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PostPosted: Sat Apr 04, 2009 2:57 pm 
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Allright... here's the story. I am out of ideas on what to do here...

Late summer of 2008 I bought a beat-up 1.0/5spd metro to fend off the ever increasing fuel prices. I bought it with about 3 PSI of compression on #2 cylinder. Exhaust valve was burned up. NO big deal, parts are cheap, easy to work on, etc.

I had the head rebuilt, although the work was a bit shoddy, I bolted it on the engine and ran it about 5,000 miles at which point I noticed gas mileage really taking a dive, lacking power, etc. (was getting average of 46, almost all highway) I had to muster it a couple thousand more miles because I didn't have time or comfortable weather to work on it. By the time I was done with it, I could barely get it started in 40 degree weather. #3 was the worst, #2 was 2nd, and #1 seemed to be the only one keeping it going.

Pulled the head, had it rebuilt by another shop who did a much better job. Stainless steel SI exhaust valves, new guides, new intake valves, properly re-surfaced, proper valve margin, etc. Looked nice, and the engine made 180 PSI on all cylinders. Changed the oil, and it ran great. Problem is, I burned up another valve on #3 before it was time to change the oil.

Things to note:
Mileage at purchase: 126,000. Current: 137,000 (that's 11,000 miles since mid-october, plus 2000 miles I that had to drive another car while this one was being worked on. I drive a lot of miles)

First set of exhaust valves were of some kind of stainless steel because a magnet would barely stick to them.

The bottom end of the engine sounds quiet. I never had it apart.
Cylinder walls looked absolutely perfect for an engine of this mileage.

I have to add a quart of oil every 800 miles. It is definitely consuming oil. No external leaks that are substantial enough to be an issue. Both head rebuilds resulted in the same oil consumption.... it has to be coming from the bottom end.

No excessive positive crankcase pressure... IE no exhaust coming out of the oil fill hole.

Looking into the spark plug holes right now, #3 has the most carbon in it. The other 2 look like an engine normally would.

The EGR system is working, and there is absolutely no blockage anywhere and there never was any blockage since I've owned the car. I just verified its operation today. Manually applying vacuum to the EGR valve easily causes the engine to stall at idle. The EGR solenoid is functioning properly--vacuum is getting through the transducer when manually applying 12 volts to the solenoid. The only way the EGR may not be working is if the engine computer is not commanding it to open. Plus, I can visually see the valve operate.

I just checked for a clogged exhaust today. I have a home-made backpressure tester that threads in place of the oxygen sensor with a vacuum line running to a vac/pressure guage. I could not make it generate more than 2-3 PSI of pressure while driving at full throttle/high RPM.... I consider than an acceptable amount of backpressure.

The tires cause the car to shake over 70 mph. So I rarely go more than that. I do a lot of highway mileage but never have I gone over 75 with it.

For those who think the oil pressure in the head is enough to overcome the valve spring pressure and cause the valve to never fully close, I run nothing but 5w30 valvoline.

For the first head rebuild, I set ignition timing to the factory 5 degrees, the 2nd time at 8 degrees.

Spark plugs look quite white right now--definitely it is burning on the lean side. It doesn't misfire or anything like that. It made plenty of power when all 3 cyls were working (I also have a Twin Turbo Dodge Stealth, so I have a general idea of what "power" is).

There is no visible smoke out the exhaust that I can ever see. I am always driving though, and don't have a "tailpipe mirror".

I gutted the catalytic converter.

I've never known oil consumption to burn up exhaust valves in an engine. I've driven some vehicles that would have a trail of blue smoke everywhere they went, (add a quart every 500 miles) and never did it result in engine damage... unless these are different.

The only thing I can come up with is possible weak valve springs causing this.... not holding the valve tight or causing valve float or something to that nature.

I have over $700 in just trying to keep a head on this thing that works.... that's a lot of gas for say, an "inferior" American car.


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PostPosted: Sat Apr 04, 2009 5:49 pm 
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Its the oil burning coupled with the late ignition timing.
The oil rings are likely stuck, due to poor maintenance.
Do the rings, install new exh valves, set the timing to 14 degrees BTDC, and call it a day.

