Jump to content

Buchanan Automotive

FINANCIAL MEMBER
  • Content Count

    388
  • Joined

  • Last visited

About Buchanan Automotive

  • Rank
    Mulsanne Meister

Profile Information

  • Location:
    Sydney
  • Ride/s
    944S2/951/928/968

Recent Profile Visitors

1,680 profile views
  1. Buchanan Automotive

    911 3.2L or 911SC R/H/D dash cover

    Hi guy's ,we have a customer who wants to buy a R/H/D dash cover for his 1988 3.2 911 , I have had a quick look around on the internet and didn't see anything , does anyone know if such a thing in R/H/D exists ? , in L/H/D , much easier to find Note } When I mean dash cover , I mean one of those custom made dash top covers to protect the vinyl dash top from sun damage Thanks in advance Bruce Buchanan Buchanan Automotive
  2. Best I've come across, of course it does come down to the springs you use. The shock is only there to control them. We have about 4 street cars with the MCS and 2 with Moton many more crossovers or full track cars running them though. I personally use Moton in our own car but our new track car will be MCS. Just a little back story the owner of MCS use to co own Moton sold out to run his own company, that why i like both of them. Moton is now owned by AST. The one thing i do love about these shocks is their range of control. Most shocks even high end ones will only have a control of about 400-500 pounds. As in the last post these are just as happy with 200 pound springs as with 1500 pound. Just on a different note I'm all for keeping these cars stock as well but i can't help but to recommend a coil over kit, particularly for the rear (for 1986>) to save the customer some money in the long run as reindexing the torsion bars as what Sebastian would like to do is quite labour intensive for a spring and height change. Even after reindexing what might seem like over 100 944s in my 20years as a Porsche tech you can still get it out by a mm or 2. I guess thats why Porsche gave us that eccentric on the spring plate for minor adjustments. I would also hazard a guess that 6-8 hours to do the job i wouldn't consider ridiculous that includes a rear wheel alignment. Its usually more to be honest as when your in there you will find the rubber bushes on the spring plate to be shagged, you then have the option to burn them off and replace them with rubber / polibronze or entirely new plates, add an hour or 2 if you go the aftermarket bushes route Regards Sean
  3. Maybe best to skip the KW's Justin, PM me if you want some more info. The Koni kit from paragon is a great budget coil over kit, for the entry level price you can't beat it. Its good for an everyday 944 and the occasional track day 944. The Konis can handle a range of springs from around the stock 200 pound up to about 500 pound, beyond this they will need to be revalved. This kit comes from Paragon with springs next step up from the Konis would be the old Bilstein Escort cup, they are old tech but they are sturdy units. More track orientated and a much firmer ride, can handle spring rate from around 200 up to 800 pound. The KW's fit in here as well, they are newer tech but fall short in a few areas. The next step is when you get serious about good suspension. Motion Control Suspension (MCS), they offer both the non reservoir and reservoir shocks. from memory they are about $2700US for the non remote and $4500 for the remote. They can handle spring rates from 200 all the way up to 1500 pound. unbelievable build quality. The kit is targeted towards the racer so they are a bit short in the back, but we get them made up to suit both road cars and track cars. Personally this leaves only 2 real choices, the entry level Koni kit and the MCS kit. Springs are not included in the high range stuff so you need to but them yourself, a usual spring setup consists of 2 front main springs, 2 front tenders, 2 collars, 2 torsion release bearings and 2 rear main springs cost about $1000+au from Eibach. We don't sell any of this stuff its just for your information Regards Sean
  4. Buchanan Automotive

    RP968 wins World Time Attack 2018

    It an amazing car. Great vision from Rod and the team at PR Tech to make this monster. The incar footage is mindblowing. to think there is still more in this car to, you would have to think the official lap record will be broken soon
  5. Buchanan Automotive

