Guest Report post Posted November 4, 2014 I'm off sick today with ManFlu, so have spent hours browsing the 'net. I've been reading about decking the blocks of Subaru engines to increase rigidity and extend their boosted life. Has anyone in the UK gone to this trouble on our engines yet? Is it deemed unnecessary? If required, where would one get it done? I have read some horrific facts if it's not done right first time!! Share this post Link to post Share on other sites
Twigman 93 Report post Posted November 4, 2014 This may seem an ignorant queation but are they not machined to fine tolerances to start with? Share this post Link to post Share on other sites
Guest Report post Posted November 4, 2014 I may be using the wrong terminology here Ian, as I have always considered "Decking" a block, machining the block true to the crank centreline and to the correct height for the pistons being used. In this instance I am discussing the process where the machinist removes most of the aluminium bore to insert a sleeve which gives the bore radial support, rather than having it sticking up in fresh air as stock. Here's some info. Apparently, in high power applications the tops of the cylinders can vibrate, rubbing away the seal at the gasket? Doesn't sound too good to me!!http://www.iwsti.com/forums/built-motor-discussion/148184-subaru-2-5l-engine-motor-building-101-a.html Share this post Link to post Share on other sites
hashiriya 52 Report post Posted November 5, 2014 The water jackets on the FA20 are huge and is about as open deck as you can get. You certainly don't want to be looking at taking any material off the stock sleeve if you are going to run higher power. I believe a couple of places have re-sleeved these engines for high power use. The HKS stroker kit uses stock 86mm bore and just a longer stroke to increase displacement for this very reason and have seen 500-600hp from the engine so I'm guessing the stock sleeves aren't too bad as long as you don't reduce it's thickness. There is a process (I forget the name) where you knock dowels into the water jacket to help support the sleeves, I don't think it's practiced much anymore though. Share this post Link to post Share on other sites
Guest Report post Posted November 5, 2014 Thank you for your great reply Hashiriya. I have seen the knocked in dowel scenario, and to be honest, thought it a bit of a bodge!! I assume you've seen what is done for this mod? The top of the cast bore is completely machined away and a one piece steel liner is inserted, with a "Top hat" which sits in a machined recess in the deck. Share this post Link to post Share on other sites
hashiriya 52 Report post Posted November 5, 2014 I agree that the dowel solution is not the best of ways to do things. the stock engine block itself is proving to be quite a bit stronger than anyone expected. A good set of rods and pistons is looking likely to be strong enough for most peoples unless you are after an extreme (and by that i mean 600+hp) amount of power. I keep toying with the idea of building my engine up and releasing the rest of the power from my supercharger... maybe about this time next year... 2 Special K and chillismoke reacted to this Share this post Link to post Share on other sites
tegunulgener 84 Report post Posted November 5, 2014 I agree that the dowel solution is not the best of ways to do things. the stock engine block itself is proving to be quite a bit stronger than anyone expected. A good set of rods and pistons is looking likely to be strong enough for most peoples unless you are after an extreme (and by that i mean 600+hp) amount of power. I keep toying with the idea of building my engine up and releasing the rest of the power from my supercharger... maybe about this time next year... and how much are you planning to spend on this? I am asking more like to see how much roughly I have to spare for more... Share this post Link to post Share on other sites
Kodename47 446 Report post Posted November 5, 2014 and how much are you planning to spend on this? I am asking more like to see how much roughly I have to spare for more...Pistons: http://www.fensport.co.uk/Parts/Model_108/Category_12/4672Rods: http://www.titanmotorsports.com/pauter-rods-scion-frs-subaru-brz-fa20-.html (Pauter or Carrillo, Pauter is cheaper and probably suitable for your needs) Decent engine builder labour (I'd recommend Abbey) will be a fair few hours too.As a quick guide, here's what a company in the states will charge to do it:http://www.frsmod.com/products/fa20-built-motor-package-for-frs-brz 1 chillismoke reacted to this Share this post Link to post Share on other sites
hashiriya 52 Report post Posted November 5, 2014 HKS Stroker kit of crank rod and pistons retails at £2700+VAT (£3240 in the UK). It has stock 86mm bore and stroke is increased to 90mm. It's a bit more money than the examples knightryder gives but then you aren't getting the crank etc with that. Share this post Link to post Share on other sites
Guest Report post Posted November 5, 2014 I haven't looked into cost for any of this, I just decide what I need and go for it. If the cost is, in my mind, prohibitive, I look at other ways around the problem. If cost per BHP were the ultimate goal, I would throw a V8 in it. One way anyone could go about this is keep the engine stock, then, when it blows up, think again?? I will probably go the forged pistons/rods route and Turbo charge it? It's interesting to read this engine is holding out at 500bhp with no block mods? Is this also with a stock crank? Share this post Link to post Share on other sites
Special K 442 Report post Posted November 5, 2014 I think 500bhp with the stock crank / block is realistic. It is a very, very strong base unit. LFA (Ed) has a low compression engine built by Mark at Abbey fitted in his BRZ. Dunno if he's tracked it yet (he's a Nurburgring addict..) but it would be good to hear his experiences, although I don't know what his power output is.. Spec K 1 chillismoke reacted to this Share this post Link to post Share on other sites
