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Discussion Starter #1
Hi,

for those who did not follow my "how much oil" thread: My Viggen uses excessive amounts of oil.

Today, we did a "pressure loss test" (not a compression test), and all 4 cylinders proved to be faulty: Pressure loss was 32%-22%-38%-26%, 20% being the tolreance. On the third cylinder, we could really hear the air "swoosh" trough the oil sump. So the piston rings seam to be deffective.

My Saab dealer wants to sell me a brand new base engine, delivered completely assembled from Saab, including crank and pistons. Just the head/cams/etc need to be installed, then the whole lump can be reimplanted into the car. This is not much work (1200 EURO), but the block cost 3500 EURO including the little bits.

Those 4700 EURO seamed a little steep to me, so
I phoned around a little bit and mailed to Fredrik at MapTun. MapTun and Gasparatos (www.saabtuning.de) told me that they think the stock pistons of the B235R are to weak to stand much more than 100hp/litre. They want me to replace the pistons with either Saab 9000 2.3T pistons or forged pistons. This action requires to redo the crank and the cylinders (I don´t exactly know the english terms). The total cost will be roughly the same than the new engine (3500 EURO if I use the forged pistons, a little less with the 9000 pistons). My car warranty will pay up to 5000 EURO (all the work, 70% of the parts), so the question really is: Which is the better alternative?

Thanks,

Philip
 

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Um, I can tell you a story or two (literally!) wbout pistons supplied by Gasparatos, but won't.


Personally, I would go the 'performance rebuild' route rather than spending almost 5K to merely restore things back to stock. Saabine's short engine including forged Cosworth pistons, a 2 mm overbore, shot peened rods and crankshaft, supply of a 'new' crankshaft (mine had wear ridges on the bearing journals) and everything weighted/balanced, cost in the region of 2,2xx euro. I paid my local Saab garage 700 euro for putting it all back together and removed/installed the engine myself.

For this kind of work, I can definitely recommend Sweedspeed in Neer, The Netherlands. Just ignore Frank's talk about how bad the ECU mapping of Hirsch and Abbott is blah blah, he is a bit peculiar about these things...
 

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I guess that I would go along the performance rebuild route as well. If you got all the stock stuff again, how soon until it needs to be done again? It may be worth something to ask Hirsch if what they do internally to their engines in the 305 hp Troll R models, I am pretty sure they do something with the internals for the Rs. I wouldn't get the work done there because of the cost but if they can tell you what they do, the info may help.
 

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Installing oil injectors in the block for cooling the pistons was also included in the price.

Got the receipt here - it was 2,290.75 euro and says

"Saab engine; oil injection, weighted, pistons, con rods shot peened, main bearings, big end and thrust bearings"

Then, I paid an additional 300 euro for a 'new' crankshaft, shot peened and balanced, because the one I had turned out to be shot on assembly
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So my first post wasn't wholly correct: the total bill for the short engine was 2,590 euro.

Getting my Garrett modified and rebuilt to 'full race' spec (including 360 deg thrust bearing) was an entirely reasonable 532.83 euro.

Originally posted by Leon [9-5 stg2]:

wow Eric, thats a keen price for that sort of work    :eek:    
Philip, if 'your' spending that sort of money, as Eric says, why put it back to stock when you could acheive so much more    :fawlty:    
Maybe give Eric's suppliers a try? [/QB][/b]
 

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That looks like some bad luck there Phillip! I hope no other B235R owners report similar problems in the near future.
Not looking forward to that sort of bill.

As for new pistons, the B234R's pistons are stong I'm sure, but you might consider getting some that are slightly lower compression. You're already MapTun stage 3 and it couldn't hurt to give yourself that extra breathing room. 8.8:1 or so would probably more than sufficient.

I still have a hard time swallowing the whole "New 2.3L pistons aren't stong" deal. I knows guys with some 1980's Chrysler cars who have CAST pistons and run upwards of 25 psi without any trouble. The only difference "they say" between cast and forged is how much detonation they can withstand before they turn into ashtrays. But if they say the pistons aren't strong enough, I suppose they aren't. Oh well ... good luck with getting yours fixed Phillip! May as well turn it into a beast while you're "in there".


Cheers,
Dubbya
 

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Discussion Starter #7
Wow, 4:0 for the performance way - I should have expected that from a performance forum

Mind you

- the process of pulling out the engine and putting it back in is much more work on a 9-3 than on a classic 900 - the air con has to be evacuated and taken out, etc. So a price of about 3500 EURO inluding tax seams to be ok for the kind of work that has to be done - inluding 4 forged pistons.