    968 "Green Stripe " clutch pressure plate

    Hi Justin , you do not have to do the 3.0L 16v Turbo ( project ) like we did , we just wanted to use a known "Strong " clutch / drive-line set up from the word go & we knew full well that at 580+ HP accelerating flat out coming out of a corner at a race track with 11' wide rear wheels with new very stick "R" spec tyres , something has to give and a small"ish" 944/944S2 clutch will not do the job we need to make that part of the equation as reliable as possible , so hence the 951 set up Remember Porsche spent a lot of money at the time to change all those parts on the original 220HP 951 ( 1986 model ) , meaning from the very beginning the 951 had } Different bell housing Different flywheel ( larger contact area for a larger clutch ) Different ( larger / stronger ) clutch pressure plate Different ( larger stronger ) clutch friction plate Different clutch fork Different release bearing And all that re-engineering expense was for a 220 HP (1986 - 1988) 951 When you think of it , its all quite logical & its not rocket science Regards Bruce Buchanan Buchanan Automotive
  6. Buchanan Automotive

    968 "Green Stripe " clutch pressure plate

    Hi Justin , they are NOT interchangeable , meaning the 944 S2 ( stepped ) flywheel has to take the smaller diameter 944/944S2 clutch plate & matching smaller pressure plate ,where as the 951 clutch plate ( larger diameter ) will not fit , you can NOT intermix 944/944S2 flywheel & clutch parts with the very different 951 flywheel & 951 clutch plate ( larger ) 951 pressure plate ( larger ) , even the 951 release bearing is different , even the 951 clutch fork is different You can not fit a 951 flywheel into a 944S2 because the trigger wheel teeth number are different ( engine will not run ) , + you need a 951 Bell Housing & then a 951 engine wiring harness & 951 engine management system Now with Nik's old car , it started life as a standard 944S2 coupe ( 2nd hand car ) and Nik experienced the performance of Sean's 3.0L 16v 951 ( E85 fuel ) and was entranced . So we started with a 3.0L 944S2 , the advantage there is we have the 3.0L 16v engine & the low ratio final drive as opposed to the standard higher ratio 951 final drive ratio that we do not want , but we were going to NEED from the Very Beginning of the build the 951 clutch set up & the 951 flywheel ( different number of trigger teeth and correct dia for the 951 clutch ) , we then needed a 2nd hand 951 engine bell-housing & a 2nd hand 951 engine harness & 951 ECU's ( engine management ) & running a piggy back Vitesse system Naturally we had to lower the compression ratio of the engine , stronger aftermarket pistons & stronger aftermarket con-rods , custom made inlet manifold & custom made exhaust manifold & a Vitesse stage 5 turbo & the car runs two maps , one for E85 & another for 98 premium unleaded We knew from the start what we needed to control the 580+ HP and that was } 951 Flywheel 951 Bell-housing KEP II pressure plate ( for a 951 ) 951 / Porsche / NEW clutch fork ( remember we did this years ago when we could still purchase the new fork from Porsche ) Sachs 951 sport clutch plate ( because it will be driven on the road we needed to reduce shudder as much as possible) 951 release bearing The above clutch has been in the car for years and years & has copped a flogging & still working Regards Bruce B
  7. Buchanan Automotive

    968 "Green Stripe " clutch pressure plate

    Hi Mark , the slave cylinder ( I think that is what you mean ? ) is different on the 968 compared to a 944S2 as the bore dia is different which means different piston and seals , & yes the seal kit is only available for the 944 / 944S / 951 / 944S2 up to & including the 1991 year model & also fits the early 928 series slave cylinder ( up to 1986 ) Where as the clutch master cylinder ( R / H / D ) 931 , 944 , 944S , 951 , 944S2 up to & including the 1989 model part number = 478 721 171 is quite different to the Clutch master cylinder ( R/H/D ) 1990 year model onwards 944S2 , 951 & 968 , part number 945 423 149 00 Regards Bruce Buchanan
  8. Buchanan Automotive

