MANUKAU MODEL POWER BOAT CLUB Inc
Venue: Wattle Farm Rd Pond Manurewa
2nd & 4th Sunday of each month from about 10.30 am
President: Malcolm Miller Editor Chris Breen
93 Sykes Rd 12 Sunset Rd
Ph 268 2742 Ph 4445 482 October 2003
Our next regular evening Club Meeting is set down for Thursday 2nd October. Cosmopolitan Club, Sykes Rd, Manurewa, 7.30 pm as usual.
SUHA Diamond Cup at Lake Cowley Waitara (Taranaki) on 4 & 5th October – Contact Merv for details if you have not received them by E-mail
York – 1/8 scale hydro
NZMPBA “Thunder Down Under” Oval Sprint Fest at Lake Moana-nui (Tokoroa) on 25-27 October (Labour weekend) – Contact Malcolm for details if you have not received them by E-mail. Includes the first regional challenge guys ! – lets show what we got !!
TECH NOTES (Thanks to Terry for the copy)
Engine Timing and How to find out what it is by Ultra Bold
Have you ever wondered what your Exhaust timing or Boost and Transfer timings of your engine are? Well the good
news is that it is not that hard to find out, all you need is a simple tool that you can make yourself for just a few dollars, but first you need to go down to your local stationary store and buy a circular protractor or two (these are normally used to measure angles and are used by mathematics students)… Maths Yuck, I hear you say, not so just bear with me and all will become clear.
Now you have your protractor, it is time to disappear into the workshop.
In the centre of the protractor you will notice a small magnifying lens, we need to drill a hole the same size as the crankshaft in the exact centre .How this is done is by lining up the 0 degree mark and 180 degree mark with a ruler and scribe a small line in the centre of the magnifier, now repeat the procedure using the 90 and the 270 degree marks, now you can drill a hole the same size as the crankshaft at this spot. (Editor’s Hint Drill a small hole and enlarge it using a taper reamer. This stage is also why you should buy two protractors!!)
Now we need a pointer, this is easily made out of a stiff piece of wire or brazing rod, cut it long enough to go from the front of the head to the end of the crankshaft. Now bend a loop in one end big enough to hold one of the engine head bolts. You may need to build a couple of these to fit different crankshaft sizes.
Now you have built this high tech measuring instrument it is time you learned how to use it. Firstly undo your drive collet or square drive and take it off, now slip on the protractor and finger tighten the collet back on. Now unbolt and take off the water jacket and remove the head button, next get a head bolt and put on a washer, then the pointer and then another washer. Now screw this into the closest head bolthole to the exhaust port (making sure the pointer rests on the circumference of the protractor and make sure that the bottom washer is down hard enough to stop the liner from popping up when you rotate the crankshaft later). You are almost ready to measure.
What you do now is rotate the crankshaft until the exhaust port has just fully closed and hold it there, while turning the protractor to read 0 degrees at the pointer and do up the collet so the protractor is held tight to the flywheel. (Editor’s note this is not as easy as it sounds. Provided the protractor is tight on the crank You can just read the angle on the zero to 360 degree protractor scale). Now rotate the crankshaft so the piston goes down to BDC and moves up to where the exhaust port is only just fully closed again and read the figure on the protractor, the difference gives you what your exhaust timing is (It can be used to help determine your tune pipe length, but that’s another story for later). Now write it down for safekeeping.
The figure will be somewhere between about 150 degrees and 185 or maybe 190 degrees. Large angles are typical of high rpm (but low torque) motors such as our typical rear exhaust racing motors, while lower angles are typical of side exhaust aircraft style engines offering lower rpm but higher torque. Very small differences in manufacturing can make a surprising difference to timing, as can tiny bits of crud trapped under the top flange of the sleeve when you re-assemble, so take care during re-assembly.
Now repeat the same procedure for the boost and transfer ports. And I bet you all thought it was hard eh… Nah
Racing at the Club Day 14th September
Overcast weather again greeted us with a threat of rain that (mostly) stayed away until the racing was over.
Three 1/8th Scale hydros (Merv’s new Bud in primer finish, Malcolm’s Miller High, and Jason’s Winston Eagle) were ready to battle it out
We had five good races with Merv’s new Bud hull looking very fast and reliable, particularly after race three where he flipped and wiped out the tail feathers. Malcolm suffered a DNF in a particularly close competition with Merv and a DNS in the final heat. Jason started out well but was a little off song and could not finish the last three heats through a variety of reliability problems.
Hyper going slow !
We only had three race-ready Class I boats. Merv ran Video Express. Chris was back with L&P after re-mounting the motor and adding an after-muffler to get noise down to the club standard, and Dean with Hyper-something-or-other. Dean had a frustrating series of sprint heats with Hyper lacking its usual performance (Editor’s note See last item of the newsletter)
Chris took out the day with good finishes in all heats. Merv took four of the five guns but his one DNF proved that consistent performance will often beat superior speed.
The Class II heats were a bit one-sided with Jason’s Coca Cola running against only Tony Bella’s new modified sprint cat. Tony could not get a good needle setting.
L & P going fast !
Enduro was split into a pair of 10 minute duration runs for both classes. Again Chris in L&P took out the day for Class I with a total of 43 after running without incident in both runs- even though he ran out of fuel during the last 20 seconds of both! Merv and Dean were not even close needing several protracted rescues. Class II was similar but interesting in that Jason’s Coca Cola also totalled 43 laps (Editor’s note – WITHOUT running out of fuel)
The days racing had been very exciting with a good crowd watching and hope we see more competitors next month.
Thanks to the Guys who turned up early to help set up, and to the Burns entourage for procuring some tasty hot pies for lunch !!
Special thanks also to Tony for some excellent new signs asking spectators to switch off their cell-phones near the Pit area.
Tony’s new Class II cat
The “IF IT ‘AINT BROKE DONT FIX IT” Section (thanks Dean for the copy!!)
Well there is a lot to say for “if it's going sweet don't touch a bloody thing” .Saturday my boat was going sweet. Sunday, I thought OK, racing now, must go just that little bit faster .So I had a think what I could do to get boat going harder (I know change spark plug ), and get a bit of stick from Merv . So I changed the plug and the boat didn't go all bloody day.
Well I changed fuel (more like donated five litres to the clubs rescue dinghy so just be a little bit careful on the throttle next time someone goes out to retrieve a boat cause dinghy's gonna go hard).
Long story short… changed transmitter, changed fuel, changed strut, changed servo, changed batts, there was no need for all of this. All I had to do was put my old spark plug back in the boat and it went sweet .
FOR SALE/WANTED COLUMN
Paul Lindberg (from Aussie, was at the pond last Sunday) is looking to buy a 81 OS or similar. I don’t have his number but he is sure to be back next club day.
Brett’s “Ballistics” is also for Sale
Daytona motor RTR except for radio gear.
$800 ono ph 2678 478 or 0274 799031
That’s all for this month folks.
Chris Breen – Editor