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Discussion Starter · #1 ·
After ideas and opinions. This is a bit long winded but I want to pass on as much as I know about the problem. I appreciate anyone who can offer help - thanks.
My car is a JDM 95 TT 6spd Supra and had been running well with no problems at all. The car had FMI, AVCR - boost controller (1bar), cat-back exhaust, HKS pod filter, mapped ECU (Sard). I took the car in for a service and had new spark plugs installed, new timing belt and adjustable cam gears fitted and all the usual fluids replaced. The car on the dyno made 320hp at the wheels and a A/F of 10.5:1.
I drove the car home on the highway and after accelerating(not WOT) from some traffic lights the car at around 4000rpm hessitated made some rattling type noises (bad misfiring?) and then blew smoke out the exhaust with a bang!! I had never experienced that in any car so I had no idea how serious it was but I knew it couldn't be good. The car still ran so I limped it home.
I took the spark plugs out and found 4 of the 6 to have chunks of missing insulators with 2 of them having melted and damaged electrodes. (If people are interested I can post some photo's). I did a compression test and found 2 cylinders to be well below normal and so I did a leakage test. Found one cylinder to have valve problems and No.5 blew straight into the sump (toast!!!).
I took the turbo's off and found No.2 had lost it's exhaust wheel completely and No.1 had some missing fins. In front of the first cat was bits of turbine and some fragments of spark plug ceramic.
My first thought was what had changed from driving in to the service and then driving out:
- Spark plugs were IK22(OLD) but were changed to PK20R11(NEW)
- Cam gears fitted (Titan cam gears) 2.5 markings Advance on the inlet and 1 marking of Retard on the exhaust. (not sure but I think 1 marking is 2degrees???)
- Timing belt fitted
- New timing belt tensioner fitted.
- Fuel filter/oil filter replaced and new fluids throughout.
I do have some additional information but I'd like to hear what opinions people have without me swaying your opinions with possibly incorrect information. Thanks again.
 

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Theory:
Belt wasn't tensioned properly - jumped timing - running super advance timing = hot condition - insulator being damaged drops on top of piston, smacks it then sends it through the turbo - turbo tries to chop the insulators - and loses the battle?
HAHA..
I dunno it's 5am.. I should go to bed :p
 

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Discussion Starter · #3 ·
Thanks for the reply. I checked the timing belt tension and positioning of the timing marks on the cam gears and the crank at TDC and everything appears to line up. I am concerned about the adjustment to the cam gears but I don't know if it's significant enough to cause a problem.
 

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sounds like crappy spark plugs, came apart in the combustion chamber
 

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the # on the new plugs looks to be a platinum.. not typically good plugs for BPU and up correct? Look to the fuel system also.. sounds like you had a LOT of heat, and since fuel is a cooler too.. it could have melted the plugs in the combustion chamber which then broke apart and took out your ceramic exh wheels.

good luck.
 

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Supramkiv77tt said:
- Spark plugs were IK22(OLD) but were changed to PK20R11(NEW)
-
what equivalent # are the IK22s? one step colder like the 6097 (7's, stock being 6's?) in that case what are the platinums in heat range that were installed? I can see I guess that the factory gap was 1.1mm.. but not sure how to read the rest. Either way i have always heard not to use platinums in a BPU and up anything.
 

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Discussion Starter · #9 ·
I've checked the fuel system. Flows and pressures check ok, injectors removed and tested ok. Can't seem to find a fault on the fuel side. Fuel Pump ecu was checked also and performed correctly.

Trying to gain an understanding of what caused the engine to blow. Is there a way of proving that too much timing and too hot a plug destroyed my engine?
 

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Discussion Starter · #10 ·
Epik said:
what equivalent # are the IK22s? one step colder like the 6097 (7's, stock being 6's?) in that case what are the platinums in heat range that were installed? I can see I guess that the factory gap was 1.1mm.. but not sure how to read the rest. Either way i have always heard not to use platinums in a BPU and up anything.
As far as I'm aware Denso IK20 iridium plugs are for standard supra's whereas the old plug in my car was an IK22. The new plug fitted to my car was a PK20R11 which I believe is the standard recommended plug for a supra.
 

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As you can see from the image above, your pk20r11=BKR6E may have been a bit too hot of a plug. I woulda gone with something colder like the BKR7E. Your spark plug may simply have been at fault.

The PK20R11 is a direct replacement for IK20, so your stock supra setup.
Iridium and boost is usually not a great combo.
 

