Butty

iTrader: (2)

I have an MY97 with nasty sounding piston slap. I've looked at having the No.4 piston changed with a bore, but wondered what else can I do for the same money (£2000).
The engine is in a Forester S/tb and all I know is that it should be a Phase 1 EJ20G with compression of 9:1.

I want to look at having a totally new short block but what do I do?
1. Can I only put on a Phase 1 open deck block? Can I use a Phase 2 EJ20G block as a straight swap?
2. Can I put on a 2.5 litre block? Does it have to be the old US NA block, needing new pistons and has to be phase 1?
3. Can I use an EJ257 block? Is there anything to alter because my block is open and the STi block is semi?
4. How do I control the compression ratio? I understand that the Forester 9:1 is the highest amongst the EJ20G blocks. Are all CRs controlled by the head gasket or have I got to watch out for piston designs for the differing blocks above?

After all this sorted, will I have to get the ECU sorted?
Presently, the car is managing OK on the std ECU on 260 hp. CO% is 8% on full boost (11 psi constant) in 4th and no retard recorded.
The turbo is a TD04L, but has more vanes on the compressor wheel. This (I have been told) is giving the low down torque:

http://dyno.scoobynet.co.uk/other/nick_butt.htm

I have followed the 2.5 litre story on projects but a bit confused in the change from starting off as a 2.5 NA block to becoming an EJ257.

Basically, what I am after is what I can do different on a piston slap job for £2000, or preferably less.

Nick
1997 Forester S/tb

Pavlo

I think the EJ257 would be perfect. Not sure if the forester gets more compression from pistons or heads, but suspect former.

Ej257 would be within your budget excluding labour, and would spool the stock turbo up without any lag AT ALL.

Paul

Butty

iTrader: (2)

Thanks Paul.

The other thing I "know" about the engine is that its the same as the WRX wagon of that age.
Both had the same CR and odd TD04L turbo hybrid to give more low down torque.
If I get an EJ257 and get a std 2.5 gasket, then do I just join my head to it and pray that the CR is near enough or do a proper CR check?
If I wish to tweak the CR, is there a range of 2.5 litre gaskets on the market or do I start having to mess around with head volumes or piston crown volumes?


Nick
1997 Forester S/tb

john banks

The other issue is the ECU. Whilst it is astonishing that my car took a swap from 2.0 to 2.33 to 2.36 to 2.5 with the same ECU map and all that was seriously off was the idle, the best results will not be achieved by using your standard ECU unfortunately.

Butty

iTrader: (2)

Thanks John,
Hmm, although I was thinking of a Unichip in case my ECU starts to get stretched, its all starting to add up on a car that's six years old and 80,000 miles.
I think I'll either do the piston swap or just use a std EJ20G block then sell it.
The pennies can go towards a 2.5 turbo Forester from AUS.

Nick
1997 Forester S/tb