Team Go Dog, Go! Modified Partial Streamliners

[wobblywalrus]

Figuring out how to machine the valve pockets was problematic.  Clamping down the pistons to a table or putting them in a vise was the problem.  There is a good chance they might be damaged.  Eventually it was a late night job of holding a piston in one hand, the angle grinder in the other, and eyeballing the cuts.  The results are ugly but useable.

There is about 0.045 between the piston deck and the bottom of the combustion chamber edges.  It should be over 0.040 for this engine with steel con rods so this is OK.

This is the first time I cc'ed an engine while it was in the frame.  It worked great.  There was plenty of room for all activities and equipment. 

[wobblywalrus]

The catalog compression ratio is 10.2 to 1 for these pistons.  The head has larger intake valves than OEM and some metal was removed from around the seats to get decent air flow.  This drops the compression ratio by one.  In other words, the 10.2 to 1 pistons as advertised are expected to be 9.2 to 1 in this engine.  The preceding assumes no work was done on the pistons to remove metal.  The actual static comp ratio is 8.93 to 1.  The relieving around the valve pockets accounts for this reduction.  The dish volumes in the two pistons measured out to within 0.4 cc of each other.  This is within the accuracy range of me with the oil filled burette measuring method.  They are OK.  Tomorrow the motor will be put together.

[Koncretekid]

Bo,
You probably know this oldtimer's trick, but it may help.  If you can find a larger valve than you have with the same stem diameter, you can cut some grooves in the outer edges of the larger valves and use them to cut the pockets in the pistons larger.  Assemble the motor with the larger valves (no cam required), rotate the motor until it is close but not hitting the valves, then rotate the valves with an electric drill as you lower the valve into the piston.  I've never tried it, but it sounds like it should work.  Of course, you'll have to deal with the aluminum filings; maybe just grease up the edges of the pistons to capture them.  I'm sure someone on here knows more about this procedure.
Tom

[Old Scrambler]

+1 with Tom...............My CB750 pistons were fly-cut 1mm on a mill.........had to make a nylon piston holder to be clamped in place.  Others have welded a cutting blade across the face of a valve that is longer on one end to do the cutting. 

[wobblywalrus]

Thanks for the advice.  Those methods are better and more precise than the way I did it.  The pistons were ordered without rings.  They were packaged in a cardboard box and wrapped with wrinkled brown paper.  A couple of days ago I was tearing up some of that paper to light the fire in the stove.  Out dropped two packages of piston rings.  Originally I was going to use Werner's old rings.  I changed my mind and decided to use the new ones.  The insides of the cylinders were hand sanded using #600 grit emery paper followed by 320 grit and 400 grit.  It looks like a good surface to break in the rings.  The cylinders were put on today and the head was bolted down.  Dyno days are the 10th and 11th of Dec and it looks like this motor will be finished on time.   

[4-barrel Mike]

Lookin' good!

Mike

[wobblywalrus]

The old girl was fired up today.  No drama like leaks, odd noises, or smoke.  It sounds like a nice and solid engine.  The fuel was ordered before I decided to go to Pendine.  It was intended to be used in Africa with the high compression pistons.  The benchmark fuel is Sunoco 112 octane leaded Supreme.  The jetting and timing will be set for it on Wednesday.  The experimental fuel is Sunoco 112 octane MO2X oxygenated leaded and it will be tried on Thursday.  Jetting and timing will be optimized for it.  A run will be made late Thurs with the Supreme.  Both fuels use Marvel Mystery Oil as a top end lube at a 2 oz to 5 gal ratio.

This lower compression engine will tell me if it responds to the type of oxygenation used in MO2X.  There are various ways to add oxygen to gasoline and the goal is to see which method helps this carbureted engine.  A trip to Triumph Road is in order for Sunday.  Some break-in miles are needed.     

[wobblywalrus]

Yeas ago one of the Amo brothers gave me advice.  It was that naturally aspirated horsepower becomes harder to get the further the engine is developed.  Also, he said the limit on NA motor power is relatively low compared to other ways to hot rod engines.  He recommended turbocharging and said this form of performance tuning was relatively easy on the motor and it can produce big gains.

