Rebarreling and Home-Shop Machining

Drilling 1 inch ABS plate at 24 Degree Angle With Coolant

Thu, 20 Mar 2008 21:20:45 GMT

This video belongs to the two topics below. I might as well show the whole unedited verstion as it tells the tale of doing big work on a little machine. There was also a lot of decision making on how to make this hole. I have done similar size (3 inch) holes in flat Aluminum 1/2 inch plate. I took a bimetalic hole saw and cut a disk out. Now this type of hole saw does not like cutting more than 1/8 inch deep or so. It just will not clear chips well, but with plenty of force it does the job if you cut from both sides of the plate. Then I finished the hole up with a boring head.

Because of the angle of the hole, the hole saw will not cut all the way through this 1 inch ABS. So now the question was to use a large wood cutting Forstner bit undersized and bore to size or just use the 2 inch and hope for a good finish. Well a good finish was produced boring to full size. We had to stop once to clearchips. Had we grabbed that first tail and pulled rapidly this might have been avoided. The mill spindle stalled once or twice. I tightened the belt to cure this. The power feed did not stall and was adequate for milling this plastic. If not we would have given a hand asist.

Here is the sketch that I made to determine the angles. What I wanted is minimum angles so that the hose sections would clamp well to the throttle bodies and to the inlet runners. I offset the the runner pipes to the right in the diagram 1/4 inch to reduce the angles. The distance from head to TB is 2 inches. I measured in cm the center of the throttle body assembly to the center of each individual throttle bodies. These numbers are at the top of the sketch. I put an arrow where I wanted the short pipes to end up. Then I drew in 2 inch pipes with 1/4 inch walls. I could measure the angles directly from the sketch as raggedy as it is. The offset will be removed by porting the plastic so that there are no steps near the head. At the Throttle bodies the pipes will be ported to make them a little more round and open them up to near 2 inches. The 1.5 inch ID of the pipe can be opened up slightly to match the 42 mm butterfly diameter. More detail on request. The sketch was full size and showed only two of the four throttle body runners.

John

Quad Throttle Bodies and Trumpets Project on 2005 Ford Focus ST

Tue, 13 Nov 2007 11:58:45 GMT

Quad Throttle Bodies and Trumpets Project on 2005 Ford Focus ST

Some of you may have noticed some projects done on this car earlier in the Journal. The car has changed some since the last entry. The suspension is now complete with new Ford springs and stiffer Eibach antiroll bars (pic # 7). The car wears Motegi Rims with 205/45R x 16 Falken Azeni tires. Cornering power is right at 1.0 g's continuous in a corner like a clover leaf turn. The balance is absolutely outstanding now. The car will see some duty at MCR raceway during a test and tune session and at an auto cross. Top speed is now about 130 mph. Speed limiter is removed. Rev limit is raised to 7000 rpm. The new tire size is programmed into the computer and speedometer checked by radar to be accurate. Now its time for just a little more power.

This project will probably take some time and may require some machining. As can be seen in the third photo, this type of intake is available from SBD motor sports. A similar system using barrel throttles is available from Cosworth. Price tags are similar at about $3500. Both systems require the use of aftermarket computers and wiring. Neither attempts to be low emmision, but Horsepower can be increased to 200 to 225 HP with few internal engine modifications.

So here is the plan

Obtain some small throttle bodies as a base. The Hyundai Accent has one that is 42 mm in diameter on the throttle plate. It has been tested on this engine and it worked well. A 35 mm body would be better. (new text). I found that Suzuki 42 mm throttle bodies are plentiful and would be a better fit to my bore spacing requiring fewer mods. As a bonus they have a set of secondary throttle plates that open as the engine RPM and load increase. They keep intake air velocity high at lower RPM. The Ford Focus manifold has an actuating mechanism for the dual runner length butterflies that could be adapted to run these secondary throttle plates. I plan to keep a set of inner butterflies on the Focus Manifold that improve emmisions just off idle. They open on full throttle so should not hurt power much.

A large volume airbox will cover the trumpets. Air will feed into this air box from the current Cosworth Cold Air Intake tubing which uses a stock mass air flow sensor. With luck this and a retune will allow the use of the stock computer, Stock injectors with higher pressure. The engine computer is very good and able to be adapted to supercharging and turbo charging. I don't see why it would not work here. I found the Suzuki 750 air box to be a good starting point. See pic 4 and 5.

The stock idle air control valve will be worked into the system. The stock EGR system will be hooked up. Emissions should be very good when tuned. The car can be returned to stock with a manifold change.

