advise on engine refresh
 

I've finished my last race of the season.

Since I need to replace the clutch at this time I figure it might be easy enough just to pull the engine/trans complete; which would give me an opportunity to refresh the motor for next season.

The motor has stock internals and I run it to 7400RPM @ 11# max boost.

For the bottom end, I'd like to upgrade the rods, install new bearings and re-ring the OEM pistons.

For the head, I'd like to do a minimal port match, and then clean up the tight radius a little. Then do a std valve job and also swap in a better set of valve springs.

Does this sound like it'll cover the basics?

yep, that should do it. pistons might be a good idea if you race it
....actually billet oil pump too

Just for reliability sake wouldn't going with some ARP head studs also be worth the effort?

Sounds good to me. Maybe look into doing more headwork while it's apart. There are DIY oriented books for porting that will give you a good idea of what to do and it's relatively cheap and makes a difference.

I'm trying to keep the engine power levels/boost levels low for reliability. It seems that after 250whp folks seem to have cooling and other issues. Is this a correct assumption?

Are the OEM pistons a weak spot/ do they often fail? I'd prefer to merely stiff hone the cylds and re-ring. (it looks like all aftermarket pistons require re-bore oversize)

At what RPM have folks experience oil pump failure? Or, is it just the shock of RPM changes that kills the pump?

It looks like the ARP head bolts are an easy fix. However, I read that the main set might have clearance issues with the later style windage tray/brace. Is this true?

I should add that it is an OEM 1999-2000 crate-motor long block with 2 short seasons on it.
Thank you for your responses.

Lower power does increase reliability.

Stock pistons seem to break in half around 350whp in my experience. Stock rods bend around 250 in my experience.

I've rev'd BP motors higher than 99% of the people here that run a billet oil pump and I've never failed a stock oil pump. Just run a harmonic damper and you'll be fine. People here will turn a 500 dollar built motor to a 2,500 dollar built motor buying parts for "cheap insurance". The funniest saying ever, they'll double the cost of the motor and then some and call that cheap!

I now run ARP head studs, I don't regret buying them, but I can't say 100% they are "needed", but I did blow a HG around 350whp the last time I broke a piston. I later discovered my torque wrench was faulty though and the head was only torqued to ~42 ft*lbs, not 65. If I did it again I'd run them since pulling the head to change a HG sucks. Blown HG's are not common at all on these motors though.

I also run ARP mains. Yes with a 01+ oil pan they hit the MBSP. I trimmed my MBSP, it took a solid 3hrs to get it to fit. Sucked. Not sure if there is any benefit to the ARP mains, I've never had any trouble with the main bearings, but I only rev to 8000-8500. IF you go higher or make more power maybe they become a weak link.

How much do 3 blown motors cost when factoring in labor and rebuild costs?

Depends. Usually 500 with fluids, gaskets, and everything. I do the machine work/assembly myself.

The last motor I broke, I used a 250 dollar set of rods, a 900 dollar VVT engine core, and another 250 in gaskets/fluids. I sold 500 dollars worth of parts off the motor, gained a VVT head that I still have, and reused the 250 dollar rods I already had. Soo.... 900(ebay motor with shipping)+250(stuff)-500(value of VVT head I still have)-500(parts sold off old engine) = 150. But when it was built, it was 650 since that incudes the head.

The motor before this one I sold enough parts to cover the cost of the engine build including the cost of the ebay rods, but I was REALLY cheap with that motor, and it only lasted ~2 years with 28 PSI boost.

Also in the interest of full disclosure, I have a metric ton of cash in my current motor, like wayyyy more than I've ever spent on an engine before, or really all the engines before....

So basically none of that applies to anyone else.....

This is why I give leafy so much crap about many of his posts.

Ok, let me try to be reasonable.

OP, upgrade a few things, try to do the ones that you believe are the most important to do right now, but don't fall down the slippery slope of buying every part you see or you'll end up spending wayy more than you originally planned on your motor build. It's very easy to do.

Is that better?:party:

YEP :)
I agree completely about the slippery slope, it's why I did several rods-only builds, but when a guy that tracks his car asks about what to upgrade, that list is going to be quite a bit more expensive than your average street car on e85

What did you spend on a "rods only" build? What did you pay to have done, and what did you do yourself? I think a rods only build is the right build for most miatas, kinda curious what people spend to build this.

Also, I will say that when you only have 500 bucks in the motor, and you have another motor ready to go in the car, you don't give 2 craps about breaking it and it kinda makes the car more fun since you aren't all worried about something expensive breaking. You just enjoy it knowing if it breaks, it's cheap to fix.

I never realized this completely till I put a pile of money into my current engine. Now I'm actually being careful....... Cause I don't wanna trash this $$$$ motor. Also can't really afford to have a spare built up this well, since the parts are so expensive. I planned to run 30 PSI on this motor, ran 28 on wayyyy less-built motors, and now only at 23 and hesitant to install the 30 PSI pulley until I get everything perfect since I'm scared I'll break something.

For me, if I could cut the cost of my motor in half and it be 80% as "reliable" as it is now, I'd rather do that and have a spare motor.

I want to find this $500 that isnt a 1.6 that someone gave you for free or didnt start as a kia 1.8. I cant buy any 1.8 motor for under 600 and thats like a protogay motor, 700 steps you up to NA8 motors. Remember when you cut a block in half or disintegrate and oil pump and thrust bearing because you did a shitty cheap ass rebuild you need a new block, head, crank, and cams to replace the bits that either failed initally or got taken out by the collateral damage of having no oil on them.

You'll have to read my post for how I did it for 500. Last 2 VVT motors I bought were both 800-900 shipped.

Right and I say you cant even buy a core to use for the rebuild for that little money never mind ebay rods, gaskets, and fluids.

I have never paid more than 900 shipped for an engine, and I always buy them with all accessories/manifold, etc, so I can sell off all that crap to recoup some of the initial cost of the motor. But I shop around, browse ebay, call, email, etc. Nothing too crazy. :) Anyone can do that at least. Like I said to get the cost down I sell off some of the parts I don't need, and anyone can do that! Hell I figured everyone did that....

It makes me sad to see someone so willing to blow up our motors. I mean, they're not making more of them, right?

I know, I worry about weird things.

robert

Well I wasn't blowing them up on purpose, but it did happen a few times. Look at the bright side, the first 2 engines I broke were old kia motors that never saw boost before, so at least they got that experience later in life!