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Contemplating a new project - Building an Engine
Contemplating a new project - Building an Engine
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Old 09-11-19, 11:16 AM   #21
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Default Re: Contemplating a new project - Building an Engine

There is still machining required even with an OEM block

you should still get it honed, and pistons fitted correctly. You can do manley drop ins but they are still pretty noisy.

line boring should be done on any block. regardless of new/used.
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Old 09-12-19, 03:21 AM   #22
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Default Re: Contemplating a new project - Building an Engine

Why would Subaru not fit the pistons correctly or line bore it when they assemble it?

By noise are you referring to piston slap? If so, how is that eliminated?
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Old 09-12-19, 07:41 AM   #23
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Default Re: Contemplating a new project - Building an Engine

because Subaru mass produces these cars on a factory scale. not every bearing is measured and fit to exact tolerance. Some builders have stated they've seen Factory OEM case halves that have never been ran have out of round main journals.

likely you will want to increase clearance over factory since the FSM for my 2012 states:

Rod clearance: .00007 to .0018
Main clearance: .00039 to .0012

These are tight for an engine that is going to be abused.

It depends on how the engine will be used on how you decide the clearances, but a "general" spec is .002 on rods and .0015 on mains.

Piston slap is due to increased piston-to-wall clearance. Subaru specs this at:
-0.00039 to .00039

If you just drop in forged pistons, you're PTW clearance will likely be .0025 to .0045 or worse. it will slap bad on cold start(ask me how i Know. my PTW clearance is .0025) and "can" eventually oval the bores causing oil consumption.

to remedy this, you get your pistons sized with the bores. by taking it out to 99.55mm or 99.75mm.
Stock cylinder diameter is:

A bore: 99.505 to 99.515
B bore: 99.495 to 99.505
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Old 09-12-19, 07:59 AM   #24
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Default Re: Contemplating a new project - Building an Engine

all why I suggested just buying an IAG short block - this is all done properly . . . but i'll be the first person to admit that buying isn't the same as the building experience . . . but perhaps building doesn't count unless you do the machining yourself . . . the point of that comment is to say evaluate and and understand what your limitations are and make a wise choice for yourself.
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Old 09-12-19, 08:14 AM   #25
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Default Re: Contemplating a new project - Building an Engine

Quote:
Originally Posted by mheyman View Post
all why I suggested just buying an IAG short block - this is all done properly . . . but i'll be the first person to admit that buying isn't the same as the building experience . . . but perhaps building doesn't count unless you do the machining yourself . . . the point of that comment is to say evaluate and and understand what your limitations are and make a wise choice for yourself.
you hope its done properly

The old adage is "if you want something done right, you have to do it yourself"
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Old 09-12-19, 08:45 AM   #26
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Default Re: Contemplating a new project - Building an Engine

I don't have the equipment to line bore the block.

So, the OEM Subaru short block from IAG is approx. $400 more than directly from subaru. With the cost of machining would it be more worth while to purchase the IAG OEM Block?

Does IAG do any machining to these OEM blocks? I don't see anything eludes to that on their website.

Last edited by Soltis187; 09-12-19 at 08:50 AM.
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Old 09-12-19, 09:33 AM   #27
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Default Re: Contemplating a new project - Building an Engine

no. From the definition those are just OEM blocks from Subaru.

A good starting point is just case halves. line boring isn't super expensive. my local shop charges 165 to line bore a block with 5 mains.
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Old 09-12-19, 11:35 AM   #28
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Default Re: Contemplating a new project - Building an Engine

Quote:
Originally Posted by Soltis187 View Post
So, the OEM Subaru short block from IAG is approx. $400 more than directly from subaru. With the cost of machining would it be more worth while to purchase the IAG OEM Block?

Does IAG do any machining to these OEM blocks? I don't see anything eludes to that on their website.

Where does IAG offer any stock short block - you can provide a link? Lowest I see is Stage 1 for $3K. The description is not as specific as I'd like but does include this statement:

"*All IAG short blocks are balanced and blueprinted."

Despite what has been related here, I didn't think they line bored new blocks because they felt they were good. One reason I didn't respond earlier. They definitely line bore used blocks and use new cranks when they rebuild one. Anyway you can ask em.

We have seen OEM for a good bit under $2K+shipping not that long ago . . . figure a $1k difference between stock and bottom end IAG. Only issue I have w IAG is that all their lower end blocks use 2618 pistons. I am out of date, but the really didn't want to let me use 4032. Now they offer something - at $5K? (Nope, it's gone again) That said my engines is strong after 40Kmi - and we have User as a benchmark . . .

Not sure what the OP was using for pricing.
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Last edited by mheyman; 09-12-19 at 03:22 PM.
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Old 09-12-19, 11:55 AM   #29
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Default Re: Contemplating a new project - Building an Engine

Buy a subscription to either alldatadiy.com for a subaru manual or get a subscription to STIS. Both of these sites have a ton of factory spec assembly info
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