So what is the advantage say over a Cosworth intake with a plenum. It has to do with air velocity. at part throttle the butterflies on the intake shoot a jet of air into the intake manifold runners. The stock system has a jet far removed at the single throttle body. The jet is well dissipated before it ever sees the manifold. This jet is responsible for good part throttle performance. On a road track that is what you want. The stock manifold does have some inner butterflies that provide turbulence that help in this regard that are semiclosed at lower speeds. Now because the throttle bodies are a little bigger when added up, Wide Open Throttle (WOT) performance should also be very good. The trumpets will allow the manifold to be in tune over a wide range of throttle positions.

All comments are welcome. There must be a few of you that are hot rodders at heart.

Building a Plastic Intake Manifold for a Ford Focus ST

Thu, 03 Jan 2008 14:39:28 GMT

I thought I would start a new topic here as there will be some machining done on this part. I made this gray gasket/template by removing the stock intake manifold, putting in all the mounting bolts and then tapping around the ports with a ball peen hammer. The sharp edges of the head casting cut the intake ports. My nephew James was a great help in Removing and Replacing the manifold.

I noticed that the stock Ford Plastic Intake manifold has metal inserts to prevent the bolts that attach it to the head from compressing the plastic. This eventually would lead to a loose bolt. I have ordered some inserts from McMaster-Carr.com that may work. I also ordered some threaded inserts for plastic that can be used to attach items to the manifold.

Work proceeds on 3/18/2008

We made an 8 mm pilot from .5 inch drill rod. Drilled it .125 then .128 for a light fit of a 1.25 inch transfer punch. We used this and the gasket template to center punch the mounting holes. These were then center punched with a larger punch. The photo shows the pilot and center punch laying on the ABS plastic flange. The wiggler is installed in the milling machine (or large drill press) to drill the holes out for smooth metal inserts.

3/20/2008

We made great progress today. We set the manifold flangeon the adjustable angle table. A sketch showed I needed a 24 degree angle on the outer holes and 13.5 degree angle on the two inner runners. I used a dial protractor and buble level (the mill table is level) to set the angle on the work piece. We cut the first hole with only minor problems. A huge volume of chips was produced which we cleared by hand with the machine stopped or running. Never do this by hand on steel chips. We got a nice clean hole with a good surface finish on the wall, ready to be solvent welded to my 2 inch ABS tube runners. I did shoot a video it is posted above.

John

Ford Focus Quad Throttle Body Install

Thu, 29 Nov 2007 03:39:50 GMT

So far everything is a go. This is an install of the Suzuki GSXR 750 motorcycle throttle bodies (see the topic below) that will be installed onto the Ford Focus 2.3 liter Duratec motor. Note that this installation will not pass a visual state inspection in some states but hopefully will pass all the emissions tests and may add 20-25 horsepower. Before and after tests on a G-tech unit which can calculate horsepower will be included.

Picture 8 and 9 show some machine work which will be required on the throttle body. The large hole is where the stock Suzuki Fuel injectors go. Fortunately, the Focus has a fuel injection rail and injectors that go straight into the head. Instead, I plan to use these large size holes to inject EGR. This will improve NOX emissions and prevent the engine computer from throwing a trouble code. There is a small unused boss to the left of the fuel injector hole. This will be drilled 1/8 inch and a hose barb of some kind installed. This 1/8 inch hole will enter the throttle body bore just aft of the closed throttle plate. The EGR enters just in front of the closed throttle plate but is normally off at idle. I plan to build a 1/4 inch vacuum hose manifold to inject idle air from the idle control motor on the small boss. This will let the computer control idle and boost idle on AC and high Temperature as is normal.

I completed the drilling and threading of the fuel injector holes. (This was a ticklish job dueto very thin castings. It might be better to make dummy injectors and press these in with a permanent clamp using the stock injector seal There is a threaded clamping hole near the top of the brass fitting.) I drilled the injector hole 9/16 diameter and 1/16 inch deeper to add another thread. There was some tearout that can be seen in photo 12. This area will be sealed by High temperature copper containing RTV. The 1/4 copper pipe that goes through this fitting extends all the way to the bottom of the fuel injection port. This was allowed by drilling the compression fitting out 3/8 inch on the lathe. Any additional space in the hole was filled with 1/2 inch copper pipe so that all RTV layers are thin.