    968 "Green Stripe " clutch pressure plate

    Hi Justin , as you know the clutch size & the flywheel size are different between the 944S2 & the 951 . So lets take the 944S2 , as a road car we only use the standard 944S2 "Sachs " clutch kit & the operating pressure is nice , meaning the clutch pedal pressure is quite light and as a road car , the Sachs kit is perfect 944S2 ( road registered ) and mostly used on the road , but occasionally used at a Porsche Club Supersprint events , the standard Sachs clutch kit is fine "So" long as the human driving the car at the track matches the RPM in down shifting perfectly , because the standard 944/944S2 road clutch plate ( friction plate ) will not tolerate too many poor down shifts that results in partial rear wheel "Chirp" / lock up , you will break the center out of these road clutch' s , we do keep in stock a competition clutch plate for this poor driving style , but the stronger 944 /944S2 ( track ) friction plate will cause a lot of clutch SHUDDER in road driving , very hard to live with as a road car , but it will not break on the track being driven poorly . We generally get the owner of the said car to supply what ever they think they want or they think is the "Go" -------------------------------------------- 951 ( road registered ) and even with some Porsche Club Supersprints , we find the standard "Sachs " clutch kit is fine , even with the 951 with around 350 - 400HP , no issues at all , however saying that we tend to ( on clutch replacements ) use a Sachs combination } Clutch plate } from Pelican parts ( example only ) the Sachs "Sport" spring hub .w/organic lining ( Higher Friction ) , these have less springs , but bigger ones , quite a good clutch plate , in fact Sean uses this very plate in his 580+ HP 3.0L 16v 951 Pressure Plate } Standard 951 ( Sachs ) pressure plate Release bearing } Standard 951 ( Sachs ) release bearing ---------------------------------------------- Sean's 3.0L 16v 951 uses } Clutch plate } The Sachs one mentioned above Pressure plate } KEP stage 2 Release bearing } standard Sachs 951 release bearing ------------------------------------------------ Regards Bruce Buchanan
  9. Buchanan Automotive

    968 "Green Stripe " clutch pressure plate

    This week we installed a new clutch into a customers recently purchased Porsche 968 & with this 968 being a near concourse condition 968 & with the customer very unhappy with the amount of effort required to push down on the clutch he ( the owner ) wondered was there something we could do to reduce the effort needed , because as is his wife refused to drive it & to give you some guide on what this car was like to operate the clutch , well, it felt just like my 968 & all the other 968's I / we have driven in the last 20 + years & thats because the only clutch kit you could purchase from Sachs "Never" ever came with the special 968 pressure plate , from Sachs the "kit" ( aftermarket least expensive ) pressure plate was for the 964 ( 911 , 1990-1993 "Blue Stripe" ) = heavier clutch pressure plate diaphragm spring. So even though this 968 was relatively low kms indicated and the overall cosmetic condition is exceptional I was pretty sure it has had a clutch replacement done at some stage in its life & it was the the Sachs ( aftermarket) 968 clutch kit & that means it gets the only pressure plate Sachs can supply = the 964 "blue Strip " one = heavier than normal clutch pedal pressure So we removed the old clutch from this 968 and sure enough it was the blue strip ( 964 one ) , but before I removed it I wanted to find out if Porsche Germany could still sell us the correct one ( green stripe ) = less pressure & correct one for the 968 & the great news was they had stock of the "green Strip" one in Germany & yes it has its very own part number , now this is where it get interesting because when I last enquired about these years & years ago they ( the 968 one ) was NA or even NLA which means you buy what you can & that made the Sachs ( aftermarket) kit the only choice . Note 1 ) When new the 968 had a clutch components ( 3 ) & dual mass flywheel made by three different companies , the pressure plate ( green stripe ) was made by Lockheed in the UK , but the 968 only clutch plate ( friction plate ) & the 968 only release bearing assembly were made by Sachs of Germany & naturally the dual mass flywheel was made by LUK of Germany & the 968 dual mass flywheel is unique to the 968 Note 2 ) Some years after the 968 was discontinued the Lockheed ( Porsche genuine only ,green strip ) pressure plate spare parts stocks were used up & at some stage later Porsche has had them remade & the new Genuine Porsche 968 "green Strip" pressure plate is made in Italy , how do I know its made in Italy ? , the one I ordered from Porsche Germany two weeks ago & when we opened the box , on the alloy pressure late casing it states "made in Italy " not the UK , like the rear original ones were , and it had the "Green Stripe " identification of pressure plate spring force So we did the usual , removed the old dual mass flywheel & had the surface lightly radial machined to get rid of the hot spots ( very important for getting rid of clutch shudder ) and being a relatively low km 968 , the condition of the internal springs within the dual mass were OK ( not many machine shops will or want to machine a dual mass ,because the surface moves unless locked in some way , new spigot bearing , new 968 Sachs friction plate , new Sachs 968 release bearing , new flywheel bolts & new pressure plate bolts & the new genuine Porsche "Green Stripe " 968 pressure plate Oh my God , what a difference , it brings back memories of what these were like when there were new at the Porsche dealership I worked at all those decades ago , its that good , nothing else compares to it for use as a road car I have already order the same for my 968 , its that good I don't even want to drive my 968 much more until I get rid of the incorrect pressure plate Regards Bruce & Sean Buchanan Buchanan Automotive
  10. Buchanan Automotive

