refresh951

I have been closely following Sid's (Blown944) build thread and I absolutely love his concept. I love the idea of developing reliable, large displacement motors at a reasonable cost. Therefore, I decided a while back to start collecting parts and doing the research to make an attempt at my own 2.9L build. Sid has graciously given me a great deal of advice and I appreciate his assistance. I am close to assembling the motor as I am only waiting on the crank. This motor will be used mostly for street use with occasional track days. I have had a couple people tell me I am crazy to try this. I enjoy a good challenge and if I fail (and I do not plan to fail) it is my time and my money. Either way it will be a great learning experience for me. I have had an absolute blast so far working on this. I have some very high goals for the build:

- 400 rwhp/400 ftlbs torque at 6200rpm
- Near k26/6 bottom end performance
- Total cost under $4200 for everything, including my "High Flow" head

- Using 86 Block, dry sleeved, bored to just over 102mm, windage ports added, half filled
- JE Small Block Chevy Pistons, Forged 4032
- Eagle 150mm Mitsubishi Rods
- 86 2.5L crank, offset grind, 86mm stroke, cross drilled
- Compression Ratio is 8.1:1
- ARP Head Studs
- Cometic Head Gasket
- ACL Race Rod Bearings
- Crank Scrapper
- Stock Cam (still researching options)
- MoCal 13 Row Oil Cooler, 235 mm

My current 2.5L motor is running great but after the Concours this weekend I will be pulling it out of my car to install the new motor. I will be re-using a lot of stuff from the 2.5L to keep costs down (turbo, M Tune, water pump, cam tower, ect.).

V2Rocket

Awesome - I too am dreaming of this, but the $$$ just isn't there yet.

That said, how much material did you have to bore out to fit the 102mm sleeve? I measured the other day and the cylinder walls are between 8 and 9mm thick (seems to vary a bit depending where on each cylinder you measure, but I guess if the hole center is right then it's OK).

The intertube says the (dry) LS1 cylinder liners are only about 1.5mm thick. A 102mm bore with that thickness means 105mm hole in the aluminum. That still leaves ~5.5mm (~0.22") aluminum wall...how big can we go and stay with a dry liner?

blown 944

Right on!!!

Remember, you may need to fly cut the pistons slightly for a fully non-interference fit.

I'm looking forward yo seeming it get done and your comparison dynos as well.

I'm sure you'll love it.

User 52121

This is awesome... though I gotta say, I was a fan of your stock-ish setup! Your existing 2.5L (w/T04) is pretty much what I want to do with mine....

Good luck - will watch this closely!

86 951 Driver

Why not 9:1 compression? I would think this would really help with low end performance. Very cool to see yet another stroker motor. I need to learn how to build motors. 2 Strokes are not a huge problem 4 strokes with these valves just trip me up. Hehe

Good Luck!

refresh951

Thanks Sid! I REALLY appreciate your help on this.

I should be "claying" the valve clearance this weekend then I will know exactly what I have.

refresh951

It is a great setup but....wait until you see what this can do!

refresh951

I am using off the shelf pistons to keep cost down. This limits the options wrt CR. But with custom pistons as Sid is planning...

black944 turbo

Awesome Shawn. Your car was already pretty incredible, nice to see more people trying this. If my motor ends up having issues, I think I will attempt this as well.

Rogue_Ant

Awesome Shawn!
Any pics of the windage ports?

Regarding compression, the stroker motor will have so much more bottom-end grunt, keeping CR around 8.0 isn't an issue - it will help keep peak cylinder pressure down and be less likely to knock.

Rogue_Ant

Notice I said "peak cylinder pressure".
What kills these engines is the peak.
Extending cylinder pressure duration, but at a lower peak will also accomplish the same end-goal (more power/tq).

Regardless, I just had one of my own threads dragged way off due to an irrelevant contention, lets not do this to Shawn's thread.

User 52121

Knock schmock he's running E85 already...

I wish that stuff was readily available here!

Scott H

Could this theoretically be done with a 3 liter crankshaft in conjunction with MID sleeves to make some stupid 3.2L+ setup?

David Floyd

106mm has worked for me for the last 10 years

Very cool project

CyCloNe!

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