1939 Wraith Engine Overhaul
Detroit, Michigan

Part II - Assembly


August 14, 2007

It's been a few weeks, but quite a bit has happened.

The RROC National Meet was a bit smaller this year, but the location more than made up for it. This is a view from the judging field at Skamania Lodge in Washington with a view of Oregon in the distance.

All of the parts are back from being cleaned. Here are the upper and lower crankcase.
Remember the block? How's this for clean?
Crankshaft is cleaned and polished. Journals are in spec, no need to turn down.
Here I have begun to reassemble the lower crankcase. Doesn't look like much, but it took me three hours.

August 15, 2007

Here is the oil level float assembly installed.

My good friend Jeff has volunteered to sand-blast a bunch of stuff in preparation for painting: tappet chest and water jacket covers, upper radiator hose connection casting, generator straps and the exhaust bracket mounted to the sump.

Talked to Restoration Stuff, Fiennes Engineering and RI Wiring today. All kinds of packages coming that include valve stem seals, wiring for the whole car, fender welt and water pump grease.

August 27, 2007

All of the "stuff" has arrived including the new pistons. John at B&F has the valve stem seals and clips from Fiennes. He will have the head done Monday or Tuesday.

Here's part of the generator drive going back in to the upper crankcase. That steel spacer at the bottom of the taper is chosen to net end play of 0.003".

Originally, the "fitter" had a half dozen or so spacers of different thickness to acheve this.


In my instance, the end play is 0.007 in. Since I do not have all of the hardened steel spacers at my disposal my choice is to live with it or tweak the torque on the large (left hand threaded) nut. You may recall that during disassembly, I did manage to reduce this to zero through inadvertant overtightening.

Here I have installed new cotter pins in the original Rolls-Royce style. The head of the pin is twisted 90 degrees to the legs so that they can be bent around into the adjacent teeth of the castle nut.

Bear in mind that this is heavily magnified. The diameter of the bolt is 0.250 in.

The front bearing assembly consists of two bronze bushings that are pressed into an aluminum housing (not shown). They have spun in the housing and are now a slip fit. The front bushing is shown removed and the i.d. appears to be machined undersize. Correct clearance is 0.0015-0.0030 in.

Hopefully, I will be able to remove the rear half without destroying it. Then the cam can be polished and the bushing id's enlarged (lapped?) to get the proper clearance. Then they can be installed in the housing with Loctite 620 retaining compound.

August 28, 2007

Forgot to mention: at the RROC meet, I finally found the correct center foglamp bracket for the Wraith after a year and a half of trying. Had to trade equivalent brackets that I had for the 4-1/4L Bentley and Rolls-Royce Phantom III.

This one originally belonged to a Hooper-bodied Wraith Limousine that perished in a fire. For some reason it's brass plated (sort of). We'll correct that in due course.

Got the cylinder head back today. Now it's pretty much down to me to finish this thing other than line boring the mains.

September 12, 2007

I decided to have a machinist remove the bronze bushing mentioned above. In preparation, all five intermediate bearings need to be removed. The bearing halves are held together with these spring clips. (Each bearing assy is then held in place in the crankcase with dowel pins.)

Naturally, all the pieces are separately bagged, numbered and marked so that they can be reassembled in exactly the same position and orientation.

I regret not bringing my camera to Bob Archambault's shop in Fenton. He chucked the camshaft in his lathe and removed the bushing by turning it. (For the non-geeks: "turning" as in removing concentric layers of metal a little bit at a time.) Easy as pie as long as you know what you're doing! Here's all that is left.

Now he will make me a new set of bushings with a slightly enlarged O.D. to match the worn housing. We decided to make these from SAE 660 bronze.

September 18, 2007

A banner day today. Received the complete bearing housing back from Bob. The bushes look perfect plus they stay put in the housing AND allow the camshaft to turn! He also Tig welded the ear shown in the 4 o'clock position that I managed to break off.

Also received the re-polished crankshaft from John at B&F and it looks great.

Tomorrow morning I plan to order main bearings from Fiennes.

