t-von

iTrader: (8)

That's not true. 3mms are stock equipment on the 1st gen rotary's(12A & 13b). Those engines last forever. Their not really designed for higher revs which is one of the reasons Mazda went with a lighter 2mm seal.



My point about the 2mm 3 piece is that the top piece gets shorter with mileage making it more brittle. It's true that it takes a long time for the top piece to wear down however, the shorter the top piece gets, the more prone it is to breaking under detonation. They just don't have the structural support like the 2 piece design does. Just recently I torn down a S4 block with 110k and intentionally broke one of the apex seals just to see how brittle is was. The top piece snapped like a tooth pick. The bottom part of the seal was a little harder to break because it wasn't worn down any. I also tried the same thing with my 12a which has 3mm. This engine had 134k. This seal had far more structural support and was harder to break.

dhahlen

iTrader: (5)

Loi from sportcarmotion had 100k on his engine and he had 400-420hp on his ride.

Tim Benton

iTrader: (1)

Not sure what the cause was but all were hi load and WOT. On the datalogged runs, what was the time span in between the data? No high knock? Did you have a wideband hooked up on the runs? What A/F was it showing?

Might help others if you share what was going on in your case to see what the rest of us can steer clear of in the future. For example, what A/F was it tuned for, what it was showing, timing at that point where it popped.

Tim

dgeesaman

iTrader: (7)

How many of those miles were at 400hp?

Dave

dhahlen

iTrader: (5)

Not sure on that, I'll ask him tomorrow =)

FLA94FD

Before my rebuild at 88K, coolant seals, My car saw multiple red lines everyday that it was driven as a DD. For the most part after proper warm-up. All scheduled maintenance was observed and oil was changed every 2500-3000 miles. My car was extremely reliable. Had the car not gone the dealership to replace a bad water pump that was delivered without the gasket which lead to overheating while it warming up while completed the paper work. Can you say pissed. Initially it seemed to survive but it started to smoke on start up intermittently.

With good maintenance and tuning they can hold up to quite a bit of frequent abuse at least when under 300hp. I not so confident after my rebuild but I don't plan on keeping it long enough to find out.

Oh yeah my driving record is clean.

Gamezilla

What failed on it? Apex seal? Overheat the engine? Overrev? Fuel starvation?

Why the hell did the apex seal run into the spark plug? Were you using the kind that actually has an arm on it to arc to?


I posted this on the first page -

"All the guys that push their cars everytime they drive them break stuff left and right. All the guys that drive it around like a normal car and get on it every once and a while have dead reliable ones. "

Im gonna make an assumption the majority of that cars life is spent racing considering you blew every engine under WOT. And you pointed out that you blew the gearbox out (which either takes a ******* lot of hp or some really hard racing). No high hp race car is gonna be dead reliable. You push it to its limits on a regular basis. What do you expect? Now if it blew all 3 of those times and those were one of the few times you really got on it, well damn, you have some really shitty luck.

z-beater

No that is not true, 3mm were only offered on the GSL-SE from 84-85. And I don't know if I believe the higher rev comment either. I have seen plenty 12a motors that have been drilled for 3mm that rev up to 8k.

Not trying to cause problems just trying to clear up some mis given information.

Z

Robertio

On the second engine I was mapping the car with my mechanic driving. Had done the same pull about a dozen times without issue. No knock values (only time I've ever seen a value over 40 was when engine 3 let go) running around 11:1 AFR as the turbos were still spooling (this was about 18 months ago, so all from memory). The car runs a wideband at all times, as I now have a healthy level of paranoia). Was running hardly any boost (0.8 bar) and all seemed fine - had simply set the car up to run a 12 second quarter as I had a qualifying event the following day which requied a <13 time. Many people have seen the map and can see no reason why it decided to let go - seems it was fate. We were simply running repeated 30-100mph pulls (3d gear) while I tidied up the fuel map, timing map was a 2 degree retarded version of what I had been running for 6k miles (was simply a very safe map).
Engine was built with 2mm Ianetti's as an extra precaution after the first engine's death, as it was it let go without any det. Strangely this one let go with an audible pop noise, but no smoke or anything else. Pulled up straight away and it stalled - wiped out a set of apex seals.

Engine 1 was completely stock, just driving down a motorway when I came up to my exit in the wrong lane. Dropped down to 3rd gear and put my foot down - from 70-90mph, lifted off at 90 and took my exit. On a light throttle the car didn't feel right as I joined the outside lane of the next motorway, foot flat on the floor and it would muster 55mph as I navigated my way through traffic and off at the next exit where it stalled - dead apex seal. No sign of anything up with the car prior to this, no obvious det or any strange sound.

