Sepher0

I am curious, how hard were you running it? I have been curious of how hard you can push a rotary engine.

txturbogs

That's what I did when I sold my previous RX. I warned the new owner that the car is expensive to mantain, that I just replaced the turbos, etc. He wanted to buy it even after I told him all the things that could go wrong.

dgeesaman

iTrader: (7)

Reading your old posts about backfires, bucking, and other stuff, it makes me wonder if this happened because of major fuel injection problems or a fuel/tuning setup that is simply way wrong.

Simply putting in another engine without attention to verifying and fixing this would probably blow the new engine, too.

Dave

c.stenson1

thanks for the help guys, to answer some of you, SEPHERO i had the car on the driveway for about half an hour then took it up the road not thrashing her, turned round floored it to around 4k changed gear then it had no power like it was on two spark plugs and the turbo metre was flickering. HAROLD93 i am in the uk so if you want anything just email me or use this thread, i wont be stripping her till after christmas now im too pissed to even think of it at the moment as she is beautiful to look at but in a month or so she will be a bare shell im heart broken. MAHJIK the compression was 8.5 on the rear, DGEESMAN i worked out that the wire from the ecu to the fuel pump relay was grounded and i was in limp mode which caused all the back fireing from hell, i fixed that a week or so ago, she was running sweet for a week till two days ago when this happend.

Sepher0

you make its sound like it must of blew due to age or something else... not cause you were running it hard (I mean 'a bit hard' ... 4k isnt 'a bit hard' ... ???).... god that sucks...

dgeesaman

iTrader: (7)

The FD motors generally don't blow an apex seal due to age. It's usually detonation caused by something like bad gas, fuel starvation, overboost, or bad tuning that pops the apexes.

Motors that never see detonation will die of old age, but usually at a coolant seal.

Dave

c.stenson1

i ment it was hard up to 4k but not spinning, i think it was something to do with it on tick over for half an hour and being very hot like harold93 said, these engine must can take more than that, they go up 8k and 9k easly for gods sake. the more you guys reply the more i get tempted to fix the engine. i have got to take the engine out anyway to sell it, i might aswell take a look at it first, if the spring has failed that pushes the apex seal up will it loose all the compression and if the housing is damaged will the rotor be damaged aswell.

RotaryResurrection

iTrader: (8)

This is true, but an apex seal with 50k miles has some significant wear on it, at least 25% of it's total original height. A seal with 125k miles (fd's dont make it this far usually) are worn just about 40%. Some of the old NA engines that I've seen get to 175k were worn halfway or more.

The more the seal wears the weaker it gets, especially the stock 3piece design. When that upper seal wears, it can become as thin as 2mmx2mm. You can snap a seal worn down like that with 2 fingers and a thumb. People are shocked when I demonstrate this in person using old seals. This is why I go back with 2 piece seals in rebuilds (and possibly a factor in why mazda switched).

Also the compression drops quite a bit as the seal wears...not because the tip is in bad condition, but because the seal height is less and therefore the springs underneath are under less tension, and don't "push" as hard most of the time. THe more worn the seal, the lower spring tension becomes. This mostly comes into play at low rpm and cranking.

c.stenson1

this is interesting, since i had the problem with the fuel pump relay wire to ecu 1k and being in limp mode i kept my car off the road and i did a compression test about 4 months ago, the result was that they were all 8.5 so i knew to rule this out as my problem. now i find out that the compression gets lower over time, i am thinking that it is more likely to be the springs that are gone, i am no mechanic but the facts are there. what would i need to replace if the springs have gone.

dgeesaman

iTrader: (7)

When you're in limp mode there is practically no way to detonate and damage the engine. As well, if you're not getting boost (which I think you said is a problem you recently fixed), you'll have a hard time damaging the engine.

It's when you're at full boost where detonation is most likely and most dangerous. If you had very good compression recently, it's very unlikely that wear would weaken the seals or springs to the point of losing compression like RR is talking about. That takes 10s of thousands of miles. I'd guess something was wrong with your fuel delivery or tuning, and you ran lean, but now that it's getting full boost it finally detonated. No rotary motor, with new or old apex seals, can handle much of that.

In either case, it doesn't matter. Damaged apex seals usually tear up the turbos and a few pieces of engine hard parts, and the cost of all of this is what makes it more painful.

Dave

c.stenson1

i think i know why this happend, i have put on a 3" ss dp mp and cat back box, simplified the system with saxymans990 custum solenoids, front mounted intercooler, induction kit, fuel regulator and underpullies all this and no apexi fc, i was getting one soon but i just thought i would try my car on the road for a few minutes, so i warmed her up like i said for around half an hour then took her out, i knew it was risky to run her without an fc but it wasnt for miles and miles it was just for 3 minutes and this happend, anyway how much can you guys get the kit i need for over there, i will call in a few favours if its not so bad, just the kit i can get hold of the hard parts i wil need.

DCrosby

Also if you're running your motor (idle) and your boost gauge shows low or irratic, not steady vaccuum, that would be another sign....

It does point at some sort of ignition problem if you can't start the motor... since I had 2 blown engines, and both times they started when cold but would get worse and worse once warm...

-DC

c.stenson1

it does start when cold thats right, when it happend i tuned it off but couldnt start it again.

nopistons94

if you were running all those mods stenson, with a stock ECU, your motor is blown or will be soon.


Are you going to sell the saxyman solenoids? I'll get them off you

ArmenMAxx

iTrader: (21)

I would think that the stop ecu should handle all those mods cause he hasnt raised the boost. I think. If anything maybe ur opened exaust might cuase some tunege problems, but not a blown motor.

nopistons94

??? sense you no make with this post buddy. The guy has FMIC, full exhaust with no restrictons, and open intake. No way you should be running a stock ECU with this setup. Tunage problems? You mean wrong ecu. He'd be lucky if the boost stayed at 10 with his setup, and I know it gets cold in England.

c.stenson1

your dam right its cold, hey jersy if you want the solenoids they come with three viton check valves all the vac pipes and resistors, you can have them for $240 deliverd.

c.stenson1

hey gersy when you wake up let me know what you think of the solenoid deal, cheer phil.

Kevs

When you run a compression test make sure that you remove all the plugs first, if you have blowen an apex seal, it will compress from the traling to the leading on the houseing that has the damaged seal, on the Bossted units the RX has a fault off also stripping the plateing off the inner houseing under high boost, your problem sounds more like fowled plugs and I would be checking these first, see if they have fowled.

c.stenson1

its too late things are being sold, there was no compression at the front anyway, thanks for your concern.

c.stenson1

come on gersy get up.

c.stenson1

youve got to be up now

7racer

the pm system works better then bumping a thread to contact an individual person

in regards to your car. Its a shame that you had so much into it and not had and ECU to control it. I personally think if you went that far, that you should just get a remans and a PFC and keep your aftermarket parts and enjoy the car...FWIW

BTW, who advised you to run an open exhaust with no tunable ECU???