BSA B50 -500 APG Build

[Koncretekid]

Tom...........your owner's manual gives instructions on the de-coke requirement for the piston and valves.  Looks like a little extra fuel & carbon in your oil.......

Dennis,
I can assure you that there is no build-up of carbon in the head or on the pistons.  I re-built this motor after the Speed Trials.  I did re-use the rings, as there was no sign of combustion leakage below the top ring.

There are oil testing services that will analyze the oil and give you some recommendations.  A lady where I work sends in samples from her diesel truck and when the lab indicates the oil needs to be changed, she changes it.  I think she uses Amsoil and they test it.  Some of the labs can give you a lot more info than when to change the oil and this might help you.

As for drilling my nuts, I use a method somewhat like yours.       

Bo, I am aware of this service.  Caterpillar used to check our oils for our trucks but it was expensive. I should pay the piper and get it done.
 

Tom,
Your oil looks like it has been contaminated by combustion, blow by past rings and fuel down the cylinder wall.

Rex

Sure looks that way.  It must have been the 17 pulls on the Dyno after the rebuild.  I'm thinking that because I re-used the rings that they essentially needed to re-seat themselves.  I should have changed the oil before Loring, but I had only a week to put the bodywork on and make some other adjustments.  I did drop the sump (dry sump) to check for metal, but I guess I just forgot to change the oil.

Just think how good it's going to run when I get it all sorted out!

Hi Tom

Have you ever tried the Aircraft all metal loc nuts, they have a little washer built in with a size smaller hex head and a thin section on top that is crimped to a oval shape

They are meant for one time use only, because it expands the oval shape

They hold damb good, yrs ago Bell used them to build the choppers with and they shake pretty good too

G Don

They sound like they should work.  Are they much better than the all steel grade 8 locknuts that I am using?  In any case, I'll be testing Loctite at the BUB speed trials.
Tom

[Koncretekid]

quote from BAK189 on July 29, 2013
"Back in 2002 we ran our Rotax (Can-_Am) powered 125c.c. with front wheel covers (time only at SCTA/BNI) BIG, BIG handling problems with even a very small cross-wind.......Ran a Dustbin on the same bike (time only) Yes, there were handling problems with a cross-wind, but not something I was not able to cope with.....
the bike could not be ridden at speed with the wheel covers......May work better on a heavier bike, but not on our small 125c.c..

PS.  The 1973 125c.c. Can-Am bike also tried the long tail....looked great in the tunnel, did not work on the salt......However, they are now being used on the larger displacement bikes with success.....just wondering if that may be some of the problems regarding some of the bad crashes of late............................."

BAK,
My bike with the fairing weighs about 380 lbs with 180 on the front, 200 on the rear. I ran the full tail as is legal for SCTA and LTA (8" beyond the real tire) with a rear wheel disc at Loring.  The front wheel was still mostly open.  I did not experience any handling problems at 140 mph as long as I kept my head down.  On one run, my chin rest had moved and I couldn't get my head down behind the windshield.  I aborted that run rather than take a chance.  It would have been slower, anyway, but I did break the 1 mile at over 125 mph.  Do you have any photos of the "long tail" version of the CanAm?  Do you remember what it weighed?  What about wheelbase, as mine is 72"?  Also, I presume bias ply tires on the CanAm, is that correct?  What about tire pressure?  That bike sure flew for 125cc.
Tom

[fredvance]

I have Blackstone Labratorys(sp) test my oil.

[Koncretekid]

More information on the dirty oil

I checked compression today and got 190 psi, using my roller starters with the bike in 1st gear.  I then checked my B50 roadracer, which I rebuilt several years ago. Its compression was 210 psi.  The roadracer is standard bore and stroke, 84.5 x 90, while the landspeed bike is 92 x 75.  Both use a Megacycle X4 camshaft.  The Landspeed bike cam is retarded about 2-1/2 degrees, and has higher lift rockers (about 10% more lift).  Compression ratio on the roadracer is about 12.5/1, while the landspeed bike is about 13.25/1. 