Engine 3 was back on Mazda seals - almost all of the last engine was scrap metal, so decided to go with something that would cause less damage when it let go. To be fair this was a semi-desposable engine. Was running 360rwhp at a bar and mapped at high tens:1. Was having problems with the turbos, suspect a bit of apex seal damaged them when engine 2 left the building, so couldn't get more than a bar out of them, hence the disappointing rwhp.
During a brief spell they were runnning 1.2bar happily, alas it was very wet on the only 1/4 runs I managed at this point - rear wheels still spinning at an indicated 120mph across the line. During this spell the 'box started playing up - only on launch, fine on the road so weight transfer / twist related.
On the day of death I lost 3rd, 5th & reverse on my first run, tried another couple of runs and 4th joined them. After a little persuasion the box reinstated 4th so I decided to use the rest of the day to test out the 50 nitrous jets. Had 25 jets on the car for a while, running around 9:1 without any real benefits. Switched the gas on and went for a run - 1st, 2nd to 8.5k rpm, then into 4th and flicked the switch. It was the first run with 50 jets on and it picked up really well (alas my mind was elsewhere so I forgot to get the slip) and at around 120 the knock light flashed twice so I came off the throttle. Seemed fine on the return road, then when I slowed down it stalled, I started it back up and it sounded like a tractor. Seems I chipped / cracked apex seal as the car was fine above 2.5k rpm, but rough below that. Should be stripped down shortly to verify the exact condition, while gearbox and turbos go away to be rebuilt.
Was a shame the laptop decided to wipe the datalog when the car stalled, so no info from the run where it died, but should have been around 9:1AFR, running 4 degrees retard over my normal safe road map. Aswith the 1st engine there was no sign the engine had let go at the time.

First engine was on 98RON, latest 2 on approx 100RON (98+booster), water injection was running on engine 2, but switched off when nitrous used on engine 3.

TBH, other than being under WOT there is nothing in common between the failures. The next engine is going in to run 410-430rwhp at 1.2-1.3bar on WI & 98RON & booster, and whatever the turbos max out at (1.6-1.7bar) plus 75jets on race fuel. Hopefully by running 2 entirely seperate maps for the different uses we can prevent any more unexpected popping moments.

Robertio

Contrary to how it may appear, most of my cars life is spent pottering along motorways at around 71mph. Engine 1 let go on practically the first time I used WOT. Engine 2 did < 1k miles on track, but did do quite a few track days during it's few months of life. Engine 3 did have quite a hard life, due to spending most of it's lifetime either being mapped or with us trying to diagnose turbo problems, but had no track days and < 10 quarter mile runs.

It still stands that most of the boingers I've owned have had harder lives and not felt the need to go bang. Even the Impreza which is known for not liking sustained WOT is still alive and well, and my old Westfield is still competing in sprint events.

My reputation for bad luck with cars is well known, since before I got the FD, but this car has taken things to a new level. When you are taking out a customers car to map it and your mechanic shouts over to ensure you have your breakdown cover card you know a change of hobby is a good idea Worth noting I've never blown up anyone else's car (rotary or otherwise) just my own.

'85GSL-SE

iTrader: (2)

Hell I have yet to blow a motor on my cars or have one that has had a rebuild.

*My '78 RX-7 has 511,015 miles on the rolled odometer on the original '78 Motor. I have all service records since it was bought in march of '78. And for all you guys yes she still backfires from 1st-2nd and to 3rd

*My '85 RX-7 has 110,255 Miles on the odometer and pulls like a bat out of hell thats for sure.

*Now for my '93 RX-7 Fully Stock I mean no modification what so ever since it was bought stock precat, maincat even original muffler. It has 129,004 miles on it and it pulls very well for a stock car. But I have a Greddy intake, catback exhaust, downpipe on the way so she can get going abit more faster. I love to run her to redline and she loves it too .


Just my 3 cents

my FC's I havn't messed with just yet after selling my '90 GTU

What ever, I bet if you tune the engine just right you can get 100,000 miles with 400WHP no problem if you expand the water jacket abit and race prep the motor with cryogenics plus an oil change every 1,500 miles and full service tune-up. If you put the right amount of resources and DO NOT half-rig everything you shouldn't have a problem at all.


My own oppinion that can't be swayed becouse anything is possible. Make a pure titanium engine with titanium everything and I bet if you can blow that, you are worthy of blowing any motor


Just my [Good] 5 nickles worth of info


P.S. My '83 RX-7's original engine had 3mm apex seals. I had to pull the engine becouse the car was wrecked when my Dad ran her into the back of a truck doing 5mph and pulled out into the highway and my dad didn't have no where to go and slammed the back of the Truck doing 55mph. But yes the '83 GSL has 3mm Apex Seals stock..

cbf246

^^^Agree^^^
If you cryo-treated the seals, rotors, and a couple of other things, I think you could make 400whp and "maybe" make it past 100k. Of course that also depends on if this car is to be a track only car, where it sees redline pretty often, or a DD where it sees redline every once in a while. A good tune is neccesary as well as a good cooling system and proper maintenance.

t-von

iTrader: (8)

Well your the one that's causing problems by not knowing the true specs of a 12A engine.

Apex seal length 69.85mm (2.750 in)
Apex seal width 3.0mm (0.118 in) same as the GSL-SE except not as long.

I have a 12a and S5 rotors apart right now and the 12a seals are clearly 3mm. The 12a seals will not fit in the S5 rotor grooves without milling. Also the facts are factory 3mm seals are heavy and cause more chattering at really high revs. That's why lighter seals are used in PP's

t-von

iTrader: (8)

Wow who owned this car before you got it? I'm not trying call BS on your experiance with the car. It's just that the car is older than your are. It's odvious someone really knows how to take care of a rotary. I got 98k on my original engine in my Fd. It runs great. Care to share some of the maintenance secrets?

