If you aren't a semi expert on this, please don't answer. I don't want a bunch of rif raf to sift through.

I've got a unmodded 90 vert that has 0 compression. Looking through the exhaust ports, I can't see any obvious damage to the seals. There is however tons of **** and rust built up in there. My question is, do these n/a motors break their apex seals often or do they just eventually corrode up until the apex seals get stuck?

I've only built 3rd gen motors so this is somewhat new to me. Hopefully RotaryResurrection or someone else will chime in.

Thanks.

 

not nearly as often as FD's

 

So basically with these N/A motors, one could just clean things up and replace the coolant seals and throw it back together if everything is in clearance?

 

NA motors almost never, and I can't stress that enough break apex seals.

 

Uhh...I have a S5 NA engine in the garage that was NEVER modded and it shattered an apex seal on the front rotor. The entire rotor is now completely useless and i think the housing might be gone as well.

It DOES happen.

 

Says who? This is the biggest load of crap I've ever heard. Any rotary can chuck an apex seal after enough time and enough miles...

To answer your question, yes an unmodded n/a motor can break an apex seal, any rotary boost or not can, especially after a bunch of miles.

How many miles are on the vert?

 

Says me, who has about 300,000 miles of actual use. Sure they can break an apex seal, and the Boston Red Sox could win the world series. But by and far they just don't break, let alone break like boosted rotaries do.

 

After 180k+ miles they do tend to break a lot easier... SURE boosted rx7's and FD's will break much easier, but they can break just like any rotary. The consensus is that the n/a can go about 150-180k miles fine without chucking an apex seal, and sure people have made it over 200k even, but it happens eventually just like anything that can wear out...

 

I have found (In my limited, personal, local experience) that turbos are vastly more prone to blasting apex seals.

On the N/A cars that have come through the garage here, I have had more total problems with the oil seals and side seals.

Every single one that blew an oil seal, blew the front oil seal. How strange is that?

 

160,000 miles. I'd like to hear from someone who rebuilds alot of 2nd gens.

 

Side seals sticking or breaking?

 

My NA engine had 125,000 miles on it when the apex seal broke.

 

This is by no means definitive, but through measurements during my rebuild at 186K, the three-piece apex seal could have theoretically lasted another 30K or so before it would have met limits and perhaps "rolled out". The only way I could envision an NA seal going before it's time is maybe by detonation, due to bad timing or other strange factors...

 

By rolling out, does this mean rotor groove clearancing out of whack?

 

The FC motors used 3 piece Apex seals. As the engine wears, the apex seal slot can wear to a V shape rather than the flat U shape it should be.

When an apex seal rolls out, the top section of the 3 piece apex seal can slide out of the worn V shape grove of the rotor.

 

Yeh, what Mark said. Or, the rotor seal groove could be fine, but the apex seal wears to the point that the rotor groove just can't hold it any longer, and it "rolls out"...We should get much longer life out of the 2-piece seals we're using in our rebuilds now, because there's that much more seal "body" for the rotor grooves to hold on to...

 

Any rotary can break it's seals due to plain out wear. I just took apart a 1gen GSLSE motor that the seals were worn down to half their original height. So much so that they weren't even being held in contact with the rotorhousing surface, the spring was at the top of it's travel and it still wasn't enough.

Turbo rotaries usually die from detonation and abuse, they never get the chance to wear themselves out. NA rotaries can die from either, but carbon buildup and wear are most common.

IF the seals are stuck and everything is rusty, then it sat too long, or it had a waterseal problem, was let to sit without being run, and there is your result. Rusty parts are nearly impossible to free up and make work properly again, and usually arent even useable in a rebuild.

www.rotaryresurrection.com ---> tech ---> internal engine damage

 

Bullshit. I get them in every day. Broken seals and all. You do see a lot of oilseal problems and the occasional waterseal motor, but 90% of all rotaries, to include nonturbos, are blown apex motors.

Probably 2% are oilseal motors, 3% are waterseal motors, and 5% are just too weak to run anymore, though they didnt break any seals, they are worn far beyond limits.