carbon locked TII??
Thread Starter
Joined: Aug 2002
Posts: 3,099
Likes: 4
From: Richland, WA
carbon locked TII??
hey
i just bought a TII with a locked up engine. guy says he drove to his friends house, shut the car off, came back out later and it turned for a sec then stopped and wont turn now. he replaced the starter, didnt help. i tugged on the front pulley pretty hard with a breaker bar and couldnt move it. could this be carbon lock? (if not how much damage should i expect when i tear it down?)
thanks,
Pat
i just bought a TII with a locked up engine. guy says he drove to his friends house, shut the car off, came back out later and it turned for a sec then stopped and wont turn now. he replaced the starter, didnt help. i tugged on the front pulley pretty hard with a breaker bar and couldnt move it. could this be carbon lock? (if not how much damage should i expect when i tear it down?)
thanks,
Pat
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
Could be two things:
1. Carbon lock. Some say it's very rare, but I have seen several carbon locked engines that were freed using ATF and the "rocking" method. A search will turn up lots of info.
2. More likely, a rolled apex seal. Do a search as Kevin Landers posted an excellant description.
Either one is terminal, though carbon locked engines can sometimes be saved.
1. Carbon lock. Some say it's very rare, but I have seen several carbon locked engines that were freed using ATF and the "rocking" method. A search will turn up lots of info.
2. More likely, a rolled apex seal. Do a search as Kevin Landers posted an excellant description.
Either one is terminal, though carbon locked engines can sometimes be saved.
Thread Starter
Joined: Aug 2002
Posts: 3,099
Likes: 4
From: Richland, WA
and how much damage will there be from the rolled seal? (engine only has 72k miles) also i have seen a carbon locked engine, and used some parts from it in a rebuild once. seemed like it would have been fine if it had been soaked in solvent. i question whether it could be stuck that tight from carbon tho....
thanks
pat
thanks
pat
Refined Valley Dude
Joined: Oct 2001
Posts: 2,283
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From: Kitchener, Ontario (Hamilton's armpit)
Here's the post:
Yeah dude, that engine is toast inside. There has been internal damage that is irreversible except by rebuild.
What generally happens here, despite the name, is that when the stock apex seals wear down enough, and you shut the engine down one day, one will actualy roll sideways partially out of the rotors tip, and wedge itself between it and the housing. When you try and move it, either way, you're generally driving a stuck seal farther into something it shouldnt be against, one way or another (rotor or rotorhousing). Obviously you're only doing more damage the more you try and move it. Not only do you have to rebuild, but youll also need a replacement rotor and rotorhousing in most cases.
Im NOT saying carbonlock doesnt exist...just that true carbon lock is much more rare than the condition described above, but both exhibit the same symptoms, and are both referred to as carbon lock.
What generally happens here, despite the name, is that when the stock apex seals wear down enough, and you shut the engine down one day, one will actualy roll sideways partially out of the rotors tip, and wedge itself between it and the housing. When you try and move it, either way, you're generally driving a stuck seal farther into something it shouldnt be against, one way or another (rotor or rotorhousing). Obviously you're only doing more damage the more you try and move it. Not only do you have to rebuild, but youll also need a replacement rotor and rotorhousing in most cases.
Im NOT saying carbonlock doesnt exist...just that true carbon lock is much more rare than the condition described above, but both exhibit the same symptoms, and are both referred to as carbon lock.
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
Originally posted by patman
and how much damage will there be from the rolled seal? (engine only has 72k miles) also i have seen a carbon locked engine, and used some parts from it in a rebuild once. seemed like it would have been fine if it had been soaked in solvent. i question whether it could be stuck that tight from carbon tho....
pat
and how much damage will there be from the rolled seal? (engine only has 72k miles) also i have seen a carbon locked engine, and used some parts from it in a rebuild once. seemed like it would have been fine if it had been soaked in solvent. i question whether it could be stuck that tight from carbon tho....
pat
I came, I saw, I boosted.
Joined: Apr 2001
Posts: 1,921
Likes: 0
From: Windsor, Ontario, Canada
When my engine carbon locked at about 130k km's, I only had one rotor with a slightly deformed seal grove. I just had them machined out for 3mm seals, good solution! The housing was fine.
BTW- Don't try to crank it too hard in the regular (clockwise ) rotation direction, you can make things a little worse, and they may be salvagable. Try to turn it backwards after soaking in any form of carbon dissolver.
ATF seems to work....
Doubtful that you rolled an apex seal at 72k miles unless your OMP hasn't been working.
BTW- Don't try to crank it too hard in the regular (clockwise ) rotation direction, you can make things a little worse, and they may be salvagable. Try to turn it backwards after soaking in any form of carbon dissolver.
ATF seems to work....
Doubtful that you rolled an apex seal at 72k miles unless your OMP hasn't been working.
Refined Valley Dude
Joined: Oct 2001
Posts: 2,283
Likes: 2
From: Kitchener, Ontario (Hamilton's armpit)
Originally posted by Bambam7
Try to turn it backwards after soaking in any form of carbon dissolver.
ATF seems to work....
Try to turn it backwards after soaking in any form of carbon dissolver.
ATF seems to work....
