Cleaning, Preparation, and Bearing Gaps

There isn't much to tell about my progress. I received another order of parts from Stewart Eng. I've cleaned the engine block and checked the new rings for clearance after honing. Everything checks out there.

The next step is the big one. I need to find a reliable machinist to turn down the journals on my crankshaft. I'll also be ordering a set of big end shells and a new rear bearing. I need to get a good idea of what undersize bearings to order.

Below is the measurements of the crank that I've taken.  It looks to be a 30 thou under on the big ends, and a 20 thou under on the rear main.

Anyone know, what measurements I should tell the machine shop?

I would think:

-0.030" bearing shells... grind the big ends area "A" to 1.5950" / 1.5945"

-0.020" rear main grind the rear shaft area "C" to 1.4795" / 1.4790"

But would it be more wise to hand the machine shop the rods, and bearing shells .. and ask for a gap.  What gap?  Would that be 1.0 thou or 1.5 thou gap?

Opinions?

Eduardo joins the family

In 2005 it became quite clear that my wife wasn't going to let me drive the Red Imp very often, and if I wanted to drive an Imp, I would have to obtain one of my own.  After passing up a few on eBay and going to see a Mk3 in Maryland, I finally found the ONE.

September this car came up for auction on eBay.  It seemed well cared for, and had a bit of history to it.  The body was the best I had ever seen on an Imp (which wasn't much).  It was a California car and hadn't been sujected to the snow and salt of the north east.



Val and Tiger Tom went to pick him up while I went on my annual motorcycle trip to Elk County with the Friends of Nature.  We discovered some important aspects quickly.  No brakes, No Oil Pressure, No compression on number 4 cylinder.  Just the kind of work I can do... the body was fine, all it needed was a bit of wrenching.  There wasn't a spot of rust on the undercarriage and the only issue was a leaky steering rack boot.

The wrenching took four months.  Looks tiring doesn't it?



In the meantime, we learned some of the history of the car.  The original owner Eduardo Pallazo from California must have loved this little car.  He painstakingly maintained it, kept his reciepts from Sunbeam Specialties, and created a one of a kind wooden dashboard for it.  Legend has it Mr. Pallazo was a Hollywood carpenter and set builder.  The dash was fitted to take the place of the Mk2 cardboard shelf in the standard car.  We refer to the car as "Eduardo" now in honor of the car's first owner who cared so much about it.  Originally taitian blue, the car had been resprayed Toyota Super White II, which makes it a bit stark like a rolling refrigerator, but the interior makes up for it.  The stock Imp seats had been replaced with VW bug seats, with the bottoms cut off.  The rest of the interior which would have been orginally vinyl was decked out in a blue velour.  Oh, Eduardo is a pimpin' little Imp.

Sorting the brakes was no big deal.  The master and slave cylinders were stripped and redone, and refilled with DOT 5.

The oil pressure problem was the big deal.  The mains were shot and so were the big ends.  The engine bearly made oil pressure at idle.  Someone screwed up majorly, and had installed an external oil filter in a way that basically short-circuited the lubrication system.  It was basically a new block for goodness sake, and it was almost ruined!  We took the claptrap off, and concentrated on new bearing shells from Speedy Spares.  Luckily it wasn't too bad and we didn't have to turn the crank.

Number 4 piston had us going for a while.  It wouldn't develop compression, and would simply leak by the exhaust valve.  We pulled the tappet shims and measured them all.  Oddly enough the number 4 intake and exhaust tappet shims had been reversed by the previous klutz to put the engine together.  They were swapped, and the engine ran like a champ!

I took a few victory laps outside Tiger Tom's workshop in 4 inches of fresh snow, drifting the Imp happily around the snow covered blacktop.



Later I pulled out the Subaru radio and put in an MP3 CD player out of a Ford truck.  I can now play all my bagpipe music on MP3s.  The dash was refinished and restored to its original glory.

I later replaced the transaxle mounts... with the engine still in.  It CAN be done, but I don't recommend it.  The front of the gearbox would fly up and hit the bottom of the tunnel... so new transaxle mount were a MUST, and of course supplied by Uncle Malcolm Anderson.

The work wasn't over though.  The Solex (err Slow-lex) carb kept acting up.  I couldn't tune it right, I even got a rebuild kit of Uncle Malcolm and it still wouldn't tune up for me.  I finally gave up and in an impulse ebay purchase got a set of SU HS2 carbs and a LYNX manifold from a fellow in Oz.  Now I was commited to getting the engine to run right.