'85GSL-SE

iTrader: (2)

This is the story behind the car the first person to own the car was a Navy Commander Woman who bought it in March of 1978 she got the GS package with the 5 Speed Tranny and sunroof and wider rims and all. Every 7 months she put the car in the dealership for a full tune-up and replacement of everything, ignition wires, points, oil, radiator fluid, fuel filter and filled the car with 89 or 91 octane fuel to reduce carbon deposits.... etc. Yes she kept a running log of all this. I will have to bring it all to a meet or something sometime. It is incredible.

Next she sold it to a Staff Sargent in the Marines and he drove the car to and from a base in California for 4 years. Just about no records from this guy except he replaced the starter, fuel pump, points.

Next he sold it to a 2nd class petty officer in the Navy who took the car to his duty station in Texas. He didn't drive it much at all and sold it to my dad who was stationed there and my dad drove it back to NC.

My Dad loved rotary engines ever since they first came out and he especially loved the SA Series 1 RX-7's '78-'80. He is a maintenance buff on these things.
Every 2 months it was always the same routine; complete change of Oil to 10W40 non synthetic Pennzoil, replace spark plugs with Bosch plugs, replace points and set the gaps which he checked every week. Always used '93 octane Pump Gas. At every oil changed used a can of this stuff called engine flush to flush the oil lines oil Pan and engine of carbon deposits and gum.
I know Engine flush works Excellent because every time he changed the spark plugs they almost looked brand new and he shined his flash light into the holes and it looked shiny shiny shiny the rotors looked shiney and he would crank the rotors around until we could clearly see an Apex seal and those things looked Excellent and were shiney as well!!
He replaced the oil metering pump and lines every 2 years and the radiator once. He put on new fuel lines and oil sending unit to a dummy light since it doesn't have a oil pressure gauge. every 3 years he rebuilt the carburetor with a full rebuild kit.
The car still has its stock thermo reactor and exhaust. Really it is weird. But the exhaust has leaks out the wazoo. he always kept the cars engine bay washed out and the undercarriage washed as well. He always used racing ignition wires and plugs.

He has all service records from it and not one states that engine failure has been documented. But here is the catch. The engine does have compression loss. It doesn't have the power it should have but it is fast none the less.

The whole rear end has been replaced with my '83 GSL and full front suspension as well from my '83 GSL. I must say the oil cooler for the '78 RX-7 is front mounted right below the radiator like in the GSL-SE, which I had and kick myself daily for getting rid of the GSL-SE.

In a nut shell a FULL TUNE UP EVERY 2 MONTHS is what keeps these cars going full strong. I do the same with my '93 and '85 RX-7. a full tune-up every 2 months which includes plugs, plug wires, oil change and engine flush to also flush the turbos from carbon deposits which I will talk about in a moment. I change my '93's oil with 10W30 as prescribed in the owners manual.

I stand by engine flush 100%

I just recently bought a non running '93 RX-7. When I replaced the Boost sensor she cranked right up but was slow as the day. My '85 could outrun her . I engine flushed the car the first time I changed the oil and I couldn't really tell a difference so after a week I changed the oil again and it was pitch black. So I engine flushed her and put new motor oil in her and I noticed a difference in power levels almost immediately. So after a week again I changed the oil and engine flushed her. I put new 10W30 Motor oil in her cranked her up and took off and man oh man let me tell you what.......... " I am sitting in mid air and where in the hell is my car of **** let me go run after it it left me sitting in mid air and took off.... " I believe the engine flush flushed all the carbon deposits out and flushed her turbos of carbon build up and I use it every 2 months and I just recently did one when I got back from Rotaries at the Zoo in with the Raleigh Rotary Crew! and the oil was still looking new. I went ahead and engine flushed her and I changed her plugs. I crawled up underneath the car and put a mirror next to the Spark Plug hole and it was shiny in there just like my '78 and that's when I knew that she was happy and revving freely and I use the K&N Oil filter BTW on all my cars.

**** if you read all of that man you are a hero!

Sorry for the long post but you asked and so you received the info you requested.

Claim BS all you want but I know better because I have lived it.


Cheers,

Dan

t-von

iTrader: (8)

No need to cry BS my friend. Thx for all the useful info. So I guess preventive maintenance is key. I can easily see how rebuilding the OMP that often would help out in the long run. You never can tell when those things go bad. Did you just follow the manufactures recommendation for the engine flush or is there a secret that is done for our rotary's? I'm mean does it need to stay in the engine for a longer period of time so that it works it's way through the OMP lines? You have me so interested in this stuff. I never would have thought that it could benefit our engines especially with reducing carbon build-up in the combustion chamber. When this engine finally gets rebuilt, could you post pics of the internals. I would love to see them.

Trexthe3rd

I always wanted to know from the folks that had cermet coated engine parts, has the longevity of the engine significantly increased with the ceramic coating or is it the same?