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PostPosted: Sat Apr 04, 2009 6:43 pm 
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Pulling the head twice without rebuilding the bottom end :huh:

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PostPosted: Sat Apr 04, 2009 11:49 pm 
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I am tending to agree with the oil burning causing it... everything else checks out to the best of my engine building knowledge. The only reason I would contest it is that I've owned and driven oil burning pigs for a long time in the past, and it never caused me any problems. The problem seems specific to cylinders #2 and #3. #1 has been the least troublesome. All this points to a problem elsewhere and one thing that wouldn't lose consistency in this short of a time is the piston rings.. All 3 cylinders should be getting equal amounts of fuel, so that shouldn't cause single lean cylinder

Pulling the head and not freshening up the bottom end.... yah, this time the bottom end is coming apart as well. After I disassembled the head after the first rebuild, I discovered that the intake valves' stems were beat up, as though someone threw all the parts into a tumbler to clean them. I figured that could very well be a source of oil consumption so I put it back together without touching the bottom end.

I'm tempted to buy an EGT guage to put on this thing. The temperatures must be insane. Makes me wonder how in the world the turbocharged ones manage to hold up... unless they have more advanced fuel management and enrichen the mixtur to prevent this from happening.


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PostPosted: Sun Apr 05, 2009 11:43 am 
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phantomrt wrote:
First set of exhaust valves were of some kind of stainless steel because a magnet would barely stick to them.


Might want too try some of suprf1y's SS valves the next time around. When I ordered some, my shop tried the magnet test and didn't indicate there was any magnetic attraction at all. Possibly a different grade of SS?

This is a tough one alright. It'll be interesting to see what the final solution is. If your EGR channel is clear of deposits through the port on the exhaust manifold, through the head and intake manifold to the EGR, and also clear from the other EGR port on the intake all the way up to the carb, then yeah, the EGR system shouldn't factor into the equation.


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PostPosted: Tue Apr 07, 2009 12:14 am 
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My kid has burnt valves for what is likely a third time using Bosch Plus 4 platinum plugs.

After Phil & Ed pointed out valve problems with these plugs, I have to ask...
What make/model of plugs were you running with when you had the valves burn?


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PostPosted: Tue Apr 07, 2009 8:46 pm 
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having issues with exhaust valves burning as well.bought my 1996 geo 3 cyl 5 speed with130000 km onit and drove to19600 before it refused to start anymore .a compresion check revealed 0 compression on cls 2 and 3 and about 40 psi on cyl 1
.did a complete rebuild including head and block and crank .left no stone unturned and cut no corners .the goal here is fuel mileage and reliability .have always used sunoco 87 octane fuel and mobil 1 oil and ran timing at 8 degrees and did 5000 km oil changes .am fussy about maintenance and I am a professional automotive tech with lots of engine repair and diagnostic experience and have also built dozens of performance engines and race engines.I now have almost 100000 kmonthe rebuild and recently noticed a steady drop infuel mileage .a compression test showed 70 psi on#1 105 on#2 and 130 on#3.I feel this is a premature failure of the valves and am looking for any info I can find as to why this happened ?
at this moment I am replacing the #1 exhaust valve ina 1999 metro which only has 120000 kms on the odometer. seems like this is a common fault with these engines .comments ?


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PostPosted: Wed Apr 08, 2009 12:25 am 
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It pretty much has to be the oil consumption. I fix a huge number of these engines. I always replace all three exhaust valves and rings(sometimes bearings etc). They just don't seem to like having only the head done unless you know the entire service history and exact past of the engine. I have done the odd head only job, but only if it just burned a valve, and the customer knows its oil change history very well. I have had quite a few work well this way but its not the best solution.
I don't use special valves, they come from Altrom brand. Seem to fit and work very well.
Not sure how many i have done, but in the area of 200+ with no returns. I have concluded that with new rings and exhaust valves you will not have further issues.
I used to run nothing but 10w30 in these engines, and now switched to 5w30. Of all that i have seen there is really no pattern to why they burn valves IMHO. I think they just work hard and the heat gets to them. I've never had one use any oil or burn another valve, with some going on 100,000km's since the re-ring/valve job. On the other side of the coin, most don't get massive miles put on the second engine go round....

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PostPosted: Thu Apr 09, 2009 10:54 pm 
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I'll have to check to see what kind of spark plugs I am using. I do know they are at the gap specified in the emissions label and they do not appear to be anything fancy like platinums or whatnot. They're probably autolites or similar..

And also, not all stainless steel is created equal. There's several different grades of it, and which works best for this application, I do not know. I'm not that smart.

These are definitely hard working engines, and it wouldn't surprise me if they have some pretty high exhaust gas temperatures at freeway speeds. But to destroy valves in a matter of a few thousand miles means something is wrong or quality in parts is lacking.. There is no way that Suzuki / GM would have been able to make these things last the 3yr / 36,000 mile warranty or whatever they had at this rate. They would ALL be bought back under the lemon law or something.

One other option I was thinking of is going with the lesser duration XFI camshaft to increase valve contact time with the seat. Do the XFI's have this problem, too? It'll detune the engine as well and *should* in theory, cool the exhaust off.

