onl  spare hole in the panel was the clock opening, covered with the blockoff plate since the clock was not present. But, the hole was too large for the standard gauge size.

The solution was simple. The clock blockoff plate is made of two sections; a metal ring and a plastic disk. The disk is held in place by some little metal tabs. Carefully bend up the tabs, and the disk comes out.

Now you have a choice. The gauge body will fit through the clock ring, but the gauge’s trim ring won’t The easy way is to install the gauge is to drop it in through the ring, widen its U bracket and you’re done. I didn’t like the way it stuck out, so I chose to mount it to the ring from the rear.clock

I bent the tabs that held the disk to the gauge in place behind the ring. They are not strong enough to do the job alone, so I used a “hot melt” glue gun to secure it I really globbed the stuff on, making a complete ring around the gauge and fully immersing the tabs. This glue sticks to itself well, but doesn’t do as good a job sticking to other things.

With the complete ring and the immersed tabs, it holds together well. But if I ever want to remove the gauge and replace the disk, it should all come off easily. To be cautious, I didn’t tighten the U-bracket nut too much.

With the ring and the gauge’s trim polished, the size difference is noticeable, but not remarkably so. It’s far less obvious than the front mounted option, and it certainly makes the panel look more complete. And the price is right.

Additional note: The Smiths voltmeter I used had been salvaged from a TR-6. The inner portion of its trim ring was painted black. This paint came off easily and the whole thing polished up nicely with some Simichrome. The pointer was white, so while things were apart, I used some Testors orange to make it match the other Tiger gauges. I didn’t try it, but a “black ring” gauge might look good behind the polished blockoff ring, also.

L1 – Tire Selection

by Steve Hansen

Now that our Alpines and Tigers are between twenty-five and thirty years old, they are probably not riding on their original 6. 00 X 13 Dunlops any longer. Still for those who may be interested in upgrading their Sunbeam’s shoes, a short primer on some of the considerations involved may be in order.

The original tires on our Alpines and Tigers were the state -of- the-art for their day: Built with the latest nylon or rayon cord construction, they had an aspect ratio of 80, that is the tire’s sidewall height was 80% of its width. Later advances in tire technology brought the so- called “wide oval” bias ply tire (for example “A 78 -13″), with an indicated aspect ratio of 78%, and the first- generation radial ply tires, which introduced us to metric tire width designations (for example” 165SR 13″, where 165 refers to the tire width in millimeters – in this case, just under 6 1/2″. The “S” designation refers to the tire’s maximum speed rating, in this case 112 -MPH. “R” is just shorthand for “radial”).

More recent developments have included the introduction of tires with lower and lower aspect ratios- such as the “70- series” tire (185/70SR 13, for example) and the still wider and lower “60- series” (205/60HR 13). Careful readers will have noted the “H” speed rating of this last example, indicating a safe maximum speed of 130- MPH.

All of the tire sizes I’ve listed can be successfully substituted for the Sunbeam’s original 6.00x 13 rubber provided that wheels of the correct width and offset are used. Wheel width should be obvious, however the term “offset” refers to the distance between the wheel’s centerline and the mating surface where it contacts the hub. Further, offset can either be positive (wheel center line inboard of mating surface) or negative (outboard of mating surface). Standard Alpine and Tiger steel wheels have a positive offset of 1 – 1/8″. It’s important that this original offset be matched or closely approximated when replacement wheels are fitted, otherwise wheel bearing life and static wheel balance can be negatively affected.

Another recent trend in tire/wheel upgrading is the “plus” concept, in which the original wheel diameter is increased by one or two inches (so -called “plus one” or “plus two”). This enables the use of lower aspect ratio tires while approximating the overall diameter of the original tires, to which the speedometer is calibrated. Generally speaking, if a “plus” wheel and tire package is desired, the overall diameter of the lower- profile tire should be within about 2 1/2% of the original. (For those of us who are absolute sticklers for detail and function, a knowledgeable speedometer shop can fabricate a small gearbox to attach to the back of your stock speedo so that its gear ratio can be increased or reduced to match the different diameter of substitute tires!)

According to one major manufacturer of radial tires, the following tire sizes are direct conversions for the 6.00 x 13 originals on our Sunbeams. The italicized wheel rim width represents the rim used for measurements only. It is strongly suggested that candidate replacement tires and wheels should be checked on the car, if possible. Neither the author nor the Editor assume responsibility for verifying proper clearances under all operating conditions!

