CARBON SEAL

[GARRICK.CLARK]

Hi Guys.
I have a GT2556S turbo off a JCB on my draw through engine.
The engine was blow through.
Now its a draw through set up the vacuum is pulling some oil into the manifold.
The local turbo shop says my turbo cannot be converted to use a carbon seal.
Is this correct.
The exhaust/ manifold etc have been designed and built around this turbo.
Its only got a few thousand miles on it.
What should I do.
My thoughts are to either just run it, or try and use the turbo exhaust housing from the gt2556s and fit the internals off a different turbo.

[volksbugly]

Talk with Shag he might be able to help you with this.

[Piledriver]

I'm reasonably sure the carbon seal fits in the same place as the dynamic seal, may require trivial machining to fit, even units that only come with dynamic seal have been retrofitted.

I'd call around a bit, aren't you in UK?
If you ordered it with a carbon seal from the local shop, they may just be trying to get out of doing the right thing.

You dont want to run like that as oil in the intake will cause knock and/or preignition.

Carbon seals are a bit delicate and an additional possible failure mode, that's one reason ~all OEM turbo cars these days are blow through, and blow through is usually recommended for retrofits.

[GARRICK.CLARK]

Well I've rang round most of the turbo shops in the UK and they are saying the same thing, in that this turbo cant be converted. So I'm gunna have to start again with a turbo that can be converted.

[Piledriver]

Or go blow through.

[Clonebug]

Or go blow through.

He was blow through and couldn't make it work so is now trying draw through.

The money you have in swapping could have gone a long way to FI.

[Piledriver]

OK...I think I remember... he was originally running a really high CR with a mild cam, then de-domed the pistons etc?
That wasn't a blow vs. draw through issue, that was a lack of fuel and spark and knock control issue.

i guess old skool works OK if you don't use much boost, or compression, and run rich as hell with very retarded timing.
Of course it will run hot and not make as much power, but it probably won't blow up as quickly.

So... What turbos can be had with carbon seals?
Old T3s?

[GARRICK.CLARK]

That's right I did try blow through 1st, it didn't work out, So far the draw through with the 2" SU is giving good power so far.
My original choice of turbo was a bad one. It was on the shelf at work, and was cheap. unbeknown to me it was just wrong in many ways. So I'm gunna get a T3 built, position it higher up near the pulley wheel to get a better oil return height/angle.

[GARRICK.CLARK]

I was reading about tuners having to use oil inlet restrictors on there motors to stop the oil leaking, that got me thinking if mine had a restrictor from the factory or not, so I checked it. the hole that feeds the bearings is 3mm.
the oil feed pipe from the oil pressure switch is bigger. oil pressure from cold is 60psi. with 20/50. I no but it seems to like 20/50.
So I'm going to put a restrictor in at 1mm and try it.
What's my chances of this working.
Thanks.

[Piledriver]

ball nearing turbos need a restrictor
Sleeve/plain bearings are their own restrictor unless worn.

Crankcase blowby and the resulting backpressure can make even good carbon seals leak if it's excessive.

[Clonebug]

My oil pressure is right up there too when cold.

I feed my turbo with a 3/16ths line or AN-3. I have not had any problems with oil even though I drain into the 3/4 valve cover.

Make sure you have good drainage and a 5/8ths diameter or AN-10 line draining the turbo with an almost straight line.
Anything less will more than likely give problems.

[fall-apart-dave]

I just went through all this pain.

The only way through in the uk (for mot silly money) is and T3 turbo and a new backing plate and carbon seals thrust parts etc. Thats the only way I found. At least I dtarted with the right turbo (accidentally). Aldo I have lists of turbos that left the factory with carbon seals. Most have been rebuilt with dynamic by now.

Parts were about £70 from turborebuild.

[GARRICK.CLARK]

OK Cheers Dave i'll ring them if this don't work. Turborebuild are only about 3 miles from me.

[GARRICK.CLARK]

Evening Guys.
So, i've done every thing I can to this turbo to try and stop the smoke
Repositioned it higher in the engine bay to get a better position on the out pipe.
fitted an oil restrictor.
Still smokes.
I asked the local turbo shop if he could change the cartridge ONLY, and use the original hot and cold parts but he's reluctant to do it for some reason, Why is this, he didn't give me a proper answer really.
I no why, cause it cant be done.
T3 here we come.

[fall-apart-dave]

T3's are easy to come by buddy, there's plenty out there. Just buy a used one that is in good nick and a carbon shaft seal kit and you're away. Just make sure you put it together EXACTLY how it came apart to keep the balance etc.

That said I've not test driven mine yet (major chassis resto underway).