    PCNSW Driver Championship 2018

    Today , EasternCreek ( Sydney Motorsport Park skidpad ) PCNSW Motorkhana no 4 and last one for the year & the decider on who wins the Motorkhana Championship for 2018 . But before we get into todays results , Sean Buchanan co -drove another 951 in todays Motorkhana , thats because Sean's 3.0L 16v 951 is out of action at the moment & we are waiting on parts from Germany ( it happens with old cars & metal fatigue ( I will give more technical details on another post ) & yes you can & and a lot of competitors do drive different Porsche models in the Supersprint & Motorkhana events because some Porsche models are way too hard to drive in Motorkhana events , like competition versions of the GT3 & GT2 are just near impossible to drive in Motorkhana events so the owners can drive their "other" Porsche in Motorkhana events , but Sean only has one Porsche and its out of action , so in this case you just nominate another Porsche mid stream so long as it has a lower power to weight ratio , meaning less performance , you can go down , but not up mid stream A big thank you to Andrew Hibbard ( Porsche Cayman GTS ) who rang Sean a few weeks ago offering his Cayman for Sean to drive today , Andrew & Sean were co winners of last years Motorkhana , meaning they had the same points score at the end of last year & Andrew couldn't make it to todays event ( long week end ) , but Sean had already lined up driving Chris Moriarty's 2.5L 951 ( 944 Turbo ) in todays event . Back to the Motorkhana , and as I mentioned it was the deciding event , on the first run, Sean driving Chris Moriarty's 951 hit a cone ( witches hat ) which instantly means you get a big penalty of many seconds added onto you time which instantly threw Sean back to 28th position ( yikes ) , meanwhile Paul Rodgers in his 986( Boxster ) kept his cool and placed himself in a good position & Chris Moriarty in his 951 keeps driving safely and smoothly and was holding a good position , Sean through the day moved up and up until he was running second place behind Paul in his 986 leading up to the final run of the day , & then Sean decided " alea iata est " and went for it flat out , remember its all about a fraction of a second that matters , but Sean spun out & the final results for the day Paul Rodgers in his 986 came in 1st place Chris Moriarty in his 1991 951 came in 2nd place Sean Buchanan in Chris's 951 came in 3rd place Not confirmed , but by our calculations , Sean Buchanan ( accumulation of points ) may have won the Motorkhana Championship for 2018 Wow what a year Regards Bruce Buchanan Buchanan Automotive
  11. Buchanan Automotive

