High powered setups dying of old age

sa22c · 05-28-2012, 07:51 AM

My built 12A started out at 97/102 compression. Its now all the way down to 85/94. Tested low cost piston engine tester. Its possible the front rotor has 2 weaker faces but can't be 100% on that.

Don't think I've ever had knock 3000rpm/part throttle. I would guess the usage around 80000kms/50000miles since rebuild. This includes years worth of cruising more than 150-200 1/4mile passes, some high rpm action >9000rpm years ago when it was nonturbo and lately >120kpa boost(operating at 170kpa atm) boost. Side plates, shaft and gears now have ~185k miles / 300k kms on them. Rotors ?kms bought used unknown km. Rotor housings and all other internals ~80k kms.

I'm in 2 minds about whether to pull it apart, build something more powerful and more refined. Or just leave it be. I would guess I use the car for ~240 1hr trips a year in its current usage + shops/gym when I need to.

For all these years I've never had an EGT on it so don't know if I could be flattening the springs or warping the apex seals.

If I cracked it open and the housings looked good. I would be up for minimum based off what I already 'know'

#1 Side Housing grind + lap + renitride
#2 12x FD3S corner seal springs + 12x Corner seals+ rubber plugs
#3 4x inner+4x outer rubber oil seals
#4 12x Side Seals
#5 Replace any out of spec/flattened springs

? Apex seals
? Rotors
? Rotor housings NLA
? Metal Oil seals

If it could still be good inside I'd be happy putting ~$1kUSD through it if it came back above 105 even on both rotors. Scored/Damaged Rotor housings basically leaves my 12A rebuild dead in the water, I have high standards.

It is still making good power. I think it is getting harder to start since I started racing on >120kpa boost. Also the fuel consumption has degraded, but then again I use the power whenever I get a chance.

Mazdabater · 05-28-2012, 05:40 PM

Well have you considered getting the housings and plates refurbished if they are out of spec. Given how rare 12a stuff seems to be getting, that's what I'd be looking in to. It's starting to get pretty low, I'd pull it down and freshen it up before something actually lets go.

sa22c · 05-29-2012, 04:21 AM

Quote:

Originally Posted by Mazdabater

Well have you considered getting the housings and plates refurbished if they are out of spec. Given how rare 12a stuff seems to be getting, that's what I'd be looking in to. It's starting to get pretty low, I'd pull it down and freshen it up before something actually lets go.

refurbish plates is an option. but it has to be considerably cheaper than new ones. If the 12A housings are damaged in any way I would just build a 13B.

05-28-2012, 07:51 AM	#1
sa22c The Newbie Join Date: Jan 2012 iTrader: (0) Posts: 21 Rep Power: 0	High powered setups dying of old age My built 12A started out at 97/102 compression. Its now all the way down to 85/94. Tested low cost piston engine tester. Its possible the front rotor has 2 weaker faces but can't be 100% on that. Don't think I've ever had knock 3000rpm/part throttle. I would guess the usage around 80000kms/50000miles since rebuild. This includes years worth of cruising more than 150-200 1/4mile passes, some high rpm action >9000rpm years ago when it was nonturbo and lately >120kpa boost(operating at 170kpa atm) boost. Side plates, shaft and gears now have ~185k miles / 300k kms on them. Rotors ?kms bought used unknown km. Rotor housings and all other internals ~80k kms. I'm in 2 minds about whether to pull it apart, build something more powerful and more refined. Or just leave it be. I would guess I use the car for ~240 1hr trips a year in its current usage + shops/gym when I need to. For all these years I've never had an EGT on it so don't know if I could be flattening the springs or warping the apex seals. If I cracked it open and the housings looked good. I would be up for minimum based off what I already 'know' #1 Side Housing grind + lap + renitride #2 12x FD3S corner seal springs + 12x Corner seals+ rubber plugs #3 4x inner+4x outer rubber oil seals #4 12x Side Seals #5 Replace any out of spec/flattened springs ? Apex seals ? Rotors ? Rotor housings NLA ? Metal Oil seals If it could still be good inside I'd be happy putting ~$1kUSD through it if it came back above 105 even on both rotors. Scored/Damaged Rotor housings basically leaves my 12A rebuild dead in the water, I have high standards. It is still making good power. I think it is getting harder to start since I started racing on >120kpa boost. Also the fuel consumption has degraded, but then again I use the power whenever I get a chance. Last edited by sa22c; 05-28-2012 at 08:06 AM..

05-28-2012, 05:40 PM	#2
Mazdabater FC3S Join Date: Jun 2010 Location: Townsville, QLD, AUS iTrader: (0) Posts: 326 Rep Power: 15	Well have you considered getting the housings and plates refurbished if they are out of spec. Given how rare 12a stuff seems to be getting, that's what I'd be looking in to. It's starting to get pretty low, I'd pull it down and freshen it up before something actually lets go.