Would the lower compression reading of the landspeed motor be significant in this case?

Chris (Milwaukee Midget) sent my a personal message and I responded to his questions with this:

"Chris,
For the dyno runs, I was using last years BUB Speed Trials 110K which had been stored in a closed plastic container.  For the Loring event, I used event gas, but it was a new vendor and I don't know what their designation was.  It was supposed to be equivalent to VP's C-12.

I don't have the equipment to do a leak-down test, but I just did a compression test which yielded 190 psi (about 10 compression cycles, bike in 1st gear, roller starter on rear wheel)

As for crankcase vacuum, I got 12-13 inches of H2O when running the motor at rest with no load.  I don't know what I was getting during the runs, but I did see oil drips from the exhaust pipe after the runs, and had oil in the reed valve when I took it apart.

There is another possibility.  I had of course drained my oil when I pulled the bike apart last winter and drained the oil tank as well.  I usually blow the oil out of the oil tank by pressurizing the vent hose, which forces the oil out of the tank very quickly.  I say usually; it's possible that I just let it run out on its own last winter, but not likely as it takes about 15 minutes to empty that way.  On the possibility that I didn't blow it out then, I did blow it out this time.  It's therefore possible that I blew out some sludge that had settled in the oil tank, got shook up, and then got blown out yesterday."

Regardless, I'll run at BUB speed trials and change the oil after a few runs to check it.
Tom

[wobblywalrus]

The different rocker arms might change the valve timing enough to account for the differences you are seeing in cranking compression ratios.

[Koncretekid]

The different rocker arms might change the valve timing enough to account for the differences you are seeing in cranking compression ratios.

Along with the retarding of the cam, with later closing of the exhaust valve, maybe?

I did a forensic examination of my oil filter today.  Pictures tell the story. Small metallic bits are most aluminum, but some of them stuck to the magnet.  I'm thinking the ball bearing or roller bearings on the crank may be due for replacement.  The filter being on the scavenge side is always a controversy, but the effect is to filter out those bits before the oil returns to the tank and not into the motor. Nothing alarming in my opinion, but I'm sure glad I have that oil filter, as capturing those little bits can't hurt.

[fordboy628]

More information on the dirty oil

I checked compression today and got 190 psi, using my roller starters with the bike in 1st gear.  I then checked my B50 roadracer, which I rebuilt several years ago. Its compression was 210 psi.  The roadracer is standard bore and stroke, 84.5 x 90, while the landspeed bike is 92 x 75.  Both use a Megacycle X4 camshaft.  The Landspeed bike cam is retarded about 2-1/2 degrees, and has higher lift rockers (about 10% more lift).  Compression ratio on the roadracer is about 12.5/1, while the landspeed bike is about 13.25/1. 

Does the 2.5 degrees of cam retard give you the bhp/torque peaks where you want them?

Would the lower compression reading of the landspeed motor be significant in this case?    Well, it's less.  9.6% less in fact.  This indicates a LOWER effective C/R than your other engine, REGARDLESS of the build differences.

Chris (Milwaukee Midget) sent my a personal message and I responded to his questions with this:

"Chris,
For the dyno runs, I was using last years BUB Speed Trials 110K which had been stored in a closed plastic container.  For the Loring event, I used event gas, but it was a new vendor and I don't know what their designation was.  It was supposed to be equivalent to VP's C-12.

I don't have the equipment to do a leak-down test, but I just did a compression test which yielded 190 psi (about 10 compression cycles, bike in 1st gear, roller starter on rear wheel)

As for crankcase vacuum, I got 12-13 inches of H2O when running the motor at rest with no load.  I don't know what I was getting during the runs, but I did see oil drips from the exhaust pipe after the runs, and had oil in the reed valve when I took it apart.

