SCAT forged rods

[rav]

Any of you guys use these? Eagle was the only one I was aware of that made one.
http://www.offroadxtreme.com/features/s ... t-engines/

[Cheromaniac]

Scat Crankshafts is reaching out to the many hardcore Jeep enthusiasts who have yet to accept the new V6 engine in the Wrangler, preferring to stay with the venerable inline-6. The company’s new rotating assembly kit offers 3.905-inch-bore pistons, 6.125-inch 4340 Pro Comp I-beam connecting rods and a 3.895-inch-stroke Pro Comp crankshaft.

“It comes as a fully balanced rotating assembly with bearings,” says Scat owner Tom Lieb.

With 60cc combustion chambers, pistons can be ordered for either a 10.7:1 or 9.6:1 compression ratio. Applications include 1987-2002 Jeep 4.0-liter I6 engines, resulting in a final displacement of 4.6-liter.

Looks like Scat have come up with a stroker kit tht uses the 258 crank, 4.0L rods, and Keith Black ICON forged pistons (IC944 for a 9.6 CR and IC945 for a 10.7 CR).
The Eagle rods were slightly longer at 6.150" and were forged, whereas those Pro Comp I-beam rods are probably exact copies of the stock cast 4.0L versions.

[rav]

Thanks Dino. Eagles are not available any more right? I am getting back to piecing a stroker for my 99 two door. I am not sure if you remember but almost 10 years ago I had outbid you on some 4.2 rods time flies...

[Cheromaniac]

Yeah I remember but I didn't take long to find another set of rods. I can't believe it's already 10 years since I started my stroker project.

[rav]

I know you did. I so regret selling that 88 but had to at that time. I just scored these on ebay:
http://www.ebay.com/itm/301095247230?ss ... 1497.l2649
I think I got a good deal

[Cheromaniac]

I think I got a good deal

You can say that again! That was a steal.

[rav]

So this stroker is going to most likely have an M90 supercharger too (may have to go with an M62 if the m90 kit does not come through). I am looking to build a low compression (I know most of you guys want the other way) engine so that i can run a higher boost. Since this is going to be supercharged I am looking to get the forged pistons and rods (might have to sell the 4.2 rods/pistons that came with the crank). So going by your recipe Dino:

Jeep 4.2L 3.895" stroke crank
SCAT Jeep 4.0L forged rods
Keith Black UEM-IC944-030 forged pistons
Increase piston dish volume to 30cc
8.75:1 CR
CompCams 68-115-4 192/200 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.035"
Mopar/Victor 0.043" head gasket
0.058" quench height
Ford 24lb/hr injectors for '87-'95 engines, Accel 24lb/hr injectors for '96-'04 engines, '98 Chevy LS1 25.2lb/hr injectors for '05-'06 engines
240hp @ 4700rpm, 315lbft @ 3000rpm
I am currently reading Chris aka Talyn's build and he had issues with his Comp cams and you had issues with Crane. Would Isky be a better choice? I am still reading and learning again. I seem to have forgotten most of the things I had learned 10 years ago. Thought and suggestions are welcome.

[rav]

Never mind just spent almost 3 h reading SilverXJ's 4.6 build and my head is spinning. I am questioning if I even want to stroke it as i neither have his skill set or the patience. What i do have access to is a very good engine rebuilding shop 7 miles from my house:
http://www.huntsmachine.com/index1.htm
They build a lot of race engines and strokers but have not worked on a jeep though
So Dino can you give a good recipie for a stroker with low compression that can accept a supercharger with about 8-10 pounds of boost?

[Cheromaniac]

If you're going to supercharge the engine anyway, why not keep the stock cam and just build a copy of the modified poor man's stroker recipe?

4.6L "poor man's" stroker

SCAT Jeep 4.2L 3.895" stroke crank
SCAT Jeep 4.0L 6.125" rods
SCAT Keith Black UEM-IC944-020 forged pistons
9.25:1 CR
Stock 4.0 camshaft
Ported HO 1.91"/1.50" cylinder head
Mopar/Victor 0.043" head gasket
0.070" quench height

You could lower the CR further by increasing the combustion chamber size (the above recipe assumes a 57cc chamber).

[RenoF250]

I think I got a good deal

You can say that again! That was a steal.

You guys are making me really happy with my CL purchase yesterday - 1974 258 crank and rods $75 and the guy met me on the way to where I was going.

Crank does need to be machined though. It will save me from having the engine out of my CJ while I do the build.

[rav]

good for you!!You got the heavy crank too.

[jsawduste]

Talked with Scat, they are using the 6.125 4.0 length rod and KB Icon (944/5) pistons. Nominal dimension at TDC is .025 below the deck. Add in a .043 gasket and you end up with quench of darn near .070.

They did say that if you wanted custom pistons they had several sources.

Sorry but not my cup of tea for building a good running stroker.

[rav]

Sorry but not my cup of tea for building a good running stroker.

Could you elaborate? I am planning to build the motor to work with a ford M90 supercharger and want to build a low compression engine with forged internals. I am trying to learn as much as I can before taking the plunge and throwing $$$.

[jsawduste]

The quench with the Scat set up is too high.

You want to keep the quench at around mid .040`s and adjust compression with the piston dome or dish.

[Cheromaniac]

The quench with the Scat set up is too high.

You want to keep the quench at around mid .040`s and adjust compression with the piston dome or dish.

Agree that the quench should ideally be lower. In that case he could have 0.020" shaved from the block to reduce the quench to 0.050" and recover the loss of 4cc compression volume by smoothening/polishing the combustion chambers/piston dishes.