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The head stud is a personal choice, the 11mm ARP studs are good and as you say should suffice up to 500bhp, but for the sake of a few hundred extra pounds I'd always take the option to upgrade them while the engine is out. It's very easy for an engine build to snowball and it can become very expensive, but for me it's one of the best pound for pound modifications you can make to these engines in terms of longevity and safety factor. I can totally understand if it's one step too far for you, just giving my own view on what could be done seeing as you have a few options open to you.
I'm guessing you don't realise how heavily specced my car is then lol.
Its been built by scoobyclinic as a 500bhp daily, so speced for 550+ to maintain reliability
Unfortunately the twin scroll engines still use the Hypereutectic pistons so are still prone to failure. the 2.5 is a fantastic engine when built properly and I firmly believe that makes the best road going engine of the lot due to the useable torque. The 2 litre engines do like to rev, and the twin scrolls are an improvement with the way they deliver boost, but still not on par with a properly built 2.5 in my opinion.
In fact the blob UK 2.0 was the last factory forged subsru engine, the bug jdm was the last jdm.
I agree with you on the 2.5 being a big improvement over the 2.0 twinscroll in terms of a road engine (ignoring the 2.5 reliability issues)
I'm guessing you don't realise how heavily specced my car is then lol.
Its been built by scoobyclinic as a 500bhp daily, so speced for 550+ to maintain reliability
I am aware mate, and a very nice spec it is too. Like I said, only my personal preference as the cost to do so is relatively low when you factor in the cost of a forged engine including removal, installation, mapping etc.
So what im seeing as the upshot from all this is..... closed deck it and get some of your money back when you sell (but you wont as its sooo good) or put in the parts that no body wants and get **** all back and always be worried about the engine and never enjoying the car ?
Does closed decking the block prevent the liners cracking?
Yes because it prevents movement of the cylinders within the block but doesnt stop the balooning of the bores as they are thin on the 2.5 as i understand it.
Yes because it prevents movement of the cylinders within the block but doesnt stop the balooning of the bores as they are thin on the 2.5 as i understand it.
Correct, the walls are extremely thin in places which brings us on to the topic of whether you should re-bore a 2.5 or buy new block halves, and down the rabbit hole we go. In essence, if you want a reliable sub 400bhp car then a semi closed deck block, pistons, ARP studs and a rebore with new ancillaries (oil pump, gaskets etc) can get you there on a budget. Adding a closed deck insert and rods will give you greater security. 14mm head studs will give you further security. New block halves would be a good move if you are looking for big power and ultimate strength from a 2.5 without going down the uprated liner route. At the end of the day, it’s as much about your spend limit as it is your hp goals.
Correct, the walls are extremely thin in places which brings us on to the topic of whether you should re-bore a 2.5 or buy new block halves, and down the rabbit hole we go. In essence, if you want a reliable sub 400bhp car then a semi closed deck block, pistons, ARP studs and a rebore with new ancillaries (oil pump, gaskets etc) can get you there on a budget. Adding a closed deck insert and rods will give you greater security. 14mm head studs will give you further security. New block halves would be a good move if you are looking for big power and ultimate strength from a 2.5 without going down the uprated liner route. At the end of the day, it’s as much about your spend limit as it is your hp goals.
will depend on how damaged they are wehn inspected, sometimes they can be too far gone even for that.
Absolutely mate, very easy for a broken ringland to chew into them and leave a case half as scrap. Or them being too far out of round.
so when people mention these darton liners, what are they meant to do? I’ve had 2 spec d’s and I love the drive of a 2.5 on normal roads because of the power delivery etc...I’d love another 2.5 down the line but only fully forged now. When I had my spec d’s I didn’t have a clue
so when people mention these darton liners, what are they meant to do? I’ve had 2 spec d’s and I love the drive of a 2.5 on normal roads because of the power delivery etc...I’d love another 2.5 down the line but only fully forged now. When I had my spec d’s I didn’t have a clue
Aftermarket cylinder sleeves give you the option to add extra meat to cylinder walls to add strength and stiffness, the trade off is that you will lose some capacity. For instance a 2.5 would be sleeved down to a 2.35, but the cylinder walls will be much thicker than the original 2.5. This is only really required for very high horsepower builds. Many people will talk about sleeves dropping but this often comes down to poor tolerances on the initial machining work.
And Martyn. And the same mechanics. It's a bit of a jump to compare them to a firm where the new owner stole parts and cars from customers.
Also Enginetuner is owned now by more than one person, so this scenario is highly unlikely.
And Martyn. And the same mechanics. It's a bit of a jump to compare them to a firm where the new owner stole parts and cars from customers.
Also Enginetuner is owned now by more than one person, so this scenario is highly unlikely.
Just be clear i never compared enginetuner to API. That was someone else. 👍
Personally I would go with what Alan offers in the way of advice and recommendations. Great guy and brilliant outfit.
Underlined this. Though have a good listen to Ben these days as Alan is taking it easier (some of the time anyway)
On any rebuild , Id be changing the oil cooler verbatim as a fair deal of unwanted fine debris can unfortunately end up in these ( an earlier post looked at the condition of the Modine's pipe too )
I once thought about keeping mine until I started to look at the magnetic rust debris that Id just washed out it and that had ended up in the washing up bowl together with the petrol.
Always ensure the sump is spotlessly clean. There is nothing like that magnetic metallic silver paste in the sump to ruin your bearings in short order.
or possibly to people who have had them built and are still going strong after being properly pushed and tested lol ,my old one is still going strong after many many years now and is still running over 500bhp,, a lot of builders won't rate them over 450bhp ,, thats the builders I wouldn't be using as what's the point in spending all that money and have a "forged engine" thats only rated the same as the standard 2ltr will take ,,, id want it rated to at least 500bhp just for the extra head room so I could make the most of that extra torque lol
I went to a forged Mahle piston and Manley Rod spec EJ207 on my 2.0 WRX exactly because I wanted some "headroom and security" and that was "only" for a 5spd max target of 350bhp ,
I'm not a great fan of the 2.5 in its original form because of its fragile nature but a properly rebuilt one using forged components and some 11mm ARP studs /ACL bearings is surely good enough for the OP's modest aims.
From another post Id agree checking the flow of the injectors before re-fitting would be a good idea, as the root cause to the original failure remains unknown, If rebuilt on a tight budget a new fuel pump could possibly wait
and Martyn can also build in some security at time of mapping, the build doesn't need to break records.
08 January 2021, 04:09 PM
Well done
