Broken Saab 99 Turbo Pistons – Options?
Posted: 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
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