alright so i just got done with a 6-port turbo swap on a GTU and i gave it to the guy that i did the work for and he tells me 2 days later that the car just died and it wont start. so i go out to help him to see and find out what the deal was. i get out there and try to start it and just check what i normally would check to see why it wasn't running.

i try to start the car and the starter just bogs out. so i go and check the battery connection and its good. so i try to turn the motor by hand and its a no go. we try to pull start the car and see if that works and its no got. we also tried to get the motor to spin backwards but it wont even budge. so obviously the motor is seized some how and im trying to figure it out.

mods on the car----
4X550(low impedance)
2.5 inch exhaust
3 inch intake
top mount
stock turbo
all turbo manifolds
turbo fuel pump
safc neo (tuned rich)

now the car did just have about a quarter of a tank of 87 octane in it when i gave the car to him. i told him that he's gonna need to run a few tanks of 91 through before he starts boosting. he swears up and down that he wasn't boosting and that all the temp were good and the oil pressure was good also. he also stated that he put a little bit of 91 octane in the tank. im not sure but probably just a half tank to get around. so do you think with the mods and if he did boost it he would of seized the motor?

thanks.

 

I could be wrong but to me it seems that he has a lot of carbon built up try putting some ATF down by the spark plug holesand let it sit for a day at least and then try to spin it again. how much could he have been boosting? and if you were running it to rich and with low octane fuel then yeah it probably locked by carbon build up not because of boost.

 

ok i did tell him to do the atf to try to unlock it. it didn't make any since that it would do it while he was driving it initially when it happened. i figured if it was going to lock up it would of been sitting for a while.

 

First thing I would do is check the oil-level. Next thing would be to remove the turbo and see what's going on internally via the exhaust ports...

 

yeah i checked the oil level. it was no different than when i filled it up. ill have him take the turbo off and see whats going on in there. i just would see why it would lock up between shifting from second to 3rd

 

sorry didnt realize this happened while the car was running.

 

LOL its no problem. i should of been more clear about it.

i was talking to another friend of mine and he said that he feels that they guy was boosting with the 87 octane in there and that he blew an apex seal but instead of it going out the exhaust it got lodged into the housing and thats why it wont move.

 

It's possible an apex seal jammed the engine. That's very rare as they are normally ejected through the exhaust.

Drain the oil and check for metal fragments.

Strange question, but do you have access to a boroscope? If so, then look through the spark plug holes for damage...

 

no unfortunately i don't have a boroscope. we will try to look in the plug hole and the exhaust ports to see if we can find any damage.

would this of happened from him boosting on 87 octane?

 

Is there a boost-gauge installed on the RX-7? Also, did you port the wastegate on the turbo? If no WG porting, there's a good chance that the boost was creeping pretty badly with that straight 2.5" exhaust and 3" intake... 10+ psi, 87 octane and stock fuel-setup could easily blow an engine. You say you tuned the fuel-controller... How? Wideband?

 

It could have happened for many reasons, but I certainly would not suggest running low octane fuel on a turbo-NA rotary.