Engine bay covered in oil, now low vacuum & lean at idle

[soldave]

Was driving home tonight and close to home I put my foot down. Felt a little sluggish going into boost and then like it was misfiring. I let off and got the short distance to home. Turned the car off and opened the hood. Valve cover has a bunch of oil over it, as well as other places in the engine bay. This, I presumed, was not good.

Cleaned up the oil and put more back into the car. I then started the car up again and the car is idling low and rough, with lean AFRs and low & wavering vacuum (i.e. around 10inHg). Am currently very worried and not so sure where to start looking. Any ideas what could have caused this? Am always worried when I have problems it's going to be something that is gonna need a rebuild.

EDIT: Just stuck my head under the car. There's also some oil on the ground and on the outside of the sump near the drain plug (although drain plug is tight). Am thinking a huge build up of pressure. Again, am assuming not good.

 

[habitatguy187]

Sounds like it just might be the oil cap leaking. If the pcv valve goes bad then when you go into boost it will pressurize the crankcase, causing the oil cap gasket to blow. (I'm an expert on this one) Check your pcv valve, also are you using a valve cover breather filter? Oil can come out of that too if your pcv valve is bad.

As for the low vacuum and misfire take out your plugs/wires and clean them off real good, you're probably missing out which is causing you to run rich which will kill the vacuum, but then there's the issue of the A/F's.... Just do what I suggested and then see what happens with those.

BTW: How did you run an 11.6 in the quarter at 113mph with a 2.0 60?

 

[soldave]

Sounds like it just might be the oil cap leaking. If the pcv valve goes bad then when you go into boost it will pressurize the crankcase, causing the oil cap gasket to blow. (I'm an expert on this one) Check your pcv valve, also are you using a valve cover breather filter? Oil can come out of that too if your pcv valve is bad.

As for the low vacuum and misfire take out your plugs/wires and clean them off real good, you're probably missing out which is causing you to run rich which will kill the vacuum, but then there's the issue of the A/F's.... Just do what I suggested and then see what happens with those.

BTW: How did you run an 11.6 in the quarter at 113mph with a 2.0 60?

Took out plugs and, expectedly, cylinder 4 had a bit of oil in it from where it had come out of the filler cap. Cleaned plugs and wires with paper towels and hooked it back up. Did the exact same thing. Also tried a different coil pack but exactly the same result. I think I did a decent enough job, at least to show some sort of difference, but nothing.

You mentioning pressure does remind me that a couple of days ago I noticed a few puffs of white smoke from my catch can breather. It went away after a drive so I thought nothing more of it.

 

[habitatguy187]

There's an easy thing you can do to check the pcv valve, just take it out and see if you can blow through it, as if you're blowing from the intake manifold into the valve cover. If you can blow air through it, then you know it's bad, as it's allowing boost from the IM to enter into the valve cover, then out one of the two exits.

You may also have a clog in the pcv valve or in the vacuum line, could also have a cut in the hose, because under vacuum it pulls gases out of the valve cover which then enters the combustion chambers, without this gas you will might be running lean if your tune incorporates these gases. (which it almost certainly does)

 

[soldave]

My PCV valve doesn't go to the intake manifold any more - it goes to my catch can, along with the breather hole on the side (I know I need much wider ones).

 

[habitatguy187]

My PCV valve doesn't go to the intake manifold any more - it goes to my catch can, along with the breather hole on the side (I know I need much wider ones).

Well that could be bad then, you're either making too much power (happened to fast91dsm http://www.dsmtuners.com/forums/drag-strip/286914-sexy-grandma-15-day-build-20.html ) Or it could be too much blowby, causing too much pressure to build up. Might be a good time to do a compression test, especially with your driveability issues.

 

[soldave]

Started it up this morning and exhaust & catchcan were making smoke almost straight away. I'm no expert, but would guess it could be oil. Also, no oil on the intake side of the turbo.

 

[rush2252]

the 2gs are bad about blowing the dipstick out of the tube. This can make a mess. Also pull the charge piping loose and make sure its not doused in oil. If the turbo went or a seal went it could be dumping oil into the charge side and into the intake causing poor idle performance. Small amounts of blow by are okay but if the piping is saturated on the intake side then this could be the culprit.

 

[soldave]

the 2gs are bad about blowing the dipstick out of the tube. This can make a mess. Also pull the charge piping loose and make sure its not doused in oil. If the turbo went or a seal went it could be dumping oil into the charge side and into the intake causing poor idle performance. Small amounts of blow by are okay but if the piping is saturated on the intake side then this could be the culprit.

