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Tony's speed tips.


Tony Cerovski (The Montana 500 Kid)

Tony is a Civil Engineer (PE), working for the Montana Department of Transportation. He designed bridges for 7.5 years and now does construction review, which he describes as a tough but enjoyable task. He is in his forties and enjoys T's, especially running in the Montana 500 mile endurance run.

His first T experience was in the 60's when he was 12. He said "My dad and I rebuilt a '23 touring from a rust bucket half burried in the dirt. He sold it about 10 years ago for $3000 (the motor was worth that alone in todays money!) I just had to have a T of my own. So I bought one from an elderly gentelman who used it in the 500. That was maybe 6 or 7 years ago. Since I have logged about 500 hours a year (shop time and computer analysis time) discovering what makes a T go faster and better, ie., for cross country racing with stock components!)"

Tony was President of the Montana Cross Country T Association for two terms in the mid '90's



Tony's speed tips.

Body and Chassis:

Q: What is the best body style to run?

A: Most people use 26-7 roadsters as they are by far the most aerodynamic. They seem to have an advantage on the flat and down hill. 23-5 roadsters are second most popular as they are lighter than 26-7's so they have an advantage in hilly country.



Tony's speed tips.

Spark:

Q: How can I make a degree wheel?

Photo copy the "30" scale from your Engineering Scale and reduce it so that zero degrees meets 360 degrees when the photocopied scale is wrapped fully around your crank pulley. This will give you a degree wheel of the most accurate and most econmical type. I use scotch double side sticky tape for this and wrap the outside with regular scotch tape. Place the tape where the fan belt doesn't go.

Remove a sparkplug and determine where Top Dead Center (TDC) of the #1 piston is. Fasten a wire to one of your timing case bolts for a timing index marker (like on a modern auto with timing marks and pointers).

Q: How should I then adjust my spark timing?

A: Be sure that the #1 coil just starts to buzz at top dead center when the spark controller rod is up all the way. Bend the linkage rod if necessary. Now you will have a safe sparking place to fire up the T. When pulling down on the spark lever the spark timing will advance.

Q: Where do you set your spark lever?

A: When running 500-1000 RPMs, I usually carry the spark handle at about 10 o'clock (say 10 to 15 degrees of spark advance). For RPMs of 1000 to 2000, I carry the spark lever at say 9 o'clock (say 15 to 20 deg of spark advance).

More retard=more heat=more power at a given rpm and duty. Practicing with the spark lever positioning can get rid of over heating problems due to retarded spark. Don't let your exhaust manifold get red, ever.

Q: Any tips on rebuilding coils?

A: Be sure to wash the point sets in hot dish-soapy water and use a bed sheet cloth, about 1/8" wide by 6" long to wash the millings and stamping materials and oils from the points epecially between the upper vibrator and bridge. Rinse and dry thoroughly.

Now the secret and tricky part, do not bend anything on the upper point set with your hands or pliers. What I intend to have you do is to make an upper bridge gap setting tool for setting the upper air gap to 0.005 ", which is about midway from the foot to the head of the brass rivet.

To make the tool, obtain a half inch diameter bolt or steel rod about 6 " long. Measure up from the bottom about 3/32 " and with a hack saw make a cut above the line (barely) about one third of the way through the 1/2 " rod. Make another hacksaw cut above the first one so that the upper point bridge material that lies between the ear holes will slide into the cut rod. This will be your upper bridge adjusting tool.

Don't bend the upper bridge until the points are securely fastened to the coil and set to 0.030 air gap at the platinum points. Setting the points up to be level can be done with washers, but the washers should not touch any thing but the post and riser. Insert the tool onto the bridged vibrator and with a firm grip, rotate the rod and bridge along the x-axis (inline with the longitudinal direction of the point set) and at the same time, hold the lower vibrator down all the way.

You will be setting the upper air gap at the rivet to 0.005". Obtaining 0.005" brass shim stock from a good hardware store is most helpful for a narrow feeler gauge. Hopefully this can be understood with out having a live demonstration.



Tony's speed tips. Piston:

Q: What should the side clearance be for aluminum pistons?

A: All of the aluminum pistons I have used in the last 10 years or so have had the proper clearance built in to the size of the piston itself. By this I mean that a .030" oversize piston will actually measure about .026" oversize at 90 degrees (right angle to) the wrist pin. All modern cam-ground pistons, including new T pistons, are measured for clearance this way. Thus, if the block is bored exactly .030" oversize, the clearance will be what the manufacturer intended, usually around .004" to .005" at a point perpendicular to the wrist pin.

The coefficient of thermal expansion for cast iron is 0.0000061, for aluminum it is 0.0000128 or twice as much. For Aluminum pistons I have used 0.006" clearance measured through the diameter of 0.040" oversized (AL) pistons. This setting may have been a bit tight as I later pulled one piston out for checking and the mill marks on the sidewalls of the piston were about rubbed off at 800 miles. So 0.006" clearance is my personal minimum for aluminum pistons of standard size up to 0.030" oversize. For Aluminum Pistons of 0.040" to 0.060" oversize I would try 0.007" and 0.008" of clearance respectively next time.

