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Discussion Starter · #1 ·
Today I was doing the head gasket on my 900T. I came to clean up the head up to refit it, and found a big crack! :cry:
I guess the reason i couldnt see any hugely obvious blows between the water ways and anywhere oily on the old gasket is because there wasnt any! :(

I'm on a bit of a tight schedule here, and that head looks like it is now scrap (the crack goes right from the valve to the waterway, and down as far as i can see)

In the shed I have a head off a N/A 900 of the same age (which was good when i removed it!). Can i fit this instead?

I'm assuming that the head itself is identical, and the cam is different. Is that it?
Are the valves the same too?, or are the turbo ones harder or anything. Can i fit the N/A head and valves as one anyway, and just accept that i have to be careful with it, or replace them soon?

The reason i ask is that I need to car running by friday, and things just seem to be getting worse! :cry:.

I'm not adverse to running it on base boost if i have to. I just need to do about 600 miles, and then i will have time to work on it properly!
 

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bad week for Saaba

Is this catching or something? To many Saabs dying at the moment!

I could'nt say what condition it's in (maybe buggered too) but i don't need the head off my spare 8v engine as i want to put a 16v one on.

Your welcome to pop back and pull it off, see if it's OK, if your stuck anyway.

Let me know.
 

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Discussion Starter · #3 ·
I've looked at the N/A head, and it looks the same to me, so i'm going to assume that all i need to do is swap the anciliiaries and manifolds across, and also swap the cam (so use the turbo one), and then set all the clearances.

Si - I might take you up on that offer if anybody dives in here and says that they are actually different!.
I'll give you a ring later if i need to!

I now own 3 non running saabs and 1 runner without an MOT! (which was to be my project for 2 weeks time!..) It's definately not saab season :(

My dad also owns a 900i which needs a head gasket... hmm.... might be worth doing that one instead since its the same gasket kit as my 900T
 

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The N/A valves should also be coated. I'm not sure about the cam, I know the 16v N/A has a different cam, and I don't see why it would be different for an 8v, but I don't know for sure.

I'd just put the cam from your cracked head onto the N/A head and then you wouldn't have to worry about anything being different, you'd know it was right.

Good luck with it.
 

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Discussion Starter · #5 · (Edited)
I'm glad the valves are the same! (saves me going out and buying a valve spring compressor!) I'm assuming the cam is different from what i know about 99's. There are 3 different cams in the 99 for carb, injection and turbo.

I'm not sure i really want to set up all the clearances though (which i presume would be prudent when doing a cam swap!). It looks complicated!.. I've got a big pot of shims and have to try it some time though :(

I'm now going out to start stripping the turbo head down. If anybody would like to dive in and tell me why i can't do this, please feel free! ;)
 

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If it's an APC car the cams are the same I believe.

The inlet valves are probably ok, but the exhaust ones will be sodium cooled in the turbo head. Possibly in the injection head as well - I think later 99 injection cars used the same valves as the turbo.
 

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Hey - I may be incorrect, but I think that in general, most turbo'd motors will have a lower compression ratio - that means that the head from a N/A motor MIGHT have a lower clearance than a Turbo head to give it that extra psi on compression... that may mean valve interferance with the top of the piston, also the N/A pistons may be shaped differently to allow the valve to get closer to the piston w/o intereferance.



I'm not sure if this is the case, but it may be something you want to look at to make sure that things dont get worse... my saab seems to like to make things worse and worse, but in the end, we win!!



Scott
 

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Heads are identical save for the cam. The lower compression ratio comes from the pistons.
 

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Discussion Starter · #9 ·
Thanks guys!. i knew that the compression ratios differences were made using the pistons (I had to work out what pistons to order for my 99). There are non-APC. APC, and normal pistons (check out the listings on the scantech website).

the spare head i have is from a carbed N/A model, not an injection. What is the consensus on the valves then? Same or different.
If the valves are different, what would i risk from using the n/a ones in a turbo? I could go and buy a valve compressor tommorrow and swap them - but would i also have to get valve guides if i did this (dont really have time)?

I now have both heads stripped, and all the bits i want cleaned and waiting on the bench. (N/A head, turbo cam and holder and turbo ancilliaries)

I shall try to go and fit the cam and get it as well set up as i can after i've had some tea! Then hopefully i can get it all back together and running again tommorrow.
 

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Discussion Starter · #10 ·
It doesnt half take a long time to do valve clearances on a saab!
Its a 10 minute job on my landrover :eek:

I'm glad i dont have to do that very often! I have now sorted out the big box of mixed shims that i had though so when i come to do my 99 it should be a lot easier!
 

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Hi, my 84 turbo had a 1983 casting on the head . I replaced it with a 83na head,The cam and valves were the same part number.I only had to reset the valve clearances for the turbo.;) Pat
 

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Discussion Starter · #12 ·
car is fixed now!. There appear to be no problems in fitting the N/A head. Ended up not driving it on holiday - we had to squeeze up lots and use a mates car :(

I did have a bit of trouble with the exhaust manifold - the studs that the N/A head had on cannot be used with the turbo manifold as they are too long and you cannot actually get the exhaust manifold onto the studs past the metalwork of the car.

If anybody else does this - take the studs out of the N/A head (and fit the turbo ones if you have them) before you fit the head back onto the block.

I also had trouble with the oil return pipe for the turbo. This is not even mentioned in the haynes book (I am ordering the bentley very soon!) but is easy to knock when you take the manifold off and fairly tricky to seal up afterwards from under the car with the engine complete!
 
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