Wheel Rim SizeRange Tire Size
4", 4-1/2", 5", 5-1/2" 165 SR 13
4-1/2", 5", 5-1/2", 6", 6-1/2" 185/70 SR 13
4-1/2", 5", 5-1/2", 6", 6-1/2" 185/70HR 13
5-1/2", 6", 6-1/2", 7", 7-1/2" 205/60 HR 13, -VR 13
5", 5-1/2", 6", 6-1/2" 185/65 HR 14
5", 5-1/2", 6", 6-1/2", 7" 195/60 HR 14. -VR 14
5-1/2", 6", 6-1/2", 7", 7-1/2"205/55 VR 14
5-1/2", 6", 6-1/2", 7" 195/65 HR 14, -VR 14
5-1/2", 6", 6-1/2", 7", 7-1/2"205/55 VR 14
5-1/2", 6", 6-1/2", 7", 7-1/2" 205/55 VR 15
6", 6-1/2", 7", 7-1/2", 8", 8-1/2", 9" 225/50 VR 15
6-1/2", 7", 7-1/2", 8", 8-1/2", 9"225/50 ZR 15
6", 6-1/2", 7", 7-1/2", 8" 215/50 VR 15
5-1/2", 6", 6-1/2", 7", 7-1/2", 8" 195/50 VR 16
7-1/2", 8", 8-1/2", 9" 225/45 VR 16

B1 – Heating Solution No. 999

The original Heating Solution No. 999 published in 1980, and No. 999 revisited in 1981, 1983 and 1984, have assisted dozens of Tiger owners in the U.S. and Canada resolve their overheating problems. Here is the latest information on what some call the “INDIANA CORE.”

Increased cooling with the “INDIANA CORE” is provided by the use of small scoops or louvers cut into the fins between each radiator tube. These louvers force the air to circulate inside the radiator a longer period of time, allowing it to remain in contact with the fins longer and exchanging more heat. This louvered design is now used by all radiator manufacturers in custom cores. One of the concepts in core design is the use of staggered tubes. Instead of having three, four, or five tubes running across the radiator one in back of the other, they staggered the tubes front to back each slightly below the one in front. This allows for more tubes per inch of depth and, in turn, more water volume and flow.

The cores mentioned in this article are manufactured by Mangum and are available throughout the U. S. The Mangum core uses 1/2″ tubes on 5/8″ centers. Your stock Tiger core is 18 5/8″ high, 15 1/2″ wide and 1 3/4″ deep. The replacement R series core in the stock dimensions is a three tube design with 11 continuous fins per inch. The tank plates are 2 1/8″. Experience has shown that the replacement of your stock core with the stock dimension Indiana Core could give you 5-10 degrees improvement. For those who need additional cooling, the next available step is to a 2 3/8″ core. This core has four tubes for an even greater capacity and additional flow. The tank plates are 2 1/2″. This radiator should handle the majority of street Tigers short of all-out extreme racing conditions. Installation of this core should not require modification to the radiator bulkhead. The brackets on the radiator are set 3/8″ to the rear from the stock location to allow for the radiator to fit deeper into the bulkhead. This fitting allows for fan to radiator and radiator to rack and pinion clearance.

ARADAC core is now available from North Side Radiators. This core is 2 1/8″ deep with 4, 1/2″ tubes on 1/2″ centers. It provides the same amount of flow as the 2 3/8″ Mangum core but in a shallower package, for those of you who want a very stock appearance. The cost is a considerable increase over the Mangum, but if originality is a concern, it is an alternative. This radiator was installed in the Harrington-bodied Sunbeam Tiger with excellent results. The custom radiator people at North Side Radiator are familiar with the Tiger radiator and the cores available. When shipping your radiator, in­clude your name, address, phone, and the core size, and 11 louvered continuous fins per inch. Turn-around time has been running about two weeks. The price is still reasonable, and the service quality. One of the biggest advantages of this modification is that it is a tum key setup. The radiator comes to you ready to install.
Don’t hesitate to call me with questions or problems. Barry Schonberger

T1 – Preparation of Production Sunbeam Tiger Solo II/Pro Solo

by Barry Schonberger with Bob Jardine and Tom Patton

In 1975 STOA reprinted an article by L.C. (Bud) Bohrer, the 1974 SCCA Solo II “B” Prepared National Champion on “How to Autocross a Prepared Tiger.” To this day, that article (see attached) remains an excellent reference for preparing a Tiger. In the 14 years since that article was published, SCCA Solo II rules have changed considerably (they even let us run tube frame cars), so a few comments are in order. My reference points for this article are two MK I A’s and an MK II that have won consecutive Divisional Championships in competitive SCCA Divisions and one SCCA National Championship. Preparing a car is like climbing Mt. Everest; the goal is to get to the top, but there can be a wide variety of successful paths taken to get there.

