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16V block 8V head

2K views 10 replies 6 participants last post by  Shan 
#1 ·
Hi,

I've tried searching, but i guess my searching skills are not good or no one has ever tried it.

This question is from EdwinJ (a forumer), he can't log in the website cause his company forbids "surfing" :roll:

Would you think it's possible to bold the 8V head to a 16V block? What would be the pros and cons? Higher compressions so we can't run too much boost?

This would be keeping the existing K-jetronic system too.

Thoughts please!

thanks :cheesy:

des
 
#5 ·
Hi All,

Yes, its me - the namesake of this thread, blew the engine the other day. Plan now is to take a 16V engine, and use the block while maintaining the 8v head.

Need some ideas/tips.pointers for the following:

1: head gasket, which would i be required to get? 16v or 8v?
2: compression - will i have compression issues using a 16v block with a 8v head? Anyway of reducing compression to prevent this from happening - double head gaskets or perhaps enlargening the head?
3: bits and pieces like mounts, timimng gear etc

Appreciate any and every input!!

EJ
 
#6 ·
I used an 8v HG.
No issues with compression that I'm aware of - I used a 16vi engine with an 8v carb head (now converted to K-Jet but haven't really used it yet...)

I needed the timing chain, guides, sprockets, cover, oil pump, pulley all from the 8v donor engine. I bought a new oil pump, chain and guides.

Can't comment on mounts as this was in a 99.
 
#7 · (Edited)
You may end up with higher compression ratio, as the dish on the piston top is smaller on the B202 turbos, compared to your 1981 B201 engine.
Following are the specifications from the Saab manual.




However I can't see why a 8v head can't be fitted to a 16v block, when vice-versa is possible.
Following are some pics of an early 8v block with the starter motor beneath the exhaust manifold, and fitted with a 16v head, running on k-jets ! (see fuel pipes in the last pic below).





 
#8 ·
SHan,

Glad to see you contributing!! Anyways, looks like the 8v will mate no probs with the 16v block. Again I say, I am worried that this match will cause compression issues just like you have mentioned, where the dish on te 8V pistons are more than the 16v pistons. I will have to see into this a bit more in detail, esp since I am pushing boost 1bar+.

Another question is should I discard the old 8v power sterring pump/reservoir in favour of the new power steering pump?
 
#9 ·
Again I say, I am worried that this match will cause compression issues just like you have mentioned, where the dish on te 8V pistons are more than the 16v pistons. I will have to see into this a bit more in detail, esp since I am pushing boost 1bar+.

Another question is should I discard the old 8v power sterring pump/reservoir in favour of the new power steering pump?
Edwin, you may have to retard ignition timing with the higher compression ratio. 1 bar boost is not a problem on the 16v engines with 9.0:1 compression ratio, EFI and APC. However on your 1981 8v with no APC and running K-jets, running 9.0:1 compression will probably result in heavy knock.

Not sure if the 16v power steering bracket will fit onto the 8v head, you may have to try it out. The late 8v's ('88-'89) used the same power steering pump as the 16v, but I'm not sure if the bracket is similar.
 
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