[Mk2] [Turbo] ST205 ENGINE BLOWN? ADVISE PLEASE GUYS!!

[mazzerdod]

Hey guys been a while since I posted on here but I need some advise PLEASE...... ok here goes all you 3SGTE gurus!

A friend of mine has an ST205 GT4 excellent condition 60k miles you get the picture!

We have fitted an induction kit, exhaust inc decat and a real crap manual boost controller off Ebay

So on Sunday I was trying to dial in the boost controller looking for approx 1.2bar anyway this thing is a nightmare to adjust from one extreme to the other.

We ended up hitting 1.5bar boost maybe more the gauge does not go any higher.

During this over boost we did not hit fuel cut and the car was “pinking” massively!

After this the car would not stop pinking when on boost any higher than .7bar.

Took it back to my friends house in the morning when he started it from cold he said it was tapping on what he thinks was the top end but this stopped after 5mins once warm.

Again after work from cold the same tapping noise occurred until warm!

Driving along and the temp gauge started to shoot up and loads of smoke out the exhaust! I haven’t seen it yet will pop round tonight to take a look!

Any ideas?

What would have made the tapping noise whilst cold?

Why was it continuing to pink after the over boost was rectified?

What could have broken i.e. head gasket, piston?

Any advise would be gratefully received!!

[bobhatton]

That will be a piston or two.

Bob

[mazzerdod]

Update

I've seen the car tonight and started it from cold it's missing on tick over and burnt oil is pouring out the exhaust!

My plan is to compression test it on Sat and get the head off!

[bobhatton]

It may have damaged a big end too so once you have found out what piston it is take the sump off and check that too. If you take the breather pipe off the cam cover I bet it will be blowing oil out there.

Bob

[mazzerdod]

Ok got you... check bottom end!

Remove breather pipe and start car to see if oil is being blown through due to crankcase preassure before I take any spanners to the engine!

Thanks for your advise!

[mazzerdod]

I've removed the breather today and started the car.... loads of smoke coming out of the breather in time with the misfire

[Dale_V]

sounds like a ringland

[bobhatton]

I think you know what to do now, top and bottom off. May only be one piston to change, but you could hone all the bores and fit a set of rings to all the pistons as its apart.

Bob

[mazzerdod]

Yea or we may put a set of forged pistions in and some uprated rods, there is a set of used ones on Ebay at the moment but they do have a small amount of scoring to the skirt I've emailed the guy and he reckons a set of rings and they would go again?

http://cgi.ebay.co.uk/MR2-Turbo-GT4-3SG ... 240%3A1318

I have found these pistons new for $550 dollars + a set of rings

[mazzerdod]

Hey guys its stripped and piston No3 has melted

And there is some damage to the bore some minor scoring..... but a small nick is also present!

So what do over sized pistons go upto?

I know I can get +1mm i.e. 87mm replacements but I'm unsure if half mm will be enough

Suggestions?

[JJ]

If you goto 87mm, the integrity of the block will be compromised... and its possible under a high boosting situation, you'll crack a liner.

Couple of options, block bored to 86.50mm .. if he's plans for big power in the future, try and get a liner fitted to the damaged bore and get a full setup 86.00mm

I think you can see what I'm suggesting.. long term relibility !! Take away materila from the block = less strength.

If you just want to stick it back together, toyota do stock material but over sized 86.50mm

I'm assuming theres problems with the head as well being marked... its possible just getting a replacement engine and fitting that... and build on the current one in a long term view ( £££ dependant )

Either way, you'll have to strip the engine to nothing as they'll be contamination around it that will only cause you grief on start up if the particles are in the main oil galley already.

Dont take the chance as it'll only damage the bearings which will just screw the crank up... then back to stripping and rebuilding again.

Block cleanliness is paramount on a build especially if its had any machine work / issues in running.

Cheapest option - another engine.

Harder option .. rebuild it completely.. meanign complete strip and replace oil pump, all the gaskets, new shells etc...

[mazzerdod]

JJ thanks for the advise..... so liners are available then?

Will an ST185 bottom end be an option if the block has had it?

Will the ST205 head fit an ST185 block?

Do you know of any real differences?

Cheers!

Mario

[mazzerdod]

Ok guys I've spoken with a machine shop I know and most likely will get the following done,

Rebore cylinders 1, 2 and 4 to suit forged pistons i.e. 86.5mm £60.37.

Press liner into cylinder 3 and machine to suit forged piston i.e. 86.5mm £80.

[JJ]

Get some new clevite 77's bearings as well.. and a full gasket kit from toyota.. and stick it all back together !

Try to see what went wrong with the boost controller !!

I still can't see why you were able to hit 1.5 bar.. the ecu should have hit fuel cut !! you havent fitted a FCD to this have you ??! They need to be ripped off on the ST205 setup !!

[RobCrezz]

Dont use that boost controller again. If its a cheap MBC then bin it, as it must be faulty and for the price of them you might as well get another.

Like JJ said, sounds like its got a FCD, get it off there to prevent nuking your engine again.

[mazzerdod]

Hey guys,

Yea I wondered why it didn't hit fuel cut? I have never checked the ECU could be it has an FCD or maybe an aftermarket ECU I will certainly look into this and report back!

The MBC was a load of S***E.... it has been binned!

As for the motor I had the following in mind,

The above block reworked as described.
Forged pistons but using standard con rods.
New big end, main, thrust bearings.
New standard head gasket.
ARP head and con rod bolts.
All belts, pulleys, water pump had been done 5k ago so thats going back on.

Questions....

Is there any point uprating the head gasket as the standard one is steel anyway?

Is it worth putting ARP replacements in?

Is it worth replacing the oil pump?

[Marf]

Is it worth replacing the oil pump?

I would, just for piece of mind.

[bobhatton]

Every rebuild should have a new oil pump. I would go for a thicker heat gasket if you are going to run higher boost on a standard ECU.

You only need ARP head studs, not bolts unless you are going to take the revs much higher then you would need better rod bolts

Bob

[JJ]

Is there any point uprating the head gasket as the standard one is steel anyway?

Is it worth putting ARP replacements in?

Is it worth replacing the oil pump?

Stock HG is a TRD type anyway.... clamp it down with ARP's and its going nowhere !

Oil pumps - without hesitation.. I know its additional cost, but with bottom end failures, its possible the pump may have some scoring = less effective...

Oil circuit = Oil pickup > oil pump > oil filter > oil galley > mains / turbo / head > back to sump

Yea I wondered why it didn't hit fuel cut? I have never checked the ECU could be it has an FCD or maybe an aftermarket ECU

Ive seen a few rev 3's / ST205 be fitted and died because of this. The FCD are designed for the AFM driven ecus and the FCD taps into the map sensor. Where the ST205's Rev 3 MR2 differ, fuelling is only calculated through the map sensor = stick resistance through it ( FCD ) and the whole lot runs leaner ( ecu sees less load on the engine )= fried engine !

Only the voltage clamping FCD can be used, Paul Port developed one which doesn't affect the values up to the limit, then you're allowed to exceed the fuel cut point as the max level is "voltaged clamped"

[mazzerdod]

Excellent advise!

Std head gasket with ARP's.

New oil pump.

Ecu I'll have to check what has been done!

Thanks for your replys!!!