Suspension

Start here before you invest big dollars in your engine. All of the power that money can buy won’t get you around the course unless you can get the power to the ground and make the car handle. Starting with the front end, don’t hesitate for a minute to reinforce and rebuild the cross member as to the specs in Tom Hall’s and Torn Ehrhart’s tech tips. The stress that the front of the car will take when you bolt on race rubber is well beyond the original design. Pay special attention to the welds around the shock tower and A arm bushing sleeves. Check the threaded plates where the lower A arm attaches. Don’t hesitate to tack weld the upper ball joints in place. Also, you must reinforce the sway bar clamp bracket slot in the lower arm. (Tom Patton failed to defend a Divisional Championship one year because of this failure). A strip of metal welded across the top will do the job. All inner A arm bushings should be replaced with a solid material impregnated with a lubricant. The solid bushings give the driver a much better feel for the road and eliminate the suspension settings changing as a result of the rubber bushing flexing. ‘The upper A arms may be lowered at the shock tower to obtain an improved roll center and improved camber gain. A 1″ solid or preferably hollow front sway bar set in solid bushings seems to do the job. I would recommend Koni shocks on the front set full hard. Because of the front wheel spring rate on a Tiger, the springs need all the help they can get a spring rate of 250 lbs. and custom 70/30 shocks would be optimum.

Concerning front springs, I found the CAT replacement springs acceptable when used with the rubber seats. I have known people to run them without the rubber seats to lower the car. A hard to get item, but one that makes a world of difference, is a quick steer rack and pinion as offered by Bill Miller in the 70’s. This unit reduces the lock to lock from 3.2 to 2.6 turns, providing a real asset in Solo. (This rack is no longer produced). Front-end alignment was 1.5 degrees negative camber, 3.5 degrees castor and 1/16″ toe out. Toe out helped the car turn in faster.

Current Solo II rules allow 12″, 13 “, or 14″ x 10″ wheels or 14″, 15 “, 16″ x 8″ wheels. The only two wheel sizes that are even up for consideration are 13″ x 10″ or 15″ x 8″. The reason for that is the availability of race tires from the major manufacturers. The current situation is not good. The 13″ tires are still being developed, but not for cars in the Tiger’s weight class. Only two companies have 15″ tires available with a third possible in the future. However, limited development is taking place in this area. The big advantage of the 15 ” wheel is the possibility of running bigger brakes. If you choose that route, however, you will be considered a GT spec car, rather than production, and may have to run the 10% weight penalty (not a good idea with a production car). The best answer seems to be a 13″ tire, 9″ to 10.0″ tread face by 20″ or 21 ” tire circumference. This tire is available from a number of manufacturers. When considering wheel offset, remember the stock front suspension geometry win only accept a 3.5″ backspace before the rim hits the rack and pinion arm. Most applications are only 8″ rims in the front because of this clearance problem. With a 10″ front wheel the offset is to the outside, causing scrub problems because of the design of the spindle and Akerman angles. (Look for new rules allowing 16″ X 10″ wheels in 1992.)