Yeah, that's something I have to do when I get home from work tonight. Was too tired to do it last night but it might give me a clue whether it was the turbo or something else than went. Would a turbo/turbo seal going cause oil to go all over the engine bay though from the filler cap? Don't know much about that part of the car so sorry if it's a dumb question.

 

[habitatguy187]

What color was the smoke coming out of the tailpipe?

 

[soldave]

Whitish. Had a smell but wasn't the pungent coolant-type smell I don't think.

 

[rush2252]

Yeah, that's something I have to do when I get home from work tonight. Was too tired to do it last night but it might give me a clue whether it was the turbo or something else than went. Would a turbo/turbo seal going cause oil to go all over the engine bay though from the filler cap? Don't know much about that part of the car so sorry if it's a dumb question.

I had this problem with the dipstick blowing out. I had installed new rods and mains about a month ago and still running 15-40 Rotella T w Lucas oil stabilizer. With the new bearings installed huge increase in OIL PSI. Apparently this is what caused it. It also splattered enough oil to douse plugs wires etc. Try going to the carwash and powerwashing under the hood. Then remove plug wires and blow out the plug holes (w spark plugs still in) w compressed air. Then add some dielectric grease to both ends of the plug wires and see if it fixes it. Have you checked the Oil line running to the turbo? I know sometimes those things corrode and leak over time.

Did you determine that the oil came from the OIL cap?

 

[habitatguy187]

It's sometimes hard to tell the blueish (oil) smoke from coolant. I still suggest that you do a compression test.

 

[soldave]

I had this problem with the dipstick blowing out. I had installed new rods and mains about a month ago and still running 15-40 Rotella T w Lucas oil stabilizer. With the new bearings installed huge increase in OIL PSI. Apparently this is what caused it. It also splattered enough oil to douse plugs wires etc. Try going to the carwash and powerwashing under the hood. Then remove plug wires and blow out the plug holes (w spark plugs still in) w compressed air. Then add some dielectric grease to both ends of the plug wires and see if it fixes it. Have you checked the Oil line running to the turbo? I know sometimes those things corrode and leak over time.

Did you determine that the oil came from the OIL cap?

Not checked the oil line to the turbo, although if it's corroded I'd be surprised as it's only 6 months old.

Intake pipes beyond the turbo are clean as a whistle. No sign of oil. Looking like the engine then...

 

[soldave]

I return with good news to report! I am happy to tell you all that cylinder 2 came out pretty well in the compression test! There is slightly worse news though: well, just read on.

Got the compression tester yesterday and knew I had to warm up the engine for it to be accurate. Wasn't a nice experience, especially because as soon as it started up it was smoking out of the catch can, and if I took the oil filler cap off it was puffing out of there too. Left it for about 7 minutes to warm up and then shut it off to stop any further damage. Did tests with throttle plate closed and then open, and got the following results:

Cylinder 1: 145psi, 155psi
Cylinder 2: 155psi, 160psi
Cylinder 4: 140psi, 145psi
Cylinder 3: 0psi, 0psi

Signs weren't good when I took the spark plug off piston 3 and smoke started coming out of it! So, as is said to usually be the case if a piston/ringland goes, it's in cylinder 3. Hopefully the cylinder walls aren't scored much and not much other damage has been done. Does leave me with 2 options the way I see it, given the lack of decent 4G63 engines in Okinawa in decent condition:

1. Throw a set of stock pistons in there from one of a couple of people I know. I'd probably have low compression but I'd have a car on the road relatively cheaply and could go back to thrashing the hell out of it!

2. Go bigger & better. Would be costly & would probably be looking at pistons, rods, bearings & possibly water & oil pump, and any headwork that might need doing.

 

[soldave]

Call it an omen, impeccable timing or a scary coincidence, but a review copy of this book just landed in my mailbox today:

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[soldave]

I know I will only find this out when I get the engine beheaded (hopefully this weekend), but we do reckon it's most likely the piston that's gone, as opposed to valves or something else like that?

 

[rush2252]

Its hard to say but id have to say ive seen more 4G63's eat valves or headgaskets than pistons or rings.