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Sorry to hear about your engine... :(

Okey Guys, we all know all the possible reasons off a blown engine, but the good point here is why the turbos failure at same time? did they happen first or second??

In a stock intercooler setup, it is possible for the turbo fins from turbo no 1 has gone trough all the system and found its way to the cyl chambers and mess the spark plugs and there after pistons etc....? hard to beleive, but there`s got to be a connection.

What about a sequential twin turbo malfunction with a huge overboost/spike? 4th gear is a tipical one for this kind of scenario.

Do you have the stock boost cut working properly? I guess not with a sard ECU.

In the end to see the real situation given you would have to tear apart that engine and inspect closely all the parts involved.

Time for a new short block and make things easier with a single...


Later

DJ
 

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TeckniX said:

As you can see from the image above, your pk20r11=BKR6E may have been a bit too hot of a plug. I woulda gone with something colder like the BKR7E. Your spark plug may simply have been at fault.

The PK20R11 is a direct replacement for IK20, so your stock supra setup.
Iridium and boost is usually not a great combo.
Wait...it's not good to use Iridium plugs??? I use IK24 (two heat ranges colder than stock) in my Supra with around 18 psi on pump 94 gas....don't want this to happen to me!! Sucks when a motor blows for no reason/because of something stupid like plugs.
 

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Iridium is fine, in fact IK24's are probally the best
 

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Discussion Starter · #17 ·
DWSUPRA said:
Sorry to hear about your engine... :(

Okey Guys, we all know all the possible reasons off a blown engine, but the good point here is why the turbos failure at same time? did they happen first or second??

In a stock intercooler setup, it is possible for the turbo fins from turbo no 1 has gone trough all the system and found its way to the cyl chambers and mess the spark plugs and there after pistons etc....? hard to beleive, but there`s got to be a connection.

What about a sequential twin turbo malfunction with a huge overboost/spike? 4th gear is a tipical one for this kind of scenario.

Do you have the stock boost cut working properly? I guess not with a sard ECU.

In the end to see the real situation given you would have to tear apart that engine and inspect closely all the parts involved.

Time for a new short block and make things easier with a single...


Later

DJ
No.1 turbo did have some fins missing but the main damage was no.2. I can't say whether or not fins were pushed through the exhaust ports and back out again. I can say that the spark plug damage was spread across #1 #4 #5 #6 cylinders.
The noise which I heard which I'm starting to believe may have been misfiring/pre-ignition happened first and then the big plume of smoke out the back which as I've read sounds exactly like what happens when a turbine wheel pops off.

I have an AVCR which measures the peek boost and it didn't register a reading above 1 bar - ~14psi so I think a boost spike although fits nicely as a scenario may not have happened. You are correct the Sard ECU removed the factory boost cut.

As you could imagine this is very frustrating but I need to make sure that I rule out other problems first as a cause because I definately don't want it to happen to the replacement engine - THAT WOULD BE FRUSTRATING!
 

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Discussion Starter · #18 ·
Do you guys know of anyone with enough experience in reading spark plugs that they can tell whether a lean condition caused the damage or over advanced timing in combination with too hot a plug caused the damage? I've heard the NASCAR guys are pretty finatical at reading spark plugs after only a couple of laps!
 

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How long have you been on sard`s ecu?

You need indeed a way to see if the engine is knocking, so If I were you I would bought a knock link and have it installed in my dash, so when it knocks I will see it and back off the pedal at least and check everything...

I had been trough the same BIG BANG, and my exhaust wheel came through the exhaust and It started burning oil LIKE MAD!! I knew it was just the turbo center section as it instantly "dissapeared". I went single and then started the engine with a new exhaust and no oil, compression was PERFECT!

Now Let`s think about your facts:

Cars was running perfect before the timing belt/cam/spark plug change, right?

How much power was it making before the car went to service?

How was the car feeling after the service? a noticiable increase in performance? accelerating faster?

I really CAN^T think about a destroyed to the sump piston 5 with a partial throttle acceleration on traffic, was it a instant or progressive WOT pull?
 

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To blow the spark plugs apart like that, you will have had some pretty serious detonation going on. This happened to me quite some time ago when I blew several spark plugs apart and the bits of the plugs took out the #2 ceramic turbo when they went out the exhaust. One possibility not already mentioned is that you got runaway boost, which is what happened to me. Possibly caused by a sticking wastegate(?) or the boost hose to the wastegate coming off?
 
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