I have a friend that's going to buy a pair of ported housings I have. He wants me to put a motor together for him. But wants to hear other people's opinions on how long a street port motor would last as a daily driver.

 

Depends on how he treats it. I've been using mine as a daily for several years, never had a single engine-related issue. A streetport is not going to reduce engine life per se.

 

the same as a stock port engine all other variables the same. the ports dont affect anything that would make a difference, just air and fuel intake and exaust.

 

as a dd is only gonna be slightly worse on gas.

 

Thanks guys.. I told him the same thing but he wanted other opinions.

 

So long as he doesn't over rev it, he keeps up on standard maintenance like he would with a stock port engine, and it's assembled well (no pinched seals, no bad seals/springs from the kit, etc.), it will last as long as a stock port motor. If he were wanting you to build a BP or a PP motor with carbon seals, etc., it wouldn't last very long because of different seal materials and a higher rev limit. A properly tuned SP will just use more fuel.

 

A street port doesn't really get into the seal issues like a bridgeport does. The only way he'll reduce the lifespan is by revving higher enjoying the extra power and a power band that is higher in the rev range....

 

He wants me to put rb carbon apex seals, to increase oil pressure & rb oil pump.

 

Carbon seals will put a definite lifespan on the motor (I think they're good for like 10k miles).

 

I know that carbon apex seals are better than the steele ones. I heard from Rob at Pineapple Racing that he has a customer with a bridgeport with carbon apex seals that uses it as a daily drive & he told me he got 55,00 miles.

 

WTF? Carbon apex seals won't increase oil pressure. They also make the car harder to start and don't last very long. Only reason they're used is to reduce chatter at high RPM (8500+).

 

I know carbon apex seals don't increase oil pressure. He wants me to increase oil pressure and wants me to put in carbon apex seals instaed of steele ones.

 

Why does he want carbon seals? There's no point in using them unless he plans on racing and constantly revving the engine past 8.5-9k. If that's the case, the engine needs to be balanced/clearenced along with hardened stationary gears, 3 window bearings, and oil mods. What are his plans for the engine? Granted, carbon seals are dirt cheap, but steel seals will outlast them many times making the use of steel seals cheaper in the long run.

 

I told him the same thing but he's young & got rx-7 fever. This is his first rx-7.

 

knock some sence into him then!!.. or at least tell him not to ask for opinions/advice if he doesnt want to listen to them... everyone is saying he doesnt need them..than well he should listen because this is his first 7 and probably doesnt know a whole lot about them and just likes the sound of "carbon apex seals"

 

He hasn't seen this thread yet but when he comes over, I'm going to show it to him.

 

Standard apex seals can go for 200K miles or more (I got 213,000 out of my last motor). Carbon, like Trochoid said, are made for very specific purposes. They are lightweight, so you can rev higher, but so many other things also have to be changed to make it worthwhile that they tend to be used in 15,000 dollar pure race engines. Those are expected to get torn down and rebuilt every season, so a long life apex seal just isn't required.

But if Rob from Pinapple Racing is telling you they're good for 55,000 miles, then maybe he knows something I don't. He certainly has more experience in that than I do. But it does go against what I've read and heard (for whatever that's worth).

I can understand your frustration with a stubborn kid who thinks he knows what he wants. Maybe you should send him to us, and let us straighten him out for you..

 

yea, did you see what happened to this kid?

https://www.rx7club.com/1st-generation-specific-1979-1985-18/rebuilding-nikki-819658/

 

Well, that ****'s over and done with. Everybody got a little excited and some of us forgot our manners. Dead threads sink to the bottom for a reason.

 

It should be noted that even Pineapple Racing would consider 55,000 miles as an exception to the rule. Carbon apex seals are only good for race motors or people with bottomless pocketbooks.

 

i just couldnt help myself.

 

This is just a stray thought... would carbon apex seals be less likely to ruin a housing or rotor when they come apart, compared to steel? I've not worked with them, and don't know their relative hardness. "Carbon" doesn't tell you much about their physical makeup; everything from graphite to diamond is just different forms of carbon.

I understand that they are more sensitive to fracture from detonation problems than steel seals. Just wondering if they might have a small saving grace in that they're less likely to ruin other parts when they go? (providing the apex spring doesn't make it all moot)

 

I have heard that they're kinder to rotor housings if they fail, but detonation usually isn't a big problem for NA engines, and if you're using carbon seals with forced induction, you're insane.

 

Carbon seals cause less damage than iron when they break. But you only need carbon when you're reving the motor over 8500. Stick with stock seals, 80 psi oil pressure regulator, use a gsl-se oil pump, and a rev limiter so the kid doesn't buzz the motor. It'll last a long time, be a blast, and survive 8000rpms.

 

I've come to the conclusion that you should build the engine with carbon seals. Since he doesn't want to listen to why it should be built with steel seals, then chances are he won't follow the proper beak in proceedure. This way, when he tears up the engine, the carbon seals won't damage the housings and maybe you can build the next one with steel seals.