    My 944 Cabriolet

    Hi Steve , I may be seeing things that are not there , but do I see cross hatching in one of the photos of one of the alusil cylinders ? , I /we have never seen that on Alusil cylinders , it may be a process I have never come across , but normally we see the cylinders with a NON cross hatched mirror finish The below is the process Honing Options for Hypereutectic Aluminum Cylinder Bores Background Alusil®, Lokasil®, Silitec®, DiASil, Mercosil, ALBOND® --- it sounds like a foreign language, but these are all trade names or trademarks for what is generically known as hypereutectic aluminum, a new/old material for cylinder bore wear surfaces. Hypereutectic aluminum is both new and old. Its cousins, hypoeutectic and eutectic aluminum, have been used for pistons and connecting rods for a number of years. Hypereutectic aluminum saw one of its earliest applications as the wear surface in an unlined cylinder in some Porsche engines in the 1960's. The 1971 Chevrolet Vega was the first true production automotive engine with a liner-less hypereutectic aluminum cylinder bore as the wear surface. Despite the car's reputation, the cylinder concept was ahead of its time. No matter what trade name is used for this alloy or how the cylinder was created, this material is something rebuilders should understand because it may represent the future of cylinder technology and will probably start showing up more frequently in rebuild shops. When properly finished, hypereutectic-aluminum cylinder bores present a surface to the piston rings that's roughly equivalent to glass [Figure one]. The resulting engine has lower friction, excellent sealing, improved dimensional stability, improved heat dissipation, reduced weight, better recyclability, lower manufacturing cost and higher durability - compared to the traditional aluminum block with cast-iron cylinder liners. Aluminum cylinder evolution. Since gasoline burned and forced a piston down a cylinder for the first time, aluminum has been the metal of choice when light weight was the most critical requirement for an internal combustion engine. This is as true today as it was in 1902 when the Wright Brothers were unable to purchase a suitable commercial engine for their experimental airplane and built their own, casting the aluminum block. Automotive OEMs seized upon aluminum for the same reason and found manufacturing advantages, too: lower cost casting processes and easier machining. Aluminum automotive engine blocks are pretty much the norm today, and the standard solution for a cylinder wear surface has been, and still is, a gray iron liner. While low-cost, durable, and easy to manufacture (the key decision points for OEM's), engines using the iron-liner solution have inherent disadvantages in weight, size, thermal conductivity, differential thermal expansion and recyclability. Consider that a minimum land width between cylinders must still be maintained, even with an iron liner. So the liner-equipped engine is still unnecessarily large, still has differential expansion and reduced heat dissipation issues, still needs a heavier and larger cooling system, etc. A major advance came in 1971 when GM used Reynolds A390 aluminum alloy in the linerless Vega block. A390 is a hypereutectic alloy saturated with silicon, such that silicon particles are dispersed throughout the alloy similar to chocolate chips in cookies. "Saturated" is the key word. Small amounts of silicon will dissolve in aluminum and become inseparable, but above the saturation point (the "eutectic" point), silicon will precipitate out in crystal form. Typically, this begins to take place at around a 12% silicon concentration, and the hypereutectic cylinder surfaces in use today range from 12% to 20% or more in silicon concentration. Depending on the manufacturer, traces of other elements likely to be in the alloy can include copper, manganese, magnesium, phosphorus and strontium. After traditional machining of the Vega engines, the factory cylinder surface was produced by chemical etching to create a surface where individual silicon particles protruded a small distance (perhaps 0.00004"/1 µm or a little more back then) above the aluminum cylinder surface. This process in cylinder preparation was, and still is, called the exposure step, whether done by the OEM or rebuilder. The intent is for the piston rings to ride on the silicon particles, not the aluminum cylinder wall. Hypereutectic aluminum cylinders have evolved considerably since the Vega. And while GM led the way with the Vega engine, today Europe and Japan are leading the trend to the linerless aluminum block. OEM's using the material include Mercedes, Audi, Porsche, BMW, Volvo, VW, Jaguar, Yamaha, and Honda. Manufacturers of power sport vehicles, outboard motors and compressors also use hypereutectic cylinders. Finishing without chemicals. For the OEM, chemical etching of the cylinder wall was a non-traditional process and an intermediate step. The OEM wants to pour the block and put it in a transfer line. Chemical etching also became increasingly burdensome as environmental regulations tightened. Whether it's in a rebuild shop or an OEM plant, the key to preparing the cylinder surface is to expose a tribologically optimized wear surface of silicon that