The rear suspension can take on a number of different configurations. I found that the forward spring mount needed to be reinforced. It’s very common for this area to be rusted and cracked. I used the CAT springs in their hardest arrangement. Bob Jardine uses stock springs with additional clamps on the front half of the spring to prevent spring windup. I tried a number of different approaches to traction bars before I discarded all of them and went to Ford Mustang quad shocks. Talk about eliminating wheel hop and being able to launch a car, these babies do the job! Brackets were fabricated for the inside of the frame rails and the axle tubes. Credit for this application goes to Bill Miller, who was familiar with the use of shocks as a torque reaction device on the Hollywood car. The rear axle was raised in the chassis using 1 ” blocks at the spring pads. Blocks could be eliminated by de arching the rear springs. This, in relationship to the front ride height made the car just a hair higher in back. Under acceleration, the suspension would even out. A new panhard rod running from driver’s side to passenger side was fabricated to allow for rear roll center adjustment. A 3.73 LSD with the MKII wide ratio transmission allowed for the car to be driven in only 2nd gear on most courses. Shocks were Sprax Adjustable, set on three clicks or in Bob and Tom’s case, Koni’s set full soft. The softer setting allows the power to get to the ground. I didn’t install a rear sway bar. The car only pushed in tight off camber turns and I would compensate by braking deeper in those comers and getting the rear end to come around. Both Bob and Tom used a 5/8″ rear bar. Stock springs and a bar just might have the same roll stiffness as the CAT springs. Bob likes the stock springs with a 5/8″ bar, because it “gives me a little more compliance on the rear with rough surfaces.” I ran a disc brake conversion on the rear, and Bob ran the LAT disc option, but we’re not confident that it helped in the Solo application. My rear wheels were 13″ x 10″ with a 4″ backspace. The car did have Gremlin metal flares on all four comers.

Brakes

Use a soft street Datsun Z car pad. No metallic or semi metallic, because they don’t heat up fast enough. Datsun pads give you a little extra pad area. Braided brake lines with an adjustable brake bias in the rear line were installed. Bob kept his brake booster, because “It is a lot easier to modulate the brakes if you don’t have to stand on the pedal!!” Bob also suggests “looking at Datsun for rear wheel cylinders that are direct replacements for the Sunbeam, but of different diameters.”

Engine

With the new rules, you can run a 302 bored out .047″ over with any head. This appears to be the hot ticket in the Tiger vs. small block Corvette game. A number of Tiger owners have installed SVO aluminum heads with success. Other full comp heads could be a problem when it comes to headers. For Solo purposes, you want your torque range to be very broad, i.e. low duration, high lift and possibly a split profile. Unless you use a roller cam, it is difficult to get this profile. Big dollar item, but could make the car very drivable in one gear. As a starting point, I found the General Kinetics Co. “Redline” hydraulic cam with 290 Duration 438 lift strong (this area needs more discussion). Because of the RPM range involved and the torque needed, the Edelbrock Torker II with a 600CFM double pumper was used, and time was spent timing the carb (see reference book at end of article). A good electronic distributor with a computer ignition will do wonders in Solo because of the ability to keep the plugs from fouling. If you want to save a little weight on the front of the car, use an early timing cover with the exposed impeller aluminum water pump. A bigger radiator core is a must, along with an electric fan upfront and 6 blade behind. An electric water pump drive comes in handy also to cool things down between runs. You are very limited when it comes to headers. The lack of space is your problem. A set of headers from CAT or J.C. Whitney will do the job.

Don’t go too radical with your compression ratio if you intend to drive’ on the street. Ratios in the 10 to 1 range give you the power without excessive heat and octane problems. Compression does help torque however. Oil control in comers is a problem with the small block Ford. For Solo purposes, a Boss pan and windage tray will solve most problems. However, the investment in an Accusump system is recommended. For Solo, you might have your engine builder set the engine up with pretty wide main and rod clearances. You don’t get much of a chance to warm the oil, and the clearance helps. Bob recommends a good oil cooler to help in cooling.

Engine and Transmission Mounts

Drill an extra hole and add a 5/16″ bolt to the driver side mount. Weld up a solid mount on the passenger side. Bob says enlarging the plate on the tubular transmission mount can control wheel hop. This restricts the movement of the rubber mount.

Rear End

The Dana 44 rear end is plenty tough for Solo. The Power Lock LSD is as tough as they get with its four spider gears. You might consider shimming up the LSD so that the release pressure is higher. Use a gear lube additive to control clutch chatter.

Clutch

Quick acceleration and engine braking are important elements to a successful Solo car. For Solo II, a double or triple disk, racing clutch is essential. With its lightweight (18 21 lbs.) and small diameter (7 9 inches), the racing clutch will make a significant difference. McCleod makes one of the best, followed by RAM and Quarter Master. The down side of this clutch is its in/out characteristic. There is very little feel. Starts can be a problem, it is not streetable and for a Pro Solo launch, you lose the weight of the flywheel. Use a soft diaphragm spring if available with not too high a ratio.