As a side note, McMaster-Carr sells stainless steel pipe brushes with sizes in 1/4-in. increments. You can buy two sizes: 1-1/2 in. for the main bearing sludge traps and 1 in. for the big end sludge traps. Makes the cleaning process much more efficient.

Here we have the crankshaft with all of the aluminum sludge trap bungs in place. Only three of the 26 kotter pins are installed as of yet. Maybe I should leak test it first!?

September 20, 2007

The intermediate camshaft bearings have these nice markings to identify the mating halves as each bearing pair has a different number. In addition, each pair is oriented with the numbers facing the rear of the engine.

Bearing #5 appears a little fried but we'll give it a try as there is no perceptible dimensional change. The locating dowel pin that keeps it from spinning is hollow and serves as the oil supply. The pin that held this bearing in place had some gunk down at the tip preventing oil flow.

Here's the camshaft reassembled with the intermediate bearings all lubed up with assembly paste. (Distributor drive to the left has nothing to do with anything at the moment.)

Inserting the camshaft assembly into the upper crankcase is a rather tedious affair but I suppose it is easier than if it were a straight eight.
The key is to get the little holes atop each bearing lined up with the mating hole (out of focus to the right) so that the dowel pin can be pushed home.
The rear bearing is a machined aluminum casting. The locking tab washers are not all the way home as I may have to disassemble.

Front of cam with fibre drive gear installed temporatily. End play is measured at 0.016 in. It should be 0.003 in. There's a select fit washer just behind the front thrust bearing assembly that will have to be swapped out with a new one that I'll hopefully get Bob A. to make for me.

While he's at it, he can make one for the generator drive in the background. End play is 0.007 in. and also needs to be 0.003.

Gear lash appears to be near nil and certainly not binding.

September 23, 2006

On second thought. the generator drive end play was so close to spec, I tweaked the reverse-threaded nut about an eighth of a turn et voilá 0.0029" end play.

Block prepped with lacquer thinner and primed with two coats of Eastwood Rust Encapsulator.
Many small parts similarly prepped and primed.

September 25, 2007

It has been too humid to paint for the past two days. Here the upper crankcase is shown with its complement of studs 75% reinstalled.

Many of the threaded holes had to be chased with their respective (BSF) taps because there was just enough corrosion on the threads to make life difficult.

The main bearing studs have not been tightened, yet. Speaking of which, my main bearing order from Fiennes will take 3-4 weeks from now to arrive.

October 3, 2007

Bob finished the new camshaft spacer. In the end, it is 0.0790 in. thick which is within the very tight spec I gave him.

The end of the shaft is tapered, once the spacer is pushed against the bronze bushing it's a close fit.

With everything installed, the new spacer gives an end play of 0.0039 in., which is perfectly acceptable. The number may even shrink a tenth or two after I check the torque on the nut tomorrow.

Oct. 9, 2007

Here we have the bottom of the oil pump spindle where it will mate to the oil pump. End play should be 0.0030.

This spindle is driven by the generator drive gear via a worm gear.

Here we have the drive gear in the distributor drive recess at the opposite end along with the old spacer washers in their former spots.

(Take my word for it.)

With all of this in place, end play worked out to 0.0031. I'm a little concerned about how sensitive the reading is to torque on the nut as I can torque it to zero end play pretty easily. Maybe I should go a few thou thicker on one of the spacers.

I'll have to take it apart again once I am ready to set the distributor drive correctly relative to crankshaft position.

In other news, I decided to replace the original rods with Bentley Mk VI rods which use modern steel shell bearings. Here are the new rod bearings from Albers. Rods are on their way from Tony Handler. The parts bill for this project is escalating rapidly!

The block and ancillary items have their final topcoats of gloss black applied.

One of the front fenders is almost removed to facilitate engine bay cleaning and wiring. Besides, the fenders need some rust repairs underneath where they meet the running boards, anyway.