What about weak valve springs? I did not check for that. Suppose they are weak, they could, in theory, start floating at higher engine speeds and by not closing, that could, in theory, heat them up a bunch more than they should be? I'll ask the guy who last rebuilt this head what he thinks of that idea.

I always thought that more spark advance caused higher combustion chamber temps while less advance generates cooler combustion temps, but can increase temps farther down the exhaust. The base timing number doesn't mean much because it is up to the engine computer's programming to decide how much advance it really gets during normal operation.

And an interesting tidbit is that the #3 cylinder is the one that burned first last time, and it did it again. When I first got the car, it was #2 that was, by far, the worst. #1 was and still is the strong one. And of course, that side of the engine is the first to see coolant, so that side of the head is more cooled than the other side.

Has anyone used valves from the GM/Suzuki dealer? Is there a better place than the auto parts store to get rings and bearings? This engine is coming out and getting redone. The oil consumption is too great regardless if it is the problem to the valves or not.


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PostPosted: Fri Apr 10, 2009 2:14 am 
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Send a personal message to Suprf1y (web page: http://www.teamswift.net/3tech/ ). That's the best way to contact him. Just log onto your user ID and then click the "pm" button at the bottom of his post up above.

My metro XFI conversion has his economy cam, +6 advanced cam sprocket, stainless steel valves, and non-stretch head bolts (in addition to a wrecking yard Xfi ECU and tranny).

I also plugged the existing PCV valve, flipped the T-hose between the air filter housing and valve cover, and rerouted the crank case gases through a new PCV valve to a T-connection in a vacuum line at the base of the intake manifold next to the firewall in order to evenly distribute those gasses across all 3 cylinders. The stock setup tends to run the #2 cylinder lean, causing the ECU to overcompensate by pumping too much gas into the #1 cylinder after getting feedback from the O2 sensor.
I don't know if it would help with your scenario though.

So far, so good using Bosch Platinum Plus 2 plugs. No burnt valves yet. I ought to pull the plugs and see how they look...

You might want to check out my son's thread if you haven't read it already...
http://www.teamswift.net/viewtopic.php?f=22&t=42797


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PostPosted: Fri Apr 10, 2009 6:44 am 
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Back in late January I emailed 3tech (the only method of contacting them that I was aware of) and was also told the oil consumption is related to it. But, I strongly hinted in two emails that I wanted to buy some of their valves, but got absolutely no sales pitch in return. I also asked for a phone number, and got nothing. So.......someone else gets my money.

The drivetrain is probably coming out of the car this weekend.

And interestingly enough, how in the world do these valves hold up to turbocharged duty? Dang.


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PostPosted: Fri Apr 10, 2009 8:18 am 
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If you want to buy something, you pretty much need to tell me.
A hint won't do it.

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PostPosted: Fri Apr 10, 2009 7:27 pm 
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Cool beans. Let me know how I can get my hands on some of those valves because I need a set again. PM me whatever info that would help us out. I'd like to put heads together and figure out what is going on here and to make sure there isn't something obvious that I have overlooked. If I just toss in new valves, I think we can agree that the problem isn't going to magically go away. I am also going to re-ring this thing and possibly toss in a set of bearings depending on how the bottom end looks so I would need to buy a set of rings as well if you can help me out there. I assure that I am easy to work with and not some internet wanna-be kid.

I just checked my spark plugs, and they are AC Delco's. All 3 look like they're burning equally.... no big deposits on them or whatever, but they do look white in many places. No difference in color. I took a better look at the piston tops through the spark plug holes--they all look the same. I just did a compression test (lukewarm engine at best) and got 175 175 65 (PSI). Same cylinder died as before.


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PostPosted: Sat Apr 11, 2009 3:04 am 
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Yeah all of mine died on number 1. These heads like to be consistant it seems. I would've thought the number 2 would burn out more frequently, running as lean as they do.

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PostPosted: Tue Apr 14, 2009 1:56 am 
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All this because the hyd lifters are pumping up (not bleeding fast enough) at
higher rpms. This significantly reduces the valve seat pressure.
Not much of a problem with inlet valves but it plays havoc with exhaust valves.
i.e. then they overheat and fail.

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PostPosted: Wed Apr 15, 2009 11:39 pm 
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time to find a 98+ 1.3 :)


good luck with that thing. funny how we keep running into each other on various forums.

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PostPosted: Fri Apr 17, 2009 12:30 am 
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Burning oil! The first engine in my 96 burned alot of oil, owners before me didn't have the airfilter together correctly so it got dusted. Had over 100k miles and all valves looked good.
There are a whole lot of things that can cause the problem.

