stroker 4.6 compression question

[Cheromaniac]

after shaving off .5000 from the block he said I would be at 9.8 to one and he said I should reach 400 foot pounds of torque. Russ said 350.

They cut a half inch off of the deck? So it's an open deck block now? Do you mean .005"? Also, 24# injectors will not support 350-400 ft# of torque. There isn't a stock fuel pump that can support that either.

With a ported 0331 head, 231 cam (incidentally that's a good N/A cam), and a port matched stock intake manifold, I'd say 265hp & 325lbft is as much as he's likely to get. The 24lb injectors will probably be OK at that power level as they'll actually flow 25.5lb/he at 49psi.

[Randy Bobandi]

after shaving off .5000 from the block he said I would be at 9.8 to one and he said I should reach 400 foot pounds of torque. Russ said 350.

They cut a half inch off of the deck? So it's an open deck block now? Do you mean .005"? Also, 24# injectors will not support 350-400 ft# of torque. There isn't a stock fuel pump that can support that either.

With a ported 0331 head, 231 cam (incidentally that's a good N/A cam), and a port matched stock intake manifold, I'd say 265hp & 325lbft is as much as he's likely to get. The 24lb injectors will probably be OK at that power level as they'll actually flow 25.5lb/he at 49psi.

What makes the 231 cam good for naturally aspirated Jeep engine's? What makes any cam with negative valve overlap good for any NA engine? That cam has very little duration at .050" as well.

[len1xj]

I have 1 to 7 roller rockers. I trust russ to all the porting, polishing and valve work that he is known for. I also got his custom pistons. it will be interesting to see what becomes of this monster. I have a tuner lined up here that I will be going to and if I need bigger injectors I will get them and or fuel pump. you all have gave me a lot to think about. when I do get it running and dyno tuned I will post the numbers here, the injectors and fuel pump if i need them.

[Randy Bobandi]

I have 1 to 7 roller rockers. I trust russ to all the porting, polishing and valve work that he is known for. I also got his custom pistons. it will be interesting to see what becomes of this monster. I have a tuner lined up here that I will be going to and if I need bigger injectors I will get them and or fuel pump. you all have gave me a lot to think about. when I do get it running and dyno tuned I will post the numbers here, the injectors and fuel pump if i need them.

1.7 ratio rockers are the way to go with that camshaft and you might actually be able to reach your 350 ft# goal at the crank. You should probably get the specs on the valve springs to know how much room you have to grow if this setup doesn't quite get there. You might want to verify what fuel pump you have. If you have a 190 LPH pump, you might be fine.

231 Cam with 1.7:1 Rocker Arms

23117cam.JPG

[Cheromaniac]

What makes the 231 cam good for naturally aspirated Jeep engine's? What makes any cam with negative valve overlap good for any NA engine? That cam has very little duration at .050" as well.

The 231 cam has a valve overlap of 32 degrees (advertised) with duration specs of 250/258 (advertised) and 206/214 @ 0.050". I don't know how you can call that "very little". Lift specs are 0.462"/0.485" with 1.6 ratio rockers. The 1.7s would increase lift to 0.491"/0.515" and certainly gain a little more power by exploiting the higher lift airflow offered by the ported head.
If you want a nice even spread of torque from 750-5250rpm, this cam does very nicely. The more popular 232 cam is a bit more low rpm biased but gives up a bit of power higher up. This spreadsheet shows how all the available aftermarket cams compare to stock.

https://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm

[Randy Bobandi]

What makes the 231 cam good for naturally aspirated Jeep engine's? What makes any cam with negative valve overlap good for any NA engine? That cam has very little duration at .050" as well.

The 231 cam has a valve overlap of 32 degrees (advertised) with duration specs of 250/258 (advertised) and 206/214 @ 0.050". I don't know how you can call that "very little". Lift specs are 0.462"/0.485" with 1.6 ratio rockers. The 1.7s would increase lift to 0.491"/0.515" and certainly gain a little more power by exploiting the higher lift airflow offered by the ported head.
If you want a nice even spread of torque from 750-5250rpm, this cam does very nicely. The more popular 232 cam is a bit more low rpm biased but gives up a bit of power higher up. This spreadsheet shows how all the available aftermarket cams compare to stock.

https://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm

You're referencing "advertised" specs which we can not use. We don't know at what position, in crank angle, Comp is using to make these "advertised" claims. I've already provided a visual for the 231 cam in previous posts. As you can see, at .050" tappet lift, there is 12 degrees between the exhaust closing and the intake opening. If we look at what happens under .050" tappet lift, we see a total of 14 degrees of overlap. With 1.7 ratio rocker arms, we can expect 2 more degrees of duration on both valves. Overlap at .050" would still be negative but would improve under .050" to 16 degrees. How much scavenging would you expect under .050" for an NA motor? Not much if any right? Why do we use .050" tappet lift as an excellent reference as to what is actually happening in valve events? We lose valve lift and duration in our lifters, hydraulic or solid. We also have shrouding in our combustion chambers under .300" valve lift.

[Russ Pottenger]

I’d suggest going back over your numbers and make sure that they’re inputted correctly.

I don’t have your build sheet in front of me but my fully Ported Including combustion chambers 0331 TUPY or Promaxx is typically 65-67cc.

Don’t hesitate to reach back out to me if you have any further questions or need clarification on the numbers.

Thanks,
Russ

[Brianj5600]

231 cam

Your IVC is off by 20 degrees or more.

[Brianj5600]

With a ported 0331 head, 231 cam (incidentally that's a good N/A cam), and a port matched stock intake manifold, I'd say 265hp & 325lbft is as much as he's likely to get. The 24lb injectors will probably be OK at that power level as they'll actually flow 25.5lb/he at 49psi.

Are your numbers based on the stock ECU?

[Cheromaniac]

With a ported 0331 head, 231 cam (incidentally that's a good N/A cam), and a port matched stock intake manifold, I'd say 265hp & 325lbft is as much as he's likely to get. The 24lb injectors will probably be OK at that power level as they'll actually flow 25.5lb/he at 49psi.

Are your numbers based on the stock ECU?

This is with fuel and timing optimized.

[len1xj]

well it has been a while but I have this jeep on the road. Holy mother of God. this is way more then I expected. from a dead stop on the street or dirt ( new tires) when I punch it, it will set you back in your set, hard. a friend of mine wanted a ride, and I wanted to show off, so as he set down I punched it. he went back so hard in the seat he broke it.
I fixed it all ready but i had a small on my face I couldn't get read off.
I am going to get a custom tune July 20. I cant wait to see what this motor can do after the tune.
I will keep you informed of what happens.
Rus I thank you for putting up with me and showing me the way to a good, no, a more then good motor. I am so stoked.
also I would like to Thank you all for your input.