October 15, 2007

The main bearings arrived from Fiennes as promised. While they were on their way, Todd Nagler convinced me that I should have my crankshaft balanced so that I can preserve the Wraith's legendary smoothness and silence.

Since all of the reciprocating elements need to be weighed, I need to wait for the Mark VI connecting rods to arrive and then plan to get the job done at Cornell Engineering in Troy.

October 22, 2007

There's plenty to do while I wait for those rods. Here I'm cleaning the paint out of the threaded holes on the block with a 2BA tap.

The block can be used as a precision screw holder to paint all of the screws.

Altoids® tins are great tap and die storage devices. You will note that the tin is for the rare ginger flavored ones.


Here are the water jacket covers all neatly covered up with fresh die-cut gaskets. Yes, I will retouch those two nuts that hold the fuel lines.

Next on the docket is to finish removing the front right hand fender.

October 28, 2007

Yesterday, we toured four of Detroit's cemeteries to pay our Halloween respects to deceased automotive greats.

We saw the graves of Henry Ford, Henry Leland, Alvan Macauley, Robert Hupp, David Buick, Henry Bourne Joy, the Dodge Brothers, to name a few. The Dodge Brothers are buried only about a mile from Sherbourne Mews.

The weather was miserable. This set back the Wraith timetable this AM because the Silver Shadow had to be cleaned top to bottom.

I resumed removal of the right front fender. This gem stone fell out of the fender welt onto the garage floor.

I have no idea what it is. I'm assuming it is a replica as opposed to the real thing. It's pretty small: if it were a diamond, it would probably be worth less than $1K.

After fussing with the spare tire carrier brackets, the fender came off without protest.

This is going to make it much easier to clean and rewire the engine compartment as well as make the reinstallation of the engine a bit more graceful.

The fender needs to be repaired at the end where it butts into the running board.

It is a rust prone area because it catches mud, moisture and stone chips kicked up by the front wheel.

October 30, 2007

For those of you that remember my Chocolate Lab Dave, he passed away yesterday. He was about 10-1/2.

I took today off from work to clear my head with some therapeutic suspension and frame cleaning.

This is the right hand spring and damper assembly. The coil is mounted transversely in the large, oil filled cylinder beneath the upper control arm. The copper pipe behind feeds the automatic jacking system.

Here's a photo of Dave watching me try to remove the fender from the Wraith about three weeks ago. Boy, I miss him.

November 3, 2007

Finally found a stud tightener that I like. Here is a view of torquing one of the 5/16-in. studs that retain the main bearing caps.

The Bentley Mark VI connecting rods arrived on Halloween. If all goes according to plan, I'm going to drop off the crankshaft, pistons, rings, conrods and conrod bearings to be weighed and balanced this Monday.

Next major step is to get the upper crankcase in a proper state so that the main bearing can be line bored, preferably with the block and head installed.

I should have waited to put the camshaft and distributor drive in, all that will have to come out so that it doesn't pick up any swarf from the boring operation.

November 10, 2007

Time to install the head bolts. These are threaded into the upper crankcase and run through the block and head. A high quality connection is imperative, so all 26 5/16-BSF holes have been chased with a tap and cleaned with a bottle brush and kerosene.

All of the head bolts have been installed. They come in three different lengths: 12.25, 12.50 and 12.65 in.

This past Wednesday, the crankshaft and associated connecting rods, pistons, bearings, etc. were dropped off at Cornell Engineering in Troy, Mich. to be weighed and balanced.

The clutch was dropped off at Clutch Masters, Inc. in Warren, Mich. to have new friction material riveted on.

Sears was having a sale on hydraulic shop stools today. Couldn't resist.

The camshaft has been removed. I'm on the fence about removing the distributor drive as it is difficult to do so. I can probably mask it off sufficiently in place. With the camshaft, masking is not practical.

Tomorrow, the upper crankcase assembly will be returned to the garage and put back in the engine stand where it will be temporarily married to the block for line boring purposes.

November 11, 2007

The crankcase has indeed found its way back to the engine stand in the garage. All seven main bearing caps have been cleaned and temporarily installed.

