pmhellings

in the course of looking around learning and researching for a future motor build, I came upon this:
McCully Racing Motors- Don't want a V8? How about a 2.0?
It is a company that sleeves 1.8 motors to yield a displacement of 1.952 liters. Their reasoning is that gaining displacement by bore was better, in the case of the Miata motor, than stroking it because it would keep the rev characteristics the same. They sell everything from a bare block to short block with forged pistons and forged rods ( quality commensurate with price ). I would like to have a built engine even though my power goals are modest. I'd just like to know that my engine would be pretty much bulletproof for my needs ( street driving and occasional auto x) at about 250 -275 whp. The Miata is one of my hobbies in my retirement and it doesn't need to be a budget project.

Even though I have assembled,engines in my younger days, I would need a machine shop in any event, so buying a pre-built block isn't out of the question.

Does anyone have any any experience with these folks? Opinions on the motor? My concern would be no, or minimal, space between the sleeves might reduce ability to cool. But then again, I really have no idea if that would be the case. The photos show the block, after being sleeved, and the sleeves would literally have to be nearly touching each other.

Thoughts?

Paul

ryansmoneypit

iTrader: (6)

before i went that rout, i would just put a K series honda into it.

matrussell122

iTrader: (1)

As sweet as those blocks look I agree with the K swap and there are a billion parts for a k series

Savington

iTrader: (31)

MCM has been around for a while. For your power goals, sleeves and 85.5mm pistons are way, way overkill. Stock displacement is 1839cc, 84mm overbore is 1884cc (2.5%), their sleeved "2 liter" is 1951cc (6%). IOW, you can get about half the increase for far less than half the cost. Stroker setups like FM's 84.5x89mm produces a ~1996cc powerplant, but the extreme cost makes them very difficult to justify for most customers.

More to the point, the money is simply better spent elsewhere at your proposed power levels. I personally suggest 83.5mm to most people which makes the blocks serviceable in the event of a future incident or future rebuild, since the ~1% displacement gain is going to be difficult to measure, let alone feel or notice in the real world.

Spend the extra money on a better turbo setup, or a better intercooler, or a better exhaust, or better injectors, or a more modern ECU, or a new intake manifold, or more tuning time. All of those will make a bigger difference in how the car drives than the extra displacement.

pmhellings

Thanks for the responses. Going with a different motor ( K -series) is pretty much out as I already have a nice turbo setup, ECU, cooling system, transmission, etc. If I were just wading into this, perhaps I'd consider that route.

Savington, good advice. I'm pretty happy with the power levels of my FM2 but just want to go bullet proof. My current motor has about 105k on it and seems healthy. So, I have time to plan my build. I would like to acquire the block and build while using the car with the current motor. Overbuilt for the power I'll be asking is kind of what I'm looking for. If I ever get the bug to go to a bigger turbo, more boost. I'll have the option.

I'm sort of keeping my eyes open for a decent engine candidate for a build and would like to track down a machine shop that can do the work and give me input on bearing sizes, etc. I don't want to assume that I know something and screw it up. I know that:
I want to go forged pistons and rods. 9:1 Compression ratio sound right? Good bearing and main and rod bolts per Emilio's sticky. Probably stock VVT head valve job, seals new stock or slightly better springs. Not looking for crazy high RPM.
ARP head bolts, coolant reroute with appropriate head gasket, upgraded ( inconel?) exhaust manifold bolts. Boundary oil pump?

I live in Northeast FL. There are a couple of Spec Miata shops in the Daytona vicinity that would probably be a decent choice for the matching shop work.

Sound about right?

Paul

z31maniac

When you post looking for validation vs real info.

shuiend

iTrader: (24)

Either just write Savington a check for a built motor and be done with it, or find out whatever machine shop BogusSVO is at and go there.

albumleaf

iTrader: (7)

+1

Your power goals barely require spending any money on top the parts you already have. Listen to Sav

miata2fast

iTrader: (2)

I’ve always wondered how well a sleeved block holds up in the real world. Wish someone with experience with a McCully motor would join in. Also wished money was no object....

Savington

iTrader: (31)

Empirically, they hold up well as far as I know. I have no personal experience but I've heard good stories from others. If I were building a max-effort motor to withstand an EFR7163, they would be on the build sheet. For a 250 or 300 or even 450whp non-competition motor, no way.

miata2fast

iTrader: (2)

I certainly agree with that. For my dreamy naturally aspirated aspirations however.....

McCully AND a stroker, oh so yum yum!

ctdrftna

iTrader: (1)

come on, the BP is a pooch, why would you even for the slightest second consider stroking a BP. Thats like having Michael Pelphs swimming while breathing through a cocktail straw.

miata2fast

iTrader: (2)

Part of the thrill for me is seeing how far I can go with what makes a Miata a Miata. The motor they came with is an important part of that journey.

No disrespect to those who enjoy swapping motors. You guys have made some impressive cars. If I wanted to go really fast, I would go that route, or go back to my Camaro and Mustang days where I went pretty fast.

Twibs415

iTrader: (8)

I sleeved a block for personal use. (haven't built the motor yet) the one issue with a highly boosted >350hp sleeved build would be worrying about the block cracking around the head bolt threads. It could be ok but its not worth the extra few percent imo and would rather see 83.5-84mm pistons go in as well.. i might even go as far as stroking it.

my97miata

What about using Supertech 85 mm pistons for a naturally aspirated engine instead of the 85.5 mm? Does the 0.5 mm make any real difference as far as safe margin in engine build goes?

AlwaysBroken

Yeah, there's less material around each cylinder, due to the hole of the neighboring cylinder being bigger. That's why there are only NA type pistons available in the 85.5 size. I'm up to 84.5 (second rebuild on this block) and will probably retire the block if it gets up to 85mm and needs more work. But that could be years.

On a miata, spending over 3k to increase displacement by a tiny amount is a pretty poor investment. All of the gains from this undertaking can be replicated by running a extra pound or two of boost.

glade

iTrader: (2)

If I'm dropping that kind of coin, and dedicated to keeping an old school Mazda, I'm running an Fe3
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sixshooter

iTrader: (12)

Adding displacement isn't necessarily the most cost-effective way to increase the volume of air entering and leaving our engines. If you've done everything else or money is no object and you have to stay with the BP, then sure.

ridethecliche

iTrader: (2)

Wicked overkill for 250-275hp. Wowza.

Midtenn

iTrader: (15)

I have a spreadsheet of parts for a dream NA build and this and a FM stroker kit are both on there. Along with a 949 Racing CNC head. Will I ever do it? Probably not, but I can dream.