[LuukvdHeiden]

Could anyone tell me what the difference is between an 8V and a 16V turbo shortblock? are these interchangeable?

 

[jetman]

You mean the bottom end? As far as I know if you were looking at a swap, the pistons would be the only difference.

 

[LuukvdHeiden]

Yep: I need to replace the shortblock of my 16V turbo because of worn crankshaft bearings and i was wondering if a good 8v turbo shortblock could serve as a direct replacement. But is there a diffrence between the pistons of an 8v/16V turbo? I thought they had identical compression ratios?

 

[nutcase]

Apart from the pistons, you'd also need to transfer the timing gear over and maybe one or two other bits and bobs. But the block is totally interchangible. I took a 1992 16v injection engine and rebuilt it to suit a 1983 8v carb engine. Only problem I had was a slightly longer crank bolt meant I had to make some clearance on my 99.. But as yours is a 900 that isn't even an issue.

 

[Matthew]

B201T CR is 8.5:1 while B202T CR is 9.0:1. I'm almost certain that CR difference comes from the pistons and not the head.

The blocks are the same, barring any minor revisions Saab made during the years. They will be interchangeable.

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[LuukvdHeiden]

okay all, thanks for your swift replies!

 

[jetman]

But I think one could recover that .5 difference with head work, no?

 

[Matthew]

The CR difference comes from an additional 1.9mm and 2.75mm piston dish depth on the B202T (1984-86) and B202T (1986 onwards) cars, respectively.

How much cylinder head material that equates to, I don't know but I think it could be a significant amount.

okay all, thanks for your swift replies!

I've just looked at the times for the messages - this must be one of the quickest threads in SaabCentral history! LOL

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[jetman]

Well, either way, with the heads off and blocks out of the cars, swapping the pistons isn't too bad a job anyway.

 

[Matthew]

I thought the pistons were individually matched to bores? The book lists A and B sizes, plus first and second oversizes for the bores, and six different piston sizes

Also there's three different manufacturers!

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[jetman]

So an over bore and new rings/pistons would be in order then?

 

[CoastCard]

For what it is worth, I have just replaced my oil filler tube with one from an 8v. I got it from a breakers with the dipstick 'cos it had a nice red top . However I checked against my 16v turbo dipstick and the 8v is slightly longer and the fill level markings are in different places. Whether this is just because the turbo needs more oil or may be other differences that you need to investigate.

 

[Matthew]

So an over bore and new rings/pistons would be in order then?

I'd assume that finding a donor piston of the same size designation as the original would work okay. After all, Saab had a finite set of sizes to choose from.

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[jetman]

I'm still used to my old RZ500 where it was a new set of pistons and rings every winter!