braggy_g2

yep... im one of those unlucky people who experienced overheating, which most of us suspect it to be a bad coolant seal on which the only way to fix it is a full engine rebuilt. well, next week ill tow my car (rx7 N/A 86 gxl) to R&R Rotary in Upland, CA. the guy gave me an estimate of $1800.00 w/ teardown and install, tax and labor. good price yah think? well, id prolly replace my rad and fan clutch too. Now, out of curiousity, WHAT IS THE NORMAL LIFESPAN OF A REBUILT ENGINE? What steps to make it live longer? And what is a "break-in" anyway? ... i apologize if i ask too much, its the only way for me to get information.. im new to RX7. ideas are greatly appreciated.

sharingan 19

iTrader: (16)

I'm interested in the life span of a good rebuild as well as I just got mine back from the shop a week ago.

As far as the break in process there's a thread directly above this one that talks about just that, I'll see if I can find the link to Fc3spro that talks about break in
....found it
http://fc3spro.com/TECH/FAQ/breakin.html
.

Sideways7

iTrader: (7)

Honestly, it depends on the parts used. On an NA with new housings, you're looking at easily 100-150k if its taken care of. The life goes down from there depending on the condition of the housings. Remeber housings only have a certain amount of life in them, so if you re-use the old housings the life of the rebuild with be less. Assuming you use housings in good shape you are looking at at least 50-75k of good life.

braggy_g2

sharigan, whats a "break-in"? is that type of process gonna help ur engine live longer?

braggy_g2

thanks for the good info. 50-75k, its probly 2 -3 yrs... i think its not that bad, at least i have time to save some money for it untill it needs another rebuilt.

sharingan 19

iTrader: (16)

Pretty much. It's the process you use to ensure all the seals in the engine have a chance to seat properly before you go wailing on the engine. It helps prolong the life of the engine cuz if you go boosting right after you leave the shop, it'll probably be a rather short trip

slo

iTrader: (1)

anywhere from less than 5 minutes to as long as any rotary engine of that series could last if new. Depending on which parts where replaced, and how correctly the engine was put back together.

Before having it rebuilt at least flush the cooling system, refill it with water and pressure check it to make sure that it doesn't just have a leak externally. It shouldn't drop more than a few PSI overnight. If it does or quicker than that and you can't find a leak then you know its actually bad. There are other sysmptoms, search this forum to find out. You have an S4 which actually has an accurate gauge, if the gauge is running a little or even a lot hot for a short period of time you may not have cooked the seals yet.

Sideways7

iTrader: (7)

Even then, it would still most likely run. Most failures I hear about on NAs are from coolant seals or oil seals going out, not popped seals. On a rebuilt NA engine that is treated well, I think the life is more likely dictated by when it just gets too slow from low compression than true failure. Also, 50k in 2 years? How much do you drive it? I drove mine all over the place and only saw about 15k. Not sure where you're from, but I am talking about miles, not KM. Anyway, any rebuild that uses even decent housings should last you 2 years minimum.

braggy_g2

wow! i love this forum... there are so much information in here. well, i hope R&R Rotary Specialist will live up to their reputation. 50k in 2 yrs, i think i can do that, if i dont drive my car all over the place.

slo

iTrader: (1)

BTW 86 cars also had a cooling system recall, basicly because of the location of the overflow tank and radiator cap they wouldn't suck fluid back in, they would keep pushing it out indefinatly. The recal involved a funky coolant level sensor that had a port in it. But you can effectivly get the recal by getting an aftermarket radiator with the pressure cap on top of it. And you replace the cap thats above the thermostat with a block of plate.

If your car is just pushing coolant out and not sucking it back in when it cools and it still has the original 86 radiator without the recall then this could well be the reason. It may not need new seals.

braggy_g2

well, i believe a few times, when i noticed that the tank was overflowing coz of that buzzer, i hurriedly went home. the next day i noticed in the tank, coolant is back to the level between full and low. so i guess, its been sucking the coolant back in. However, yeah ... i agree with you. the overflow tank is kinda far from the radiator with the S4's.

