85 900 Notchback arrives in Vermont

[Crazyswede]

I went down to bennington vt today and picked up 3 free 16 viking wheels for my ng 900...bonus they came with good toyo summer tires....good as in decent looking tread pattern and good depth...a full summer maybe two depending on how they wear.


On my way home I stopped at chris's shop and helped for a bit. Also did some cleaning. I have decided to put a 2.1 motor in the car until the future engine is done. Figured it might be a nice setup with the bigger intake, a lightened flywheel and the mss headers. I have an lh harness which I think is from an 88 turbo. I will probably just run the turbo ignition unless ezk is enough of a performance upgrade to install...or maybe some sort off aftermarket igntion.

[airsweden]

I'd still like to see some progress on this soon. This is an obvious match for the LeMons car, lets make it happen.

[Crazyswede]

Well...let's hang out at chris's and set one of the 2.3 engine on a transmission and see what interferes. I suspect that we need to turn the balance lobes down on the crank and change out the rods and pistons.

[Crazyswede]

So I stripped a 9-5 2.3 turbo block down today that had a broken piston. Turns out the block and crank are fine...no scoring on the cylinder walls. I then placed a c900 transmission case on the block to check the fit. Here is what I learned: the 9-3 and 9-5 blocks will not bolt onto a c900 transmission without serious modification. The bolt pattern is completely different between the two. I looked at an NG900 engine and I don't think that block will work either. These engines are all the newer "short" block designs so I suspect that the 94 and later 9000 short block engines will not work either. That said, the 93 and earlier "long" block 9000 motors do have the same bolt pattern as the c900 transmission. So in order to do the vertical block we will need a 93 or earlier 9000 block.

I suspect that the short block crank from the 2.3 will not fit a long block...and it looks like the rods in the 9-5 are cast.

[Crazyswede]

My 16v headers arrived last night and are waiting to go on the 2.1 motor which I have just started to pull apart. I want to inspect the block deck and make sure its decent before I put this engine in the car.

[Crazyswede]

So I have the headers, the lightened flywheel, the later turbo clutch, the limited slip diff...etc I still have to get back down to the shop to assess the health of the first 2.1 engine.

Soooo....lets talk cams. Thoughts on stock cams to use...just stick with the 2.1 intake and exhaust cams or run the 2.1 intake with an exhaust cam from a different year. I currently have a pair of cams out of an 85 turbo and another set out of an 86 non turbo.

[Luke]

As I recall the best stock intake cam setup is actually the 86-93 turbo Don't use the 2.1 cams or the 85 exhaust cam's for an NA.

[Luke]

Ok I fould the spec's for exhaust

Type Lift mm EVO (BBDC) EVC (ATCD) Duration
85T Exhaust 8.65 - - 56.0 16.0 252.0
86T+ Exhaust 8.65 - - 61.0 13.0 254.0

So looking at the difference the duration of the 85 cam it is only slightly less, but the overlap is different, the 85 cam being slightly more retarded. I can't say for sure what difference this would have on the NA motor, but generally retarding a cam will raise rpm where a motor makes the most power. But of course its not that simple to say without looking at the whole system in combination with the intake cam.

[Luke]

Best bet, find a place to make a custom set of cams somewhere around 270-280 duration with more lift. It will be money well spent. Then when you get the crazy 2.3 bottom end together with a T7 head you can use these cams on that too. You'd be well over the 200 HP range with that combo for sure.

[Crazyswede]

Did some calculations and research today.
The 2.0 bore x stroke is 90mm x 78 mm.
The 2.1 bore x stroke is 93mm x 78 mm

So the same crank with a bigger bore block

The 2.3 out of an earlier long block 9000 is 90mm x 90mm.

If you fit the 2.3 crank to the 2.1 block your now at 93mm x 90mm which brings displacement up around 2.4 liters.

Lastly I think the rod journals are 2.0 inches in diameter. You can get rods for a chevy with 1.85 inch diameters. Since you will have to grind the rod journals down you might as well have them offset ground. If you can get the full .075" offset thenyou gain another 1.9mm on the stroke. This brings your total displacement up to 2.49 liters.

Also did a quick ebay search and found lots of cheap H beam Carrillo rods in sets of 7 or 8 for sale. Need to figure out what length is needed. Might have to go visit claude hutchins for some mentoring

[Luke]

Lastly I think the rod journals are 2.0 inches in diameter. You can get rods for a chevy with 1.85 inch diameters. Since you will have to grind the rod journals down you might as well have them offset ground. If you can get the full .075" offset thenyou gain another 1.9mm on the stroke. This brings your total displacement up to 2.49 liters.

Hey Seth, the saab journals are ~ 2.0470 What you want to do is use a pre- '68 small-block bearing and rod which is 2.00" That way its not such an extreme amount to have ground.

[Crazyswede]

Lastly I think the rod journals are 2.0 inches in diameter. You can get rods for a chevy with 1.85 inch diameters. Since you will have to grind the rod journals down you might as well have them offset ground. If you can get the full .075" offset thenyou gain another 1.9mm on the stroke. This brings your total displacement up to 2.49 liters.

Hey Seth, the saab journals are ~ 2.0470 What you want to do is use a pre- '68 small-block bearing and rod which is 2.00" That way its not such an extreme amount to have ground.

Unless I could have it offset ground down to a 1.85 or 1.88". Then you could increase the stroke by about 2.5mm which brings your motor to over 2.5 liters.

Of course this is one of those cases where it is easy to get carried away....My thoughts on the offset grinding are that if you are already having to grind the crank then if its not a lot more expensive have it offset ground for the increase in stroke...bring the engine closer to a square bore x stroke.

[Luke]

You might be on to something Seth, a 92mm stroke with a 94mm bore (2.1 bored 1) would be a torquey little powerplant for twisty rally use. The key would be keeping it all together at high rpm, everything would have to be as light as possible.
With a T7 head, proper cams and nice intake with the MSS headers the thing could really move!

[Crazyswede]

Any idea on the necesary length for the new rods? A quick search for Carrillo H and tapered H beam rods on Ebay turns up a lot of used sets of 7 and a few of 8 in the less than $100 price range. They are from circle track cars running constant high rpms but would probably hold together just fine in a 4 cylinder running less rpms and rarely hitting say 8000 rpm.

[Luke]

Well, the swede I was talking to said to use 5.7", but that seems really long, For that to work the piston would have to be really short, with the wrist pin tucked way in there. Best bet would be to take measurements off a block and crank and draw a cross section in solidworks and simulate it.