withstands the grinding friction of pistons rings on the bore surface [Figure 2]. This requires relieving a small amount of aluminum from around the silicon particles. The ideal surface should have flats on the silicon crystals and crystal protrusion of 0.00002" to 0.00004" (0.5 to 1.0 µm) above the aluminum, with a minimum of holes (crystals torn from aluminum) and fractured crystals. The end product can be visualized as lily pads (hard silicon) sitting on still water [Figures 3 and 4]. Hypereutectic aluminum crankcases present another obstacle for metal cutting, which has led to advancements in the way the alloy is formulated. Silicon particles quickly destroy cutting tools. Several solutions have evolved. Tooling has improved with PCD and similar materials. Much effort has also been focused on improving tooling life by altering metallurgy to reduce silicon particle size, while retaining the excellent tribological properties of the hypereutectic surface. Based on SEM (scanning electron microscope) and VEECO-Scan studies of early cylinder surfaces and new products on the market today, it appears the silicon crystals have been reduced in size from about 10 µm originally to about 1 µm today, which would materially improve the machinability of the material. [Figures 5, 6, 7] OEMs also devised ways to localize and limit the use of silicon through the use of cast-in hypereutectic aluminum liners, selective die casting and flame-sprayed coatings. Casting the block around special liners complicates the molding step and production rate. Flame spraying represents an additional process step between the mold and the transfer line. The Holy Grail is the ideal combination of metallurgy, cutting tools and lowest-cost casting technology that allows machining blocks straight from the mold, and some OEMs have found it. Finished Cylinder Bore Specifications. On the rebuilder's side, Sunnen developed a GM-certified method for restoring a factory-quality surface for the Vega engine. Damaged bores were honed oversize using conventional abrasives, followed by an "exposure" step using a special lapping paste and felt honing pads. The process could be used with hand-held portable tools or honing machines. It produced excellent results and was ideal for occasional users. That process has since evolved, thanks to metal-bond diamond abrasives, and today there is a new honing option for OEMs or production rebuilders, as well as the low-volume rebuilder. It should be noted, too, that rebuilders have the option to use a replacement, press-fit hypereutectic aluminum cylinder liner available from Kolbenschmidt, if a cylinder is damaged beyond the point where it can be repaired by over-boring or honing. The honing process described here will work with this replacement liner, too. In our honing process development work, we found that no two manufacturers of hypereutectic cylinders have identical specifications - similar to the situation with plateau specifications for cast iron. Several block manufacturers have patented manufacturing technologies, so rebuilders can expect to see variety in the alloys and the physical make-up of the cylinder wall. There are, however, some generally common requirements for honing hypereutectic aluminum cylinders. First is the need for excellent geometry. Cylindricity limits of 0.0005" (0.013 mm) are typical. Limits are also placed on the percentage of fractured or displaced silicon crystals at the surface, which must be free of any torn or folded metal. Because the silicon crystals are distributed throughout the metal in a homogeneous manner, there will always be some that are nearly machined through and will be displaced from the surface. Specifications typically call for about 80% intact particles. There must be a minimum of sub-surface fractured material. This is largely a function of the prior boring step and the amount of material removed by honing. Lastly, the exposed silicon particles must protrude above the base aluminum from 0.000004" to 0.00004" (0.1 to 1.0µm). The exposure height is related to the size of the silicon particles in the alloy. Smaller particle size will mean less exposure height. Average exposure height today is about 0.00002" (0.5 µm). Honing Process. Assuming the cylinder was bored using high quality machinery and PCD or equal inserts, the honing process will have two or three steps: honing, finish honing and exposure. From a honing standpoint, working with hypereutectic aluminum is somewhat the reverse of working with cast iron - the end result is measured as a desired roughness or peak height of the exposed silicon. The essence of the honing process for hypereutectic aluminum is to first produce an ultra-smooth, mirror-finish surface with the initial honing steps, then finish with an exposure step that will actually increase the roughness, as measured with a Profilometer, by relieving softer aluminum from around the silicon. The desired end result is an exposed surface of rounded-edge primary silicon particles. Tooling for the initial steps should be selected according to traditional guidelines for high-precision honing. Machine settings, such as RPM, stroking speed, stroke length, etc. should be similar to those used for ordinary precision work. Feed rates are selected to complement the part geometry