Broken Saab 99 Turbo Pistons – Options?

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Neil_G
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Broken Saab 99 Turbo Pistons – Options?

Postby Neil_G » Wed Jan 25, 2017 10:35 pm

Hi All

I finally got around to investigating the poor running issues of the 5 door 99 Turbo.
A compression test revealed the following results:

1. 120
2. 140
3. 140
4. 70

Pulling the motor out and inspecting the pistons revealed that 3 of the 4 pistons were cracked!
Unfortunately, I do not have any spare 7.2:1 pistons and the usual internet sources seem to have run out as well.

So what are my options?:
- Beg, borrow and steal from Saabists around the world?
- Install 16V 900 Turbo pistons? - however this will increase the static compression ratio. Is this advisable?
- Aftermarket suppliers – any preferences?
Your thoughts?

As to why the pistons have cracked, it appears that the car has been driven in the past with a stuck waste gate (original Saab 99 Turbo type) – too much boost – with the usual results.

Unsticking the valve in the waste gate is another challenge … I can get the valve to spin and move in / out a couple of mm but it is not showing any enthusiasm of coming out any time soon.

The turbo has been rebuilt recently so I am reluctant to change to a later 900 turbo / waste gate combination at this time.

Any Ideas?

Thanks Neil
_____________________________________________
Oh why can't I play the triangle. I don't know after all those lessons.

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Krizzie
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby Krizzie » Thu Jan 26, 2017 12:17 pm

If one of them is still good you might be able to send it to a piston builder like Ross or Wossner. They can make a forged copy of it which is much lighter and stronger.
My ride: MY91 Saab 900 Aero T5.5 Converted, 9000 Aero interior, Xenon projectors and many more mods/upgrades

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Crazyswede
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby Crazyswede » Thu Jan 26, 2017 2:18 pm

You could put a set of pistons in from an 8v 900 engine...they were around 8.5 compression as I recall. If you could get an 8v 900 exhaust manifold then you could run a wastegate and APC.
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vintagesaabs
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby vintagesaabs » Thu Jan 26, 2017 2:48 pm

Where are you located ?
I'm outside Portland, OR and may have some options for you.

Neil_G
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby Neil_G » Thu Jan 26, 2017 6:35 pm

Thank for the replies.

The suggestion of getting a local manufacturer to make a new set was a great idea that I did not think of. Luckily one of the pistons is still OK and could hopefully be used as an example to remanufacture a new set.

Regards
Neil
_____________________________________________
Oh why can't I play the triangle. I don't know after all those lessons.

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99Super
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby 99Super » Thu Jan 26, 2017 8:35 pm

As much as I like Seth's suggestion, considering the rarity of 5-door 99Ts, I think I'd actually want to keep it original.

John

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Crazyswede
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby Crazyswede » Fri Jan 27, 2017 1:42 pm

I believe Luke paid around $600 for a set of custom pistons with rings and pins for one of his engine builds.
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Neil_G
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby Neil_G » Thu Feb 09, 2017 6:46 am

Thanks to a local Saab enthusiast for the NOS turbo pistons and rings.

Image

Image
_____________________________________________
Oh why can't I play the triangle. I don't know after all those lessons.

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99Super
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Re: Broken Saab 99 Turbo Pistons – Options?

Postby 99Super » Thu Feb 09, 2017 9:12 am

:yay: :yay: :yay: :yay:


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