MyE28.com

Lucifer's Hammer Series Index: Part 1 • Part 2 • Part 3 • Part 4 • Part 5 • Part 6 • Part 7 • Part 8 • Part 9 • Part 10 • Part 11 • Part 12 • Part 13 • Part 14 • Photos

We are dug out from the recent snowstorm. There was two feet in Denver; about 3 at our place. We were housebound for, what, 24 hours? BFD. Listening to the media bleating, you would think that driving thru Denver was Napoleon's Retreat From Moscow. What will you do when Winter gets here?? What will you do? What WILL you do?? Jagoffs.

Rant over. Back to this drizzle.

10/22/04 Piston rings are in from Total Seal.
Test powdercoating looks good.
Getting the turbo CHRA properly oriented for oil and coolant flows is being a headache. We can get the oil outlet to locate OK at a 7:30 position, setting up the inlet on the opposite side as circumstances require. Can't quite get to an ideal vertical alignment, however.

10/26/04 Spoke with Raceware about their having head studs for the S38. Can do, but might be 2-3 weeks. Cost around $250 for the set of 14; info forwarded to Paul.
There are some potential problems with clearances around the sides of the block and manifolds for the power steering and A/C pumps and hoses. Bimmerhaus has another client's M5 in the shop at the moment, so Mark will have a look and get some installed dimensions on the A/C pump. This is the first time Paul has sounded rattled about anything on the motor.
Went into SCE and Gasket Works websites for info on their products. Gasket Works uses annealed pure copper sheet, recommends using YAMMABOND and Hylomar as sealants around the water and oil galleries to control seepage. They also have a proprietary product used to aid in sealing the copper-to-block/head interface. Question comes up about the need to retorque the head after break-in or at intervals thereafter. They concede copper gaskets do need retorqueing and are prone to weep. Probably not an issue on an OHV motor in a drag car where the motor is pulled frequently, but pulling an S38 open to get to the head bolts/studs is not trivial.
"YAMMABOND" is a sealant Yamaha sells for their crotch rocket motors. Effective and readily available, FWIW.
With info on possible head gasket thicknesses, the compression ratio will be between 8.6 and 8.9 to 1. We are leaning towards using the SCE gasket which has a cutting ring feature.
Paul isn't having a whole lot of luck getting through to HPC in Salt Lake on the turbine and head coating situation. Swaintech is being vague about when they could get an order completed, so we are pointing towards PolyDyn or Calico.
Called Todd at TCD regarding any experience they have had with Raceware vs. ARP. Both good, just follow directions.
Todd thinks the stock head gasket should be fine at 15 psi. They have run upwards of 20 psi on a stock-gasketed M30 without problems, tho' I have pics of a definitely blown gasket from a myE28.com post published by TCD. Todd regards the gasket as the fail-safe link in the motor in case of an overboost condition. Given Todd's experience with FI, a point worth noting.

10/29/04 Rear seat hedrests here from Dave Maisenhelder. Condition OK. Headrests now at European Auto Interiors for recovering to match the "Natur" interior.
With the clearance info from Mark, the power steering pump and hose clearances shouldn't be an issue. Jury is still out on the A/C.

11/1/04 The block has been ground six ways from Sunday and hot-tanked, with the mung boiled out of the water jackets. New freeze plugs in, block now ready for painting. Glyptal for the crankcase interior is coming from Eastwood.com.

Sidebar: Glyptal is an enamel with high dielectric properties. It also has a very low affinity for oil or solvents. It is used to provide corrosion protection in industrial electric motor housings and on power plant generators. When applied it leaves a very smooth surface and fills pores and unevenness on castings. Because oil "sheets" off of Glyptal, it aids in crankcase oil return and significantly reduces any sludge buildup inside the motor.

Where feasible, other raw casting surfaces will also get Glyptal coated, including the water pump area on the block. See doggunracing.com/mye28/LucifersHammer Page 1, images 20 & 22. When the pictures were taken, the pump area was awaiting further die grinding and smoothing of the opening into the coolant galleries.

Paul has talked with HPC. Some issues regarding their willingness to guarantee durability of the ceramic coating inside the turbine housing. He still wants to talk further with Swaintech before making any decision.