Rotarctica

My engine has 181k on the supposed factory build. I both believe this and I don't...181 k is a LONG ways for a Rotary, in my opinion. I do have that throttle spring wear thing that tells me it was driven pretty lightly. But 181k? It runs just a tick over the 1/4 mark, but not near half (temperature gauge), oil pressure is completely normal...just a tick over 30 at idle, 60 at 2,900RPM and over 60 if I'm near my redline, which I don't do that often (Once or twice a week). The engine doesn't flood. It always starts. No excessive smoking. There's a very thin amount of white smoke that comes out on startup and lasts about 30 seconds, but I'm not entirely sure that's really smoke considering it is getting colder and I never noticed it when it was 80 damn degrees out (And I check). So it's probably just it being cold weather.

It runs great...there's no hesitations, it doesn't eat oil and surely doesn't eat coolant. It has an oil pan gasket leak and a power steering leak, but that's it.

The man I bought it from has only had it since 1999, so maybe sometime in it's life before him it had been rebuilt? I know it's possible to have 181k on it but it seems to be in great condition...

RotaryEvolution

iTrader: (30)

i have 185k on an original engine in my daily beater, what's not to believe?

Rotarctica

-shrug- It just seems odd to me because it runs so well.

slo

iTrader: (1)

I put about 175 on one and it was running when I sold it, I see cars at the junk yard all the time with over 200. My dad works with a guy thats the original owner of a 79 that has 260

RotaryEvolution

iTrader: (30)

and mine is quicker than most cars with less mileage, that just means it is running right.

Rotarctica

I'm hoping to stretch this engine life to it's maximum Well over 200k. Wish me luck.

braggy_g2

its really overwhelming to know that a rebuilt engine can be reliable. now im more convinced that mine will be reliable too. i excited about it, i miss driving my RX7.

stylEmon

iTrader: (2)

This question has no definite answer. There is so much that depends on the parts used and the builder.

As for break in... My engine will have about 5 minutes of break-in time. I'll be able to boost my first time around town. That's the benifit of having a blue printed engine, studs, PolyDyn coating, external oil pump and widened passages.

More and more, I see reasons for engine failure amoung RX-7s. My mechanic told me today that the acceptable wieght offset for the weight of rotary engine parts is 50grams within spec! On a piston engine, the acceptable weight per part is less than 10grams to spec. That's quite a difference. If you get your engine balanced, it could literally add 10s of thousands of miles to the life of your engine.

Digi7ech

iTrader: (1)

^ that stuff would give the engine overall longevity. I don't see how it would reduce breakin mileage though?

Did you use new housings and seals?

classicauto

iTrader: (3)

Care to elaborate on how having an external oil pump and the other jazz you mention will make the apex seals seat to the rotor housings in less time then it takes to properly warm up the car?

stylEmon

iTrader: (2)

I kinda see break-in-time as a myth, or urban ledgend.

when you blueprint an engine, everything sits where it's supposed to. If everything is clearenced to spec (or better), why would it need to seat? Plus, premix aids in this process. So 5 minutes, maybe a little exaggeration, but 10-20 miles, definetly.

I am also entertianing the idea of using piston technology to help the apex seals seal better at higher velocity. By drilling tiny holes under apex seal, air will aid in the process of making a tight seal. Not sure I'm gonna go for this on this engine tho.

DigiTech7, new housings and new seals. Is there another way?

RotaryEvolution

iTrader: (30)

you, sir, need to quit giving people stupid ideas... and quit listening to your cat, he isn't a rotary mechanic.

stylEmon

iTrader: (2)

LOL, actually, he did give me most of these ideas, after we choked on some cat nip!

I probobly shouldn't post stuff like this. Not trying to start an uproar, just maybe get peoples minds spinning a little differently.

These things work on other applications, that's all I'm saying.

RotaryEvolution

iTrader: (30)

yes but the rotary engine is not even remotely like any other engine.

Mazda nearly went bankrupt in designing the rotary engine, i doubt you have millions upon millions to dump into research and devolpment or are smarter than Felix Wankel. uproar isn't the word, it did give me a chuckle though.