There is another possibility.  I had of course drained my oil when I pulled the bike apart last winter and drained the oil tank as well.  I usually blow the oil out of the oil tank by pressurizing the vent hose, which forces the oil out of the tank very quickly.  I say usually; it's possible that I just let it run out on its own last winter, but not likely as it takes about 15 minutes to empty that way.  On the possibility that I didn't blow it out then, I did blow it out this time.  It's therefore possible that I blew out some sludge that had settled in the oil tank, got shook up, and then got blown out yesterday."

Regardless, I'll run at BUB speed trials and change the oil after a few runs to check it.
Tom

Tom,

I added some comments in blue to your text.

The different rocker arms might change the valve timing enough to account for the differences you are seeing in cranking compression ratios.

As I recall the rocker ratio is higher on the LSR engine, correct?   A higher rocker ratio gives MORE net valve displacement with the same cam.  This in turn CHANGES ALL THE VALVE EVENTS, INCLUDING DURATION AT OVERLAP.   This is the same as using a different camshaft.    The "effective" intake valve closing point is later, because of the 2.5 degrees of retard, AND, the higher rocker ratio.   The "effective" C/R is now lower, because of the later intake closing point, and the cranking compression is lower for the same reasons.   

It is difficult to know if the lower "effective" C/R is a positive or a negative without modeling the engine's dyno results to solve for volumetric efficiency %.   If V/E is under 100% and/or bmep is lower than target, then lower "effective" C/R is the wrong direction, in my opinion.

If anyone is unsure about compression ratio(s), and how I define their importance, read my comments in "Technical Discussion"
http://www.landracing.com/forum/index.php/topic,12353.0.html

Hope this helps.
 
Fordboy

[Koncretekid]

Mark (Fordboy),
At the danger of exposing my ignorance on the subject, is this the correct formula for determining VE? VE = ( 9411 x HP x BSFC ) / (DISPLACEMENT x RPM) where BSFC (brake specific fuel consumption) is assumed to be about .45?  If so I am woefully short of 100% VE according to dyno data.  The problem with the dyno data that I have is that it is from 2 very different dynos in 2 very different locations operated by 2 different people.  I don't know if either one is accurate.  But it makes no difference if I use 44 hp at 8000 RPM in Colorado (corrected rwhp) on a "Dynojet Wynpep" or 40 hp at 8000 RPM in Sussex, N.B. on a "SuperFlow Wyn Dyn", I don't get any better than about 75% VE by using the above formula.

I think I need a lesson on calculating VE and BMEP and how to maximize these numbers.

But there is one thing that baffles me about CR, whether static or effective.  If I have only 12.5/1 CR, how can I get 210 psi cranking pressure at near sea level?  12.5 x 14.7 only equals 184 psi.  Does this mean I actually have more than the 12.5 CR that I measured?

As for my cam data, I have measured the opening with the high ratio rocker arms and gotten the following info: 298.5 degrees of duration at .040" valve lift with intake lobe center at 110.75 degrees.  The data I measured at the pushrods, which should be indicative of standard rocker arms which are essentially 1/1, is 293 degrees of duration at .040" lift with intake lobe center of 110.5.  Because it is a single camshaft motor, the exhaust lobe centers are reduced to about 107 degrees with the setting I have chosen.  I have pages of measurements using different lobe centers arrived at by using a multiple keyway pinion gear, but this is the one I have chosen and used in the two dyno runs.  BTW, the 44hp reading in Colorado was with standard Rocker arms; the 40 hp in N.B. was with the high lift rockers.  Can you make any further comments on this info?

As to your questions, I don't know if the 2.5 degrees of cam retard give me the bhp/torque peaks where I want them.  Maximum hp occurs near 8000 rpm.  I'll try to attach the latest dyno info from Sussex, N.B. Be careful reviewing the graph, as the numbers on the "X" axis are not rpm.  The printed data shows the correct hp/torque/rpm numbers.

Thanks for you consideration.
Tom

P.S.  Converting the xls document to a pdf doesn't work very well (unless you want to print and tape 6 pages together).  I'll try to email you the xls.

