mike, unusually, it is you who is talking bollox.

The mazda rotary engine (****el) is made up of a sandwhich of seperate rotors on a common crankshaft.

They come in 2 rotor guise (all production RX7's)
3 rotor (rare race engines)
4 rotor (Kudzu mazda Le Mans Cars, ie Jonny Herbert winning car)

My mate Pip Gardner of WGT in cheshire is the UK expert on these engines.

He is racing a 3 rotor RX7 in the formula saloons championship next year. It produces over 400BHP in normally aspirated configuration.

My mate Chris Maries raced a westfield powered by a 2 rotor RX7 N/A motor in the westfield championship 2 years ago and won every race. They then banned him.

These engines are serious pieces of kit but take specialist knowledge to stop the rotor tips from melting.

 

Dear John,
By bollocks, I meant the size was incorrect. They are actually two 654cc rotas with twin sequential turbos making a capicity of 1302cc NOT 2600cc.......
Sorry I didn't elaborate on my posting, but I like to take the ****.....
Best regards
Mike

 

I love how the swear word editor deletes "w a n k e l"

Mark

 

Anders
What was the exact symptoms of your failure?

RichiB

 

Pete Croney was with me on the course at Wroughton whilst gingerely picked my way through the boulders (stones!) and rivers of water.

A faint detonating noise was first heard by Pete this became louder so he ordered me off the track. As I came into the parking area at a crawl it sounded like a bag of bolts!

The track was very slippery, as people were spinning left right and centre I was taking it very carefully as the 22B bodywork is expensive to repair!

 

Dear Anders,
I have NEVER heard of detonation being a symptom of oil surge! Oil surge (where the pick up briefly sucks air instead of oil) usually causes the bearings to run dry and throws the crank out. Does NOT cause melt down or detonation (although with the crank "thrown out" it might then, but you would get the bag if nails noise BEFORE the detonation). As I suggested earlier have the internals inspected by the top people so NO-ONE can argue with their findings.
Regards
Mike

 

Dear Mike Rainbird,

I hear what you are saying with the WRC and BTCC cars. However, even with these no-expense spared applications, engine failures seem to pretty common-place in rallying, even over the relatively short distances they run. I know that the level of abuse dealt out to these cars is far higher than any road car would normally face, but any form of track driving and very high-speed autobahn driving will put a great deal of stress on a road car.

I am not suggesting that the power output of a standard 22B, STiV or EvoVI is in any way pushing engine technology to its limits. I am merely suggesting that modifications to these vehicles are pushing them out of the envelope in which typical levels of road-car reliability and engine longevity are to be found.

Yes, your cossie *may* be an exception, but in 10 years of reading the motoring press, 1 year of reading this BBS, modified cars always seem to attract trouble. Just look at David Yu's Skyline in Evo Magazine for a prime example....

 

after reading your last post i have to agree that it is not oil surge but detonation.
Heres a thought for you.

If the boost presure is raised above 1 BAR (14psi) you will get more piston ring blow by. This will increase the amount of oil vapour comming out of the breather system and into your airbox.
If you add oil vapour to your inlet charge then the octain rating of the fuel/air mixture is reduced which will lead to detination/pre-ignition. On all properly built cossie motors running over 14psi boost a breather system is fitted which seperates the oil vapour back to a liquid which then runs back into the sump, any uncondensed vapour is then fed into a seperate oil catch tank which vents to atmosphere. Properly built cossie motors also breath from both sides of the engine block so that if the oil blocks one side breather, the other remains open to vent the exess gasses. If you dont vent both sides you can blow gaskets.

The question then is 1) is it over 14PSI boost?
2) do you have a suplementary breather system fitted?

 

Anders
Do you know whether the pistons melted or whether the big ends failed?

RichiB

(bear with me I am going somewhere)

 

Hi there..

I would assume the 22B was running 1+bar..

