Miata Turbo Forum - Boost cars, acquire cats.

- Engine Performance (https://www.miataturbo.net/engine-performance-56/)

- - Engine build (https://www.miataturbo.net/engine-performance-56/engine-build-50958/)

Quote:

Originally Posted by wayne_curr (Post 621376)

I did this with my last engine. Spent 1400 bucks total rebuilding it and getting all the baller machine work done to it and paid them to assemble the short block as well. Lasted 2 years with track days, autox and rough daily driving. Then I had a freak megasquirt issue that killed it. I built my current engine for ~200 bucks total and it runs as good or better than the expensive one. I trust it just as much, actually I trust it more since its got better rods.

Moral of the story? 1.6s are cheap and plentiful. You're eventually going to blow your engine eventually anyway and you'll feel a lot better about blowing a 200 dollar engine than a 1500 dollar engine.

Also, I feel like a sucker paying them to assemble my short block way back then. After doing it a few times since then I realize its just as easy as doing anything else when working on a car. This is not rocket science or engineering, its just following instructions and being detail oriented while you assemble something.

Edit: I dont see anything in there about balancing the reciprocating assembly. If you're balancing the crank you need to balance the rest of the moving parts as well.

No, no, nuhno-no-no! The moral of the story is to be very cautious and caring with your engine management system.

Also, why does your $200 engine have better rods than your "built expensive" engine? If you're building a miata engine for boost, the absolute first thing to do is to put forged rods in it.

Quote:

Originally Posted by NickC (Post 621474)

Its not that I wasn't being cautious. My TPS connector fell off, the wires shorted together and this tells megasquirt to lock the injectors open. The motor hydrolocked. Was a freak accident.

The new motor has 323 GTX rods in it. Not forged, I dont see forged rods as being anywhere near necessary for my power level. If I knew then what I know now I would never ever have paid so much to have an engine rebuilt to stock specs or even had an engine built to stock specs in the first place.

After watching bbundy go through 2 FM built stroker motors in 2 years I just do not feel like throwing any amount of money at an engine is going to make it bullet proof in a heavily abused, high strung track car.

Quote:

Originally Posted by falcon (Post 621302)

The main reason I want to do it is I don't trust ANYONE and want to check their bore work and make sure all the bearings are spec'd correctly. I have trust issues.

Wise man.

Last time someone else worked on my car, I dropped it off at a service shop where I know the guys professionally, and where their shop car has won its class at the 25 Hours of Thunderhill. Fifteen minutes after picking it up, I had a sweet view in the mirror of parts that had just broken and fallen off my car bouncing down the freeway behind me, getting run over. Plus they charged me $40 for a valvecover gasket I'd replaced 12 months earlier myself for $20, and it now leaks when it didn't at the time I dropped it off. This wasn't a Miata.

Carroll Smith wrote that the only reason it made any sense for pro-built race cars to be delivered assembled was so it would be easier to figure out which parts were missing. Pretty much.

I do trust Cosworth.

Mmmm a cosworth engine would be nice.

I've pretty much decided to assemble it myself. I found an excellent step by step online that was one some honda forum. Really goes over everything well. And this way I can check the machine work and KNOW everything is spec'd correctly.

Quote:

Originally Posted by wayne_curr (Post 621643)

Yeah, some definite bad luck there, but to be a complete dick I would say,"should've made sure it was a better connection!"

I haven't looked too much at the lower hp FI stuff, but I think forged rods are a good idea for anything over 200-220whp.

Alternatively, I've heard too many stories of people blowing stock motors. However, a stroker motor and its lowered rod to stroke ratio, especially as a heavily boosted track car, will experience a shorter lifespan.

Quote:

Originally Posted by falcon (Post 622107)

Do you have a link to that guide? One can never have too much engine building info.

Like I asked someone else...

How will you know the engine block was balanced?