I shimmed my block but have not yet tuned. I would be comfortable running 400hp. 450hp could be pushing it without forged pistons and rods.

From the Pumaspeed site (they sell a lot of Focus ST225 parts including hybrid turbos - same engine)

Will the car need an uprated engine ?
Pumaspeeds Experience of the ST225 has led us to recommend the following additions to the internal spec of the engine:
300-330 bhp - We suggest a Block Mod Shim kit be fitted to strengthen the Deck of the Block
380-450 bhp - We suggest Forged Pistons and Rods be used as the OE items are just not upto the job

Excerpt from Focus ST225 X48 425bhp 7 Blade Hybrid Turbocharger - Focus ST225 / XR5 Turbo - Uprated Turbochargers - Pumaspeed Milltek Ford Performance Tuning Milltek Sport Exhaust Ford Fiesta Focus ST RS Parts Specialist

 

thanks man i really appreciate your response. i figured that i atleast wouldn’t have to sleeve my block, as that would be an expensive route. also how was it shimming your block? i dont have any experience with engine work so i’m not sure how capable i’d be doing it myself.

 

It's the same amount of work as doing a head gasket replacement. Invovled, but also not so difficult that it can't be done if you haven't done anythign like that before. Installing the shims is the easiest part - just tap them in between each cylinder. Some people recommend measuring the gap and ordering the correct size shims. Others suggest buying all 4 the same size to match the factory spacing and smashing it in if required. I went the former route.

If you do some searches for S40/V50 T5 cylinder head removal/replacement or head gasket replacement, you should find some great resources and videos.

 

Some people recommend measuring the gap and ordering the correct size shims. Others suggest buying all 4 the same size to match the factory spacing and smashing it in if required. I went the former route.

I went the latter router. Just did the block mod whilst i was at it anyways. Was replacing my headgasket and ordered the shims. They're installed now because why not. I don't think i'll ever tune mine, but who knows. At best i'll go with software, I don't want to install other hardware for more performance, so i don't know what would be possible anyway.

 

Is it good to shim even if power goals are just below 300hp? Or not a necessary?

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Is it good to shim even if power goals are just below 300hp? Or not a necessary?

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this probably will help to save the block if the engine overheats badly and or detonation. the cylinder wall is practically held by nothing in that area.

IMHO, shimming the block is very important to strengthen it in that very weak spot.

At some point in the future, I'll have to do this on mine.

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Some ST225 owners report cracked cylinder walls even on the stock tune, and many suggest it at or around 300hp. Less common on Volvos for whatever reason (gentler drivers?). I shimmed my block because I had to take the head off for machining anyways (snapped exhaust stud extraction).

 

I read the same but in the P2R forum.

Volvo pushed it too far with 83mm bore. 81mm was basically bullet proof.

Regarding the ST225 cases. I did some comparison between engines a while ago, and found something that caught my interest: ST225' and RS's have smaller coolant system capacities. IIRC it was a difference of 1~2 liters and I wondered if they had a smaller radiator.

If they do, then that's not good for vehicles that are more likely to be driven harder than the average Volvo driver does.

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Now I’m wondering about of what material the shims should be. Because I’ve seen them online, either stainless steel or aluminum (T6061?).

I think aluminum should be best since it should have a more similar thermal expansion ratio compared to the block than stainless.

What are your thoughts about that?


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My shims are 301 stainless from DeeWorks (Volvo WhiteBlock 5 & 6 Cylinder Liner Shim Kit - DeeWorks). I haven't had any issues, but have only run them for about 8000 miles.

I am not a metalurgist, and have no practical knowledge about this, but aluminum is likely preferred for thermal expansion reasons, though that thickness of material probably doesn't expand all that much anyways and the cylinder walls can expand in other directions if the fit gets tighter under high temperatures.

 

did you have to pull your engine in order to shim it?

 

No - the job was done with the engine in place.

 

*without the cylinder head.

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Material type is probably negligible difference since you already have two materials with significantly different thermal characteristics. I would recommend only using a .035 shim as the slit is cut with a .035 slitting saw. Anything thinner will likely wind up doing nothing. I see no reason to go into the radius of the slit since the cracks are never lower than 1/2" below deck.

 

Material type is probably negligible difference since you already have two materials with significantly different thermal characteristics. I would recommend only using a .035 shim as the slit is cut with a .035 slitting saw. Anything thinner will likely wind up doing nothing. I see no reason to go into the radius of the slit since the cracks are never lower than 1/2" below deck.

When I shimmed my older S40, I went into the radius as much as I could because, at that time, I thought it would create a hot spot if coolant became trapped in there. I spent a good time measuring to get the correct circumference of the slit while leaving the shim 1 mm below the deck.

Also, after I finished shimming the block. I read in a forum (can't remember which one) that somebody just filled the slit with high strength epoxy. Not sure if that will last as long as a metallic shim.

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My intuition says epoxy is "spongier" than steel/aluminum, but who knows. Also, not sure how well it would play with coolant. I'm sure it's better than nothing.

The DeeWorks shims have a V shape at the bottom so they fit into the radius, but don't trap coolant.

 

Yep, imagine beating the car thinking "don't worry, it shimmed" without knowing the epoxy has disintegrated and all that trash running in the coolant system.

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I read on another thread that the 2008+ T5 blocks have smaller coolant passages between cylinders vs the previous years. Can anyone confirm this?