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PostPosted: Fri Apr 17, 2009 8:05 pm 
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phantomrt wrote:
I just did a compression test (lukewarm engine at best) and got 175 175 65 (PSI). Same cylinder died as before.

That makes sense.
Using the same (defective) hydraulic lifter as before produced the same results.

At least you have consistency with the problem until you actually fix it! :)

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PostPosted: Wed May 27, 2009 4:52 pm 
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*bump*

I finally got around to tearing into it. I was able to verify #3 exhaust valve leaking by filling the bowl with gas and it poured right through and out the exhaust port. There's quite a bit of carbon buildup in the combustion chamber. #1 and #2 are holding up perfectly it seems despite having the same amounts of carbon buildup.

The lifters were rebuilt during the last head rebuild, and the valve springs were also shimmed for a little more valve closing power... at least that is what I have been told by the last rebuilder. He claims to have rebuilt hundreds of these cylinder heads and I have no reason to discount that because rebuilding cylinder heads is literally the only job he's ever had in his entire life. He has machines dedicated and set up for Subaru cylinder heads... I guess they are a hot commodity.

I popped out pistons #3 and #2, hoping to find something wrong there. Everything looks to be in excellent condition. No rings stuck to the pistons, no unusual amounts of piston slap, no cylinder wall scoring, the bearings have some slight scoring, but are otherwise in excellent shape. Cylinder walls look beautiful. But there is no doubt that this engine is consuming excessive amounts of oil. Hopefully new rings fix that issue.

I need someone to convince me that the lifters pumping up with oil can keep a valve open. Granted, these valve springs can be compressed with your fingers, but with the oil supply restrictor between the head and the block, that alone lowers cylinder head oil pressures by significant amounts. The only thing I can figure that could be going on is if the oil pump's relief valve is stuck closed, and MASSIVE amounts of oil pressure is being built up, and despite the restrictor being in place, the 150+ PSI in the bottom end could be 50 psi in the head, and thus cause this exact issue. Nothing but theories at this point, but I gotta think of something.


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PostPosted: Wed May 27, 2009 6:10 pm 
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The lifters are not your problem.
If the valve is not burnt, but you have leakage past the seat, barring some valve/set damage, the problem will likely be worn guides.
The valve, when closed will not sit straight (true) to the seat, and seal.

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PostPosted: Wed May 27, 2009 9:15 pm 
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phantomrt wrote:
I finally got around to tearing into it. I was able to verify #3 exhaust valve leaking by filling the bowl with gas and it poured right through and out the exhaust port. There's quite a bit of carbon buildup in the combustion chamber. #1 and #2 are holding up perfectly it seems despite having the same amounts of carbon buildup.


Was there any carbon buildup on the valve seat?
If not, I'd have to agree with suprf1y.

Looks like the PCV hose flip may not be all that effective...
Just got a call from the kid. He's limping his car home even as I type.
You guessed it... backfiring through the throttle body again. It's sounding like there's new carbon buildup on the replacement valve.
Sigh... :(


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PostPosted: Thu May 28, 2009 8:05 am 
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All 6 guides were replaced along with all 6 valves the last time around. I have been fooled before, but I have pretty good faith that the head was rebuilt properly and ultimately isn't the problem. Valve seals were new. Engine continued to consume a quart of oil every 700 miles or so.

The valve tip of the problem child cylinder is no longer round; that means it has erroded away (burnt). Without even removing the valve, I can see that that is the case.

Cylinders have about .003" out-of-round according to my inside micrometer. The specs in Mitchell says .0039" is the limit... which is too much by my book. Interestingly, both piston rings are all square cut--no chamfers on either side of either one. I find that to be unusual. I didn't feeler-guage the end gaps, but they didn't appear to be monsterous or anything like that. The existing pistons are clean, minimal scuffing, cylinder walls look perfect. As you can see in the pictures, that's quite a bit of carbon buildup on the cylinder head. I've seen this much in other engines in the past and they didn't have any problems with ruining valves, but I figure that since this engine is on a much smaller scale, this amount of carbon is substantial. Piston picture is how it came out of the engine--I did absolutely no cleaning, except I wiped the bearing area with a rag and such.

I think I am going to rebuild it. What is a good source for oversize pistons? Will those ITM ones on Ebay work okay? Cheap ebay stuff frightens me.


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PostPosted: Thu May 28, 2009 8:29 am 
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I would just throw a set of rings, and maybe rod bearings in, and fix the head.

