First rebuild pointers.
09-09-12, 06:05 PM
#1
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First rebuild pointers.
So I just bought an 87 gtu that's been made into a turbo ii for pretty cheap with a fresh rebuild 3000 miles ago (all new seals & housings) then a few days after getting the title & driving it around it starts to sputter around 4000 rpms. So I change fuel filters & the injectors we're supposedly new. Still sputters & it gets worse. So I get a compression test & sure enough two apex seals are damaged on the front rotor. It's got a microtech ecu in it & I believe the apex seals got damaged because of an improper tune & ran too lean because of intake modifications. (He also let it sit 4 months straight prior to selling it to me) I'm going to pull motor & take it apart hopefully starting this week. A few questions I have are; should I go with a full atkins rebuild kit or an RA? Because nobody I know around here (virginia beach) can properly tune a Microtech, should I just sell it & go with a Haltech or PowerFC? Also, I just don't see why the seals got damaged after a fresh rebuild, maybe he ran it hard I'm not sure because if the problem is still there after I rebuild it, the same thing could happen again. Thank you for any information you can give me I'm just now getting into rotaries 
.
Here's a couple pics:
.Here's a couple pics:
Last edited by misterstyx69; 09-09-12 at 11:31 PM.
09-10-12, 09:07 AM
#2
Probably leaned out from running higher boost than the setup can handle.
Running lean cause pre-Detonation and its rotaries worst enemy.Thats why people who dont have a tune yet should be running rich a conservative fuel map.
Start out with a low boost baseline tune, running rich. there is no reason to run high boost until you know what kind of afr's you are running and know what your car can handle.
If you dont have a front mount intercooler you will be limited, no matter how much fuel you can get into the engine.
As far as rebuild kit, ra has the stronger/harder apex seals of the two (wont break as easy). Atkins are softer and will break in faster than ra, but being softer material will obviously break easier.
As far as your Microotech, id keep lookin for a tuner.Many people use them.
Running lean cause pre-Detonation and its rotaries worst enemy.Thats why people who dont have a tune yet should be running rich a conservative fuel map.
Start out with a low boost baseline tune, running rich. there is no reason to run high boost until you know what kind of afr's you are running and know what your car can handle.
If you dont have a front mount intercooler you will be limited, no matter how much fuel you can get into the engine.
As far as rebuild kit, ra has the stronger/harder apex seals of the two (wont break as easy). Atkins are softer and will break in faster than ra, but being softer material will obviously break easier.
As far as your Microotech, id keep lookin for a tuner.Many people use them.
09-10-12, 10:47 AM
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Thank you for the info. It was running at 7 psi. On the hand controller it was reading 11.0 afr but sometimes it would flash between two sets of information & it would say afr 14.7. Also when I got it, he had it running retarded idling at 2k... maybe he was compensating for it stalling but why? And I'll keep looking for someone.
09-10-12, 12:00 PM
#4
if it was idling at 2k then he was probably masking the fact that the seals were already broken and you got ripped off.
rotaries these days remind me of a merry go round, someone gets on and rides for a bit then it stops, they get off and someone else gets on, so on and so on.
ditch the OEM seals and i wouldn't recommend Atkins apex seals for a modified turbo setup. go with RA seals if you plan on DDing it or if it's just a weekend warrior go with Goopy or ALS seals.
rotaries these days remind me of a merry go round, someone gets on and rides for a bit then it stops, they get off and someone else gets on, so on and so on.
ditch the OEM seals and i wouldn't recommend Atkins apex seals for a modified turbo setup. go with RA seals if you plan on DDing it or if it's just a weekend warrior go with Goopy or ALS seals.
Last edited by RotaryEvolution; 09-10-12 at 12:04 PM.
09-10-12, 05:12 PM
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Wow that explains a lot.. I still believe I got a good deal at $3600. I'll get her rebuilt right & running right within a month or two. 
What are the odds of finding someone around 757 who can tune my ecu via the forums?
Edit: Alls I gotta worry about now is how damaged the housings are. Also, I'm gonna go off of aaron cake's rebuild video.
What are the odds of finding someone around 757 who can tune my ecu via the forums?Edit: Alls I gotta worry about now is how damaged the housings are. Also, I'm gonna go off of aaron cake's rebuild video.
Last edited by MikesFC757; 09-10-12 at 05:16 PM. Reason: Adding things
09-11-12, 06:11 AM
#7
How to rebuild the engine yourself.
Aaron Cake uses a rebuild kit from Atkins Rotary in the Cosmo's rebuild
In addition to what everyone has suggested, it is important to note that the GTU is a S5 (89-91) model, not 86-88 (S4). Judging by the pictures, this was a hackjob swap. Here is what I see wrong with it right now:
S4 engine and water pump housing (pressure cap on the filler neck) with S5 radiator (pressure cap here, only on S5): Not really a flaw since the Koyo N-flo radiator provides better cooling despite being offered for S5's only. Just use the S4 radiator brackets and it bolts right on. Overflow tube should be on the highest point of the cooling system (filler neck).
Flat black on engine bay sheetmetal: this is always body color from the factory
Single belt with airpump elimination: should have two belts on a dual sheave alternator pulley to prevent belt slippage on water pump
Inconsistent exterior paint with visible light spots (above passenger taillight): Car has been repainted, was most likely Noble White before
PM me your vin number and I'll tell you how the car came out of the factory when it was new. It'll give you a snapshot of how clueless the previous owner really was. You've definitely got your work cut out for you. With the right attitude, this car has lots of potential.
In addition to what everyone has suggested, it is important to note that the GTU is a S5 (89-91) model, not 86-88 (S4). Judging by the pictures, this was a hackjob swap. Here is what I see wrong with it right now:
S4 engine and water pump housing (pressure cap on the filler neck) with S5 radiator (pressure cap here, only on S5): Not really a flaw since the Koyo N-flo radiator provides better cooling despite being offered for S5's only. Just use the S4 radiator brackets and it bolts right on. Overflow tube should be on the highest point of the cooling system (filler neck).
Flat black on engine bay sheetmetal: this is always body color from the factory
Single belt with airpump elimination: should have two belts on a dual sheave alternator pulley to prevent belt slippage on water pump
Inconsistent exterior paint with visible light spots (above passenger taillight): Car has been repainted, was most likely Noble White before
PM me your vin number and I'll tell you how the car came out of the factory when it was new. It'll give you a snapshot of how clueless the previous owner really was. You've definitely got your work cut out for you. With the right attitude, this car has lots of potential.
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