The Headless Miata | JAMT

JAMT = Just Another Miata Thread

I picked up this miata on Saturday. I saw it on Facebook a week ago, thought about getting it last weekend and it didn't work out, but it was still available this weekend so I bought it. 

This is a 94 miata, it was posted for sale for $1000. The head was uninstalled due to a head gasket failure, but the guy had sent the head out and had it pressure tested, milled, and new valve seals put in. So the rebuilt head and a bunch of other parts were included. I picked up the whole deal for $750. 

I was a little nervous about buying a car that was already torn apart, but I figured worst case, I have a spare engine. Fortunately, the guy was very diligent in putting the bolts in Zip-Lock bags and labeling them. Basically everything was there that I needed to put it back together. So, once it was home I decided to see if I could get it together and running that night. 

Here is what I started with:

Thanks to Knurled. for the advice on how to clean the block before mounting the head. (Scotch-Brite pad, well oiled with penetratin oil.) That cleaned it up pretty nicely!

In progress.... 

And, together! First start was about 2:30am, or about 8 hours after we started messing with it. 

Other bits we messed with:

-Vacuumed interior, it is in pretty good shape.

-Pulled metal part of parcel shelf. (Super rusty, need something to replace it and carpet to cover.)

-Installed new shifter to trans tunnel boot.

The rest of the To-Do list:

-Install missing temp sensor.

-Fix leaking Tstat housing.

-Change Oil

-Swap door cards for good ones I have in storage.

-Replace gauge cluster hood.

-Replace windshield 

-Fix tiny bit of rocker rust. 

-Paint/Wrap

Nice score! And congrats on the successful head install. Does it drive yet? Challenge car?

maschinenbau said:

Nice score! And congrats on the successful head install. Does it drive yet? Challenge car?

I have not driven it yet. Need to do an oil change and fix 2 coolant leaks, then I should be able to take it for a spin. 

Tentatively this is my backup challenge car, if the drift e28 isn't ready. This would qualify for Gastropod class too. 

Since this is a second miata, not my daily driver, I may see about doing some rallycross with it too. Have to look into what the best suspension setup for that. 

Got the oil changed, coolant leaks sorted (mostly, need a new upper hose.), and gave it a good look over. Still needs cosmatic stuff, but I'm not too worried about all that yet. 

I did get to take it for a spin the other night, and found 2 things:

1. The brakes SUCK.

I'm not totally sure why yet. The rotors are pretty pitted. I did a few bots of heavy braking to try and get most of the rust off, but something else feels off. I'm going to order pads and rotors, maybe brake lines too. When I put those on, I'll do a good brake fluid flush and see if that fixes it. (Yes, the brake booster is hooked up, and doesn't look like it would be leaking.)

2. It's down on power.

Also not sure why yet. It seems like it's mostly on the low end, once it get towards the higher RPMs, it starts to come alive.

I picked up a compression tester, so that's one of the first things I'll check. It could also be because without thinking, I greased the spark plug boot where it goes to the coil, which as I found out on my NB a few weeks ago, just makes them slip off. I thought I had it secured well enough with a zip tie, but maybe not.

Some more pictures, since I haven't posted many so far. 

Interior is pretty nice. (minus the door card and parcel shelf.)

Did 90% of the brake refresh on Saturday. I ordered all the parts from Rock Auto on Friday and all but the read pads showed up Saturday morning. Sweet! New pads and rotors all thea way round, and new rubber brake lines for all 4 corners. All it needs now is the rear pads installed (should arrive today) and a final brake bleed. Hopefully that fixes the braking issues. 

As far as the lack of power issue goes, I had been wondering if I got the timing off by a tooth, and my friend agreed, so I also pulled the valve cover to check and it does appear to be slightly out of time. It almost looks like its just a half tooth out, which is weird, it'll just take a bit of fiddling to get right. I'll have to tear that down a little more so I can set time again. Kind of annoyed that I messed that up, but at the same time it was probably 1am when I set the timing. Could have been much worse.

Timing is 1/2 tooth off because the head has been milled. You may need adjustable sprockets to get it right. Try a one tooth change first, but if it still runs wrong it is milling machine/indexing table time, or purchase some from your favorite Miata supplier.

Great find and nice job of bringing this one back to life so quickly.  Under the hood, I spy the somewhat sought after idler pulley for non-PS equipped Miatas that have A/C down below.   Should be a fun Miata when all sorted out!

ToySnakePMC said:

Great find and nice job of bringing this one back to life so quickly.  Under the hood, I spy the somewhat sought after idler pulley for non-PS equipped Miatas that have A/C down below.   Should be a fun Miata when all sorted out!

You spy correctly! It is a factory non-power steering car with A/C, so it has the tensioner pulley. I've been debating on whether this car needs A/C or not so I could decide to sell the bracket or not. Current plan is to try and flip the car, but if I keep it I won't be sad either. 

TurnerX19 said:

Timing is 1/2 tooth off because the head has been milled. You may need adjustable sprockets to get it right. Try a one tooth change first, but if it still runs wrong it is milling machine/indexing table time, or purchase some from your favorite Miata supplier.

Oooooohhhhh. That could be really annoying. I didn't think of that! Off to do some research!

Got the brakes finished last night. Centric rotors, Wagner ThermoQuiet Pads, and Centric rubber lines all the way around, plus a good brake bleed/flush. (Thanks to my wife for bleeding assistance!) The brakes feel great now! On my test drive they feel like they should, plenty of braking power, now the limiting factor to braking times is tire grip.

