Any must-do things when getting rebuilt?
 

I'm on my second motor, and it appears to be knocking. I'm getting ready to get it rebuilt this time instead of dropping another used motor with an unknown lifespan. (This one has great compression and sounded perfect for the first 8 months of its life, after all)

Anyway, I'm only after 220whp ultimately, so I didn't plan to really build the motor up. I mainly want to get it refreshed and remachined so it'll last longer this time.

That said, are there any cheap upgrades that I would be stupid not to do? As in, things that cost another $50 while you're already at it, but make a huge difference in reliability or performance?

I didn't really know how to search for this question, and it'd take me years to learn everything this forum knows about various engine build upgrades and decide for myself, so I thought I'd just ask.

Thanks!

Which engine? The weakest point of all of them is the rods. You can get a set of ebay rods for pretty cheap that will hold that much power or wait for somebody to sell some used ones on here.

Sorry, derp. 94-97 1.8L. I'm not afraid to spend a little cash if it'll make a big difference in longevity especially, I'd rather this be the last time I pull the engine for a few years if I can help it.

Whew, rods look spendy though. I'll have to look up some more information about that. Thanks.

$250 for something like this: Godspeed Mazda MX 3 Miata Escort 1 6L 1 8L 4 Pcs H Beam Connecting Rods w Bolts | eBay
I can't think of anyone that has had problems with these. A lot of guys spend a little more and use Manley or Eagle though.

I know a lot of guys have success, but ebay for engine internals weirds me out for some reason... I did see a link to the Manley's in another post, though. $360 from 949 sounds like a pretty good idea and worth the money. It was the $800 wisecos that were making me wince.

Thanks!

Ebay for almost anything gives me hives, but there have been many success stories at this point. By all means buy from 949. In my opinion, the extra $100 is worth the added reassurance, and you're buying from some great guys who have contributed a ton to the community.

Yep, I agree with that. I like supporting vendors.

If you're having the head done, have new valve seals put in.

Bring the flywheel and pressure plate to the machine shop. Have them balance the entire rotating assembly. These motors like to vibrate and this helps keep it all together longer.

Buy a new OEM or BE oil pump. Take the pump apart and measure everything. Make sure everything is clean, deburred and all tolerances are in spec. Inspect the relief valve port, maybe even pre-lube? I have never had a problem but have read lots about that getting stuck.

Inspect crank pulley. These like to separate and can cause timing issues and excessive vibration.

The oil pan is something to take your time with. If not done right the first time you will pull the motor again. On that same note, the rear main is another one to be careful with.

The trans should get a new pump seal, input shaft seal, output shaft seal and turret rebuild too.

Thanks Aaron, good info. I'll note that for later. I'm probably tabling this if the VVT motor I'm getting from another member is in as good of shape as it sounds, and just hoping I don't blow that one too.

Keep oil in it. Rods knock due to running the engine low on oil. If it ran fine when you got it and then started knocking after 8 months, it either had 300,000 miles on it or you ran it low on oil.

Oil levels were fine, although I did have a crack in my pan from when I derped and used the wrong substitute for a bellhousing bolt. Anyway, I did the real oil pressure gauge swap awhile ago, so I've been monitoring my pressure and it's stayed consistent between changes. Also, of course I've been checking the levels at track day between sessions. It was totally fine and I got 3.5 quarts or so back out of it when I drained it.

In short, oil level was fine as far as I can tell. Maybe the crack allowed moisture or something and contaminated the oil. (I did replace the pan). The crack wasn't through to the oil area though, just on the outside of the pan across a transmission bellhousing bolt hole.

Anyway, first engine was my fault, overheated it. This second one, tough to say, maybe my fault, maybe previous owner didn't keep up with oil changes. Doesn't really matter, still broken. Yep, thanks, I'm aware of the need to keep oil topped up, regardless of whatever other boneheaded things I've done on this car.