The 1/8 pipetap that I had a long but gentle taper. After making three to four threads in the throttle body, the compression fittings still would not start. I cut 1/2 inch off the buisness end of the tap with a 4.5 inch grinder equiped with a cuttoff wheel while it was turning in the lathe. This allowed it to cut bigger threads. This worked OK. I finished by lapping in the threads of the fittings with some 320 grit compound. This created a little more engagement and allowed me to tighten them fully.

I needed two vacuum taps, one for Absolute Manifold Vacuum and one for Idle Air Injection. There were a couple of unused bosses in approximately the right places. Photo 6 shows drilling the rear boss. I used a transfer punch to center punch the hole. Then I used a center drill followed by a 3/16 inch drill. I found a plastic 90 degree fitting that could be tapped gently into the hole with sealant

The quad throttle bodies required dissasembly. Remove rear butterflies. The rear butterfly shaft is one piece. Remove two throttle bodies, then remove this shaft. There are six springs and four rubber tubes and a felt gasket (on the threaded end of the shaft) that must be reinstalled. See picture 6.

I needed a port to inject idle air from an idle air motor. I used the unused boss beside the fuel injection port. I set this up to drill on the drill press by angling the table. This was a pain due to the need for shims and tall clamps. Instead I drilled the last two by hand and had better luck. When the big hole was 1/4 inch deep I center punched the bottom of the hole near the back and drilled 1/8 inch to the throttle bore, keeping the hole back as far as I dared. This nicely positioned the 1/8 inch hole inside the throttle bore to completely clear the throttle plates at all positions near idle. I finished up by drilling the large hole about 3/8 inch long. See picture 4 and 5

Photo 1, 2 and 3 show the almost complete Throttle bodies. I have made manifolds for several items which I will discuss a little.

Idle Air Control (IAC)

The stock ford manifold has an idle air control motor that bleeds air from before the throttle plate into the plenum after the throttle body. Since there is no after throttle body plenum, any more, I thought I would inject air just aft of the throttle plates through an unused boss which I drilled. I made sure the path to each throttle body was identical to insure a balanced idle. The idle can be balanced further with the inter throttle body adjustment screws. I am thinking this won't be neccesary as they are balanced at the factory andreassemble in a very precis manner.

Exhaust Gas Recirculation (EGR)

The Ford Focus EGR injects semi water cooled exhaust gas directly through the head into the front of the intake plenum. I was wondering if there was efficient mixing to keep this balanced between the cylinders. To insure this, I made a copper manifold where again the path lenght number of 90's etc would be the same to each cylinder. This manifold may run a little hot but is sure to be cooled off to decent teperature before it reaches the throttle bodies. I have used high temperature sealant at the Suzuki Air injection ports and plan to use 2% silver bearing solder in the manifold. Both of these products are rated to about 700 F. The Throttle body itself will actually be self cooling from expanding gas. None of the rubber hoses nor the Susuki air intake plenum will touch these copper pipes. I have mades some minor changes to insure this from previous photos. The first 90 out of the injection port is now a little lower in photo 1.

(Absolute Manifold Pressure)

The Ford system measures Absolute Manifold Pressure inside the plenum after the throttle bodies but before the runners. This is used to calculate engine load and thus fuel delivery. I have no vacuum there so I will rum a vacuum line and make maybe a small chamber for the sensor from Vacuum taken after the first throttle plates. I have summed the fourcylinders to avoid vacuum spikes and to average the vacuum. This line will also purge the evaporative canister and run vacuum operated engine controls.

I took a used Suzuki airbox that was advertized to be for the GXRS 750/1000. The throttle body clamps are a bit too large for my 42 mm throttle bodies and will require a rubber shim. This clamp can be seen on the left in photo 14. I removed one of the stock inlets with a zip bit in the Dremmel and the Dremmel large course Drum Sander. I removed the internal filter and removed the plastic support near the Trumpets to smooth the air flow. This required sealing the outside as a narrow crack developed. I removed part of the flange just past the stock holes on the part of the Spectre inlet near the bottom in the photo. The flange here is fit into a slot cut with the zip bit into the airbox. The box can still be opened but the part near the inlet will require resealing with RTV silicone. Now I just hope I have enough space for this generously sized box. On the top most part of the box save some material from the stock inlet and fold it inward with a heat gun. Clamp two short metal blocks to it to grab with the vise grips. Heat near the edge and bend in. Then sand the flange area mostly flat on a belt sander.

Picture #18

My intention was to use the Suzuki throttle position sensor to sense the main throttle blade position. This will require some experiments of which I completed the first. According to my tech the ford sensors normally work on 5 volts. Full throttle will detect as somewhat less than 5 volts. Closed throttle above zero a small amount.