You might also consider an internal throwout bearing slave cylinder. Manufactured by Tilton, QuarterMaster and others, this item has proven to do the trick. Alignment and spacing are critical in the setup. Certain models only work with certain clutches because of clutch finger design.

Fuel Supply

A good Carter, Holley, etc. fuel pump with a constant 5 – 6 lb. pressure is what you need. Install a good, large capacity fuel filter because the Tiger fuel tanks will peel their lining. If you’re in a hot climate, consider a cool can to chill your fuel. It can be located where the brake servo once lived. The stock metal fuel lines are acceptable.

For additional information, don’t hesitate to contact me.
Barry Schonberger
(812) 985 9592

Ed note:
Does anybody have a copy of this article by L.C. (Bud) Bohrer, the 1974 SCCA Solo II “B” Prepared National Champion on “How to Autocross a Prepared Tiger.”
Use the contact form and let us know. We’d love to be able to reprint it here.
Thanks

M2 – Series IV, V, and Tiger Mark I and II Horn Hint

Over the years of use, the horn rings either break or they become bent to the extent that the horn ring hits the steering wheel spokes before it makes its internal electrical contact and turns on the horn. A broken horn ring can be replaced with one of the nice repro units being made. For bent rings there is an easy fix which can be done in about an hour.

What is done is that the horn ring is removed and reinstalled with 3 spacers under its mounting plate. These spacers could be washers for 3 small nuts like the 1/4″-20 size which you probable have in your parts bin (or they can be bought at the hardware store).

To remove the horn ring. first take off the padded center of the steering wheel. This padded wheel center is a press fit into the telescope adjustor ring. If you look around its edge, you will notice a small notch on one spot of its chrome. A thin bladed screwdriver can fit into this notch to pry out this padded wheel center.

Under this wheel center will be a bolt head with a washer under it. Remove this bolt with a 1/2″ wrench and then you will be able to wiggle off the steering wheel height adjustment ring.

With the adjustor ring off, you will see the metal center of the horn. There will be three screws, they may be Phillips head or regular slotted, which held the horn ring assembly to the black plastic hub. It’s under these three screws that we will put the spacers.

Remove the three screws and have somebody hold the ring in place as you prepare to put in the spacers. The reason to hold the ring is that there is a wire attached to the hom ring which goes through the steering wheel hub and onto a slip ring. This wire can get pulled off its spade connection on the slip ring if the hom ring is pulled away from the steering wheel (Don’t worry if this happens. Just remove the three screws which hold on the bottom of the black steering column cover and reattach the wire to the spade connection on the brass slip ring).

The only annoying part of trying to put the spacers under the 3 screws holes of the horn ring is that they will want to fall out of place as you reassemble everything. The last time I did this job, I used a model maker’s trick and tacked the three spacers into position on the metal horn ring with a few drops of Crazy Glue.

While you have the horn ring out of the wheel, you may also want to adjust the sensitivity of the switch so that you don’t have to push it to too far an angle before it honks. To adjust this, first notice that there are three small studs attached to one part of the horn ring. On these studs are springs, and plastic electrical insulating washers, with self locking nuts. The springs hold apart the two metal parts of the horn ring and when those two pieces touch – the horn blows. By tightening up the three self locking nuts so that a smaller air gap exists between the metal plate. You might use a match or thin piece of cardboard as a spacer to help gauge the gap.

When you reassemble, notice that first there is a thin copper or brass colored spring which sits against the big nut which holds the steering wheel in place (small end goes down). On some cars, you will see a small white nylon piece of plastic which holds the steering wheel adjustor shaft from falling into the steering column. If this steering wheel adjustor shaft falls down the middle of the steering column, then telescope the steering wheel down toward the dash, grab the center steering wheel adjustor shaft, and pull it back up. Put on the rest of the pans in the reverse order that came off and hopefully your Clear Hooter horns will be back in action.

L2 – Balancing of Wire Wheels

If you are having trouble getting your wire wheels properly balanced, or feel that there are too many weights on them, you might have a problem with the. method in which the wheels are mounted on the balancing machine.