- if I take the base engine block, it will not only be stock condition, but stock NEW condition - at least most of the parts. That´s nice too after nearly 50.000 miles ...

I will think about it during the week-end!

Thanks for your help!

Philip
 

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It was my understanding that 3,500 euro was the price for the short engine itself (either way - new or rebuilt) and 4,700 euro was the price your dealer quoted including removal/install. This correlates with your statement that both ways would cost about the same. So I'd taken 3,500 as the benchmark figure, taking the removal/install cost (which will presumably be the same either way) out of the equation.

Seen it this way, 3,500 for a performance rebuild seems to be a realistic price. As Sweedspeed did not charge anything for the new secondhand block and presumably the crankshaft (300 euro being a fair price for the shot peening end balancing alone), the 2,590 euro paid at Sweedspeed for the parts, machining and 'performance' work plus the 700 I paid my local Saab garage for assembling the block, head and timing gear to get a full engine, ready to install (make it 3,300 all-in) would halfway compare with the 3,500 quoted to you for the short engine. Halfway, because the block would be completely assembled but the fitting of cylinder head, timing gear and in your case sump would make part of the other 1,200 euro.
Still, it's not so far off from what I paid considering your engine might be a bit more complicated given the balancer shafts in the block and all.
 

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Discussion Starter #9
Update: Today, we wanted to order Wiseco forged pistons for my car (www.wiseco.com), and we discussed my application with Wiseco of Germany.
Wiseco thinks that forged pistons will not last 75.000 km on a 2.3 litre car with 300hp. They strongly urged me to go with thermodynamic (=standard) pistons for a car that is mainly in road use, and not forged pistons, which stand higher power outputs, but wear out quicker. So I guess we will not go for forged pistons.

The new Saab engine block seams like the way to go. I was advised that if treated properly (short oil change intervals, no cold quick starts, etc), it would probably last longer than any other alternative - plus I would get 2 years of warranty on it.

So probably no performance rebuilt ... but I don´t plan to go beyond 305 hp anyway ...

Yours,

Philip
 

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Arrggghh. Personally I think that's rediculous. I have 3 different friends all with turbo 4 cyllinders, all with over 70,000 miles and over 300 hp and all with forged pistons.

The only disadvantage to forged pistons is the increased COLD wear as, because they expand more when they warm up, they're exceptionally loose when cold. But if you take it especially easy on them during the warmup they last as long, if not longer, than any conventional cast or utectic piston. Mind you your stock pistons were supposed to be forged, as are the stock 9000 Aero's from all the information I can gather on them. My friend's Camaro also has stock forged pistons and so will the new monaro. So I don't see why your Saab would have trouble with them.

Cheers,
Dubbya
 

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I agree - that's just plain stupid. Methinks they assume just because it's a road car, you will only drive it to the supermarket and back and won't observe proper warming up procedures. I think Ford Cosworth engines, for instance, do last a bit more than 75,000 kms in road cars...
 

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Discussion Starter #12
Originally posted by Eric van Spelde:
[qb]I think Ford Cosworth engines, for instance, do last a bit more than 75,000 kms in road cars... [/qb][/b]
Funny you mention the Cosworth. That´ s exactly what the Wiseco guy told us: Those Ford Cosworths rarely make more than 100.000 km on one set of pistons...

So do you think I should still go for the forged pistons even if the Wiseco guy tells me not to go for them?

@Adrian: I was told by multiple sources that the Viggen and the 9-5 Aero do NOT have forged stock pistons.

Yours,

Philip
 

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Heres what saab say about thier pistons, make of it what you will:

Pistons  

The pistons are made of light alloy and have grooves for two compression rings and one oil scraper ring.

The upper compression ring is flat and chrome or molybdenum plated. The lower compression ring acts as an oil scraper, is somewhat wider than the upper compression ring and has three sections. The pistons are internally reinforced and designed for trapezoid connecting rods. The pistons are tin plated and their upper parts hard anodized. The gudgeon pins are nitro-hardened. The compression ratio of the B205E is 8.8:1 and of the B235E/R 9.3:1.[/b]
 

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 The compression ratio of the B205E is 8.8:1 and of the B235E/R 9.3:1.  [/b]
But with the right additional bits, and engine knowledge, that 235 can be made to produce different compression figures. Did I say too much
?
 