The crankcase has stamped numbers which correspond...

... to the respective main bearing cap numbers. This gives you the opportunity to reinstall the bearing caps in the correct location with the proper orientation.

Note for posterity: the markings should be on the camshaft side.

November 12, 2007

Here is the oil pump dismantled and cleaned with kerosene. Gasket material is a little stubborn, though.

Radial clearance and end play should be 0.002 in. I think we're good but I need feeler gauges that go down that thin. Thinnest I have is 0.005.

November 13, 2007

Cornell Engineering called and said that the balancing job was complete. The crankshaft and Mark VI rods needed almost no adjustment, whereas the pistons required a bit of work. The flywheel was 40 grams off.

This is their balancing machine. Looks like you could do the crankshaft from a ship on this thing.
The clutch disk assembly was ready for pick up at Clutch Masters. This shop is located on the Warren side of Detroit's infamous 8 Mile Road just down the street from the Dodge Plant that makes Dakota Pickup Trucks .
Here is a shot of the rebuilt disk assembly. It looks brand new!

November 16, 2007

As today is "Deer Day" for folks in the Michigan automotive world, I had the day off. Good friend Jason and I took the whole kit and kaboodle of engine parts needed for the align boring operation out to John (and wife Caroline) Twist's shop University Motors in Ada, Michigan.

Here are John and Jason with all of the items loaded onto a skid.

John went through the trouble of taking us on an extensive tour of the whole shop. His primary focus is repair and restoration of all things MG, but he has been known to take on British luxury car work now and then.

Click here to link to the University Motors homepage.

November 20, 2007

Used a pneumatic die grinder with wire wheel to carefully clean up the gasket surfaces of the oil pump...

...and the oil pressure regulator.

November 23, 2007

The regulator has been dismantled and washed in kerosene. The unit regulates 40 psi (heavy spring) and also has a low pressure feed (lighter spring) to the valvetrain. Overflow dumps onto the front gearcase.

Just bought a case of Brad Penn Break-In Oil (SAE 30) for use during initial break-in. I'm thinking about carrying Brad Penn Oils in addition to SWEPCO 306. Any interest out there? If so, send a note to us by clicking here.

November 24, 2007

Performing odds and ends waiting to get the main bits back from align boring. The oil filler pipe has been cleaned and is about to be reassembled with a new leather gasket. The stud and nut will get a drop of Loctite low strength compound.

All of the springs associated with the vibration damper have been cleaned. The pressure plate springs (l) in particular had quite a bit of sludge caked on them.

The pressure plate screws have been removed from the front face of the vibration damper to facilitate reassembly. New locking tab washers will be used.

The damper is shown temporarily nailed to the work bench to hold it in place while the screws were removed.

The new friction disks are soaking in oil ahead of time so that "proper poundage" may be achieved when the vibration damper is tested.

The oil is green because it is Brad Penn Break-In oil and the disks are dark grey because they are Kevlar rather than cotton duck.

November 25, 2007

When assembled, many of the elements have an alignment mark "0" . The middle "0" in this photo was about 90 degrees off, must have been removed and reassembled incorrectly at B&F.

No harm done, as it is fairly easy to remove and replace wth a brass drift.

Here is the vibration damper (temporarily) assembled complete minus damper springs and ready for test.

I'm hoping that Dan Docherty has the correct mandrel and poundage test bar at his shop in Windsor.

The vibration damper has a lot to do with the extreme smoothness of the Wraith's engine. It is not a simple rubber bonded affair.

It consists of a light center plate (29) which transmits torsional vibration from the crankshaft to the heavy front and rear plates (1,2) through two friction disks (28) and a set of 16 damper springs: 8 large (32) and 8 small (33).

The presser plate (30) pushes against the rear two-two thirds of the assembly to achieve the desired amount of friction. (In Electrical Engineering terms, I would call this assembly a notch filter which is tuned to suppress oscillations at a specific narrow band of frequencies.) Steady pressure is supplied by eight springs (20) secured to the front damper plate by hollow 5/8 BSF screws (18).