When it comes to the rings, try inserting the rings one at a time into one cylinder bore and with a feeler guage check the end gap of each ring and write it down. Do this at a constant distance down from the top of the deck (like with an upside down old piston with a ring in place). I have found that the ring end gap can vary by 0.002" to maybe 0.005" in a given set. I mix and rematch the top, middle and bottom rings respectively trying to obtain the same ring end gap result in each cylinder bore. I don't file ring ends!

A machinest buddy of mine says no less than 0.015" ring end gap for model T's and he is correct! Ring end gap in thousanths is roughly figured by 4 times the piston diameter in inchs. That is 4x3.75" = 15 or 0.015". I hope this helps. Let me know if you need more info.

Q: I believe that .0025 clearance is for cast iron pistons. The clearance for aluminum should be twice that or .005 to .006 . Can you confirm these measurements?

A: These are the skirt fitting clearances from the 1940 edition of Dyke's Automobile Encyclopedia for split-skirt aluminum pistons.

cyl. dia. 2 1/2" to 3"---.002"
" " 3" to 31/2"----.00225"
" " 31/2" to 4"----.00250
" " 4" to 41/2"---.003"
" " 41/2" to 5"----.00375

The clearance for the stock cast-iron Model T piston is given as .0025", (replace piston or regrind, (rebore), and fit new pistons if .006" or more). From this it would appear that modern replacement aluminum pistons for the T would be set at the same,(.0025") as the iron. The block is bored to true diameter, the clearance is turned on the piston, ie, a 4" piston would be 3.997" in skirt diameter. Modern pistons are either of the split-skirt or cam-ground design, these allow for expansion due to heat without loose fit when engine is cold and, hence, a quieter running engine on start-up.

Q: Tony --- Thank you for your answer to my question about aluminum piston clearance in the T. The coefficients of linear expansion that I used are pretty close to yours 0.00000589 Fe; 0.00001233 Al) What did you use for a temperature?

A: By using the minimum ring gap of 0.015" we can solve for the change in temperature. If we use the formula Li=C*T*L

Where Li is the length of increase due to temperature change,

C is the coeffient of linear exp for cast iron rings= .0000065
T is the temperature differential in F
L is the cool original length of the member
and when we solve for T, the formula becomes: T = Li/(C*L)
and if Li = 0.015 inches for a Diameter of 3.75 inches (which is a
recommended minimum ring clearance)
C = 0.0000065 thermal increase per deg.F
and L = Pi*D = 3.1416*3.75 = 11.78 inches
***** then T = 195F which is the difference in temperature between the piston and the block as per one recommendation.

The fuel that we use today contains much more BTU's and burns hotter than what Henry used so I ended up setting my ring gaps at about an average of 0.023" of cool end clearance with excellent results at 0.040" o.s. pistons.

The temperature of the piston at the top is important and I think that I was using something around 400F to 450F. The block will also heat up to something around 200F to say 250F in the cylinder and the piston may average around 400F to 500F. For the overall net temperature differential I probably used 200F. I have no measurements on this. Perhaps your machine shop could give you some numbers too.

Q: Piston alloys 18S and 32S have copper and magnesium added. I have not been able to find what alloy is used in the Taiwan pistons. Any idea? I do have the coefficients for these alloys if I can find what they are.

A: If you took the piston diameter measurement at a known temperature and placed it in your wife's oven and heated it to a known temperature and obtained the new diameter you could solve for the new coefficient of thermal expansion. But, the amount of alloy in the new piston should be so low that it shouldn't be much of a difference.
Perhaps the above data can eliminate most of overheating due to possible piston to cylinder wall rubbing problem. The pistons and rings will wear themselves into the best fit over time from this point forward and it is likely that you may have to suffer for 500 to 1000 miles while doing it. Change your oil often so that the magneto does not get shorted out by the metallic filings. Also place a strong magnet on the bottom pan at each dipper indentation and on the oil drain plug as so to trap all metal filings before they get to the mag.

Tony's speed tips.

Cam:

Q: Without retiming the camshaft, what are good valve timing settings to shoot for?

A: By using a degreed tape on the crank pulley or a degree wheel, you can get your valves to open and close at the same locations. This is the most accurate method of degreeing in valves. With a stock camshaft, I have had very good results with trying for the following valve timings: IVO@15aTDC , IVC@63aBDC, EVO@38bBDC, EVC@15aTDC, IVC=.020" & EVC=.020".

Q: How can I make a degree wheel?

A: Photo copy the "30" scale from your Engineering Scale and reduce it so that zero degrees meets 360 degrees when the photocopied scale is wrapped fully around your crank pulley. This will give you a degree wheel of the most accurate and most econmical type. I use scotch double side sticky tape for this and wrap the outside with regular scotch tape. Place the tape where the fan belt doesn't go.