You will find out once the head is off. I didnt take time to look at your mods and im not familiar with the EVO I but is it possible a balance shaft belt broke and caused it to jump time? If you havent pulled the head see where your timing marks on the CAMS lineup whenever your at TDC

If timing is off Id bet on valvetrain. You can also tell by inspecting the valve train with the valvecover off. Look for anything unusual on the dead cylinder by comparing valve/cam follower position. Usually the cam followers will be sitting awkward if it dropped a valve

Kolby

 

[soldave]

Balance shafts going on the early Evos are very rare, and the balancer belt still seems in place and is new. Am going to turn the engine around to TDC and try to see if everything lines up properly later today.

 

[soldave]

Well, after what seems like an age (due to my lack of skills and lack of tools) we finally got the head off the car. Didn't look in bad shape, and even piston 3 looked ok at a glance, but then we looked a little closer and found exactly what was causing the problem. Take a look for yourself:

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Yup, it looks like the piston has melted or something to cause it to do that. Looks like there's around 2-3mm between the piston and the cylinder wall. Am betting the ringlands have gone and that will be visible once the piston comes out. Don't know what caused the piston to go like that; maybe detonation and I didn't notice the CEL flashing in the Okinawan sunlight, or possibly running lean for a split second if the meth didn't start up as planned.

There also looks to be a tiny bit of scoring on the cylinder wall as you can see below, but hopefully we'll be able to get that out with a honing tool. It doesn't seem too deep but will only find out when we start to hone.

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So I'm going to order a new piston and rings (am going to try to just get rings for that piston but Mitsubishi only seem to want to sell a whole set of rings for 4 pistons and not for one individual piston). There are 3 standard Mitsu sizes for pistons but I believe it's the A-type piston that I need. Need to do a bit more research into headgaskets as to whether I go MLS or just the standard one. You're all probably screaming MLS but it depends what kind of finish I can get from my head after cleaning it with some parts cleaner and Scotchbrite. Due to the lack of machine shops on island if there are any significant marks I might even consider dropping back to a stock one for now. They've held a lot of power with DSMs and would cope with a non-mirrored finish. Plus once I'm on the road I need this to be as reliable as possible until I find out whether my future is in Japan or not.

Will report back when I've any more news but will probably be in a week or 2 when the transfer case is dropped and the piston pulled out.

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[soldave]

Might be able to get the transfer case and oil pan off tonight before it gets dark. I need to take a look at the bottom of the block anyway to confirm what size piston I need (there are markings on the early Evo blocks as to whether you need type I, II or III pistons in each cylinder). Next question is how do I go about taking the piston out? I really do know nothing about the bottom end of an engine and all I know is that when the oil pan comes off I'm going to be greeted by a face full of crank. Is it pretty straightforward from there to get the piston out and what exactly needs to come out?

Sorry for what is probably a simple question, but I like to know what to expect.

 

[soldave]

Oil pan finally got dropped and the piston pushed out (the latter probably being the simplest part of the whole damn process!). Here are a few shots of it.

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I am actually surprised the damage didn't go down beyond the first piston ring but it doesn't look too bad below there. The top is pretty well toasted though, and there is a crack big enough to see through where the top ring sat.

So now I've just got to source a replacement piston. Have a couple of possible ones but need to take a micrometer to them to find out if they'll work or not.

 

[soldave]

Well, the good news is that piston 2 actually looks like it's in reasonable condition. Same can't be said for the rest of them though! As I've got a full set of stock pistons I thought I may as well use them so I pulled pistons 4, 2 and 1 this evening. They looked ok at a glance so I just sprayed some parts cleaner on them and started cleaning the rods and pistons before I head off to my tuning shop tomorrow to get the new wrist pins and pistons pressed on. I was greeted by these 2 sights:

Piston 4:

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Piston 1:

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Looks like it was a good call to replace all the pistons as surely it was only a matter of time before these gave way completely.

 

[soldave]

All I want is a little luck with this damn thing. Got the piston rings today, fitted them and put the pistons back in. Get the torque wrench to tighten up the conrod cap nuts to spec (38ft lbs according to the 4g63 factory manual). Just as the wrench cracks the bolt just breaks clean off! I think WTF and double check the torque settings on the wrench. All is good so I pull that piston back out as I've got to get another bolt for it. Try the same procedure with conrod in cylinder 2. First bolt torques perfectly. Second does exactly the same as that first bolt!

So I've given up for the evening for fear of destroying all the rest of the bolts. So much for getting a good start on the rebuild tonight