Scoobs dont come with an oil catch tanks(waits for BPM to offer one)... It is possible for oil to get into the intake.. I have seem this.... but it is not directly related to boost (just because u run 1+ bar doesnt mean you get oil).. I have seen many cars running over 1 bar and no oil... I run 1.4 - 1.5 bar...with no oil in my intake.. I often check it.... the impreza sumps are sort of baffled....true not as much as they could be... and you can get "proper" baffled sumps...and dry sumps.... I corner hard in mine... and the G's would certainly move the oil.

I dont believe it was oil surge... this will be a grey area.. because det would cause the piston to go...then the rod...which inturn would knacker the crank... Only by close examination of the engine will you know for sure...

From people at the track... I believed the noise was classed as the heat shield pinking....which would be the same as det.

Track use puts a tremdous load on a car.... heat build up.... boost...etc...

I think what "might" have happened is that the intake temp and air was getting hotter and hotter.... boost was being applied....low air flow/cooling and basically pinking/det happened. No chasis roller can expose a car to the same environment as a track, accelerating, slowing down... short sprints..long sprints...continously pushing it to its max... hence PE tried to give Anders a good map (taking it to near the cars limits for road use), but the track just pushed it abit far.... Similar thing to the STI fuelling issue... fine on the roads... put them on the track and bang...

Please correct me if I am talking pooh... I normally do...

J.

 

I had wished to give power Engineering a smoke screen to hide behind!

Hence my statement about it sounding like a cracked heat shield!

I do not have a heat shield as the down pipe is wrapped.

Power Engineering "bought the smokescreen" idea, hence I thought they would look after me as well as the other Power Engineering victims!

I am not yet prepared to openly state the technical side of the argument as I am seeing Mr Power tomorrow.

He may yet accept that he has a moral responsibility and turn this sow's ear into a silk purse!

I would like to take massive issue regarding track versus road driving.

I am a Dr and I am called to medical emergencies and I attend as quick as is safely possible.

I have even been given Kent's highest award for bravery for attneding the Faversham M2 coach crash of Autumn 1994.

My car has been regularly put through its paces at far higher levels of engine stress, compared to Wroughton.

Including dry track days and at the hands of journalists without so much as missing a beat.

I believe the difference was that Wroughton was cold and wet and the PE1 was set up for hot dry conditions.

Does it often get cold/wet in England?

 

anders, a properly mapped ECU takes ALL parameters into account including ambient temp. We run our Group A rally car in thick snow covered hills and scorching hot summer days without any problems, you just notice a drop in power as the boost is backed off as the charge temp rises, the map should do all this for you.

As for no oil problem on the impreza, If you go above 1 Bar you will get oil vapour into the inlet charge, note the word VAPOUR.
You only get pools of oil in the airbox when the engine is fairly worn.

It is the vapour that drops the octain, not the pool of oil in the airbox!

 

Boost is increase to over 1 BAR with the PE conversion.

 

John,

I was confused too, but it seems original diagnosis was misplaced.

On the basis that detting will knacker the piston and rod before the big end bearing, then Anders problem cannot have been detonation as there was no apparent piston damage.

Scott

 

Having read this thread, and the related threads with interest, firstly I would sympathise with Anders for his misfortune. There are clearly other issues which should remain between Anders and David Power unless they wsh to make them public, however, I have some thoughts on the original failure issue.

Reading David Power's response, and having seen the pictures, it is apparent that a big end bearing failure was the problem.

Whether or not there was additional strain placed on the big end because of detonation or whether it was simply an oil starvation problem is more difficult. You would, however, expect piston and plug damage with detonation of the magnitude required to cause big end damage.

For what its worth, my Mini used to lose oil pressure due to oil surge when the level was on the low side when cornering (albeit quite quickly) on the road and on one occasion I lost all pressure on a track day (in the wet)due to this problem.

I find it quite conceivable that oil surge (or more correctly starvation) could have been the cause, particularly in view of no apparent piston/plug damage.

What may also be of consideration is that the damage to the bearing may well have originated some time ago and only become terminal on the day in question. I had a knackered bearing in that Mini and was able to trace the reason to an event over 800 miles previously (lost sump plug )

Ander's car has certainly been driven to its limits by various parties and at several track days prior to is failure.

Perhaps some of the more knowledeable posters would care to comment.