I have a variable power supply that I can supply 5 volts. I connected plus and minus to the Suzuki yellow and blue lead which are low in the pictured plug. I sensed the voltage at the black wire which is high in the plug. Firstly hooking up the power supply drew less than .01 amps. This is good as things are not overheating. Throttle closed was about .010 V. Throttle opening saw a nice smooth increase in voltage to about 4.9 or so fully open. I think the ford computer will readjust to small differences in wide open and full closed as there is bound to be a 5% or so variability in one part to the next. Anyway another short test of the car will see if I am matching closely enough. Use of this TPS will make the assembly neater by requiring less fabrication.

The TPS slides down a flat blade that becomes the throttle shaft. You can see the secondary throttle plate blade which is similar. You also get a spare TPS with this throttle body as the Secondaries have an identical position sensor that will not be used.

I used a hot air gun to soften the air box in the vicinity of the small copper 90's that will feed hot egr to the manifold. This gave them about 3/8-1/2 inch clearance on the airbox. Pic 19.

I found an ABS coupling for flat drain pipe at Lowes. I cut a piece of this 1/8 inch materialtoseal the unneded end of the airbox intake. Pic 20.

Pic 24-25-26-27

Air Intake Box is ready for glue. I put a cut down 4 inch plastic intake under the Aluminum intake to add strength and to fill the bottom two corners where the Aluminum intake flange lacked material. A couple of holes are left and will be filled with the 3M 4220 plastic mender. Also visible in this shot are the two islands that used to support the Suzuki air filter that will not be used. Left over is a gap. This will be filled with the plastic mender from the back and then smoothed over on the front. Surfaces must be scuffed and treated with an ABS primer which I bought at Lowe's. This will dry leaving surface tacky. The glue and primer are best used outdoors.Here is a picture after the glue up and a report on the glue. The 3M 4220 plastic mender comes in two large syringes. The 3M tool to squirt these is about $75 and is a good investement for a body shop. I cut two equal length dowels and used a standard caulk gun to push on the syringes. I sealed the two long seams along side the trumpets with one long smooth nice looking bead from the outside of the case using one of the self mixing tips. I smoothed the inside with my finger. This is really about all the time you have with this glue. Less than a minute before it starts to set up.
I used a second self mixing tip for the air inlet. I put a bead of sealer under the 4 inch plastic flange and on top of the plastic flange followed by the aluminum inlet and then four screws. I just barely got them tight before it all turned into a brick.
With the tips used up I then mixed the glue on a piece of heavy polyethylene. It is very liquid when it comes out, mixes and starts to stiffen very quickly. I applied it like putty to the inside of the plastic flange to smooth the air transition into the box. This worked OK but was not very smooth when I finished. I sanded it smooth and rounded off the corners. I sands and feels like a hard rubber when cured. The outside looks very much like the previous photo. Not much mess there.
It may be that Suzuki offers replacement trumpets at a reasonable price. This will allow some length and diameter tuning. Mine are a bit large in diameter, so maybe they are from the 1000 cc bike.
You might think this is a lot of work on an airbox until you price one from an aftermarket supplier.

This will probably be a long topic so as not to dilute the other content of the Journal so check back every couple of weeks. There may be more photos and progress in the topic above.

Thread on FocalJet.com on this project.

John

Freeway Dyno. Cold air Intake 2005 Focus ST

Mon, 20 Dec 2004 22:44:07 GMT

Remove the Factory Air Cleaning System

These instructions and photos are meant as a supplement for the instruction that come with the Focus Sport cold air intake. I had to ream one hole (machining) so I can include this topic in my journal.

Disconnect PVC hose from air intake. See photo 3. The screw driver points to a green lever that must be disengaged. Pushing sideways on the green lever expands the green lockring that secures the connector. Remove the plastic elbow from the stock bellows style rubber connector in photo 3. It helps to oil the plastic elbow from the inside and out and have the rubber warm. It is hard to pull out.

Remove two screws that secure the factory airbox (elbow) to the mass air flow sensor. There is one additional push in style connector on the back side of the airbox. Pull up hard and the air box will now come up and off the mass air flow sensor. See Photo 4 of the airbox out and on top of the battery box.

Unplug the mass air flow sensor connector. See Photo 5. Pull out on the red slider. Then squeeze the plug near the red slider to push the tab in. Some guys have had trouble with their mass air flow sensors that may have been caused by undue force on this plug. If you do it right it comes off easy.

