Dan_s_young

iTrader: (1)

Im just curious about what kind of life a large street port 12a would have with a full rebuild. I know its hard to predict an exact number but i was wondering if you guys had some experience with when the engine was well broken in and not abused. Any advice in building a streetported engine to live long? I dont expect my rebuild to last another 200, 000 km but I just want to make sure its going to last a practical amount of time so I dont require another hefty rebuild bill any time soon. (note i searched unsucessfully)

steve84GS TII

Well,if you observe the safe factory redline(7000-8000),it shouldnt be any less reliable than a stock engine.Granted, porting will shift the powerband to the upper RPMS,so youll spend more time up there,which accelerates wear.But it wont be like a bridgy, sometimes needing a rebuild after 15-20K miles or less.Id say anywhere from 75,000-150,000 miles.It maily depends on how many new parts are used in the rebuild and the quality of the builder.More new housings and seals,tighter/more consistant tolerances = more compression,less friction,less wear.
Stock 13BTs have nearly a streetport from the factory compared to a 12A.TII's last 100K usually even with boost .N/A 13B's can last 200K even with a factory 8K redline on the S5 models.

Siraniko

iTrader: (13)

not 12-A but my prior 13-B max out streetport lasted apppxo 130K. Daily driver and abused daiy. Here in LA, most of the old guys like me, we drive our engines to the limit. We drive it like we stole it. But again, they are maintained.

diabolical1

iTrader: (3)

in addition to the previous responses, life expectancy will also depend on what you put into your rebuild. there is a thread around (i don't have the time to look it up right now, but if you need help leter, then i will ) if i recall, mazderati started it - it dealt with building an engine for reliability.

hope that helps

Dan_s_young

iTrader: (1)

Ya i would be interested in that, its no big rush though I just am looking into it for a summer rebuild project thanks!

diabolical1

iTrader: (3)

Here you go: Mazderati thread

I think there was some stuff in there about swapping the oil jets in the eccentric shaft - i can't remember and i didn't read it again when i found it. if you're not going with a turbo setup that will get you significant more than 400 HP, then form waht i've read elsewhere it's not worth it - you can run the stock ball and spring (after cleaning the passages and parts, of course)

Siraniko

iTrader: (13)

I prefer a pre-86 E-shaft, then do the mods on it. The 86+ has a t-stat in e-shaft which allows faster engine warm up. The aftermarket t-stat is not that expensive, but as much as possible, I want to eliminate a source of failure.

851stgen12a

I agree with what was said before... it will all come down to the quality of parts used in the rebuild.... use chead apex's and seal your not gonna last long... but you put some time and quality into it it "should" last signifigantly longer.

Dan_s_young

iTrader: (1)

Do you guys have a web page with all the things I would need for a rebuild? I was looking at the one on racing beat the OEM one (not the racing one) and was just curious on top of that what else i would require and where i could get it.

diabolical1

iTrader: (3)

what you'll need will depend on what you find out upon disassembly.

anyway, here's thread that asked about sources. some may be overkill for your needs, but you do the research and decide what you want in your buildup.
Rebuild Parts Sources