and abrasive characteristics. All abrasive should be fully trued to produce 100% surface contact at the diameter corresponding to the finish-honing step. Crosshatch angle is less important than with cast iron and will typically be rather flat (5-10 degrees) due to the slow stroking speed. Instead of a crosshatch, the aluminum cylinder relies on the area between the silicon crystals to hold its oil film. Keep in mind that the goal in the initial steps is produce a very accurate bore with a fine (mirror) finish. MAN-845 Honing Oil is the minimum requirement and it should be filtered to at least 0.0004" (10 µm), preferably 0.0002" (5 µm). No water-based coolants should be used. In our process development work, we found that high-performance EP oil caused a sludge build-up, which impeded contact with the ultra-fine honing grit used in the exposure step. This is the result of the extreme surface area and high energy found in freshly cut, ultra-fine metal chips. These conditions facilitate far more aggressive chemical activity with the oil additives than would be experienced with larger metal chips. In most cases, the first two honing steps can be accomplished with conventional or diamond abrasives [Figure 8]. However, because of the high value of these engine blocks and the wide variety of OEM materials and manufacturing methods, it is critical for a rebuilder to know the exact recommendation for reconditioning abrasives or consult a honing abrasive supplier. Some cylinder materials may simply require metal-bonded diamond for all of the steps. Conventional abrasives with bronze guide shoes are unquestionably the most economical option for infrequent work with hypereutectic aluminum. In production or OEM work, diamond is preferable for the first two honing passes. The first honing step may not be required if the block has been bored with a final finish of <=19 µin. Ra (0.5 µm) If necessary, as a first honing step we recommend removal of 0.001" in. (25 µm), using classic abrasives or a 29 µm diamond, to produce a finish <=19 µin. Ra (0.5 µm). The second finish-honing step removes 0.0001" (2.5 µm), again using traditional abrasive or a 9 µm diamond to produce a finish <=3.9 µin. Ra (0.1 µm). The final exposure step requires a new specially developed, elastomer-bond abrasive (XM27), using light honing force. For the exposure step, we recommend tooling with the greatest abrasive surface contact area. This step is based on time, typically 1-1 ½ minutes for 19 µin. (0.5 µm) exposure height. Longer cycle times are not harmful, because the process is somewhat self limiting. It is absolutely critical that honing force or pressure be kept as low as possibly, while still maintaining tool stability. Surfaces shown in the accompanying illustrations were honed with less than 5 lb/in2 pressure. The elastomer based -stone- [Figure 9] is purpose-designed to overcome three limitations of rigid abrasive in the silicon exposure process. First, the elastomer serves as a cushion, deforming to allow individual abrasive particles to literally bounce over the silicon particles, while still being rigid enough to cut the surrounding aluminum. Second, the elastomer dampens or limits the overall force applied to the abrasive, making the process very forgiving of variations in pressure from the honing machine feed system. The honing tool diametrical expansion does not have to exactly match the rate at which the cylinder is increasing in diameter from stock removal. Third, the elastomer conforms to any taper or out of roundness in the cylinder, allowing it to remove very small (0.00002"/0.5µm per side) amounts of material, uniformly throughout the cylinder. With rigid abrasive, any out of roundness in the bore would result in abrasive cutting pressure variations as the honing tool rotated. Critical Point - Process Verification. Any shop planning to do work on hypereutectic cylinders must have a Profilometer® or similar instrument for contact surface texture measurement to verify results. The instrument should produce a trace, not just a readout, and must be capable of Rk, Rpk and Rvk measurements. These engine blocks can cost $4000 or more, so honing without a Profilometer to verify results would be negligent. Prior to the exposure step, the Profilometer will should show a very smooth surface <3.9 µin. Ra (0.1 µm), which becomes rougher - according to the instrument - after exposure. This is because the instrument senses the exposed silicon crystals as surface finish features (peaks). Several traces of the stylus across the surface may be needed before the stylus hits a silicon particle to verify peak height [Figure 10]. The absence of a peak means you probably need to make another trace. The presence of a peak verifies success. If no peaks are encountered after 8-10 traces, more time on the exposure step is needed. Hypereutectic aluminum is not yet a mainstream material, and the different alloys and OEM manufacturing methods ensure there is no "standard" to refer to yet. However, the honing techniques outlined here were developed for OEM use and can easily be practiced in rebuilding. Nevertheless, until it becomes as familiar as cast iron, rebuilders may want to proceed with caution, and consult a honing abrasive supplier as needed.
  12. Buchanan Automotive

