Short Block's

Hey all. So my poor baby's engine spun a bearing a few weeks back. My heads are 100% ok (besides needing cleaned). Im have decided on buying a new short block. I don't really have a question about it other then I need some tips on what else I should replace while I'm at it. And for the stock short blocks, what is the max psi I should run, crank hp, and whp?? It's on a 06 STi.

When you get your stock short block change the bearings from stock to a better bearing designed to handle more such as ACL, Clevite, etc. Max Psi depends on the tune and the capability of the fuel system.

^ personally I would look for a used shortbock or try and repair yours. the new castings are garbage compared to the casting in your vehicle.

The stock block can safely handle up to 22PSI of continuous boost and no more than 400WHP. Any more than that and you are buying time. What it can not handle is prolonged operation at high rpm.

As for the other suggestions I both agree and disagree. I would only tear apart a stock block to replace bearings and/or other internals if I plan on using the car for any kind of HPDE event. Other than that the stock block is quite robust for street level performance provided you have a proper tune.

The reason Zach suggests you replace your bearings is because our engines are notorious not only for ring landings but also oil starvation. The only thing I would add to his statement is to purchase a bearing with extra oil clearance. The stock clearances are to tight for any kind of HPDE event and they are more designed for use with thinner oils and emissions reasons more than anything. The extra oil clearances allow a thicker oil and it allows better flow through the bearing for lubrication and removal of heat. Also by being able to use a thicker oil you have improved compressibility. That means less shock to the bearing.

Lenny's suggestion is valid also because since you are in there replacing bearings you might as well drop in some pistons at the very least. In any case this is good practice because not only will you have fixed the two main weaknesses in the motor but you also match the oil clearances of the piston with the bearings and now the thicker oil you are using is compatible with all the components in the motor.

There is a lot of information you need to know going into an engine build which is why the first question always asked is "what are your goals". This is what defines the build and matching components is the big key. For instance the rods and bearings are what really define the power capacity of the engine. The pistons and heads are what really define how much boost you can run. The clearances and machining define your reliability. Top that off with the right tune and your golden.

Regardless of all that if you plan on staying on the street, then the stock unmodified block will suite you well up to 400whp and 22psi. But please get a protune from a reputable shop.

Another weekness is the stock oil pickup tube... But don't be suckered into buying a covert or a killerbee pickup. Nothing flow better than the stock unit. Ask your machinist to strengthen your stock unit by brazing a collar around the pipe where it meets the flange.

If you decided to go for a new block I may be very interested in purchasing your used block.

Thanks for the tips. Im definitely getting the new block and I'm just keeping it stock not splitting it open. I don't plan to do any serious racing or trying to get any serious hp so I don't feel the need to. She's my dd so im just trying to get her back on the road. I am selling my old block too! So let me know if your interested!

I am selling my old block too! So let me know if your interested!

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Interested...lol..PM with what you are asking for it.