This is actually an image from an early postwar Bentley Mk VI Service Manual. The Mk VI damper differs slightly from the Wraith's in the fan pulley detail at the bottom, but is otherwise the same (as far as I know). It is in fact called the "Wraith Type" damper.

November 26, 2007

Late this afternoon, I dropped off fellow RROC Motor Region member and Modern Car Society glitterati Richard Vaughan to pick up his Silver Spur at Dan Docherty's shop in Windsor.

I brought over my damper to see if Dan had a proper mandrel to test the unit. He did indeed, but did not have the right size test bar. Fortunately, it turns out that Derby Bentley engine rebuilder extraordinaire Rick Barrett does!


McMaster-Carr sent me a 5-ft. roll of 1/64" vegetable fiber gasket material. Perfect to make the majority of the odd gaskets that are no longer produced.

December 2, 2007

Yesterday I drove to Ypsilanti to attend the the monthly coffee and donut get together at the large co-op garage where I keep my Silver Shadow. I arranged to drop off the right fender with Scott from 203 Custom Car Works who also attends regularly.

Today I removed the left hand fender and plan to deliver it to Scott Monday.

In other news, Rick Barrett is bringing the vibration damper poundage test bar to our Motor Region annual black tie dinner tonight.

December 3, 1007

I dropped off the second fender today and much to my delight, Scott had already finished welding the first one.

He suggested that since the finish is in decent shape (despite the looks of this photo) and because I'm planning to repaint the car in a different color in the medium term, this would be a good place to stop. When it comes to car restoration it is often difficult to stop short of doing everything "while you're at it." Good call.

December 10, 2007

Without bothering to measure it, the friction in the damper was way too high. Sufficiently admonished by Docherty at his shop a few weeks back, I dissassembled the entire thing and cleaned all of the sliding surfaces with very light application of a die grinder using a soft wire wheel.

Rick Barrett's poundage test bar from his 4-1/4 Bentley is correct for this application as well. Now all I need is a proper spring scale! I ordered a Shimano fish scale from Cabela's, of all places.

When the oil pump was assembled with the pump gasket I made last week, there was way too much end play. The 1/64 in. gasket paper I used is too thick to achieve the desired 0.002 in. end play.

The second attempt (shown) uses copier paper that is 0.0040 thick. When assembled this way, the pump turns nicely with a little bit of oil. Although it is not binding in any way, I can't measure ANY end play. Presumably the oil film is to blame. Best bet to measure properly is to disassemble, clean everything up and reassemble dry.

December 17, 2007

This is a diagram from the "Pre-war Service Instruction" booklet of a proper set-up for poundage testing the vibration damper.

Now that the damper is reassembled with much cleaner surfaces, inital reading on the "fish scales" gave16 pounds. Too high, but something that can be addressed by shimming the eight hollow screws that capture the springs on the pressure plate.

The shims go in the gap between the locking tab washers and the hex head.

I managed to find both 14 and 18 gauge shims (machine bushings) at the local hardware store. Their id is 0.6425 rather than the required 0.7025 but the od is spot on.

The 18 gauge shims are 0.0450 thick and the old locking tab washers that I replaced with new are 0.0390 thick. I'll use the old locking tab washers (LTWs) as a temporary shim substitute to estimate how many will have to be modified with a larger id.

After shimming the whole thing with the old LTWs, it occured to me that the damper should be "run-in" by cycling it one hundred times before taking any measurements. I wished I had remembered that!

With eight shims, the reading was too low, after taking shims out two at a time and taking readings each time, zero shims resulted in a perfect reading of 12 lbs. (Spec is 11-12 lbs.)

A little wasted effort, but at least I don't have to modify any shims!

By the way, the peak reading feature of this scale is handy.

Now for something completely different: the cast aluminum rocker cover had a nasty braize on it where it had cracked at some point.
Bob Archambault came to the rescue, as usual. Most of the paint is gone from the cleaning operation, but here's a proper aluminum weld in place of the nasty lump.


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