Cheers

Scott
(hoping all is resolved soon)

 

scott,

i am confused now, an earlier post described the classic symptoms of det now you say it was big end failure.

Det will never cause big end failure unless it was so prolonged that it caused the piston to be distorted severly and jam in the bore, this would then bend/break the rod.

The only way to clarify this issue is a complete engine strip, it will then be very aparent what has happened.

I have rebuilt many race engines that have had both det and rod failure, it is very obvious which was to blame when you strip them.

 

John.

I think you should read David Power's response in the Miscellaneous section.

Stef.

 

Howdy..

Based upon the info I was given, I went for pinking/detonation...

But if the pistons/plugs/valves are "clean" then obviously it wasnt due to det/fuelling... and simply a mechanical lubrication issue...

Like I said before I have never heard of oil surging on the scoob...but.... there is always a first time for everything... and if the oil was low anyway..*shrugs*

I am not retracking my prognosis...or admitting I was wrong..*hides*.. My result/judgement was based upon the info I was given... If we had be able to see the pistons, bearing, crank, rods, valves (the engine basically).. Then maybe the my diagnosis would have been different.

I think this goes for a lot of other people how agreed on det.. the info that was given out virtually spelt the word detonation..

I bet everyone will be checking their oil levels.... do they fill them to max... but maybe suffer from map blockage.... or run them lower and suffer "starvation" lol

I will say one thing... I wish my bloody plugs looked that clean, even after one day!!! Mine are a tad black..even after cleaning... lol...but no errosion...

J.

 

This sort of prompted me to check my oil. It was fairly low - 1/3rd above lowest mark.
Does it depend which oil you use, with regards to "oil burning".
Last change I used Mobil Motorsport 15-50.
Couldn't get it for this one, using Shell Synthetic whatever, 5-40 I think.
And do Sti's smoke - I swear I get a puff of smoke on hard full bore gear changes.
Can't look in the mirror long enough to determine whether it's blue or black.

 

I maybe talking out of my bottom, and before I get flamed my opinion is purely my own.

I have to agree with J but those spark plugs are incredibly clean.

TFG

 

Craig,
The puff you are seeing is the soot from the huge amount of petrol being wasted on the over-run when you change gear (my STi did the same at Donningtion), as the engines are running very rich for protection. Apparantly if you remove the cats you can get a nice jet of flame just like a group "B" rally car

 

my cossie chucks out 6 foot flames on the overun on track days, mind i do have a 3" pipe straight of the turbo and 350BHP.

Great for paint stripping any nutter who might try sitting on my bumper.

 

That's what I wanted to happen when I changed the downpipe - the car is now catless, bangs, pops and farts on the overun, but no flames!
Sad - oh yes.

 

Jason,

The plugs would be clean if they had just been changed at the service carried out the day before.

Even so, any car running on optimum air fuel ingition (ie not an over rich running Scoob)then plugs should look clean anyway, regardless of age.

Scott

 

Scottie...

I wasnt sure if they were changed...

The plugs in a scoob get sooted more than other cars I've seen....down to the over fuelling... Its just how they are... Det will burn (destroy) the plug away... not make it just sooty

I can get flames out of mine.. but I dont want them.... I lit up the sky last down...going down the A50 when I backed off.... quite amusing seeing the sky behind you light up... lol

I think I'll adjust my fuelling alittle...

J.

 

This is a blast from the past isnt it? John, Chris is my Uncle. Fancy that eh?

Simon

 

You poor bugger.

Say hello to Chris for me and tell him the Esprit will be out again very soon this year after a lot of work, in 6 litre guise now. (chris knows me best as the spanner monkey on the Wildcat Esprit )

 

You'll probably see him before me!

Was the Westfield light blue? That was a monster.

 

yep, he wooped everyone in that and then they banned his car from the championship.

One of his funiest races was when he was running the westfield mini (bike engined mini special saloon), he was bouncing that off anything that moved, i was counting the panels dropping off each lap.

 

Maries (Ma' riece) and not as in Fairies (Fare' rees) as per Tuscan video!!