Remove one large screw securing the mass air flow sensor bracket to the frame and one hose clamp securing the filter to the mass air flow sensor. Remove the mass air flow sensor and take off the metal bracket. There is a plastic screen that stayed with the filter on my car. Nothing else to remove from the mass air flow sensor. If the car is well used jet the sensor off with a mild flow of air to remove any dust.

Now jack up the car and place on jack stands. Remove screws from about half the splash panel under the bumper. Remove two screws from lower front of the inner plastic fender well. Let the splash shield down out of your way. The Phillips head screws are screwed into expanding plastic inserts. If the insert turns you need to hold it from the back side or from the front side with a small pick. Pressure downward on the splash shield may help. See photo 6.

Remove Stock Filter from underneath the car. 3 bolts. See Photo 7. The screwdriver to the right points to the hardest bolt to get off. We used a 1/4 inch air ratchet short extension and short 8mm socket.

Remove rubber locking flaps that secure the air filter to the snorkel that rises up into the fender. See Photo 8 and 9. I pushed the filter end of the snorkel up and then pulled it out of the fender .

Installation

Install the mass air flow sensor to the upper Focus Sport pipe. Push in the plastic PVC elbow into the small hose. Install according to the Focus Sport instructions. See Photo 10 and 11 for the finished installation.We had to ream the mounting hole (in the radiator Core support) for the rubber isolator mounting screw. Pull the horn wiring loom anchor out to expose this hole.

Water

The factory filter and snorkel provide very good protection against water entry into the intake. The snorkel opening is right at the top of the inner fender. The Focus Sport intake is between the bumper and the inner fender. This area seems to be pretty dry from the lack of water spots and dirt that are on the inside. I have driven quite a bit in the rain lately. If you immerse the car above the bumper in water you will ingest water through the new lower filter. This will cause major engine damage. I have one report of a rod through the block after 12 inches of water was forded. You will have also ruined your interior. I don’t think road splash gets into this area, but some water may drip from the seams between the headlight and the hood. Not much room for a splash shield on the new filter without putting on another elbow to aim the filter up.

Modification

After a month of use I heard a change in the intake sound and felt a loss of power. I looked under the hood and one of the 6 mm bolts holding the upper pipe to the mass air flow sensor was gone. It was good and tight once. I suspect the joint works from engine movement which causes this. I have noted on the web site that people experience leaks and sometimes the tabs break off the cold air intake pipes. (Not necessarily this brand). The stock Ford system secures the airbox to the mass air flow sensor with two bolts as well, but it also has a third push in connector at the rear of the air box that helps to secure the system from movement. I decided to add a third screw and I believe Focus Sport should add one as well by tig welding a third tab to the upper pipe and using an L screw to add a rear clamping point.

Anyway I modified mine with off the shelf stuff. A Percy’s Seal 4 Good Reusable 3 inch Aluminum Header gasket from AutoZone I cut this, sanded it, and spread it to match the Ford bolt centers. The original part is round. This flange set consist of two aluminum plates with three bolt holes in dead soft aluminum. The softness will help you shape the part easily, but it lacks some strength. I added strength by spreading the two plates apart at the Ford Bolt Holes with a stack of 3 washers. These are cinched up tight with a lock washer and 6mm by 25 mm bolts. Then I squeezed the plates together at the L bolt by using one nut above and one below the plates. This formed a nice stiff cantilevered beam that could take some force. It was strong enough now for the task. I put on a brushed finish with a wire brush when I was done. See Photo 13.

Future Focus ST Mods Cold Air Intake - Freeway Dyno

One of the future mods I am considering is a cold air intake. I wanted to see if it actually provided the extra 10 horsepower that was advertized. Not having handy access to a chassis dyno I used the speedometer tachometer and a stop watch to find the front wheel horsepower using the following method.

I thought the 5000 to 6000 rpm range would be most affected, by a cold air intake, so I chose this range to test. The power calculated will bethe average over this range or the power at about 5,500 rpm. Feel free to change this range to whatever suits your modification if you would like to use this method. If you calculate several ranges you can get a power output graph.

Accelerate the car

First accelerate the car in the RPM range chosen using a single gear. I repeated this test 8 times going in both directions and took an average. I got 3.27 second average. Select a gear that gives you a fairly large time (like third gear) but that doesn’t have the car traveling too fast for the road conditions. The large time will improve precision. A reasonable speed will keep you from being arrested. At 5000 RPM in 3 rd gear my Focus ST is traveling 63 miles/hour. At 6000 RPM it is going 76 miles/hour. This is typical freeway speed here in Houston in light traffic. This was fairly easy to do on an on a level on ramp or feeder road approaching the on ramp. This time will be used to calculate the rear wheel horsepower used to accelerate the mass of the car.