No luck on head studs through ARP. Nothing in their catalog that will work. Raceware has sent a price sheet, but no sample for physical assessment (dimensions, etc.) as Paul had requested. So there are some questions about whether we want to use these guys, or simply go with the stock BMW head bolts. In this regard, if we use the SCE gasket with the self-locking ring, the pressure from the stock bolt torque may be sufficient to give us needed sealing.

More discussion on the turbine clearance issue. Cutting the plenum will provide sufficient clearance, but no heat shield out there in the parts aftermarket that looks like what we need, so this one comes from scratch.

11/9/04 Work has slowed down significantly. Until the rods are here, not much more to do on the short block.
Main cap bolts not yet in from ARP.
SCE thinks about six weeks on delivery for the head gasket. We have some thickness choices to make. .062" will give 8.96 CR; .072" = 8.79; .080" = 8.66. The thinner we go, the better the efficiency at the squish areas. This would mean better gas mileage, but there are concerns about the valve-to-piston clearances at the "eyebrow" clearance cuts being too close for peace of mind. The S38 is a "zero clearance" motor, and while no shaving was done on the head, and only the lightest of skim cuts (~.0006") was done on the block deck, the clearances with the piston at TDC are very close. The tradeoff with the thicker gasket is somewhat lower efficiency, but with the octane generally available on fuel, the thicker "non-boosted" CR may not be an issue.
Examination on the oil pump indicates it is bone stock. May require using button-head bolts where it comes close to the con rod big ends. See doggungunracing.com/mye28/LucifersHammer Page 3, images 69 & 70. We won't know for sure until the rods are in hand from Carillo, hopefully in the next couple of weeks.
Still working on the turbo oil line fittings for the pan. The adaptor and cover plates for the oil filter are roughed in on the mill.

11/15/04 Rods are here. Look good. See doggunracing.com/mye28/LucifersHammer Page 1, images 13 & 14. Ditto Glyptal. Block is about halfway done on the painting. Taking more time than we thought--prep work was fine, just taking several thin coats to get a good apperance and proper coverage.

11/19/04 Crank balancing complete, as is the flywheel, clutch and harmonic balancer. Crank was out ~8 grams. Now at zero. Yes, zero. Flywheel was also balanced to zero; was out ~6 grams. Harmonic balancer was out ~ .5 gram, now zero. Campbell knocked themselves out on this. I am profoundly impressed. The balancing on the crank was done by shaving the counterweights and not simply by hole drilling. Nice work. Piston and rod assemblies have also been matched for weight and optimized cylinder clearances.
Paul trying to find out whazza story on ARP sending the main cap bolts.
Location worked out for the knock sensor. Will live on the passenger side of the block and replace the block coolant drain. See doggungunracing.com/mye28/LucifersHammer Page 2, image 28. We may have to drill the area out and put in a permanent boss, as how deep the sensor will protrude into the coolant galleries needs to be looked at. So when the coolant gets drained, it's pull the knock sensor out.

11/22/04 We have a concern over the crank hub. Specifically, is the hub Paul has in hand (a) the one I got from Fahey 8/26/02 and installled on the original stock crank, or (b) a stock BMW hub? The Fahey hub was on the motor when the car was delivered to EB; the stock hub, for whatever reason, went down as well in a box of extra parts. I can't find the not-used hub among any of the parts I picked up at EB's in August. Called Fahey today and asked him about any identifying configuration. Fahey sez the stock hub has a groove machined into the outer perimeter of the flange; his does not, and is also black oxide coated. The hub at Paul's doesn't show any black oxide. This might have been media-blasted off while at EB's, but no way of telling. The hub doesn't have a machined circumferential groove. Fahey has hubs in stock, but I'd rather not spend $350 plus shipping if I don't need to. Based on my description of the hub, Fahey sez it is off a 633. So what happened to my Fahey hub? Draw your own conclusions. New hub on it's way, should be here around December 1. See doggunracing.co/mye28/LucifersHammer Page 1, image 17.

11/27/04 Turbo mounting flange gasket in from Limit Engineering (another non-found part). Turbine and mount going out to PolyDyn in Houston for ceramic coating. Head gasket (SCE) and main bolts not in hand yet--hoping for this coming week. ARP is being really slow on the main bolts; why, we have no idea. New BMW head bolts ordered; Paul won't reuse the old ones--probable stretching.