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PostPosted: Thu May 28, 2009 11:28 am 
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you are sure you arent sucking in any octane robbing oil fumes more than you should be? when you had the head rebuilt last time, what was your dry cranking compression at? 175 on all three? I would only think the rings would be blowing oil/combustables if you had less than 140psi in each, and even like you said, they look good, and I dont see any unusual scoring in your pics. but you said its consuming oil....

how about the little things one may overlooks? check valve in the block, oil restrictor in the head? functioning pcv system? (infact, just remove the damn thing) how about your timing? you said it was set to x*, but maybe the distributor is malfunctioning and giving you erratic timing, or maybe (I dont know the tbi systems too well.... but) the map sensor is going bad and not referencing the right part in the map, giving you retarded timing when you dont want it.

its the high egts that are killing them. electronic or vacuum advance distributor? if vacuum, have you verified its operation? im not sure how to test the electronic ones...

egts go through the roof the closer you get to 0*, so the earlier you can start the burn, the more its "cooled off" by the time it goes through the exhaust port.

I would look into the valve springs aswell, even a high school with a shop will have a valve spring tester that im sure they would let you use briefly, or a machine shop can test them.

what does the oil look like after you change it? does it go dark quickly? are you 100% sure theres no external leaks? is the exhaust visibly blue? (It should be a little with that rate of oil consumption...)

theres something being overlooked here im sure....

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PostPosted: Thu May 28, 2009 6:24 pm 
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Thanks for the tips on overlooking something. I've been known to chase my tail over stupid stuff before.

>> what was your dry cranking compression at? 175 on all three?
Yes.

>>I would only think the rings would be blowing oil/combustables if you had less
>>than 140psi in each,
I think the same as you. The rings were definitely doing their job of sealing air based on compression readings.

>>check valve in the block, oil restrictor in the head?
The oil restrictor is there... it fell on the garage floor last night as I turned the engine upside down on the stand... unsure of what you are referring to with the check valve.

>>functioning pcv system?
As far as I know. If I disconnect the PCV line to the valve cover, there isn't major suction on there or anything like that. The engine RPMS don't change. Next time, I am catch-canning it for a thousand miles or so and I am going to take a look at the piston tops through the spark plug holes in order to check for carbon buildup. If none, I am hooking it back up and checking again in another thousand miles. Process of elimination.

>>how about your timing?
Timing the first time around was set at 5 degrees. Yes, I did short the connector while I set the timing. Its electronic, not vacuum advance. The mark on the crank pulley DOES actually represent top dead center for #1. I checked that. 2nd time around I set it at 8 degrees. It didn't change the outcome. In fact, it killed a valve sooner the 2nd time around.

>>the map sensor is going bad and not referencing the right part in the map,
>>giving you retarded timing when you dont want it.
Possible. But it did run good and got mid to upper 40's in the MPG game. It never hesitated, never blew black smoke as far as I could tell...like I said, it ran great until it one day wouldn't idle on its own.

>>I would look into the valve springs aswell,
I'm gonna have the machinist double check these. He told me that he even shimmed them a few thousands for a little extra oomph in closing them.

>>what does the oil look like after you change it? does it go dark quickly?
Dirty, and it goes dark quickly. By the time 3,000 miles come around, I've basically already changed the oil because I keep having to add it. No mega sludge in the crankcase or the oil pan either.

>>are you 100% sure theres no external leaks?
There is a leak at the distributor. But it is not even enough to get a single drop on my driveway. If it was a leak big enough to cause this much oil loss, the bottom of the car would have a nice coating and be rust-proofed. I am anal about having leak-free cars. Leaky cars challenge my ability to rejoice.

>>is the exhaust visibly blue? (It should be a little with that rate of oil consumption...)
Again, I agree with you. The Mitsubishi V-6 in my Daytona was burning about a quart every 600 miles last time I drove it regularly. Every time I left from a stop light, I could see a puff of blue out the back. One of the reasons I quit driving that car is because I couldn't put up with the oil burn smell anymore.
I am always the driver, and I would regularly look in my rearview for that trail of blue, but couldn't see any. It doesn't mean its not there. Nor was there a particularly strong smell of oil burn either.

One other possibility is that I've read in many service manuals about there being slightly different valve seals for intake and exhaust valves, even though the stems are identical in size. The reason for it is that the intakes had a constant vacuum pulling on the seal, while the exhaust had pressure pushing on it. Imagine installing the rubber seal inside a drum brake wheel cylinder backwards--the seal is intended to work only one way. But in every case, the seals seemed to have been superseded to a common design for intake and exhaust.

And... do the XFI's experience the same fate with their exhaust valves? That may actually be good to know.


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