    Engine oil for 930?

    20w-50
  13. Buchanan Automotive

    How does the CEB look?

    As an interesting sub-note , the 1984 928S CEB ( fuse/relay board) , was the last year model to use the traditional 1960's / 1970's ceramic fuses , where as the 1985 year model 928s was the first Porsche model to get the next generation of fuses & fuse holders design ( blade ) & naturally a completely different CEB with newer more secure multi plug /wiring loom connections & different wiring looms at the base of the CEB , and on the subject of electrics , the 1985 year model was the first to get the much larger very powerful ( for the mid 1980's) 115 amp Bosch alternator & it was so large Porsche had to discard all the 1984 & earlier steel support brackets on the front of the engine for the smaller earlier ( >84) French alternator and Porsche cast & machined no expense spared alloy support brackets , even the power steering pump had to be changed to accommodate the larger alternator ( 85> ) Even the dash instrument cluster backing plate , circuit board & the multi plug connections were ( on the 85> ) the newer / completely different design , where as the 1984 had more in common 1983 and earlier design , along with heaps of other things , this makes the 1984 928s an interesting car because its a transition model between the older original K-Jet 928 year models & the newer next generation 928S ( with Luft Hotwire injection )& into the 928S4 Note } when I mentioned Ceramic fuses , be careful when purchasing new fuses( replacements) for any last century Porsche that has these fuses that you DO NOT buy the Chinese cheap copies that are made from plastic , you can still get these in the correct ceramic , but you have to specify & yes the plastic copies ( they are hard to pick the difference ) will melt & lose contact , particularly on a high amperage circuit like fuel pump & yes it will stop the car The early Ceramic fuse design was } 928 up to 1984 911 up to 1989 944 up to 1985 924 / 931 ( all ) Regards Bruce Buchanan Buchanan Automotive
  14. Buchanan Automotive

    How does the CEB look?

    Being a 1984 year model & most likely an Australian delivered ( new ) 928S , there is something you need to know about the CEB ( central Electric Board ) in relation to whats printed in the Porsche owners manual & even the Porsche ( pocket) spec book for the 928S 1981-1984 , they are both incorrect in relation to some fuse and relay positions The below info is only for the Australian & UK delivered 1984 year model only ( not USA / Canada etc ) Owners manual states that Fuse number 13 is not used } Incorrect fuse 13 is the fuel pump fuse Owners manual states that fuse number 22 is the fuel pump fuse } well that's obviously not the case Owners manual states that relay VIII is not used } Incorrect , relay VIII is the ignition ECU power up relay Owners manual states that relay XVI is not used ( except L-jet USA) } Incorrect relay XVI is the Fuel Injection ECU power up relay Note } the 1984 year model ( Euro / Australian version ) was the first model to have Luft - Hotwire electronic fuel injection where as the 1978-1983 models had the more mechanical K-Jet fuel injection & the 1984 year model owners manual was not changed in time & it causes a lot of confusion Regards Bruce Buchanan Buchanan Automotive
  15. Buchanan Automotive

    My 928s back on the road

    Yes I know what you mean , I agonised over this very subject ( for about 10 minutes ), but in the end its a car that is way too nice to drive from time to time , we have covered the entire underside of the cars components with a similar Cosmoline type of product that Porsche used the the 1980's , but in a more clear version , meaning not as brown in colour , and applied it with a lot more care for detail than a car maker will do , so every nook and cranny , every nut and bolt , every bracket , every alloy component , be it suspension or transmission is covered in a very uniform covering , this means that if or when we want in the future we can apply hydrocarbon liquids ( like kero or the like ) and it will all wash off which revealing ( again ) what we see in the photos . The other great thing about this type of slightly tacky to the touch under-car sealing , it just that , it attracts dust extremely well when warm and this helps in the covering of the components for future revealing , because if the components were left in the uncovered state that you see in the photos & the car was used on the road ,surface corrosion will set in very quickly & the "Look" will be lost , so very careful sealing for the future is vital ( but photos first ) On a side note , now that I have driven her , I am very pleased with the increased performance & extra engine braking from the increased engine compression & state of overall tune + the fantastic V8 exhaust sound , its the best 928 of this vintage I have every driven & naturally the A/C / climate control / ventilation system is just stunning Regards Bruce Buchanan
×