Just another sb2.2 build

[millionville]

I wanted to start my own thread specific to my own motor. Various people often have various different specs. So I decided to make one personal so I can get specific help when I need it, and not interfere on someone else's post.

To start my thread I have a pretty simple question, I will be buying rods and pistons soon and it is the next step in assembling my short block. Should I go with 6.00 rods or 6.200 rods. What is the pros and cons? Advantages and disadvantages?

3.25 stroke, 9.025 deck height, 4.181 bore. If you need more specs let me know I will provide what I can

[user-612937456]

Just curious Why such a short stroke?

[levisnteeshirt]

I would keep the pin down some on the pistons , the intake valve relief can get really close to the top ring ,, 3.625 stroke with a 5.85 rod works nice

[millionville]

From the little research I have done on the nascar stuff, short stroke equals high rpm's. The sb2.2 head loves the higher revs, the shorter strokes doesn't wear the motor as much.

Same concept as my sport bike really. A lot of Japanese motorcycles run a super short stroke/big bore ratio. These bikes loves to run at higher rpm's for extended amount of time, tend to last a load of miles as well.

As for response #2. I already have a 3.25 stroke crank, my goal is to make a 357 ci n/a motor. Nascar replica. I will be buying a takeout set of Carrillo rods from Ebay and sending them in for reconditioning. Carrillo recommended this to me, but now I'm stuck between 6.000 and 6.200.

A friend of mine told me something about rod angles....? Longer rods make a tad more power? I definitely agree with having a bigger ch piston though, to keep heat away from pins. However, I also thought about piston mass and rotational weight.

I wish there was a clear cut winner here, decisions like these seem like a coin flip really. Keep the posts coming, I'm anxious to learn more.

[Warp Speed]

6.200 with an .827 pin is your best bet.
CP for pistons. They have a nice box style forging set up for piston guided.

[Warp Speed]

http://www.ebay.com/itm/NASCAR-PANKL-6- ... 91&vxp=mtr

[millionville]

Thanks for that Warpspeed! Would you recommend pankl over carrillo?

[hoffman900]

Thanks for that Warpspeed! Would you recommend pankl over carrillo?

They're the same company. Same with CP Pistons- C(alvert)P(ankl) Pistons

[CamKing]

The sb2.2 head loves the higher revs.

Not true. The SB2 heads love the CFM demands of the 358ci at high RPM's, not the RPM's.

The heads will be just as happy on a 426ci (4.181"x 3.875") at 7,550rpm,
as the would be on a 357ci(4.181" x 3.25") at 9,000rpm.

Unless you're limited to 358ci, you would be much better off, going with a larger stroke.

[jmarkaudio]

They are happy on a 461 CI as well...

[CamKing]

They are happy on a 461 CI as well...

and the valvetrain will last much longer.

[millionville]

Would a taller stroke hold up to the high rpms as well?

[millionville]

Obviously a bigger cylinder volume requires more cfm. However, does the bigger volume require more cfm at the higher revs? For instance a 358 ci flows around 400cfm @9500rpm; (I dont know what a 426 ci would flow) lets just say about 400cfm @7000rpm would the said 426 ci flow 480cfm @9000rpm?

[Fordracer347]

Nobody has asked about what use you are building this engine for. If you are building anything class limited then its important to focus on rules first. Since you haven't said anything about that, I'm guessing its either open drag racing or it's a hot street setup.

Drag Racing: It should be fine either way but you'll make more power with a bigger engine i.e. car will be faster.

Hot Street: You'll be very pleased to have more lower end torque out of the bigger engine instead of having to always rev the engine up to really feel it pull hard.

In all honesty, If I were building another SB2.2 there is no way I'd build the 358 instead of a bigger version unless I already had the parts lying around. Either version will rev just fine but if you can get the engine to work with lower RPM then you won't have nearly as much maintenance cost in valvetrain and it will be easier on the engine.

Now to your question, The 6.2 rod would be a better choice in my opinion. The CH will be workable with a good valve relief but still will be able to work without a ring support.

[wyrmrider]

No one has improved upon the GOSPEL according to Stroker McGurk
btw short stroke may not save any lower end parts and forces tend to be square of the rpm
and
for sure, as CamKing and others have said, valve train maintenance and $$$ and maintenance schedule will be far higher at 9,000