Many unbalance problems do start with the incorrect mounting on the balancer. The following pictures show how it should be done.

wires1

T2 – Winter Storage Tips

by Robert J. Jaarsma

Depending on your personal circumstances. you might each store your Sunbeam during the winter months in a different fashion. However, what is the proper way to do this? We will have all one thing in common, to do this in such a manner, that the next spring your treasured vehicle is as good as when you put it away. A plan of attack with a yearly check-off list will help so as not to overlook any details.

  1. To guard against frost, the ANTIFREEZE should be of a 50/50 mixture, to prevent the coolant from freezing. If not sure, test with an inexpensive coolant tester. Do not risk disaster!
  2. Fill your tank with GASOLINE, this will reduce the amount of moisture which can be absorbed in the gasoline and slows the rate at which the gasoline turns to varnish. The addition of a can of “dry-gas” will be a good idea.
  3. Give your engine an OIL CHANGE before storage. This reduces the etching caused by the acidic old oil.
  4. Fill the CLUTCH and BRAKE cylinder reservoirs to the MAX level. This will reduce the moisture absorption.
  5. Always put your SOFT CONVERTIBLE TOP up, as this will avoid nasty creases in the fabric and window.
  6. Take your Sunbeam for a nice CRUISE to let all the moisture in the engine and exhaust system evaporate.
  7. REMOVE THE BATTERY, since a depleted battery can freeze up and crack. Place the battery in a frost free area. Preferably recharge it once in a while during the storage period.
  8. SPRAY a can of WD-40 or a similar oil over the engine pans, and other bare metal components to avoid corrosion.
  9. Do not put the car on the PARKING BRAKE, as the brake shoes can freeze up.
  10. Close off the EXHAUST PIPE(S) with duct tape, to avoid moisture build up inside.
  11. Cover the AIR FILTER with plastic and duct tape. to keep moisture out of the carburetor.
  12. Make sure interior and trunk are absolutely DRY, raise carpets to inspect.
  13. All doors, windows, vents, hood and trunk should be CLOSED, to keep rodents from entering.
  14. Cover your “baby”, but never with plastic.

Considerations about the storage place itself:

  1. If there is a cold concrete floor, put plastic over it, before you drive your car in place.
  2. Daily traffic around your stored prize possession? Consider the possibility of accidents resulting in that unwanted scratch or dent.
  3. If storage is outside, make sure snow cannot trap moisture underneath the car.
  4. Make sure ample air circulation is guaranteed at all times.

Long term storage considerations (12 months or longer) :

  1. All the above, except:
  2. Drain all filters, bowls and tanks of gasoline.
  3. Add several squirts of oil into each engine cylinder. Crank engine, rotate internal components.
  4. Elevate the car, using jack stands on the outer ends of the front A-frames and the If-bolts of the rear leaf springs. In this way the suspension will not drop away from the body and unduly strain the shocks.
  5. Back off the brake shoe adjustment to avoid the chance that the shoes will rust to the drums.
  6. Every couple of months move the clutch and brake pedals, and rotate the wheels.

B2 – Summary of Tiger Overheating Cures

by Dick Guthoehrlein

Tiger overheating is a problem familiar to many of us. The following article summarizes some techniques which should help cure most overheating problems.

Before discussing the cures, a quick review of the theory is in order. Starting at the front of the car, the primary objective is to get as much cool air flow through the radiator as possible. The air must be kept in contact with the radiator long enough to accomplish maximum heat transfer. The objective is to transfer the engine heat to the air via the coolant and radiator. The air must then be removed from the area behind the radiator to make room for cooler incoming air. It is also vital that the correct circulation of the coolant through the block and heads be maintained. Here again the cooling medium must remain in contact with the cast iron long enough to accomplish the heat transfer.

Now the cures. First, the airflow into the radiator must be maximized. One simple thing that can be done is to block off the holes behind the horns. This will tend to force more air to flow through the radiator. If originality is not a concern, you can remove the grill bars and emblem. Portions of the splash pan and front apron can also be removed. In extreme cases, the bumper could also be removed. All this cutting and removing can accomplish increased air flow and a cleaner, less turbulent air flow but you will lose some structural rigidity. As such, try the least obtrusive method first.

Now that we have all the air we need, how do we get the radiator to transfer its heat to the air? The first thing to do is to remove any paint from the radiator, especially the fins and tubes. Any paint or foreign matter on the radiator will slow down the heat transfer. The next stage of improvement is to obtain a new radiator with a thicker coil and/or improved design fins. The ultimate would be to recore the radiator with a thicker core and baffle fins. These fins are “S” shaped and provide more surface area for transferring heat to the air.