Do a coast down test

Second. Time how long it takes to coast from 76 to 63 miles/hour with car in neutral or clutch disengaged. Repeat, and take the average. I got an 11.73 second average for four attempts going in both directions to average the wind. This number will be used to calculate the average road and air friction in my selected interval. This will be added to the horsepower used to accelerate the mass of the car and will result in a good front wheel power number.

I am doing these calculations in the metric system to avoid the British mass unit, the slug (32 pounds), which is seldom used in conversation.

Change velocities to meters/second

76 miles/hour x 5280 feet/second x 1 hour/3600 seconds x 1meter/3.28 feet = 33.98 meter/sec

63 miles/hour x 5280 feet/second x 1 hour/3600 seconds x 1meter/3.28 feet = 28.17 meter/sec

Change the cars weight from pounds to kilograms

Car plus Driver plus half tank of gas= 2885 lb x 1 kilogram/2.2 pounds = 1311 kilograms

(I am a heavy guy)

Calculate the Kinetic Energy at your two speeds

Kinetic Energy in joule @ 63 mile/hour = 1/2 mass(velocity)(velocity)

Kinetic Energy in joule @ 63 mile/hour = 1/2 (1311 kilogram) (28.17 meter/second)(28.17 meter/second)

Kinetic Energy in joule @ 63 mile/hour = 520319 joule

Kinetic Energy in joule @ 76 mile/hour = 1/2 (mass)(velocity)(velocity)

Kinetic Energy in joule @ 76 mile/hour =1/2 (1311 kilogram)(33.9 meter/second)(33.9 meter/second)

Kinetic Energy in joule @ 76 mile/hour =756,866 joule

Power to Accelerate the Mass

Power= Change in Kinetic Energy/time

Power = (756866 joule - 520,319 joule)/3.27 second

Power = 72,338 watt

Power to fight air and road friction

Repeatthe Power calculations but use the coastdown time instead

Power= Change in Kinetic Energy/time

Power = (756866 joule - 520,319 joule)/11.73 second

Power = 20,165 watt

Total Power at rear wheel = power to accelerate mass + power to fight air and road friction

Total Power at rear wheel =72338 watt + 20165 watt

Total Power at rear wheel = 92,553 watt

Power Before Cold Air Intake

Change Watts to Horsepower

746 watt = 1 horse power

Horsepower = 92553 watt/746 = 124 horse power

This is very close to what the chassis dynos are getting as peak horsepower at the front wheel.

Power after the Cold Air Intake

I was able to time the car from 5000 rpm to 6000 rpm in similar temperature conditions, same amount of gas, but with almost no wind. I ran 3 runs South and got 2.99, 3.08, 3.02 seconds. 5 runs North and got 3,06, 3.02, 2.97, 2.95, 2.99 second for an average of 3.01 seconds. This is 0.26 seconds faster than before. You can easily feel the difference. I calculated the new power and got 132 Horse Power. This is an increase of 8 HP.

MOMO Pedal Installation & Cold Air Intake Thread

Cold Air Intake Air Box “Fording Kit”

Momo Pedal Install In this Journal

Focus Sport Cold Air Intake Thread on Focaljet.com

Accuracy testing the rechambered Winchester Coyote model 70

Wed, 05 Jul 2006 23:15:22 GMT

Accurize the Factory Barrel

If you have tried to sell a factory barrel, you will realize that they have no value. So this experiment is just to see what can be done with one.

Poor results with 165 grain Nosler Accubond

I shot an incremental load test with Nosler 165 grain Ballistic Tips, Varget powder, Federal cases and found my maximum load with this bullet was 45.7 grains of Varget. No clusters were apparent. Not good. I did some load experiments from 45.4 - 45.6 grains of varget and from 6 to 18 thousandths bullet jump (in a 3 x 3 Factorial design). The best load was 1 and 7/16 inch. The resulsts of these test are shown in the bubble chart in photo 3. The bigger the bubble the bigger the group. The jump can be read of the left axis. The powder charge can be read off the bottom axis. The barrel seemed to prefer 12 thousandths bullet jump with this bullet but the barrel seemed to be pretty whippy and produced poor groups.

