Stupid mechanics thread

[damn-I-Suck]

Soo many ppl slap turbos on their cars and don't know the first thing about compression, fuel injectors needing to be bigger (to be able to deliver more fuel for all that air you're shoving into the engine), fuel pressure regulators needing to be switched, possibly making cuts on the block as to lower compression ratio, reflashing the PCM so the system knows the proper air/fuel mixtures.

Basically, what HRD said about what happens when you're compression is too high. My dodge had a 9:1 ratio, which is normal for most naturally aspirated engines. A turbo would bump it up to prolly 11:1 and that engine was not meant for that kind of punishment.

Yeah, there's a lot of shit you have to do to add turbo and do it right. I am 1 1/2 year into my 2 year program and even I don't know everything you have to do for turbos. I'm not really interested in high performance anyways, I'm more into the day-to-day cars.

Personally, I think the best thing to do if you want turbo is to buy a car that already has turbo built into it from stock. Some people disagree, but that's my take on it.

 

[Solo]

Your story about your teacher reminded me of when I went somewhere to get an oil change. So I take my truck to the place to get an old change because family was paying it for me. First they ask me if I want a new air filter, I told them no. Then they told me I need to change my "Rear differential fluid". So I proceeded to tell him that all I want is an oil change. He asked me if I was sure several times so I just started saying I only need an oil change over and over. That pissed me off so much... He eventually gave up and said everything else looked perfectly fine then insisted I change my rear differential fluid. He's lucky I was in a good mood. If only I could have gotten his name I could have reported him or something.

 

[Hot Rod Dave]

LOL why you would put money into a taurus at all is beyond me. But yes its really easy to wrinkle up that o ring and cause a leak. Why it happened 3 months later is a little weird. Usually if you fuck up that o ring it starts to leak right away.

I know those plastic lines that hook to the pump are fragile. Ive replaced my share of those things. So before you go ripping your teacher a new asshole, see whats wrong first. Just seems to weird that it would give a problem 3 months later is pretty strange.

 

[Hot Rod Dave]

Your story about your teacher reminded me of when I went somewhere to get an oil change. So I take my truck to the place to get an old change because family was paying it for me. First they ask me if I want a new air filter, I told them no. Then they told me I need to change my "Rear differential fluid". So I proceeded to tell him that all I want is an oil change. He asked me if I was sure several times so I just started saying I only need an oil change over and over. That pissed me off so much... He eventually gave up and said everything else looked perfectly fine then insisted I change my rear differential fluid. He's lucky I was in a good mood. If only I could have gotten his name I could have reported him or something.

Thats a common tactic for shops that do oil changes. Shops dont make money selling you a $19.95 oil change. The real goal is to upsell you. They will check all your filters and fluids and recommend things based on mileage rather than "in need of repair." So you cant be to mad at the guy for trying to make some money off you.

Soo many ppl slap turbos on their cars and don't know the first thing about compression, fuel injectors needing to be bigger (to be able to deliver more fuel for all that air you're shoving into the engine), fuel pressure regulators needing to be switched, possibly making cuts on the block as to lower compression ratio, reflashing the PCM so the system knows the proper air/fuel mixtures.

*BOLDED FOR EMPHASIS*

Lesson #1 grasshopper in the high performance stuff. You dont cut the block to lower the compression. You cut the pistons. Cutting the block would make the compression actually higher rather than lower.

Just bored I guess. No offense meant hahahaha

 

[Pernicious-Soul]

Here's a couple pics of my car. Should have t3 turbo bolted up over weekend. With turbo psi set at 16 I should make close to 400 HP and tq.

Figured it was alright to post these here

 

[Pernicious-Soul]

Heres my stock $pec v

 

[Hot Rod Dave]

What happened to the days where building AMERICAN muscle was cool?

Oh wait.....It still is way cooler than you rice burnin, coffee can muffler, annoying sounding POS imports yall like!!

*shakes fist in air*......damn hippies!!

 

[Pernicious-Soul]

I've always had mustang and nothing will ever top a 5.0 but its hard to resist almost 30 mpg and 400 HP Lol.

 

[damn-I-Suck]

*BOLDED FOR EMPHASIS*

Lesson #1 grasshopper in the high performance stuff. You dont cut the block to lower the compression. You cut the pistons. Cutting the block would make the compression actually higher rather than lower.