Remove a sparkplug and determine where Top Dead Center (TDC) of the #1 piston is. Fasten a wire to one of your timing case bolts for a timing index marker (like on a modern auto with timing marks and pointers).

Q: You have spent countless hours studying cam timing. Can you give me an idea of the possible results of different settings?

A: With stock Model T camshafts not reground, and made after 1914 +/-, set all valves with adjustable pushrods to clearances of 0.015" if the cam has uniform lobes, (with the cam not advanced nor retarded.) If the cam has non-uniform lobes, try to achieve IVO@13ATDC, IVC@68ABDC, EVO@40BBDC & EVC@20ATDC for better top end. Don't use less than 0.011" or the T could start coughing and catch a bad cold. This is good for parades too!

With stock Model T camshafts not reground made after 1914 +/- set all valves with adjustable pushrods to clearances of 0.020" of an inch if the cam has uniform lobes. (with the cam not advance nor retarded.) If the cam has non-uniform lobes,try to achieve IVO@15ATDC, IVC@63ABDC, EVO@38BBDC & EVC@15ATDC for better low end torque. Don't exceed 0.025" clearance, as the T will start to run poopie. This is better for parades.

With stock Model T camshafts not reground made after 1914 +/- , ADVANCE the cam 1 tooth counter clockwise, set all intake valves with adjustable pushrods to 0.020" and the exhaust to 0.008" if the cam has uniform lobes. If the cam has non-uniform lobes, try to achieve IVO@0TDC, IVC@47ABDC, EVO@75BBDC & EVC@15ATDC for better power everywhere but, poopie idle. NOT for parade cars

With Richard Carnegie's (509-891-6461) high speed (high lift) camshaft "3041A" (sold by lots of businesses, but get it from Strong Engine) set all intake valves to 0.030" clearance and all exhaust valves to 0.035" clearance (with adjustable pushrods) Carnegie's cams have uniform (perfect) lobe profiles. Do not advance or retard. Try to achieve IVO@4ATDC , IVC@65ABDC, EVO@45BBDC & EVC@12ATDC for better lower and beter top end power. This setup will be " clattery " sounding and is just fine for parade cars too, best of both worlds!

We have tried cam profiles out of all kinds of modern cars, Chevys, Fords, import cars, etc., but they don't build good power in the 1000 to 2500 RPM ranges where the Model T needs to be. (This seams weird to me because the newer cars run in this RPM range when in overdrive!!!!! and could be making better mileage there too!!!

Q: What modern valve set up works in the T?

A: Posted by Steve Coniff on October 04, 2000

The Manley part number for the 302 and 351 Ford valve that works well in a " T " is A2223. This valve has a chrome plated stem which gives superior wear qualities as well as a hardened tip on the end of the stem. The stem is 11/32 " (.341 actual diameter) and is longer than the Chevy valve stem.

Retainers are available from Ford tractor stores only. The Ford part number for this retainer is 8BA6514 (4 retainers per bag). This retainer fits the 8N tractor. Model T valve springs are a perfect fit in this retainer.

The tractor retainer and the 302 valve use the standard two piece single groove keeper. Ford and Chevy use the same keepers for the 11/32 " valve stem. Keepers can be purchased at any parts house. The TRW part number is LK-127 and the Pioneer number is PF-555-HD. Check with your machine shop first before you purchase new keepers. Machines shops generally have lots of extras around they will give you. I hope this helps.

Steve

Model T Upholstery

I do upholstery on collector cars full time. This may provide some help. I do not have pictures of wood but in general there should be 3 vertical strips of wood with 2 horizontal pieces, one near the top and the other at the bottom, at the rear of the car.

The rear seat backrest hangs on this wood by 2 or 3 loops of strong cloth or leather looped around the upper edge of the spring assembly and tacked to the vertical wood or the tack rail that goes around the upper edge of the body on the outside.

The front backrest is installed in the same manner but I do not remember if the wood structure is there or if the springs just rest against the body metal. If this is the case, put some padding, such as carpet pad, between the springs and the body metal.

Before hanging the spring sections they should be covered with burlap stretched fairly tightly. This keeps the padding from working in between the springs. Once the springs are installed in the car to your satisfaction, place the cotton padding in place. Then mark the center of the body on the tack rail and the lower wooden piece the cover tacks to. This should get the center pleat nice and vertical.

Place the cover in the car carefully, making sure it goes over the tack rail all the way around and also covers the lower tack wood. When you are satisfied with its position, lightly tack the top center in place, near the bottom of the tack strip. Then do the same with the center bottom.

If all looks good, put a few tacks in to hold the top in place, working out from the center. Do not drive these tacks in all the way as they will be removed. Put a few in the bottom. If it looks good, install the bottom, working out from the center. Do not pull it extremely tight sideways, just enough to keep the pleats vertical. When the bottom is done, pull the center up tight and tack it. Then work out to the edges, keeping the pleats vertical.

You will install and remove many tacks, making adjustments. Going around the corners to the sides of the body is tricky.
Have fun. Keith McGowan


The Montana 500 is Sanctioned by The Montana Cross Country T Association.