What happened is that I removed 7/16 inch from the big end of the barrel for my rechambering. The front of the chamber is now in the first tapered section of the barrel from the breech end. The steel is thinner here so there is more barrel flex and there is more case stretch than originaly.

Better results with 150 grain

I removed 4 inches from the barrel to improve its rigidity and I changed to a 150 grain bullet. This barrel length is identical to Remington’s light tactical rifle at 18 inches. The incremental load test is found in photo 2. This is from 45.6 to 46.2 grains of Varget increasing each case by .1 grains to make 7 rounds. This bullet is showing more promise that the 165's. I'll post some groups if I have some luck with it. 46.2 grains showed no pressure signs but is likely to be near the maximum load. I have some very straight cases now that have been run through the rifle. When resized they are at about .0005 inch (5 ten thousandth) runout or less. This may or may not help with this barrel, but it sure does with a heavy barrel.

Best Results with Nosler 150 grain Ballistic Tip

The Incremental load target in photo 2 indicated that I should try loads at 46.2 grain and maybe a little higher which I did not test. I loaded a few loads with different overall lengths at 46.2 grains and 46.3 grains. The 4.6.3 grain target in at the right in photo 1 showed good promise. The two groups are two different loads one slightly longer. I’ll reshoot the best load and see if it is just a random good group. The left hand target were the last two shots from a box of of Winchester Supreme 150 grain Ballistic Silver tips. This showed promise as well. Note that I have put the hell for stout Farrell scope base back on the rifle and that the stock has a home built bedding block which is described in topics below.

The factorial design and Incremental Load method as well as the preparation of straight cases are show in detail in Precision Rebarreling.

Chambering the Winchester Coyote Model 70, Extending an existing thread.

Fri, 09 Jun 2006 01:45:43 GMT

Chambering

The chambering went really well. I polished the chamber, which was very smooth already, with 1500 grit. Only took a minute. I used the chambering procedure described in "Precision Rebarreling" so will not go into detail here. I got a complete fresh cut that removed all the factory chamber. Targets to come. I sold the 1 inch scope that was on the rifle, so I have to wait a bit for some new rings. They will be Leopold QR with two piece bases. I think that the esthetics on this particular rifle will be better than with the Farrel Rings and one piece base that I had mounted previously. The scope will be a 30 mm tube Leupold Mark IV 4.5 x 14 M1 tactical scope.

I mounted the barrel with a blue Loctite paste that I have come to favor. It comes in a chapstick like tube dispenser. It stays where you put it.

Matching an Existing Thread

I had to add some threads after trimming the barrel extension by 7/16 inch. This is not an easy task on a small lathe due to flex in the feed screw, feedscrew supports and carriage. The procedure is this.

Put the lathe in gear and feed left under power with the bit off the work. Park the bit by your existing threads. Lock the carriage. Now adjust the bit with your compound rest feed wheel and cross-slide feedwheel until it fits nicely in the existing thread groove at full depth. Use a magnifying glass with white paper under the work to reflect light. You can get it adjusted really well.

Now the problem is, the bit is not taking a cut. When you cut the new threads flex in the machine will offset the new threads slightly toward the tailstock. (away from cutting pressure). You are not going to get an exact match.

Do not recut the original threads, this will only makethem sloppy. Instead cut thenew threads until the receiver will just thread on. They will be more pointed that the existing threads. The thread can be made tight even though the diameter in the center of the thread profile will be smaller than stock.

I cut this thread with a straight in feed which is the habit at Shoptask. I thought this might reduce the offset. It did not. Instead it just made a more raggedy looking thread than what I have been getting in steel using the compound rest. It works fine in brass this way as there is less of a requirement for high rigidity in the lathe. I cleaned up the thread with the two tiny files. The receiver threads on tight the whole length of new thread (I need a 1 foot wooden lever). This will help my lockup to remain complete over the whole barrel extension. I will still use blue Loctite. Next time I will use the compound rest and try moving the bit to the left about .003 inches before I start the new threads. I am satisfied with the fit this time though.

