Rub20B

Action videos of the race.. Maybe I need to give my dad (driver) a racing course for christmas lol

still he ended first in his class and the blue/grey escort was 2nd.

Also the tacho was only reading half as it is an old stack st400 where the cylinder count is set with jumper, unfortunately I cannot find the info about how to set them anywhere. :/

Rub20B

Another video from outside the car. some guy made it, nice!

Rub20B

crap cannot edit post

Rub20B

sneak preview

23Racer

Dang, that looks great. I love the expansion chamber portion as I have always wanted to try this, but never had the *****. Works great with two strokes and I have always considered the Rotary a big 2 stroke.

Let us know how this works.

Thanks, you made my day.

Eric

John Huijben

iTrader: (1)

Looks good! Nice to see a rotary on the zolder track. I've been there with an FD once, nice track! Might take my 4-rotor there if I can get it to work right. We usually go to the zandvoort track in the netherlands though.

Rub20B

Damn, yesterday put the engine in the car and made a drive on the street, after 10km leading plug fell out.. my own fault as I bought the housings as good husing for not small money, and didnt check the threads in the plug holes. I found out when the engine was togheter that the rear leading plug hole was without threads.

I then tapped M16x1.25 in there and used a steel bushing to mount the plug. The M16x1.25 threads didnt look good and one can guess what would happen sooner or later..

now yesterday pulled engine back out, put it under the drill press and bored the hole 16.5mm and tapped it M18x1.5 made alu bushing and screwed that in. we hoped it would seal as we machined a shoulder in the housing where the bushing sits on to. but it was quite leaky.. ended up welding the bushing to the housing.

now all looks good and engine is back in the car since yesterday night.

some other strange findings. engines smokes blue quite a lot. the housings have been lapped and then nitrated. the front housing was after it was nitrated lapped once more as we had to fill the water seal grooves with devcon Ti putty. now it seems the front rotor is sucking quite some oil passt the rings when off thorttle. I hope it will eventually run in and seal.

After 10 min of driving and maybe 20 min of idling the plug popped out and when I removed the intake to put the engine on the drill press the engine is still just as clean as when it was assembled. no carbon, no deposit, nothing. the permanent marker on the rotors with the weight is still there as it was before

Is this normal? I am used with other engiens even if they idle 1 min they are black on the inside.

Rub20B

after fixing the plug hole and putting the engine back in the car it still smoked alot and didnt seem to clear up.. pulled the engine the night before the race once more.. the guys that balanced the rotors seemed to onlyhave a 8mm drill bit left, and little logic sense..

they only had to lighten the rotor 12g per side to match the weight of the other, which only 4g per tip... when I inspected the rotor before installation I wondered that it was so deep but it was closed.. found the piece luckily in the oilpan and not between rotor and side housing..

put the engine back in the car yesterday night, fired up, only idle on 1 rotor.. after some checking found a plugged idle jet. cleaned the yet and it idles and start perfect.

first race went really good, only 1 sec slower than a factory 911 RSR 3.0 (500k car)

won in our class and 2nd overall.

2nd race went wrong guess we sucked air in a corner and spun a bearing. oil pressure gone :/// time for dry sump probaly.

Rub20B

aftermath: engine is out of the car again and opened up, suprisingly the bearings and E-shaft are still perfect condition, I think the oil quality and dlc coating on the e-shaft saved it. I don't know why it had not more oil pressure after I started it after the 2nd race. maybe there was some much air in the oil filter and I did nto wait long enough, I only had it idle for 4 sec or so as I tought it would not benefit the engine if a bearing was spun. anyway, bought a used auto verdi pump of ebay..

Does anyne know what can be done to reduce apex lifting around the loading plug hole? both rotor housings show same pattern. also the sideseals show quite a bit of wear after just 45min of running. I made the clearances all perfect at 0.04-0.05mm now they around all in the range of 0.15-0.2mm..??

JZG

https://www.facebook.com/photo.php?f...type=3&theater

This mod will help with housing high spots. Also run leading plugs no hotter than 10's, and keep coolant temps below 90c, ideally as low as 70c.