I guess you missed this thread:
https://www.rx7club.com/showthread.p...hreadid=251048
It seems clear that ATF does not dissolve carbon. It does make things extra slippery, but that's about it...
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Thread Starter
Joined: Aug 2002
Posts: 3,099
Likes: 4
From: Richland, WA
ok just started soaking in MMO today... hafta take off the intake and pour some in there tomorrow... crosses fingers...
thanx for the help guys
pat
ps...what does everyone think about s4 n/a higher compression rotors in this motor if i keep the boost below 10 psi.... will have a fmic also... because if i have to rebuild i have a perfect set of those i might put in...
thanx for the help guys
pat
ps...what does everyone think about s4 n/a higher compression rotors in this motor if i keep the boost below 10 psi.... will have a fmic also... because if i have to rebuild i have a perfect set of those i might put in...
Thread Starter
Joined: Aug 2002
Posts: 3,099
Likes: 4
From: Richland, WA
not really...rotors look a little worn...irons have the usual corner seal marks but not too deep...rear rotorhousing is absolutely perfect, front has a wear mark across it that im not sure about....its like straight across...actually looks like a apex seal squished into the housing and left a mark...but when i took it apart they were all in place... anybody know whether the housing is usable...mark is close to the bottom of the housing, goes straight across it, is not a sharp score but slightly rounded, appears to be about 2-3 thousandths deep.
thanx
pat
thanx
pat
I came, I saw, I boosted.
Joined: Apr 2001
Posts: 1,921
Likes: 0
From: Windsor, Ontario, Canada
I agree..
Check that rotor VERY CAREFULLY!!! If the apex seal groove is expanded out, you either have to buy a new rotor, or get them machined out for 3mm seals and buy 6 new apex seals.
How do the apex seals in the front rotor look? How deep are they?
Was there a lot of carbon on the sides of the rotors and in the apex seal grooves? Doesn't sound right.
Check that rotor VERY CAREFULLY!!! If the apex seal groove is expanded out, you either have to buy a new rotor, or get them machined out for 3mm seals and buy 6 new apex seals.
How do the apex seals in the front rotor look? How deep are they?
Was there a lot of carbon on the sides of the rotors and in the apex seal grooves? Doesn't sound right.
Thread Starter
Joined: Aug 2002
Posts: 3,099
Likes: 4
From: Richland, WA
i got at least a pint of carbon outta the engine, and there wasnt an apex at that position, otherwise thats what i'd have thought too. the apex seals all look ok. im buying the rotaryaviation ones to put in it tho so.... i have decided to get a rotorhousing...anybody got one?
also.. i havent checked the rotors yet but if i do replace them, how much boost could i safely run with a set of na rotors? 10 psi would be nice.
thanks,
pat
also.. i havent checked the rotors yet but if i do replace them, how much boost could i safely run with a set of na rotors? 10 psi would be nice.
thanks,
pat
I came, I saw, I boosted.
Joined: Apr 2001
Posts: 1,921
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From: Windsor, Ontario, Canada
So the apex seal is GONE?? NO damage to the housing? Strange.
Well, i'm sure if there was any damage you'd see it..
Just be very careful in inspecting that...
10 PSI you can run.. but on 2mm apex seals I'd be carefull... a few good pings can kill you. With 3mm seals you are more likely to loose a side seal to detonation, a MUCH cheaper fix, and less likely to cause any kind of side housing damage.
You are actually gonna have to keep it corked up a bit- no 3" straight pipe exhaust or anything, and port the wastegate out like crazy. I couldn't keep boost below 12 PSI with this setup, and blew my first engine. (S5 high-comp NA rotorrs w/3mm seals)
You will NEED a big FMIC as well.
93 octane is required, LOT's of it (Walbro and at least 4x550's) (you want at least 11:1 AFR to keep detonation in check.. not the most effecient setup)
A high compression (NA) motor with a turbo is awesome, you only need about 8-10 psi to get the same power as a TII motor running 12, you just have to be carefull.
Well, i'm sure if there was any damage you'd see it..
Just be very careful in inspecting that...
10 PSI you can run.. but on 2mm apex seals I'd be carefull... a few good pings can kill you. With 3mm seals you are more likely to loose a side seal to detonation, a MUCH cheaper fix, and less likely to cause any kind of side housing damage.
You are actually gonna have to keep it corked up a bit- no 3" straight pipe exhaust or anything, and port the wastegate out like crazy. I couldn't keep boost below 12 PSI with this setup, and blew my first engine. (S5 high-comp NA rotorrs w/3mm seals)
You will NEED a big FMIC as well.
93 octane is required, LOT's of it (Walbro and at least 4x550's) (you want at least 11:1 AFR to keep detonation in check.. not the most effecient setup)
A high compression (NA) motor with a turbo is awesome, you only need about 8-10 psi to get the same power as a TII motor running 12, you just have to be carefull.
Thread Starter
Joined: Aug 2002
Posts: 3,099
Likes: 4
From: Richland, WA
no the seal wasnt gone...the rotor was just turned a different way. so it couldnt have been rolled right there because thats not where it was stuck. anyway, right now im gonna put in the na rotors with the stock IC and keep boost at or below stock. might move the ic to front mount not sure...also the rotaryaviation apex seals are supposedly much stronger..so we'll see..
pat
pat
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