JCH13 - Turbo Miata Rehab Thread

[JCH13]

lol!
That sucks man, but that engine has a good story to tell in car heaven.

Engine rebuild thread you say??

True story bro.

And definitely going to do a rebuild thread... likely won't get too crazy, but a 0.020in over bore and forged rods wouldn't be a bad way to go...

 

[JCH13]

The engine swap is getting into a realm I am not 100% equipped for... I have ordered an engine leveler, compression tester, leak-down tester, Redline MTL transmission oil, extra jack stands, and front and rear shaft seals for the transmission.

To-Pack List for the swap:

1. intake gasket
2. oil pan sealer kit
3. clutch alignment tool
4. spare OE clutch (I want to replacement the 6-puck, it's too aggressive for the street)
5. spare fasteners
6. blue loctite
7. spare OE flywheel
8. exhaust gasket
9. spare starter
10. 4qts fresh engine oil
11. 2-3 gallons of coolant and distilled water

I still need to strip down and clean the donor engine. Once it's in the car it'll need a valve cover seal too. Going to be a long/fun weekend. :awe:

 

[jlee]

Don't forget a new oil filter too.

 

[JCH13]

New oil filter on the dead engine <100 miles ago. Planning on just moving it over onto the donor engine.

 

[PseudoSport]

RIP B61P 1.6l (1991-2012)

 

[allanon1965]

New oil filter on the dead engine <100 miles ago. Planning on just moving it over onto the donor engine.


please tell me you are kidding. the engine blows up and you are going to re-use the oil filter?

its got to have contaminants in it by now, just spend the extra 8 to 10 bucks and get a good , new filter.

if it melted piston rings or pistons, its in the filter.

 

[JCH13]

I came to that realization a few days ago and picked up a new filter along with some fresh engine oil (that I needed anyway).

For what it's worth, if there was stuff caught in the filter it wouldn't magically get out of the filter and into the engine. Though you're right, it's not worth saving the few bucks.

 

[allanon1965]

think about this...if there are metal shards albiet small, they can cut the paper element in the oil filter and pass by, not only that, if there is enough in it to cause a restriction, the oil filter has a bypass valve that will open up and allow full unfiltered oil flow thru the engine

 

[JCH13]

So Bonky and I called it quits around 2am. We towed my Miata to his shop, drained all of the fluids, pulled the engine and transmission and took the head off.

Also turns out that the spare engine I have has sticky or damaged exhaust valves on cylinders 3 and 4. Cold leak-down numbers were: c1- 10%, c2 - 9%, c3 - 30%, c4 - 90%. Very clear that the exhaust valve was the culprit.

In related news: leak-down testers rock. You can test engines without a starter or disconnection fuel injectors, etc. It also clearly indicates where any problem is.

I also discovered that the engine mounts HAD NO NUTS ON THEM AT ALL! It's amazing the engine didn't fly out of the engine bay, it was literally just sitting there...

Small chunk of metal I found on the piston.

Damage to the piston head. Present on all.

One piston very clearly chipped.

Massive scoring on 2 and 3.

Yep... this poor little engine was truly boned. Hopefully I can make 1 good engine with the head of the original engine and short block of the replacement engine. *Knocks on wood*

Theories on what would cause this sort of damage?

 

[FuzzyDunlop]

*snip*

Theories on what would cause this sort of damage?

hmmm, not enough oil to the piston rings?

 

[alkalinetaupehat]

*snip*
Theories on what would cause this sort of damage?

Obviously:

Also I can't be the only one who thinks that Suburban looks just like the one out of the Swedish "Girl with the Dragon Tattoo" movies.

 

[Black2na]

hey JCH can it just be the fact the valves may be sticking a but due to the lack of oiling in the top of the head? cause when we got that motor it ran strong. and it as also been sitting out of a car for more then 7-8 months dry. im not sure as i was not there but thats certainly something to look at you run a compression test on it also?

 

[JCH13]

I supposed it could be lack of oil that's causing a sticky valve, I dumped a bunch of oil on the head and cranked it around several times by hand to try and un-stick them though.

I'll get a clutch, transmission, and the correct oil pan on that engine, fill it up to capacity, and crank it with the starter to see if it comes loose. It's no more work really, so it's worth a shot.

 

[Black2na]

yeah hopefully it pulls out of it and if it doesnt not like its hard to pull the head off

 

[JCH13]

Quick update:

Looked at the head of the engine on Saturday, noticed the same damage on the head as on the pistons. This being the worst of it:

Possibly a result of swallowing a rock when IC piping blew off, or possibly a damaged spark plug, though the 4 in it now are all intact. My theory is that something damaged it a while ago, and the piston fractured only recently, which then lead to complete failure.

