84 GN engine and trans

[tonytheplumber]

There is a posting on CL in which a guy has a complete long block (minus turbo and throttle body) for an 84 GN. Are there any differences between this long block, and an 86-87? I know the non intercooled (hot air) cars have a very different induction set up, but are the block, rotating assy, and heads different? I could pick this up cheap and have something to build while I am still driving mine if they are the same castings:biggrin:. Same with the trans. Would I be looking for the same BR, BRF coding on a GN that old?? Cause it looks like he has the trans listed too. Any info would be great. Thanks guys!!

 

[UncleDave]

The differences in the block are 1) the earlier ones have 14-bolt oil pans whereas the later ones ("109" blocks) have 20-bolt pans; 2) the lifter valley in the earlier blocks is more open; 3) the later turbo blocks have a 1/2" NPT drilled & tapped in the front for the turbo oil drain which can be added to an '84 block if you plan on using it with the later intercooled setup. Other than that, the heads (as far as I know are) the same 8445 castings.

 

[novaderrik]

the deck height on the block is different, but they changed the head gasket thickness to compensate.

 

[tonytheplumber]

What about the rotating assembly? Are the crank/rods/pistons the same? Same balance (internal/external)? And if everything turns out to be the same except the block, is this a desirable block for you hot air guys? Cause I prob would just want to find a 109 block since there are a few differences. But if the rotating assembly and heads are the same (castings) than I would probably buy this thing, disassemble it and sell off the block and keep the rest for a 109 block that I would have to find. I understand the differences are kind of minor, but since my car has a 109 block (and yes, it does), I would like to keep it that way.

 

[tonytheplumber]

I'm gonna post the question about the trans in the trans section since I haven't heard anything back on that.

 

[Turbo-Archie]

Many people use these in the '86-87 application.

The deck height is the biggest issue. Because of it, the pistons are not the same and might not work in the 109 block.

14 bolts, lifter valley, oil return are all non-issues..



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[standupjskiguy]

As an owner of an 85 T-type and an 87 G-Nat, the trans does not act the same. I believe it is the same trans but the 1-2 shift on the 84-85 is much more tame and does not chirp the tires like the 87.

 

[tonytheplumber]

Many people use these in the '86-87 application.

The deck height is the biggest issue. Because of it, the pistons are not the same and might not work in the 109 block.

14 bolts, lifter valley, oil return are all non-issues..



..

Are these engines internal or externally balanced, and did that ever change? Same balancer? Flexplate? wondering if the crank and rods are different from pre 109 to the 109s. So far what i can gather from information given here: the heads are the same (casting), and mabey the crank and rods?? I don't mean to be a pain in the ass guys, I'm just a turbo Buick newbie, and I want to know what I'm dealing with.

 

[jdpolzin]

Are these engines internal or externally balanced, and did that ever change? Same balancer? Flexplate? wondering if the crank and rods are different from pre 109 to the 109s. So far what i can gather from information given here: the heads are the same (casting), and mabey the crank and rods?? I don't mean to be a pain in the ass guys, I'm just a turbo Buick newbie, and I want to know what I'm dealing with.

Tony, take my word and buy them!

 

[Turbo-Archie]

I agree to buy it at the right price.

People have taken a running short block like this and have ran 10:50's.

They have the same crank, rods, and same pistons but with a dif CH.

14 bolt pan needs a 14 bolt front cover but it all works the same.

Your thinking more like a '78 carb turbo. Now that is getting a little too far out there and that engine would not be as good as a 84-85.



Good luck!!!


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[tonytheplumber]

Well, I bought up the engine and trans yesterday. The guy said that the previous owner told him it had only 50K miles on the whole car. He said he didn't believe it cause the car was in really bad shape. He parted it out due to rot/body filler issues.
I tore down the engine last night to see what I got myself into, and it's really clean:biggrin:! The cylinders have no ridge at the top, and if the front main wasn't a little scored, I think the crank would get by with a polish job. No blown head gaskets or nothin!!
So now if anybody wants a good standard bore hot air block, let me know. I'll let it go cheap. I really just want the heads and rotating assembly.
Oh, and the trans came with a 12" Pro Torque torque converter. Anybody have any experience with one of these?? Any good/bad??