Next, what do you do with the air after it has picked up the heat from the radiator? In stock form, the air is forced down and around the motor and into the area under the car. A first step is probably to install a fiberglass LAT option hood. This directs fresh air to the carb and provides air vents into the area in front of the windshield. A more radical modification is to cut triangular openings in the sheetmetal in front of and behind the wheel wells, in the vicinity of the windshield washer bottle and the brake servo unit. On a street car, louvers or screen can be used to cover the openings. These holes will vent into the wheel wells where the air is rather turbulent. This modification may not accomplish a great deal. The rearward holes can be vented through the fenders to the outside of the car. A simple triangular box structure can be fabricated for this purpose. Probably the most radical change but also the most beneficial would be the installation of a front spoiler or air dam. At speed, this device will develop a low pressure area under the car. There is an added benefit here. In traffic, where most overheating problems occur, a spoiler or air dam will tend to stop the recirculation of hot air through the radiator. The last modification in this area concerns the fan shroud. Ideally, the front edge of the fan should be even with the rear edge of the shroud. The Tiger has the fan recessed into the shroud. As the fan pulls the air through the radiator, some of the aids thrown off radially by centrifugal force. This air then circulates in the area between the fan and the radiator virtually cutting off circulation through the comers of the radiator. The cure, is to use your tin shears and cut off some of the shroud. Or, if you are a real wizard with sheet metal, you may be able to fabricate a new shroud. If you are that good, you can fill in the bottom of the shroud that is missing from the stock unit.

Another area of consideration is the water pump. There has been much discussion about the use of cast iron versus aluminum pumps, but there is no agreement as to which is best. If your engine is stock and the pump is in good condition, (the impellers aren’t rotted away) either pump should work. If the engine is modified and/or you have a rear end gear ratio requiring high engine revs, the pump may be cavitating, and/or pumping the water through the block too fast. The cure for both problems is to remove every other vane from the impeller.

Pumping water too fast may seem to be a contradiction when you are talking about overheating problems. What happens is that the water is not in the radiator or engine block long enough to transfer heat efficiently. Also, the coolant flow through the engine block can be disturbed. This will cause local hot spots to develop. The same problems can occur in a stock engine if you remove the thermostat. Replace it with a gutted thermostat or a flat plate with holes drilled in it. How many and how big? Cut and try.

Rust and sludge in the block can also cause problems. If the coolant does not come into contact with the cast iron, very little heat transfer will occur. This problem can be prevented by using anti-corrosion additives and by frequent flushing of the cooling system. Use a strong caustic soda solution or any of the commercial products for flushing the system. You can remove the block and have it cooked out, if necessary.

Another area with considerable deviation of opinions is what coolant to use. Opinions range from a 50/50 solution to 100% antifreeze. The consensus is that each car is different and that curing the problem is mostly a cut and try proposition. Things that have worked for one person seemed to have absolutely no affect for another.

If you use all of these tips on your car, you should be able to sit in the middle of Death Valley and idle all day long – well, almost all day!

M3 – Blower Motor

from CAT

One thing to check before replacing your heater blower motor is that it’s really broken. I discovered, after a period of non-use, that the friction in the bearings can be greater that the torque developed in the windings and mine wouldn’t tum. Since it can’t move, the wires get hot and, at best, a fuse blows. A smoldering fire is not unheard of.

If your blower isn’t working. remove the deflector assembly and associated works under the dash and remove the three main mounting bolts. Rotate the blower assembly out of the large rubber adapter and tum the squirrel-cage blade. Spin it once or twice and then apply power. If it starts up, it’s not burned out, just stuck.

The lower bearing is inaccessible without disassembling the entire motor, but it’s possible to lubricate the upper bearing if you use a long, pointed applicator and 10W oil. Keep oil away from the plastic squirrel-cage, as British plastic, like their rubber, may self-destruct. Run the fan to work oil into the bearing and exercise it regularly to keep it running.

L3 – Wire Wheels

MGB 14″ wire wheels slide right on the existing splines and clear the fenders when used with 175 x 70 tires. They have the advantages of lowering the engine R.P.M. for any given speed, raising the car slightly and having a better appearance.