[fordboy628]

Tom,

Give me the original data in .xls format.    Give me any notes on changes between pulls.   Let me know if data is corrected to SAE or STD, or is just as observed.   Won't be able to look at/analyse data until Monday.

Cranking compression can be higher because you are bumping it multiple times . . . .

This is where it gets tricky.   As I have said many times before, "It's complicated".   "Small" changes can have big effects on "effective" & "dynamic" C/Ratios.   This is the part that matters . . . . .

Will comment more later as I am pressed for time at the moment and I am still a slow and crappy typist.
 
Mark

[wobblywalrus]

Tom, I've used the same compession gage since 1970 and always use it the same way.  First, I check the compression with the fresh engine on the bench, if possible, to make sure I put it together correct.  If I cannot do this, I check the compression with it in the frame before starting it.  After that I check the compression periodically.  I make notes such as "cold compression, turning crank with wrench"  or "warm compression, kickstart."  All tests are done with the throttle open.  Trends are what I am looking for.  A rise can indicate carbon buildup or the rings are seating.  A drop can be wear.  A squirt of oil into the cyl can tell me if the drop is due to leaking rings or valves.  Looking at old notes, I see 210 to 225 psi pressure on some low performance engines like a Datsun 4 cyl pick-up from the 60's and a 1972 Honda SL350 K-2.  There are readings of 175 to 190 on some better performing stuff.  I do not see a strong relationship between engine performance and cranking pressure in these records.  I know the Datsun was full of carbon.  One thing to do when comparing cranking pressure between different engines is to make sure to use the same gage and do it the same way, and best, at the same time.  Testing environment can change results.

A static compression ratio test like I did with the burette and is a good idea, too.  They show all sorts of surprises.  As an example, the pistons in my engine are advertised as 11.5 to 1.  They are with a standard cyl head and flat faced valves.  Mine has larger valves with dished faces and the cyl head is relieved around the valves to get good flow into and out of them.  This drops the comp ratio to 10.5 to 1.  This is something consider when comparing the cranking pressure between those two engines.       

 

[Koncretekid]

I sourced a leak-down tester yesterday, after about a dozen calls.  I had to settle for borrowing one, as the nearest one seemed to in Toronto.  The borrowed one had a faulty gauge, but I replaced the gauge with one from my compression tester.  I first tested the roadrace bike and got leakage of about 40%, which I thought was bad until I tested the landspeed motor and got 70% leakage.  The main culprit was the exhaust valve.  The photos show the combustion chamber with the valves in, then with them out.  The rusty exhaust valve seat (cast iron) tells the story.  Close up of the valve shows areas of leakage.  Valve is titanium made from a used Nascar Chevrolet valve.  The valves were lapped in in March and the motor was started up before I went to Colorado. So the rusting has taken place sometime between then and now.  I of course, do not know if it was before or after the dyno runs.  But if before, could it be responsible for the reduction of 4 hp from my fall dyno run in Colorado?

Can anyone tell me what the carbon pattern in the combustion chamber signifies?

Tom

[Koncretekid]

One more photo showing the top of the piston.

[fredvance]

Man that is ugly. 70% leak down is probably more than 4hp. At the least I would clean up the valves and seats and lap the valves. also the exhaust port looks funny whats up with that?

[Koncretekid]

Man that is ugly. 70% leak down is probably more than 4hp. At the least I would clean up the valves and seats and lap the valves. also the exhaust port looks funny whats up with that?

Fred,
Of course I'm going to re-lap the valves in.  I would get them touched up if the only guy in town who knew how to do a decent valve job hadn't gone to Alberta (where the money is!)

As for the exhaust port, the surface is lightly pitted in a swirl pattern, as is the combustion chamber around the spark plugs.  Timing wrong?  Detonation?  Wrong gasoline?  Piston looks fine, but it is (was) ceramic coated.  The imprint on the top of the piston at the exhaust valve is where the valve hit it when I broke my primary chain and over revved at Loring last year.  I was hoping you could tell me what's up with that?
Tom

[Peter Jack]

Tom, I sent you a PM.

Pete