Engine rebuild?

Got my new Supra a few weeks ago http://mkivsupra.net/vbb/showthread.php?t=146525 but within a couple of weeks she started to smoke (at first just on boost and for a few seconds after full boost)

This car has a huge single greddy T78 turbo so it was easy to take off the 4 inch dia inlet pipe and feel the compressor rotor which had a fair amount of play so removed turbo and confirmed bushes were warn and it was losing oil.

Sent it off to turbodynamics who overhauled it for me, got it back (much celebrations all round) fitted it back on supra, went for a spin at fist still had a fair bit of smoke but after about 10 mins. this subsided which I put down to there still being oil left inside the intercooler.

We never completely got rid of the smoke and over the next few hours (of giving it a fair blasting) the amount of smoke started to increase but now it was also smoking on idle but more alarming I was getting a slight miss at low revs and this was getting worse by the minute so I decided to head for home (about 15 miles away at that time) and by the time I got back it really did sound quite lumpy.

Took it to a mates house ( Paul from SWZ performance http://mkivsupra.net/vbb/member.php?u=9194 ) who has all the gear and found it was not running on number 3 cylinder, checked it was not spark plug or coil pack, did a compression test and was only getting 100psi on number 3, 120psi on number 4 and 150psi on the other 4 cylinders. Leak down test confirmed we were losing pressure (about 60%) to the crank case.

So it sounds like rings or pistons, either way there will probably be damage to the cylinder wall and as that engine has done 105,000 miles will probably be due for new valve stem seals soon.

Paul is too busy to do the work and I do not have the tools or expertise so if I am going to send it away to be done then I might as well go to town with it and upgrade the engine in line with all the other mods.

What parts if any is it worth spending extra on (ie performance parts rather than standard supra parts) Pistons, cams, conrods etc. ? the car is running at around 800BHP on current boost.

If it was me id either buy a built engine from the states or a new complete short block from toyota, iirc when i brought one it was around £1800.

Id be very surprised, if you are getting 800bhp from an old T78 on pump fuel, there are much better turbo options out there these days that will make the car nicer to drive and faster.

Could be valve's not seating properlly and as you say, the rings!

One thing for it i think, get it out and stripped and have a look, might be head gasket too

If it was me id either buy a built engine from the states or a new complete short block from toyota, iirc when i brought one it was around £1800..

You don't think it is worth spending out extra on forged pistons etc.? Some people tell me the stock toyota ones are fine up to 1000 BHP

 

Id be very surprised, if you are getting 800bhp from an old T78 on pump fuel, there are much better turbo options out there these days that will make the car nicer to drive and faster.

It does have a lot other upgrades, but given a choice I would not have gone for the T78 that is just what was on there when I brought the car. I would guess there is not another that would just bolt on in it's place?

See Paul Whiffins Supra mate. Stroker at 3.4 instead of 3.0 but the man knows his stuff when we ask. Especially for this kind of problem.

As Danno says, middle two cylinders down on a straight six, possibly someone didn't torque it up right. Imperative that that is done right.

Hope you sort it though.

Andy

It does have a lot other upgrades, but given a choice I would not have gone for the T78 that is just what was on there when I brought the car. I would guess there is not another that would just bolt on in it's place?

why not?? I take it the turbo is a T4 flanged unit? there are plenty of turbos that will drop right in there what manifold is on the car and has there been any custom welding for example the exit to the W/gate being plumbed back into the exhaust system or different bits around where the turbo has been mounted? These are things that could cause problems if you were to change.

And take Jamies advice, he has prob been through more turbos than most ranging from out right obscence T88 down to smaller garrett units

in terms of a built engine it really depends on your goals....over 500 then its really a game of chance on a stock engine in my opinion although it could prob handle it a safer option would be to go for a build block

You don't think it is worth spending out extra on forged pistons etc.? Some people tell me the stock toyota ones are fine up to 1000 BHP

 

 

It does have a lot other upgrades, but given a choice I would not have gone for the T78 that is just what was on there when I brought the car. I would guess there is not another that would just bolt on in it's place?

If you are going for a laggy 800 odd bhp then a built engine is worth it but chose your builder carefully, depends if you want a fast street car or a lag monster, imo something like a T67 running 600bhp will be far faster and a hell of a lot nicer to drive on the street.

Pretty much any of the T4 turbos will bolt in place of your T78 but as its a 4 bolt downpipe you will need to mod/change that to a Vband and you may need to spacer the T4 flange up a tad so the turbo misses the manifold, no biggie i did it when i changed my T88 for a GT4088, best thing i ever did, turned the car into a lag free monster.