Also re-timed the engine. I a pretty sure it was out a little bit, and I think now it's as close as possible. The intake cam might be slightly retarded I think. Took it for a drive and at first it was worse than before. No power on the low/mid range, stumbling, etc. Fortunately, I decided to keep driving it for a bit, and it seems to have cleared up. Weird. By the end of the drive there was very little hesitation. Win! (Actually, now that I'm thinking about it, plug wire #4 is probably loose on the coil from the grease I stupidly put on last week. Meant to zip tie that...)

New Dayco upper radiator hose from RockAuto looked like it was going to fit, but then the hose was a bit to large of a diameter and was loose. I think too loose for clamps to take up. :/ Need to find a proper fitting upper hose. 

I found another person who has a factory non-power steering, AC equipped car! 

The fact that it largely fixed itself tells me bad gas or stuck injectors from sitting unrun.

TurnerX19 said:

The fact that it largely fixed itself tells me bad gas or stuck injectors from sitting unrun.

Could be! The tank was about half full when I got it, and it had been sitting for probably 6 months at least. I topped it off with premium last weekend. At some point I'll have to go pickup a fuel injector cleaner.

Nice.  I was sorta hoping this thread was going in a different direction based on the initial reading of the title, but a running Miata after proper amounts of elbow grease is always a win!

Well, I spoke too soon. I took it for a quick drive last night, and it was bogged down again. I didn't get to drive it as long as the night before to see if it went away once warm, but that does seem to be the case. 

To summarize:

-Bogs down till warmed up. Anything under 4k rpms is barely drivable.

-Smokes a lot out the exhaust till warmed up.

Next plan is to do the compression test, maybe swap the MAF out, start checking sensors maybe? It could still be the timing a little bit, but I just kinda doubt that's it at this point. My last 94 had some weird issues after water got in the ecu, not quite the same, but I might pull it out and clean the connectors and such. 

AWSX1686 said:

Well, I spoke too soon. I took it for a quick drive last night, and it was bogged down again. I didn't get to drive it as long as the night before to see if it went away once warm, but that does seem to be the case. 

To summarize:

-Bogs down till warmed up. Anything under 4k rpms is barely drivable.

-Smokes a lot out the exhaust till warmed up.

 

Next plan is to do the compression test, maybe swap the MAF out, start checking sensors maybe? It could still be the timing a little bit, but I just kinda doubt that's it at this point. My last 94 had some weird issues after water got in the ecu, not quite the same, but I might pull it out and clean the connectors and such. 

Can you tell what kind / color smoke?

Bent-Valve said:

AWSX1686 said:

Well, I spoke too soon. I took it for a quick drive last night, and it was bogged down again. I didn't get to drive it as long as the night before to see if it went away once warm, but that does seem to be the case. 

To summarize:

-Bogs down till warmed up. Anything under 4k rpms is barely drivable.

-Smokes a lot out the exhaust till warmed up.

 

Next plan is to do the compression test, maybe swap the MAF out, start checking sensors maybe? It could still be the timing a little bit, but I just kinda doubt that's it at this point. My last 94 had some weird issues after water got in the ecu, not quite the same, but I might pull it out and clean the connectors and such. 

Can you tell what kind / color smoke?

It's white smoke.

The PO told me he recently replaced the fuel pump too, so I may want to test if that is working like it should. 

Been googling a bit, and I have a list to test/replace/check.

Coil packs, test.

Engine Grounds, check

IAC, clean?

Vacuum Leak, check

Air Filter, check condition

PCV, replace

Fuel Filter, replace

O2 Sensor, test

MAF, test

TPS, test

In reply to AWSX1686 :

I had something similar years ago in a NA MR2 - low on power until the engine warmed up and then ran like a top.

It turned out the head gasket didn't completely seal cylinder 1 until the engine warmed up (assume the aluminum head expanded when it warmed). When I pulled the plug wires one at a time I determined it was cylinder 1. I changed plugs and wires but it didn't do anything to change the symptoms.

I finally figured it out after a couple of weeks when I saw a little oil in the coolant.  I didn't fix it  - drove from Nashville TN to Jackson MS and did a turbo swap over a weekend and drove it back to Nashville Sunday night / Monday morning (much younger and braver back then).

In reply to Scopecreep :

Hmmm, a leak like that should show on a compression test right? Maybe. If I do the compression test cold. 

I could pull the valve cover and give the head bolts another torque. 

Absolute worst case scenario, I do have a spare engine...

Stefan said:

Nice.  I was sorta hoping this thread was going in a different direction based on the initial reading of the title, but a running Miata after proper amounts of elbow grease is always a win!

Were you thinking it was going to be a D/Prepared Miata with the windshield cut off of it? Because that's what was going through my mind

In reply to AWSX1686 :

I would think it would show up on a compression test - I didn't have a tester at the time and it was a good excuse to do the swap that I wanted to do.

You also mentioned you had white smoke out the tailpipe which can also be indicative of coolant getting into the combustion chamber (steam).

So Friday night we got a ton of rain and wind, which may or may not be related, but I got a knock on my door from a neighbor because the horn had started going off. As if someone was just holding down the button. Had to disconnect the battery. That should be a fun one to track down...

Not sure when exactly I'll get to that one. I am hoping to get some progress on the drift car for a bit now.

In reply to AWSX1686 :

Howdy, I've been through almost the exact situation you're in now. With my na6, I replaced all the normal wear items and confirmed timing, but couldn't get rid if the low rpm stumble/ miss. As a last shot kind of thing I ohm tested injectors and had one read slight high on the resistance. This led me to pull all the injectors and attempt to redneck clean them with the spray through method. Turns out another injector would only open intermittently and was my main source of trouble.

Thing was, when running, I would pull the harness wire from the injector and the engine would stumble worse, leading me to believe live it was a good injector. Good luck on your troubleshooting!