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Originally posted by StanleyB:
[qb] QUOTE
 The compression ratio of the B205E is 8.8:1 and of the B235E/R 9.3:1.  [/b]
But with the right additional bits, and engine knowledge, that 235 can be made to produce different compression figures. Did I say too much
? [/qb][/b][/quote]No we haven't heard enough.. lets hear the full SP!
 

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Philip,
Have you shopped around for advise from any other piston manufacturers?
Cosworth,Arias,Accralite..etc.,etc...

I know the Cosworth forged pistons that I would need to fit in my Sunbeam-Lotus should last about 50,000 miles depending on usage, but then that's only marginally less than the standard ones..


If the previous mention of Cosworth pistons not lasting was a reference to the YB engines in the Cossie Sierra and Escort's, then yes they are somewhat known for not having a long life. I think this is down to usage and power levels above 400bhp more than anything else.

The pistons in the B235R may not be forged but the ones in the B234R probably are.
 

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Posted by Leon:
 No we haven't heard enough.. lets hear the full SP!  [/b]
Patience, patience . I am working on the draft, and need my "partners in crime" to go over the technical details to make sure I am not quoting from memory things that are not possible. We wouldn't want anyone to try to attempt some of them, and then blow their engine up, do we
.
 

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Discussion Starter #19
Hi guys,

I´m thinking about this problem all day long, I can hardly concentrate on anything else - new engine or forged pistons - forged pistons or new engine - new engine or forged pistons - ...

One thought that bothers me: The B235R is a highly sophisticated engine - some people call it the pinnacle in Saab engine design - because it delivers smooth, high performance and awesome torque. In stock condition, power delivery is much smoother than the B234R´s - trust me, I drove them both (I admit that B204 and B234 have more tuning potential, but that´s not the question here).

But this engine is a system, thermodynamics have been calculated with every single part in mind. Changing an integral part like a piston with a completly different make, which behaves differently, might disturb this system and make it run suboptimal. I do not plan on reaching much more horsepower or torque than I do now. I plan however on keeping the car for a few years to come and at least 100.000 more km. And I plan on driving fast on the Autobahn for longer periods, and on taking it out on the racetrack for the occasional lap. And I don´t want to rebuild my engine every 12 months - in fact, I hope this rebuild will be my first and my last. So the stock piston might be the more suitable choice after all ... I´m more than happy with its performance, and its failure might be just an unhappy coincidence.

I´m still not convinced. I would love to have a car with forged high performance pistons. But I don´t want it to be the experimental vehicle. Mind you, the Audis MarkA is writing about were designed with the forged pistons they use in mind - my Saab was not.

Good night,

Philip
 

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Even if they aren't forged, the fact that they are tin plated and hard anodized suggests they are up to the task. I know guys putting out 350 wheel hp on stock chrysler cast pistons from the 1980's!! They have no reinforcements what so ever. What the racers discovered was just that the forged pistons could take more detonation before they turned into scrap metal, but that even the cast pistons could withstand similar power levels.

Given that the Saab's are hard anodized, they can probably take a "fair" level of detonation, and are likely much lighter, and do not expand as much as forged. (forged aluminum is considerably more dense) Of course if you want forged pistons, and the B235R's are not, do what Frederik Suggested and try a set of B234R pistons. I would personally just stick with the stock pistons, or in my case here in the US, try some J&E, as they've been making Hi-Perf pistons for just about everything for a long time. (My friend has had good longevity with them in his car) This doctoral thesis is on spark advance modelling and controll and is from the Linkoping university. It has a section in it where it briefly discusses water injection. Water injection can significantly lower tendancy to knock by lowering both the peak in cyllinder pressure and temperature, without lowering the combustion efficiency (in fact it can make it more efficient under the right conditions). Adding water injection might help extend the power-life of the B235R's pistons.

When I e-mailed abbott they told me that they tried to water inject a T7 but couldn't, however another person on this board has a MY99 Viggen with aquamist on it, so I would assume it's possible. I'm not suggesting this as an immediate solution, but as something to consider. You might be able to get aquamist to let you "try" the system and if it works keep it, if not they may let you send it back. I think it's worth a shot. If you don't try it, one of these days I'm going to, so I'll let you know how it goes when the time comes.

Cheers,
Dubbya
 
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