Hardblock / Cement / filler on Miata block?
 

Does anyone have any info or experience with hard block? In talking with a local machinist he recommended it given my goal of 350 rwhp on e85 with an efr.

I'm planning a .005 bigger bore on an 03 block. Pistons, rods, bearings, porting, upgraded oil pump etc..

Based on the webpage it seems simple. Clean, mix, fill up slightly, vibrate out bubbles and let it set.

Do you Gents have an opinion on it? I searched Google but didn't find anything besides hrk commenting he did it. I called the same engine builder so I'm not shocked to hear...

Not sure about that stuff, but the weak link isnt the block at 350 hp.. a few 350 builds now. Pats holds 500+ whp

I know the jz guys do it when they go for big power, my buddy's been contemplating it but he's only sitting at 520whp right now so it'd be in the future. Haven't really heard of it done on many miatas, or rather on any miatas. Like stated, the block isn't the weak link at 350 hp

Not needed for your power goal IMO. I have considered doing some kind of block strengthening if I build a new motor, but I haven't done it yet. I think strengthening the main bearing caps with steel caps or even a full main bearing girdle would do more for reliability at high power than filling the block to support the bores.

lol 350.

there's BP's at 800hp without that junk.

Well, i know of a block filler that works great. It is called sodium silicate. Use it in place of oil. You will make mad power.

Are we talking annoyed, or downright livid?

Wait, what, me? No I was just being me. My legit answer would be sonic testing a block or two and selecting the best one if you are that worried about it.

Thanks guys

Will find something else itching to absorb that money

Yeah, you should probably go see someone about that.

It has been written that filling the block only half way up the cylinder walls leaves room for cooling(where the heat is generated), but isn't this where all the stress is also created that supposedly the hard block is to correct?????

Seems counterproductive.

Ideally you would want the support near the top, since as you say that's where all the load hits it.

I just mix in a little quckcrete with the oil.

The gain from block fill is better ring seal, not usually anything to do with holding the block together

Not remotely necessary in any cast iron closed deck block at anything remotely resembling halfway sane power levels.

My engine is grouted. Not sure how much it helps but my compression numbers have been rock solid since I've had this engine and the bores have been great each rebuild. There are no signs of cracking or breakup of the grout.

350whp in a Miata is not a big deal. Sonic test the block, don't go huge on piston bore. We stick with 84.0mm for anything over about 300whp. Close to 500whp, a Billet crank is a good idea. Wet sump still works. Replace everything else in the block with billet or forged bits.
The 340whp race engine in Bullet is a generic forged block. Stock size SS valves, no porting but billet oil pump gears, rods, pistons, ACL bearings, double valve springs. Safe to 400whp or so. OGK should make between 450-500whp, will use a Molded billet crank and ARE dry sump.