The FASTiva

[Loren]

Wasn't all that bad, actually. But, it had sat on the stand for many months, and I knew there was surface rust in the water jacket in the block. Just wanted to get some of it out. Need to get some coolant in there with corrosion inhibitors and all that.

[twistedwankel]

Which means it looked like a guy with liver disease peeing orange.

[Loren]

Yup.

[Loren]

A little behind here.

March 11 autocross went okay. Car seemed a little down on power (but, we haven't driven it in a while... it ALWAYS feels down on power) and had persistent valve tick (not unusual for a 90's era Mazda), but ran okay right up until it started making ridiculous noise. The down pipe nuts had (where there were only 2 of 3 present) backed off and allowed that joint to leak profusely... and loudly. So, we parked it. Tried to tighten things up, and limped it home.

Removed the exhaust manifold. Removed two broken studs, chased threads, fitted three new studs. Got that all back together, now the exhaust is quiet. But, there seems to be a very collapsed hydraulic lifter in the mix. We're going to have to pull the cam cover and investigate. I'll pull some lifters out of the junk engine to have on hand in case we find a bad one.

So, we're going to try to do that work next Saturday, and if we're VERY lucky, we'll be ready to race on Sunday. If not, we'll have another 2 weeks to get it sorted before the next Open event.

[twistedwankel]

You need that 3cyl. 1 liter 123HP turbo they put in the Focus and Fiesta out of a wrecked car. That would be reliable/light and cool.

[Loren]

I'd settle for reliable. But, we'll get there.

[Native]

we're going to try to do that work next Saturday

I might be able to come by for a little bit. Will know closer to next weekend.

[Loren]

Yano, it just occurred to me that Ben and I are so used to working on Miatas that we keep thinking "hydraulic lifters". The irony here is that WE HAVE HAD THIS HEAD APART. We know it doesn't have hydraulic lifters. It has old school rocker arms and valve lash adjusters.

Looks just like this:



No hydraulic lifters. The noise we're hearing is probably just a rocker that's gone way out of adjustment. Possibly something is broken, but very likely just out of adjustment.

We totally should have adjusted the valves when we had the cam cover off and checked the head bolt torque!

So... this should be easy.

Fuck, I'm an idiot. No hydraulic lifters on this damned car. Duh!

[Native]

Yeah. What an idiot. I'm not coming. Screw you guys. Sheesh. Your head is probably not as clean as that picture, either. OMG!!!

Srsly, good that's it's a "simpler" fix. I still might come by...

[Loren]

Yeah, our head is a little less clean. And probably doesn't have a piece of paper stuffed in it.

I just hope nothing is broken. Pretty easy to pop the cam cover off and look. Maybe I'll do that Monday.

(See, if I was Mike Dassatti, I'd have already done all of this 3 days ago. But, I'm me, so I'm planning to do it later. Not even tomorrow. Monday. Yeah. Monday is good. Unless I sleep in. Then, maybe Tuesday...)

[Rawkkrawler]

If you were me you'd have everything fixed before 8am, but then you'd have no volunteers to help make repairs and enjoy your wife's cookies. I think your approach is much better, and certainly more fun.

[Loren]

The plot thickens!

FIrst, look closer at the photo above. I thought those were squeaky clean adjusters on the end of the rockers... but, they're not. Turns out there ARE hydraulic lifters, they're just very different from the "bucket" style that we see on Miatas and most twin-cam engines. They're built into the rocker arm tips, and are cute little tiny things. But, they're there.

So, the good news: We don't have to adjust the valves. Yay!

Other good news: We're not going to have to remove the head. Yay!

But, there's bad news. Here's what I saw when I pulled the cam cover:
https://www.flickr.com/photos/42626344@ ... 591777686/

Have a zoom. Look around. Take your time, I'll wait.

There's clearly some damage on the top of the #3 exhaust rocker where it's been hitting the cam cover. (THAT is the noise we've been hearing) Wait? What? Yeah, that rocker has been moving far enough to contact the cam cover. A lot. I grabbed it, and the sucker was LOOSE. All the rest of them are tight, can't move 'em. That one has like a 1/4" of slop in it. Valve lash? Indeed! Look a little closer, you might notice what appears to be a mangled cam lobe under that same rocker. Hmmm...

So, here's what the TOP of that rocker looks like where it was banging against the cam cover:



And this is what it did to the underside of the cam cover: (no biggie)



With no disassembly at all, this is how much valve lash there was! (if it was an adjustable lifter, lash should be no more than .030"... with these hydraulic lifters, it should be tight!)



Here's a close up of that mangled cam lobe. It's actually a very tough little bugger, as you'll soon see.



