Camaro 3.1, 3.4, and 3400 parts needed

[bachert24]

No, stroke is the exact same. The calculator is probably filled with spec information where one source rounded up and one source did not. Both the 3.4 and 3400 use the same 981 casting crank.

The 3400 piston does come proud of the block by 0.020". It's the piston that determines this, not the block. The 3.4 piston is down in the bore a small amount, hence the positive and negatives in the calculator.

Ok so I recalculated the compression ratio and changing the gasket thickness from .040 to .060 and the deck height from .0065 to -.020 moved the compression from 9.06:1 to 9.16:1 and also moved the quench from Less power to ideal. Thanks for all the info and all the help Raven and Caffeine, you guys got me to research like crazy and now I know exactly what parts I need.

Since I am buying 3400 pistons should I go ahead rebuild them while they are out with all new bearings, bolts, pins, and rings? Or is that a waste of money? Now to find all the parts I need to beef up the heads!

[bachert24]

No, stroke is the exact same. The calculator is probably filled with spec information where one source rounded up and one source did not. Both the 3.4 and 3400 use the same 981 casting crank.

The 3400 piston does come proud of the block by 0.020". It's the piston that determines this, not the block. The 3.4 piston is down in the bore a small amount, hence the positive and negatives in the calculator.

Ok so when you say "proud of the block" you are saying that it goes above the block .020" and the 3.4L is below the deck by .0095". I understand now.

No, stroke is the exact same. The calculator is probably filled with spec information where one source rounded up and one source did not. Both the 3.4 and 3400 use the same 981 casting crank.

The 3400 piston does come proud of the block by 0.020". It's the piston that determines this, not the block. The 3.4 piston is down in the bore a small amount, hence the positive and negatives in the calculator.

[bachert24]

The 3.4 gasket is 0.040", yes, the 3400 gasket however is 0.060". This is because the 3400 piston comes proud of the block by 0.020". Using too thin of a gasket can lead to the piston and head meeting each other.

Also strokes are exactly the same between the 3.4 and 3400.

Based on the info that is pre-filled into that CR Calculator the stroke is .003" shorter on the 3.4L, is this incorrect? They are listed as 3.307 and 3.310. So you don't think .0065 deck height is enough? I only ask because the stock 3.4L is listed as .0095" while the 3400 is listed as -.020. Doesn't that -.020 clearance mean it goes above the deck that far? It's odd one is listed positive, miniscule, but still positive ; while the other is listed as negative. Fill me in Raven!

The 3.4 gasket is 0.040", yes, the 3400 gasket however is 0.060". This is because the 3400 piston comes proud of the block by 0.020". Using too thin of a gasket can lead to the piston and head meeting each other.

Also strokes are exactly the same between the 3.4 and 3400.

[bachert24]

You will need 3400 head gaskets to work with the 3400 pistons.

both the 3.4L and 3400 have the same 3.75" bore in the head gasket and .040" compressed thickness to I think they are identical. The difference between the pistons is only the size of the dish and a .003 difference in stroke. Correct me if I am wrong, but I can use either head gasket? Unless the 3500 cylinder head requires the 3400 head gasket? That would make sense actually lol.

[caffeine]

You will need 3400 head gaskets to work with the 3400 pistons.

[bachert24]

The 3400 piston with 3500 heads IIRC would be about 9.2:1. With 3400 heads and 3400 pistons you should end up at stock 3400 compression which is 9.5:1

Looks like my plan will be as follows
From 3.4L : Bottom end minus pistons/rods, head gaskets
3400 : Upper Intake, throttle body, pistons/rods
3500 : Heads, lower intake

This will net me almost exactly 9:1 Static Compression Ratio, which is right where I want to be. This will allow me to add a custom Supercharger next summer.

I am going to start a new thread now that I know more info. thanks for all the help guys!

[caffeine]

The 3400 piston with 3500 heads IIRC would be about 9.2:1. With 3400 heads and 3400 pistons you should end up at stock 3400 compression which is 9.5:1

[bachert24]

Nevermind I am an idiot, it was right the first time, you enter a +for a domed piston, so If I get a 20cc dished piston I can get the compression down to 9.7. The 3500 piston is 3.7 x 3.310 with 24.5cc volume, perfect volume, but too big, the 3400 pistons however are 3.622 x 3.310 and have 28.6 cc pistons. Will the 3.307 vs 3.310 stroke matter? I would imagine not.

[bachert24]

If they are in fact dished at 8cc then I am looking at a 16 SCR. Way too high! I may have to find some domed 20cc pistons if they exist.

What did you come up with for an SCR?

Also I'm not sure how the calculator that you used works exactly, but the 3.4 piston has a dish, not a dome, and depending on how the math works, you may need to make it a negative number.

[bachert24]

Ok so I went ahead and did some research. If my calculations are correct I am coming up with a compression that is way too high! Here is what I have included in the build. Assume all parts are stock.

Bore - 3.622" (3.4L)
Stroke - 3.307" (3.4L)
Head Gasket Bore - 3.8" (used the 3500 to lower compression a tad)
Head gasket compressed thickness - .060 (again I used the 3500 to lower the compression)
Combustion chamber volume - 32.4 cc (3500, this Is well below that of the iron heads 48.5 cc and I assume the major factor in the compression difference)
Piston Dome Volume - +8 cc (3.4L)
Piston Deck Clearance - .0095" (3.4L)

I'm going to suggest that for now you don't buy anything.

Do a lot more research, and find out exactly what works, what you need and why you need that particular combination of parts.

What do you want to keep the SCR below? IIRC the 3500 heads on a 3.4 with a 3.4 headgasket was around 11:1 or so. There's a compression calculator somewhere on this site that will help determine more closely, based on actual parts that you use.

[bachert24]

How much? It is going on a 4th gen so I'll need the 3400 upper.