The Lynx manfold came with two carbs alright... two left-handed ones.  Blast!  How I had to get creative.  The linkages didn't work out, and I had to create custom ones.  I think I'm the only person running two left-handed carbs on a Imp in the whole world.  I tilted them, cutting a groove in the bowl to housing junction to get them to stay level.  Then I changed the routing of the throttle up over the top, to meet with a custom bracket I had made.  Notice the big spring tower to hold the throttle closed (the spring came off an upright Hoover vacuum cleaner bag).  It all worked out rather well.  I even used an old clutch cable to join the enricher levers to the existing choke cable.  The whole thing was topped off with a K&N air filter from a Suzuki GS750 motorbike.

I ended up with the V3 needles and blue springs per http://www.imps4ever.info/tech/carbs.html#SUs



I thought I was done, but there was something else not right.  Every time I made a left turn.  Especially one made in anger, the oil warning light would flash.  Now friggin' what?  It shouldn't do that.

So, I pulled the sump cover off again.  Nothing looked strange, but having limited experience, I had no idea what could look out of place in there.  So I consulted the great gurus of the Imp club, and they informed me that my oil pickup was off a 930cc engine.  Well that makes sense... it was made for an engine that sits straight up rather than at a 45 degree angle.



There were no replacements of the right type readily available, so I went on modifying what I had.  I got some idea of how close it should be from the bottom of the sump and did some basic cutting and re-welding.

I think it turned out pretty good.



Now I can turn left in anger.  In extreme anger at the autocross last autumn it performed flawlessly.

Eduardo had been very reliable, comfortable on a long trip, and a joy to drive.

Worm drive unit reassembled

I actually put something back together.  The worm drive unit was an easy fix; all it needed was a good cleaning.  I made sure the shims all went in the way they came out.  I forgot about the breather hole at first, but checked it after re-assembly to insure that the passage was clear.  Nothing worse than having a rear drive unit heat up and push all its oil out the seals.  I've seen this happen on Guzzis before and didn't want my Sunbeam to do the same thing.

Here it is all assembled and waiting to go back on the frame.  Re-installation was easy, I used my method of a threaded rod to compress the springs.  The retaining shaft went in easily as well.  It will probably need a few squirts of grease before going anywhere, but its back on the frame.

I looked at the rear wheel.  Funny all the paint was missing off the drum area.  Looks like the original owner was one of those guys who only used the rear brake.

There's a stud with a nut on the rim, I assume its to keep something from turning inside the rim.  I wonder what kind of inner-tube I'll need?  Anyone listening who has a recommendation on inner-tubes?

Imp door latch repair

Here's my latest attempt to bring back life into a worn Imp door latch plate.  The hard steel star-wheel on the door wears away the soft potmetal of the door latch plate.  Over time grooves wear into the latch and make it impossible to latch the door without slamming it.

The first move is to put some washers behind it and move the contact point.  When this fails and the grooves just wear wider, then another solution is needed.

I then took and cleaned up the teeth of the latch plate, and even roughed them up.  This way the epoxy will stick better.  I coated the teeth with two-part epoxy and then fitted a thin stainless steel sheetmetal piece over top of the original potmetal.  This should prevent wear since the potmetal is protected and the stainless is a bit more resilient.  We'll see how it works.

Root Cause Failure Analysis

One basic precept of my mentor Russell, is that you never treat the symptom you always find the root cause and correct that.

Well, here's the root cause of my engine failure.  It seems a large chunk of the rear main bearing came loose, then got ground up and entered the oil hole in the crankshaft.  This distributed the ground up bearing material through the connecting rods.  Lovely, huh?

This can only result in replacement.  The shaft isn't too bad of shape.  It can probably be machined down nicely after I decide what replacement bearing should be bought.  The worst part is that I spent 20 minutes straight flushing the gunky particles out of the crankshaft.  I blew it out with air, put more cleaning fluid in, then flushed it again.  Still little sparkly bits of bearing were flushed out.  Eventually, I sprayed some seriously strong solvent in it and let it sit.

But that's the end of the story.  It all started with trying to get the timing gear off.  What a chore that was.  A little tension and some heat didn't budge it.  We broke the first puller, and finally succeeded with the second.  Once it started moving it was ok.  I hate to think how hard it will be to get back on.

The bores look good.  Thank goodness.



I lightly scribed an arrow on the pistons pointing front.  The stamped number on the connecting rod points to the left of the engine.



There's a small amount of rust damage to the top of the shaft that retains the half-time gear.  It pulls from the chain, so I don't think it will hurt at all.  I may polish it down a slight amount to make sure there are no high spots.



The engine case is free and clear... waiting to be cleaned.

The combustion chambers are amazingly clean.  Meaning, it didn't get any miles since the last teardown ... or it just ran really clean.

I think it just runs really clean, since the ports are clean as well.  The head gasket wasn't too messed up either.  I probably should replace it.  The bill at Stewart is going up.