mullins

Hi,



I'm a rotorhead based in England who's looking for some advice on building a 10a J ported engine. I only discovered this forum recentely and there seems to be some very clued up people in this tech section so thought i'd give this a go.



What i'm trying (stress trying) to acheive is a reasonably quick RX-3 street car that's a little different. I could go down the usual 12A/13B route (more reliable, more power, etc, etc) but I have 3 10A engines at my disposal so why not!?



I don't have a specific question but i'm after any general advice or pointers on what direction to head. I have some ideas but am unsure about port sizeing and what other upgrades would be ideal (oil system, etc). The car will only be used on weekends and for going to shows, etc, so I'm hopeing to go pretty wild on the porting side of things, and exhaust noise isn't really an issue.



So far I have a good base motor ready to port and have aquired some REW stationary gears which I will be getting machined down to size shortly. I have a NOS eccentric shaft which I was considering getting cross-drilled. Rotors are the later style single side seal design. I will be running my 48IDA on a 10A IDA manifold with a Holley Blue pump and reg. Flywheel will be a custom made lightened version (but I'm unsure what weight to go for). The flywheel will be machined to take a more common clutch. I have a 12A front cover and an electronic ignition distributor. I think that's everything.



Any comments or suggestions as to what size porting or other worthwile modifications would be appreciated.



Thanks,

Mullins

j9fd3s

i dont have any specific advise, but the idea of a nasty 10a is a good one!



since parts are hard to come by, i'd do like i did with the PP, make sure everything is in spec, i had mine balanced too. the more oil pressure the better, if there is a lager oil pump that fits, use it (the late 12a, 84-85 13b's have a lager pump, dunno if it bolts up though)

mullins

Thanks. I forgot to mention I have a 12A MFR oil pump which bolts up. I believe it is nitrated or something over the standard pump. I will look at upping the oil pressure by spacing out the bypass in the rear plate. Those two mods along with the cross drilled shaft and windowed bearings should be enough for effective oiling don't you think? or is there anything else I should consider?

j9fd3s

i have the same pump! its hardened or something... the FD pressure regulator is $28 and its 100psi, but if you have the take apart one, that works too.



i'd think all that would be more than fine... thats all they have done for the rx8, and it sees 9000 from the factory

diabolical1

you lucky so-and-so!!! what's the status on this project?



didn't the 10A's use 6 mm apex seals - carbon, i think? the only thing i would add to what j9fd3s has already suggested would be consider coatings, if possible and have the water jacket mods done. i'd imagine apexes that size, at J-port RPM would start to heat more than usual. perhaps i'm wrong.

EZDUZT

that would be very differnt theres a toyota corolla ke30 here in nz with a 10a bridgeport it goes well i seen it this weekend at powercruise goes very well heres a vid of it running in the vid it was still running 4barrel carb now runs a 48ida and ewp.

http://www.youtube.com/watch?v=144w9_w9ok8

j9fd3s

just a not my shimmed oil pressure regulator does 110psi on the stock gauge. i couldn't find any info on how much shim to put in, so i think i took RB's recomendation for the front reg, and tripled it, something like 1/2" maybe 3/4"



sourcing a stiffer spring might be simpler