When we start taking things apart, that's where it gets interesting. The tip of that rocker arm... is not pretty. In fact, it's gone:



But, wait... that intact rocker arm contact pad looks familiar. Could it be? Remember a while back when we first took THIS engine apart to do the crankshaft bearings? The "mystery part" that fell out and we couldn't figure out what it was or where it came from? I might not have mentioned it here, but I took a gallery of Photos of it. We couldn't figure it out, thought maybe it was a part of a broken tool that someone had used on it at some point, and let it go... but, we never took the cam cover off to look. The only time the cam cover came off was for a quick head-bolt retorque a couple weeks ago, and I guess Ben was in too big of a rush to look... and I wasn't around to slow him down.

The previous Mystery Part is a chunk of broken rocker arm!



So, I looked at the rest of the cam lobes and rockers, and found that the intake rocker right next to the shredded one has a broken off corner. Hard to tell which damage came first, or what caused the initial damage. (because race car)



Post Mortem in next post...

[Loren]

Soooo... the original engine. Was making significant racket, and had some metal in the oil, and we just assumed (never assume) that it was the crankshaft bearings going due to being run low on oil at some point in its life. We had the crankshaft machined and put new bearings in it. There WAS some wear on a couple of the bearings, but not a lot... and, in retrospect, not enough to cause the significant kind of noise that we were hearing. No, what we were hearing was that poor #3 exhaust cam rocker clanking around doing its best to keep up! And most of the metal in the oil? Yep, that was from that rocker and the camshaft chewing each other to bits!

We redid the bottom end, and put the engine back in the car without ever reallly looking under the cam cover other than to very quickly re-torque the head bolts. (we replaced the head gasket on this engine a few months before we pulled it out) Had we taken the time to really investigate the top end for the source of the "mystery part" that fell out when it was disassembled, we'd have found it.

Then we put the engine back in the car and drove it! Being the FASTiva, we drove it HARD! It was making noise right from the start, but we thought it was just a sticky lifter that was being stubborn about "pumping up" to do its job. We autocrossed it, and eventually, all of that high-rpm thrashing chewed up the rocker arm to the point that it had enough clearance to hit the cam cover and REALLY make some noise.

Damage appears to be limited to two rocker arms (one destroyed, one with a chip out of it) and the camshaft. No damage to valves, springs, or anything on the head itself. Should be an easy fix.

Ben kept saying the car felt down on power. With the #3 exhaust valve somewhere between not opening at all, and opening "maybe a little", we effectively had a 3-cylinder engine. Should have LOTS more power after we fix this!

The only other potential damage I can think of would be if the #3 cylinder got fuel-flooded due to not firing properly, washed away the oil and caused wear on that bore. Seems unlikely... but, possible. Once we're back up and running, we can do a compression test and see if #3 is low.

[Native]

Wow.
Note to self: check top of motor when chunks found at bottom.
Good detective work!

[Loren]

Wow.
Note to self: check top of motor when chunks found at bottom.
Good detective work!

Deep in my soul, I knew we needed to pull the cam cover and inspect. I was just being lazy.

[Native]

At least you know what the broken tip of a rocker arm looks like now.

[CaptainSquirts]

Geez, luckily you caught the issue before it caused total mayhem.

[twistedwankel]

Thanks for the really interesting investigation. You and Tim make great story tellers.

Reminds me of my brand new Kcar first FWD I ever owned. Great little car. At 70k miles was down on power. Due to too small of oil holes for the cam when cold (up North) all the lobes wore down. Replaced soft cam and switched to 5W-30 oil. Chrysler increased the size of oil holes on later years solving problem.

[Loren]

Successfully swapped the camshaft and rocker setup and got it all back together. Runs quietly and properly now. We'll try to blow it up again tomorrow.

[Loren]

Made it through a full autocross for the first time since sometime in February. Not without issue, of course... but, nothing terminal. The car performed well, and as far as I know, it got Ben home.

Today's issues? Did I mention the alternator belt that mysteriously turned itself upside-down about the time the engine started making racket the last time we drove it? Well, we re-seated it that day and properly tightened it. It got me home that day, and got Ben to the event this morning. But, about the 2nd slalom cone on Ben's first run, it departed the car! (no alternator and no waterpump, not good to drive that way!) Ben retrieved it from course, we reinstalled it, Ben went out again. 2nd slalom cone, off comes the belt! So, Ben went and bought a new belt. Installed that one, and it seems to be okay. (the old belt got oil-soaked by the leaky parts-car engine, seems to have made it soft and maybe that's why it wouldn't stay on?)

The other issue... investigating under the hood for the cause of a somewhat rough idle (expecting maybe a loose plug wire or something), I found that the engine was clearly moving relative to the transmission! All four of the bell-housing bolts had backed out significantly. Whoever installed them must not have tightened them enough, and we didn't think to recheck them. Got 3 of the 4 of those tight-ish, the 4th was under the starter. That got us through the day.