If you are going for a laggy 800 odd bhp then a built engine is worth it but chose your builder carefully, depends if you want a fast street car or a lag monster, imo something like a T67 running 600bhp will be far faster and a hell of a lot nicer to drive on the street.

The 800bhp laggy monster was fun, but yes to be honest I drove my standard TT faster round castle combe

Pretty much any of the T4 turbos will bolt in place of your T78 but as its a 4 bolt downpipe you will need to mod/change that to a Vband and you may need to spacer the T4 flange up a tad so the turbo misses the manifold, no biggie i did it when i changed my T88 for a GT4088, best thing i ever did, turned the car into a lag free monster.

So really for the money I saved by going for a standard short block I could buy a decent turbo that is not so laggy?

What turbo would you recommend & where's the best place to buy it and would I need to get the engine re-mapped if I changed the turbo?

If you are handy with the spanner you wont need a full kit, but it will be easier to get a full kit and sell yours on, give some of the us traders a pm for prices, Kylestt at velocity does some very good prices, try to get a ride in a few singles to see what turbo suites you best, id go for either a hks T04z or a T67 for 600bhp.

Yes you will need a remap, what ecu do you have now?

Bloody hell - don't do that to me! I opened this thread with a sinking heart.

I thought SteveR had blown his engine up !

If it was me id either buy a built engine from the states or a new complete short block from toyota, iirc when i brought one it was around £1800.

like Jamie says, if you cannot (or haven't got the time to) build your own motor the stock short block is very good value for money, i am currently building my own motor and am so far at £1000 just in parts and thats the least expensive bit the labour is the killer, it may be worth getting the head off just to see whats going on

If you are handy with the spanner you wont need a full kit, but it will be easier to get a full kit and sell yours on, give some of the us traders a pm for prices, Kylestt at velocity does some very good prices, try to get a ride in a few singles to see what turbo suites you best, id go for either a hks T04z or a T67 for 600bhp.

Yes you will need a remap, what ecu do you have now?

Thanks for that, it is an AEM ECU

like Jamie says, if you cannot (or haven't got the time to) build your own motor the stock short block is very good value for money, i am currently building my own motor and am so far at £1000 just in parts and thats the least expensive bit the labour is the killer, it may be worth getting the head off just to see whats going on

Will probably go for the short block but I guess I should bite the bullet and take the head off first, havn't really got the time though.

why not?? I take it the turbo is a T4 flanged unit? there are plenty of turbos that will drop right in there what manifold is on the car and has there been any custom welding for example the exit to the W/gate being plumbed back into the exhaust system or different bits around where the turbo has been mounted? These are things that could cause problems if you were to change.

 

And take Jamies advice, he has prob been through more turbos than most ranging from out right obscence T88 down to smaller garrett units

 

in terms of a built engine it really depends on your goals....over 500 then its really a game of chance on a stock engine in my opinion although it could prob handle it a safer option would be to go for a build block

It is a T4 flanged unit with a v band coupling adaptor bolted on to the exhaust side of the turbo.

It has an external wastegate that is just connected to a short open ended piece of exhaust pipe.

Bloody hell - don't do that to me! I opened this thread with a sinking heart.

 

I thought SteveR had blown his engine up !

So did I!!

Thanks for that, it is an AEM ECU

 

 

 

Will probably go for the short block but I guess I should bite the bullet and take the head off first, havn't really got the time though.

 

 

It is a T4 flanged unit with a v band coupling adaptor bolted on to the exhaust side of the turbo.

It has an external wastegate that is just connected to a short open ended piece of exhaust pipe.

Aem, id talk to Ryan for mapping.

Strange i thought all T78/88 turbos was 4 bolt on the downpipe, well that makes it easier if its V band, and you wont have to touch the wastegate.

Hopefully the exhaust will bolt straight back on.

The ic pipework may need a little modding but should be pretty easy with the range of silicon bends available these days.

Aem, id talk to Ryan for mapping.

 

Strange i thought all T78/88 turbos was 4 bolt on the downpipe, well that makes it easier if its V band, and you wont have to touch the wastegate.

Sorry I do not know many peeps on here, who is Ryan?

It is a 4 bolt flange but it has a V band adaptor bolted on to that

Sorry I do not know many peeps on here, who is Ryan?

 

It is a 4 bolt flange but it has a V band adaptor bolted on to that

http://www.2bartuning.com/

Id be very surprised, if you are getting 800bhp from an old T78 on pump fuel, there are much better turbo options out there these days that will make the car nicer to drive and faster.

My bad I initially (mis)read the spec when I brought the the car as 800bhp and have been living under that delusion ever since

Sounds more realistic tbh, i think jonty made about 650bhp with his T78 with full supporting mods.