A properly designed wet sump completely eliminates the need for a dry sump. If you do decide to go drysump however, the factory type front cover is the best and as far as I'm concerned, the only option. External belt driven set ups are heavy and complicated. An easy way to tell if the oil pump is sucking air is to inspect the bearings for tiny round circles on the surface of the white metal. These are caused when air bubbles burst.

The best engine oil you can run is Motul 300v. Being a double ester synthetic it's expensive but totally worth it in terms of bearing and crank life. It also lasts longer than conventional PAO synthetics.
The best 2 stroke oil to run is Motul 2T800 at 100ml per 10L. It will help with side seal wear among other things.

Next time your engine is apart replace the oil control O rings with the black Rx8 O rings.

I watched a recent vid of your car at Zolder, it looks and sounds great!

Edit - just noticed your steel apex seals (unless they are really stained ceramics). You should be running carbon or ceramic seals on the MFR chrome surface.

Rub20B

those are 2 piece 2mm ceramics, no way i would take an engine to this rpm with steel seals again, let alone on MFR housings.. =)

Ironically the rear housing had this modification done in the water jacket around the plugs, and the front one didnt, but both had in equal amount the lifting of the seal due to the leading spark plug hole sticking out. the plug hole are also carefully radiussed to prefent the edge from sticking out but this also doesnt seem to help.

Maybe the water pump was cavitating at high rpm, it was about 68% underdrive which I think is still too fast at 9500 rpm. its an S4 TII pump with cast impeller and without gasket to make the clearance between impeller and housing a tad better.

The engine was running quite lean, as the exh was white on the inside from header to muffler. the carb is 50mm with 44.5mm chokes, F11 tubes, 70 idle, 240 main and 110 air. we will now switch to F8 tubes and maybe 100 air corrector and see from there. also the delivery valve in the carb was only a 200 so will upgrade to 300.

gxl90rx7

iTrader: (1)

exactly my experience.. rotaries love big inductive ignition. really good info in this thread

Rub20B

Hmm I don't know about the factory dry sump system. Its more expensive than a external pump, its less flexible (no way to adjust pump output unless buying a different housing with diff width gears) and its toast if somehow some debris or dirt manages to reach the pressure section, then the housing is gone and you will face big €€€ cost and wait time for new housing. where as with the external pump route you just call the pump builder who will ovenright you a housing and gearset for 500€.

I think now with the pump, tank, and lines I paid about as much as I would pay for a new factory mounted housing/pump alone

The belgium 20B mazda 3 faced this issue, they replaced the engine and lost front bearing during dyno tuning. found out some debris made it in the tank and eventually into the pressure section and took out the pressure stage in the factory dry sump setup. it was for them a real PITA to find a new housing in time.

Here some pics of the route i went. I bought a 5 stage auto verdi pump from ex nascar with integrated air oil separator. converted it to 3 stage. tank is 3 gallon with 2x1000w heater, also from ebay.com ex nascar equipment. tank is trunk mounted and with alu hardlines connected to the engine. pressure stage feed is -16, oil return from from engine is 2x-12, one for air one for oil.

atm the pump is geared 18/38. oil pressure is plenty reaching 10 bar at 6000tpm with 60 degC oil temp (30mm pressure secton)

it was a bit a challenge to mount the journal on the RB crank pulley but it worked out just fine with 8xM6 bolts. you can see the threads of you look closely.

also mada a new waterpump pulley so it now has about 55% underdrive.

now building new airbox on the carb, will go testing thursday if all goes well.

WJM ROTARIES

Maybe the water pump was cavitating at high rpm, it was about 68% underdrive which I think is still too fast at 9500 rpm. its an S4 TII pump with cast impeller and without gasket to make the clearance between impeller and housing a tad better.

The engine was running quite lean, as the exh was white on the inside from header to muffler. the carb is 50mm with 44.5mm chokes, F11 tubes, 70 idle, 240 main and 110 air. we will now switch to F8 tubes and maybe 100 air corrector and see from there. also the delivery valve in the carb was only a 200 so will upgrade to 300.[/QUOTE]

I would use f2 emulsion tubes & 110 airs, they will stop high rpm lean out plus use a 3.5 mm grose jet needle and seat ,your 2mm is way too small & extend the float bowl if not all redy done.
Also on water pump to stop cavitation on every second blade in pump grind off 15 mm off the outer end of the blade ,I have done this on all my race engines and it works well in stopping the cavitation when using 9 to 10,000 rpm

Rub20B

Do you now a source for a grose-jet?