Reciprocating mass numbers:

Piston proper: 388.5
top ring: 10.2
# 2 ring 11.2
oil ring 11.0
aluminum pin caps 18.4
wrist pins 117.3
rod bearing shells 48.0
rods proper 575.0
rod bolts 66.1

Total mass: 1245.7 grams. Max variation over the 6 assemblies: .2 grams

11/30/04 The Benz rod bearing shells installed on the rods interfere with the fillets on the crank journals, and must be chamfered .050". Once machined, they fit fine.
Thr head gasket is "still in engineering" at SCE. In other words, not started yet. We are both getting worried that this may delay assembly on the motor.
The main cap bolts are in from ARP. Isn't that amazing !! See doggunracing/mye28/LucifersHammer Page 1, image 18.

12/9/04 The replacement Fahey crank hub is installed, and the crank fitted to the block. See doggunracing/mye28/LucifersHammer Page 1, image 11, Page 2 image 26.
The gas tank has been pulled to verify no rust problems (there are none), figure out how the fuel pickup is going to be configured to support a larger pump and lines.
Looking like I'm going back to see things first-hand in about a week.

The next chapter gets into a whole lot of numbers related to turbo sizing and it's red-headed stepchild, fuel system capacities. 8)

No real msg, just want to encourage you to keep up the story.

This is such a great story. I've got questions on everything from how long the primaries are on the tubular turbo manifold to piston configuration (how far is the top ring from the top of the piston) to whether the the crank received an additional nitride treatment after balancing. The approach taken seems particularly suited to a high altitude car.

I'm looking for things that can be applied to the Dinan turbo project for my M635CSi so each contribution by Ken is looked forward to.

M635, the tuned length of the headers (exhaust port to turbo inlet) is approximately 60 inches This is based on the formula Lt =(Eo x Vs)/N, where Lt is the tuned length, Eo is the exhaust open period in degrees, Vs is the exhaust pulse wave speed in feet per second, and N is the crankshaft speed in RPM.

In my case, Eo is 248 degrees--we used a stock S38 cam on the exhaust side. Vs was assumed to be 1700 feet per second. This is a nominal sea level value, and we had no way to measure the true number--the engine being built at that point. N, or rpm, used the calculated max rpm we had derived from the formula 600,000/stroke length in mm, 95 mm in my case. this gives a redline of 6315 rpm. So (248 x 1700)/6315 = 66.76 inches. The actual length is a bit short, but we used what space we had available, so the length isn't optimal. The path of the headers is downwards and forward on the RH side of the block to the front of the oil pan, across the front of the pan, then slightly aft and upwards to the turbine inlet. See the photos in the http://www.doggunracing.com/mye28/LucifersHammer collection.

Keep in mind that it isn't just header length, but total header volume that determines the exhaust efficiency. In my case, the ID on the exhausts where they leave the ports is 1.625". When they merge into the collector that goes to the turbo, the ID is 2.00" This sizing allows the gas velocity to stay high and maintains the speed needed to minimize lag on the turbine exducer wheel.

Ring location on the pistons. The pistons were designed for an FI application and are forged from 2618 alloy. The crowns are ~5.1 mm thick, with the top ring located ~6.7 mm down from the crown. A case can be made that the crown should be thicker and the top ring millimeter or two further down, but I have to trust JE's judgment here. However, the nature of the denser forged alloy acts as an effective heat sink and aids in extending ring life.

The rings themselves have an axial depth of 1.5 mm, 1.5 mm and 4 .0 mm on rings #1, 2, and 3, respectively. The corresponding annular depth is 3.68 mm, 3.99 mm and 4.57 mm. Theradial thicknesses are not standard, and had to be cut on a CNC lathe prior to the moly coating at Total Seal.

Getting the ring placement correct and not potentially put the oil scraper (#3) ring too close to the wrist pins was a really neat trick and JE deserves a lot of credit on this.

As to the crank's nitriding. The nitriding is done in an ammonium nitrate bath along with the crank being cryogenically stress-relieved. One wants the journal surfaces and points subject to wear to have the hardening, which with nitriding extends .002"to .004"into the steel. Hardening elsewhere can make the part more brittle if subjected to shock or stress. So to answer the question, the answer is No, the crank was not renitrided, the metal being removed from unstressed areas, mostly on the counterweights. 8 grams removed over the entire crank didn't move very much metal by volume.