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Lol leave it to pimprn to give that horrible advice, 200 dampers and your the one with this problem and at a lower power level and barley any miles. Don't blame the damper blame your builder or whatever is going on with your car. So many people love to blame parts in this platform.
Must not be that horrible with a guy whos 1000x smarter then you agrees he should contact fluidampr. Leave it to you for that horrible customer service just sayin hahahahaha.....
 

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I think you are misunderstanding me. Nowhere have I stated that the Fuidampr is the problem.
My build is for track days and will probably see extended running at the top of the RPM range. I dont want it to come off again.
I have ~3000 miles on this motor, which is where issues start to show up.
I have been and remain critical of Mitsubishi's design for the end of crank assembly because its compromised.
My point in conacting Fluidampr is to see if they have any thoughts or suggestions.
My point is starting this threat is to share experiences.
Keep us updated!
 

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Discussion Starter #64
Solid engine mounts? Obviously known to cause bolts to walk out from the vibrations.
Good point, not solid but stiffer 3SX urethane ones.
 

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Discussion Starter #65
After looking at options for preventing the crank bolt from backing out, I'm leaning towards making a retention plate that would bolt onto the outside. The idea is to use the 3 threaded holes that are there to attach a dry-sump pulley and then wire lock the 3 bolts.

The plate would be aluminum, 90mm diameter 2-3mm thick with 3 holes on a 72mm PCD and a 30mm diameter x 4mm deep inset at the center that would just touch down and add ~1 mm of preload on the head of the crank bolt.

I just talked to Fluidampr tech support and got the OK for this approach.

I was going to use a NordLoc but they don't make one that's thick enough to replace the thick washer and I don'nt want to add a 3mm thick NordLoc on either side of the washer.
 

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Discussion Starter #67
Update, got it back together fired it up and discovered a new tapping sound that comes and goes on a regular cycle of 4 taps followed by nothing then repeat. The noise is not the same frequency as the crank or cams. Its not a catching timing belt and is still there when the accessory drive belts are removed.

The oil was drained and some very fine alloy particles were filtered out. Its not bearing metal and looks to be of the type used for the die-cast parts. The oil pump is prime suspect - on the basis that its the only thing that has a different rotating frequency to the crank and cams.

So its tear-down time. The oil pan and front timing panel is coming off to remove the oil pump.

All of this tends to confirm what a few others have been saying - that vibration from something failing contributed to the Fluidamper and alternator nuts backing out.
 

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93 NA ATX 3000gt DOHC
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.........The oil pump is prime suspect - on the basis that its the only thing that has a different rotating frequency to the crank and cams.......
I’m not sure I understand how oil pump would have different rotating frequency that the crank that is turning it. I must be missing something there, which by the way wouldn’t be first time if so:(.

While pan is off might take good look at crank for cracks between front main and next main back and at front main bearing clearance. I’m wondering if loading/unloading of front two cylinders is causing tapping and the pause is when loading/unloading moves to any of back four cylinders.
 

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Discussion Starter #70
Ah man. That sucks. I wonder if you cracked an oil pump gear.
At this point that would be the best case scenario.

I’m not sure I understand how oil pump would have different rotating frequency that the crank that is turning it. I must be missing something there, which by the way wouldn’t be first time if so:(.
While the inside oil pump rotor rotates at crank speed, the outside ring rotates as a ratio of the number of inner and outer lobes. This makes the outer ring rotates at a different rate from the crank.

While pan is off might take good look at crank for cracks between front main and next main back and at front main bearing clearance. I’m wondering if loading/unloading of front two cylinders is causing tapping and the pause is when loading/unloading moves to any of back four cylinders.
Yes definitely going to be removing and inspecting as the investigation unfolds.
 

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While the inside oil pump rotor rotates at crank speed, the outside ring rotates as a ratio of the number of inner and outer lobes. This makes the outer ring rotates at a different rate from the crank.
I see what you mean now that being a different rotating speed, I was thinking more about a varying 4 taps and a pause. Wondering how something with a consistent rotating speed might have a pause followed by series of noise then repeat. Can’t remember but guess if pump has 5 lobes there might be something associated there.:unsure:
 

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Discussion Starter #72
If the outer ring is damaged it will make a periodic noise as it rotates in the housing. It's the outer ring that seems to fail in these pumps.
 
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Discussion Starter #73
The mystery of the periodic tapping and its bad news - the No2 rod bearing started to spin and the No2 journal is scored. All the others look good. Obviously this is a real pisser. This was a meticulous build and we believed that we were running way under the level of performance that this motor was built for.

We are continuing the tear down and analysis. So far the only notable finding is that the No2 rod journal measured .005" undersize. All the others were in spec.

Now the really bad news, - the shop that I have been working with is planning to close down so I need some options..... and a crank.
 

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Ah man. That really sucks to hear, both on the spun bearing and your shop. It's good that you probably found your answer, as to why your bolts were backing out. How many miles did you have on this build?
 

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Discussion Starter #76
Post Script - I have re-titled and am abandoning this tread as you will see, we now know why the damper came off. The saga will continue in my main build thread.

So what happened?

We suspect the cause to be the nut behind the wheel . I bungled a shift a few miles earlier and over revved the hell out of it.

I was out in the boonies running repeated 1-3rd WOT pulls to data log IATs in a simulated track-day scenario. I was planning to take it to the track in a few weeks.

On the last pull, for some reason I missed 4th going up from 3rd and miss-selected 2nd instead at 7300RPM (this was an absolute first in 26 years of ownership).

I thought I had caught it as I was letting the clutch out and got back on it. However, I saw the tachometer swing up to ~8000 RPM.

I stopped the car. Everything seemed fine (at first) no weird noises, motor idling quiet, oil pressure appeared OK and the data log showed a spike to 7900RPM - which should have been OK. So I continued on my way.

A few miles later the damper came off. An now we know No2 rod bearing span.
 

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8k rpm didn't kill it I think. It was the sudden change in speed. Didn't know you can money shift these cars with their weak ass synchros.
 

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Discussion Starter #78
Post script.
The car had been waiting patiently in a queue at Larry's shop in Oregon and the motor is now stripped down. The crank is bent and the no2 rod is shot. I did some quick calculations and its possible that the motor saw >10,000 RPM during the missed shift, which probably caused or at least contributed to the retaining bolt for the balancer to shear off. Turns out the data logger wasn't operating correctly due to a voltage variance - caused by the Alternator coming apart as the 4 long thin bolts holding it together backed out.

Found a potential culprit for the missed shift -> the shift lever weight on the transmission was fouling a hose. Larry also found a few other issues that need work so - the rebuild begins and I'm sure well find a few upgrades to incorporate. Juts REALLY looking forward to getting it back on the road.
 

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i appreciate the update.
so you are certain the damper backed out as a result of the 10k rev?
 

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i appreciate the update.
so you are certain the damper backed out as a result of the 10k rev?
Not just a 10+K rev, but a violent acceleration from an unintended downshift. It bent the crap out of the crankshaft, it's certainly plausible it spit the balancer at the same time.
 
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