One of the flywheel bolt holes was quite messed up. One of the flywheel bolts was only 1-2 turns in the hole for transport and it got dinged, damaging the first couple threads. I didn't have the right tap, but a spare flywheel bolt and a cut-off wheel make a great tap to clean out damaged threads.

Popped the old engine/transmission apart with very little drama.

Pulled the oil pan off and found remnants of every gasket maker that has ever been used on this engine. Heh.

I got the spare engine all put together, cranked it over with the starter, and noticed that the oil pressure sender wasn't in place by a nice stream of oil coming out of the block. I tried to take the sender off of the old engine, only to find out that someone had threaded an 1/8in NPT sender into a metric hole. SAD FACE. This sort of killed any chance I had of getting stuff in and working over the weekend, so with a few more failed attempts to free the stuck valves on 3 and 4 I called it a day.

Prevailing theory on the stuck valves are clogged or stuck HLAs. I can compress all of the HLAs by hand, other than those on the stuck valves. Likely need to pull the cams out and clean all of them.

 

[FuzzyDunlop]

aw, raw deal on the pressure sender. How far does that set you back, do you think?

 

[JCH13]

Looks like $160 so far... going to look around for a less expensive option...

 

[PseudoSport]

What does your timing map currently look like now that you are running a T3/T4 turbo? I&#8217;d say that damage is from detonation. Do all the cylinders look the same?

 

[FuzzyDunlop]

Looks like $160 so far... going to look around for a less expensive option...

do you gotta tap the block to make it work again? Thread damage?

 

[JCH13]

What does your timing map currently look like now that you are running a T3/T4 turbo? I&#8217;d say that damage is from detonation. Do all the cylinders look the same?

That's the same thought my uncle had (built race cars and prototype cars for a long time). There are some cylinders with more damage than others, some with only damage to intake or exhaust sides, some with damage to both.

I advanced timing a little bit over what the car had (1-2deg). It's possible that some shitty gas left in the tank over the winter caused the issue (though I filled up with 91 before pushing it hard).

This could very well be the cause... I'll dial back the timing and add a little fuel. Then get that knock sensor wired up ASAP.

Edit: thinking about it some more I realized the the T3/T4 flows a bit better than the turbo that was on it. That would definitely impact tuning, I think it would cause the car to run a little leaner...

 

[PseudoSport]

The T3/T4 will flow more air and spool later. I believe if you look at my old timing map it&#8217;s kind of U-shaped with less timing in the middle of the map. As boost would build from 2000-3500 timing fell off then a few more degrees came back towards redline. If your new turbo spooled later it would not follow the same path in the timing map. It&#8217;s possible where I use to cruise or decel at 38 degrees of timing your turbo was building boost. Do you have any data logs?

That sucks about the sending unit. I never had it off the block and I&#8217;m pretty sure I just painted over it. If the sending unit is the same as a 1.6L in the Mercury Capri I know there are a few in the junkyard near me. What about the spare 1.8L block? Does that have a sending unit on it?

 

[JCH13]

Datalog shows about 22* to 15* spark advance during a hard boost run.

But sometimes seeing nearly 30* advance under boost... with some shitty gas that could definitely be an issue...

I will look at pulling timing along the boost-build ramp and all areas on-boost and adding a bit of fuel on boost.

I didn't check the 1.8L block for the oil pressure sensor. Got a generic on order with the right threading adapter, total cost of ~$50 shipped.

 

[PseudoSport]

Looks like you found your trouble sports. You can always run the DIYAutoTune spark map from their MSPNP since its pretty conservative and tune from there.

 

[JCH13]

Engine is in. Redline MTL in transmission and turret (buttery smooth). Synthetic 10W-30 and fresh oil filter in engine. Clutch hydraulic flush and adjustment for stock flywheel (the horror that came out of the clutch system... ). Coolant flush. New conservative spark map, slight fuel adjustments.

Drove her home today with no hiccoughs. Ran really well on the road.

There's a lingering misfire, I've only really noticed it at idle... I tried to add a little fuel, and that helped for a few moments.

I should make sure the LC1 wide band has no authority...:\

 

[PseudoSport]

Nice to see it back up and running. When you swapped engines did you swap the cam angle sensor or use the one that came with the engine? I use to have random misfires at idle and while cruising that I could not tune out. I logged the stock 1.6L CAS and it dropped out every now and then. I installed a 1.8L CAS since it&#8217;s an upgrade and the problem went away.