We had massive troubles at the track with the float bowl from emptying at 8800 rpm. I had 3 needle valves, 2 200 size with the 3 holes in the sides drilled bigger and one new 300 size. with the 300 size it seemed the 3 holes in the side where too small. in then we got around using the 200 size with drilled out holes. its still far from perfect but you still notice that it struggles to keep the mixture good after 9k rpm.

Afterwards we went on the dyno at strangely enough with 1 fuelpump running we lost like 30hp and there was by the eye no change visible on fuel pressure gage. it seems its really running on the limit to get the fuel in the bowl.

We are now running F8 emulsion tubes with 230 jet in jte rear rotor and 240 jet in the front. 120 air corrector. its running massive rich below 5000 rpm but from there on it picks up well. we changed the length of the intake and found out 20mm shifts the powerband around 400rpm. I still have the feeling the float is coming too low ater 8500 rpm or so as the power flatlines there no matter the intake length. it settled on 235Nm and 272hp at the flywheel gained about 35hp by switching to F8 emulsion tubes and slightly advancing the ignition with reduced split. still slightly low but its a work in progress.

WJM ROTARIES

By using the F2 em tubes will stop the rich midrange and stop lean out at high rpm.
The grose jets are made in the UK as far as I know and are available here to in Australia not easy to find but great for flow and stopping float level from dropping at high rpm. Also what advance are you using , have found buy using 15 to 17 deg max advance is best and the split at 7.5

Rub20B

More advance and less split made it better. Ended at about 26 deg leading with close to zero split.

Also did a run with rx8 traling #9 plugs but those where worse everywhere. So swapped back to #11

First need to get the float level under control before I do any more fixdeling on the tubes etc. I sent an email to jaycee ent. Hopefully they have some. I could not find a source in the UK..

WJM ROTARIES

What front pulley are you using ,if a turbo one and using factory timing marks you are running 10 to 15 deg less because factory marks aren't at tdc. I remark all my pulleys at true tdc
If you cant find a grose jet em me and I will try to get one for you

Rub20B

no its a racingbeat pulley, the small single sheave one. timing makr should be 12.5 and 25 deg but with a degree wheel I checked and they are more like 11 and 23 deg.

I'm waiting for the answer of Jaycee. I could also get in touch with gene berg company but first I wanted to buy a whole carb from them and they where really not into to mood selling me a carb. really strange way to run a business if you tell customers you dont really know if you can make a carb and if all parts are still there etc..

then I bought a carb at CLR in september 2013. I paid it and I am still waiting on it. hopefully its gets here before the end of the season.

Rub20B

modified the 300 needle jet by increasing the holes from 3x2mm to 6x2.5mm, this increased flow into the float frpm 128 to 170 litlre/hour. should be quite a difference. next step would be to drill the 3mm hole to 3.3 or 3.5 but I am a bit worried that it will not seal anymore.

hopefully I can source some grose jets..

DriveFast7

iTrader: (1)

Why not order the grose jet from Mazdatrix?
Cart Price Check Part:GB522-3.3

Weber Jets And Emulsion Tubes

Rub20B

nice. didnt think they would have them. I'll order one or two of these.

Engine is apart again the housing where we fixed the plug boss crack at the plug boss in the water jacket. so water runs in the engine slowly. still it ran very strong in the last race.

started from last place in first race due to carb issues in the qualification. ended 12th with no visibility at all due to fogged screen. 2nd race went from 12th place quickly to 4th. then a mini we doubled drove us of the road. ending 5th..

Rub20B

something is going the right direction

We will be using early 13B housings, I think they are rx4 or rx5. does anyone have an idea if the chrome is good in these? they are new housings and we will run ceramic seals and about 9500 rpm. the reason for using this housings is that they have really small exh port inserts which can be ported to have a slow increase in port cross section and fit well to our manifld with 42mm diameter at the flange. all later housings have a much bigger insert making a very steep increase in runner cross section

WJM ROTARIES

The early housing chrome will be ok just use a bit stronger [more]premix oil with the ceramic seals

Rub20B

at would you run with these? we now used to run 1% and after 3 races the chrome in the mfr housings is perfect, cannot tell they have been run.