That was a long time ago when he said this.  The advice has been kept in mind through the intervening seasons.  Nothing major is done to the bike that will need to be tossed when going to a blower.  Effort is focused on developing the NA engine using technologies that will be helpful when forced induction time comes.

Thermal management is an issue with air cooled engines.  The traditional way of dealing with this is to use alcohol based fuels.  The struggles of Tiny and other with blowers, alcohol, and carbs are noted.  Electronic fuel injection is a big part of the answer.

A budget limit is the kiss of death to a LSR program.  The tried and true method of getting around this is innovation, building things oneself, and scrounging.  The Triumph club met for breakfast this morning.  A fellow gave me this almost brand new EFI fuel tank.  The pump, fuel line, etc were pirated from Werner's wrecked scrambler.  Now I am looking for a throttle body/injector assembly and wiring harness.  Progress is being made.

[wobblywalrus]

The engine was broke in today.  Triumph Road and some of the streets it connects to are in an isolated corner of the county.  The place is German Catholic with nice neat farms and hardly any crime, plus it is Sunday.  My figuring is all of this adds up to reduced chances of coming across a copper.  One big loop had the rings broken in.  It was so much fun I did another loop.  Then, the wet spots on the pavement started to get frosty in the hollows and it was time to quit.  The bike sputtered and died while coming in from the last loop.  Ran out of fuel.  It would not restart so something is wrong.   

The engine is smooth and it pulls hard.  It is 865cc with 8.9 to 1 compression and it is not as strong as the 995cc one with 10.5 to 1 slugs.  This race is at sea level and the gearing will be much higher (numerical ratio) for the short track.  This little engine should put down considerably more tractive force than the big motor does at Bonneville, for these reasons.  It is not the best engine I have had but it should do the job.       

[wobblywalrus]

The vehicle identification number on the frame headstock needs to be read during customs inspection, I am told.  That is a big project on my bike with the fairing.  It needs to be uncrated so someone can peer down behind the fairing to read the number.  Does anyone have any special procedures to make this easier?

[wobblywalrus]

I am sot sure how to handle the VIN number inspection problem.  A sign on one side of the crate will say "Open other side to see vehicle identification number."  A sign on the other side will say "Remove this side to see vehicle identification number.  Pull hinge pins to remove panel."  This is the best idea I could come up with.  Hopefully it works.

The engine died during my break in run.  I was close enough to the truck to coast in and put the bike on the trailer.  It would not restart after it was refueled.  Sometimes an engine will have just enough compression to run but not enough to start.  Compression while cold with the throttle open is 190 psi on both cylinders.  That is great and the rings are seated.  The cylinders were getting fuel.  Voltage across the battery with the engine running is just that, the 12 volt battery voltage.  Normally it is between 13 and 14 volts.  The charging system is kaput.  This has happened before.  It was the regulator/rectifier unit.  My guess is the current put out by the engine while racing is too much for the unit to handle on a long term basis.  Tomorrow is dyno day so fixing the charging system will be done first.

Break in was to assemble the engine with automatic tranny fluid lubricating the bores and Yamalube 10W-40 in the sump.  The all-purpose mineral oil is chosen.  The engine is ran with lower rpm bursts of acceleration and deceleration.  Care is used to create as much cylinder pressure and vacuum as possible.  The bursts are gradually increased in rpm and duration.  Sustained hard running is avoided.  My guess is the rings need to be seated within 20 miles from new or the cylinders will lose their hone.  The oil is changed to racing synthetic before the dyno work.  This method gives me good results.     

[tauruck]

Dentist's mirror or a variation thereof.

I'll speak to Willie and ask his advice.
He's dealt with VIN and stuff related to your problem for years.

[grumm441]

one of the most common jobs I get in at work is replacing Triumph alternator stators
unplug it from the regulator and check to see if any of the three yellow wires have continuity to earth
If they do , it's rooted (Australian slang for broken)
we use these guys http://www.electrexworld.co.uk/acatalog/Online_Catalogue_Generators_32.html
Yep , I know they call them generators
But they don't seem to fail
G

[wobblywalrus]

Graham,they do not list any for the Bonneville.  Which one do you use? 

[grumm441]

I'll have a look in the book at work.
Have you checked to see if it's cactus yet
G