Winchester Model 70 Coyote (WSM action) in .308 Part II

Barrel Work

I mounted the barrel and aligned it radially and axially with the methods shown in Precision Rebarreling. After this I had to decide how much to shorten the barrel. Close inspection of the factory chamber showed that it was not as crooked as I first thought. This was good. It would allow me to put in a new chamber with out overly shortening the barrel. The .308 case does not have much body taper. It might take quite a length of cut with the chamber reamer before it will remove all of the old chamber. The barrel threads are 16 thread per inch. This means that each thread is 1/16 inch (1/ Number of Threads per inch). To keep the factory lettering aligned you would need to shorten the barrel a whole number of threads. I decided 7 threads or 7/16 inch (.4375 inch) would be the best compromise to insure cutting a completely new chamber and neck and also to leave enoughthreads on the end of the barrel for a good barrel to receiver lockup. I will again use blue Loctite as there is no way to expand the original thread diameter. (If I were cutting a new blank I would make the threads oversize to fit the receiver and use a custom thread profile that I describe in the book.) The new thread will have an interruption in the middle which will cause little problem as the thread is way oversize for the thrust involved in firing the cartridge. ( I have calculated this)

Parting

I used a high speed steel parting tool with coolant. The parting tool holders (flex slot) is welded solid for added rigidity. I got fairly continuous chips and fed the tool inward by hand. See photos 1 and 2. There is a slight 60 degree center in the breech end of the chamber to help feeding or for production reasons. I plan to put a similar center in the new end.

Coolant Nozzle from Grizzly

After sitting with coolant for a few months the nozzles leaked this time I used them. I was able to tighten the valves to cure most of the leakage. Some of the leakage happens in the plastic of the nozzle itself. This causes little problem in that it is always over the main pan. I am using a gold coffee filter in the pump itself to take out fines from the return oil that tend to clog my final after pump filter. Seems to work OK at this point.

Breech end Chamfer

The factory Chamfer on the breech end was not 30 degree (not a 60 degree center). I put a 45 degree chamfer on this end of the barrel to match the factory chamfer. I used a small boring bar on the compound rest to get my 45 degree angle. I fed the bit by hand with the compound rest feed wheel. I adjusted depth of cut with the carriage feed wheel.

Errata Data

Mon, 04 Jun 2007 16:49:05 GMT

A careful reader has pointed out an error in "Precision Rebarreling" on page 32 The bottom of the table.

The actual measure from the Go Gauge to the Shoulder should be .898 inch

Please correct your copy of the book if you have purchased one. Note that all new copies after this date are now correct.

John

Adding Larger Diameter Threads to a Tiny Shaft

Sun, 19 Nov 2006 03:51:47 GMT

I needed to shorten a small shock a bit for use on a Radio Control car. I needed to add 4-40 threads to the end of a 1/16 plain shaft on the shock in order to install the plastic shock end. We mounted a 5/8 inch long 4-40 set screw, which has an Allen head hole already, in a drill chuck installed to the headstock. We used a Cobalt 1/16 drill bit driven by hand to drill 3/16 into the Allen screw using the Allen hole as a pilot hole. This went very well. I then cut the Allen screw ¼ inch long and installed it on the shock shaft end with red LocTite. The project came out well and should withstand the rigors of racing this car.

Panhard Bar Mounts for an RC car

Mon, 19 Mar 2007 02:33:41 GMT

Panhard Bar Mounts for an RC car

Work continues on the 3-link Radio Control Car with Panhard bar. The second photo shows the location of the Panhard bar and the current mounts which work just fine but need an appearance improvement. I had made these out of tear away material to protect other parts of the car in the crashes.

The third photo shows a second prototype car with minor improvements without the Panhard bar. Testing has shown that the low left frame rail extension to which I mount the Panhard bar is plenty tough so the mounts can be aluminum. My nephew James has started machining new Panhard bar mounts in T6 Aluminum.

The fourth Photo shows a piece of half inch stock which we milled a 1/2 inch plus .050 inch slot. The part will be .70 inch long with a .2 inch thick ear hanging down on the left side of the car. We will produce four parts. We have set a .032 inch slotting blade up to saw the parts length wise. Use paper to set the cutter to height then we will downfeed .25 inch plus the width of the paper and the blade for the second cut. We had to Dremel a flat on this cutter's arbor to make it hold securely in the 3/8 inch milling cutter holder. The cutter worked fastestest and produced better chips with a standard shallow milling cutter cut followed by deeper cuts rather than taking the cut it all in one pass.

Cutting G10 and Graphite plate

All the G10 (phenolic fiberglass laminate) and Graphite plate on the back of this car is cut on a scroll saw and then sanded. I made some progress in finding a blade that would actually do the job. The problem is the material is very abrasive. I took a rod saw blate from my Hacksaw and cut it in half. This made a great blade. I could run the saw at full speed and it lasted a good while. Dremel makes a similar tungsten carbide coated rod blade for the scroll saw if you have time order these ahead of time.