Just bored I guess. No offense meant hahahaha

None taken. Actually I'm facepalming right now because I realized how what I said was that dumb. I'm still learnin', kay :)

 

[damn-I-Suck]

And BTW HRD, this POS 1994 Taurus is the ONLY car I have right now, so spending money on it was a no-option.

This is because my damned GF wrecked the car that I actually liked to drive. I'm still pissed about that

 

[damn-I-Suck]

Okay.. so here's what transpired at the shop in school today.

I get the car on the lift, first look under there with my flashlight. The entire bottom half of the tank is wet with gas, all around. Hmm..

So I drop the tank about 6 inches just so I can get my arm in there to disconnect everything.

I get the damn thing on the workbench. I plug up everything, I stick the smoke machine in one hole, and the goddamned thing starts pushing gas out just above the horizontal seam that goes all the way around. I wipe it clean just to be sure, the whole is too small to see with the naked eye, but I could clearly see gas getting pushed out and dripping.

Can you believe it? The goddamned fuel tank itself was leaking! Steel tank BTW.

So then my buddy gives my a ride up the street to napa and I get me some permatex gas tank sealer.

The directions on the back say DO NOT drive until 4 hours after applying. By the time I got it on there, my class only had 2 hours to go. So I basically had to sit there for 2 hours AFTER class was over just to wait for the damned thing to dry.

It was a bullshit day, but I am VERY relieved that the gas leak wasn't anybody's fault. It's one hell of a coincidence, but shit happens I guess.

I'm not 100% sure if this permatex shit works well or if at all. It was a 7 dollar gamble VS spending 150$ bucks on a new fuel tank that would have taken 4 business days to order from napa.

Hey HRD, do you have any experience with permatex gas tank sealer and does it work well?

 

[Hot Rod Dave]

Hey HRD, do you have any experience with permatex gas tank sealer and does it work well?

I do have experience with that shit. And lemme tell ya, its shit. If youre just looking for a temporary fix to get you by for a few months then its fine. But dont be suprised if a few months down the road it happens again.

Where do you live? Yall got snow and salt and that sort of shit out there or what?

ALSO:

Out here in san diego, most radiator shops also deal with gas tanks. They might be able to braze that thing up to seal it correctly. I suggest getting out the phone book and call radiator shops to see if they will mess with your gas tank.

 

[damn-I-Suck]

hmm..

Well I'm all about learning how to do that shit myself, so I might look into something else.

I live in NC, not much snow, hot and humid summers, and NO they rarely salt roads only when its black ice and that aint often

 

[damn-I-Suck]

Also, I don't know how to change the thread title, so if any mod or whatever is listening, if you dont mind, can you please change the thread title to " auto-mechanic/customer horror stories"

But then again, that what I just wrote sounds kinda lame, IDK, I'm not creative enough.

If this Mod can some up with something that sounds better/more suited to the content, be my guest. I trust you'll come up with something more interesting than what I did :)

 

[Hot Rod Dave]

So today at work, i actually thought of you damn-i-suck. Going back to the machine shop shit that i do, there are several engines you see on a regular basis. The infamous 3.0liter ford is a set of heads i see bout 3 times a month.

The problem with the 3 liter heads, is that the exhaust valves will actually pound themselves into the valve seat and actually start to pull themselves through the top of the head.

The above pic shows the bottom of the cylinder head. As you can see the exhaust valve has sunk far into the bottom of the head. When this happens the valve losses its valve adjustment and the car runs very poorly with the addition of a compression loss. As you can guess an engine doesnt run very well with compression missing from a few cylinders.

The common thing i see is that most mechanics will condem the entire engine. All they see is no compression and noises and will usually sell a customer a long block as opposed to a valve job.

This is what you would expect to see on an engine that has a few hundred thousand miles on it. This exhaust valve will be replaced as well but its nothing unusual.

Also notice that the valves are a different color. The top picture indicates major run-ability issues and the valve is just fried. As to where the bottom pic shows a valve that has seen better days, in fact looks like its been running pretty lean for a long time.

Moral of the story, 3liter fords are notorious for this issue. If you look in AllData you will see bulletins for days. Its also in rangers along with the taurus and believe it or not in some older marine applications.

An old man taught me a long time ago a remedy to fix this issue. From the factory, the valve seat in the heads is made of the same material as the rest of the head. Usually this is ok but the 3 liter has pretty high combustion heat. And the exhaust valve is the poor guy that has to do all the hard work, so an exhaust valve is made of a harder material than an intake valve. Hope that wasnt confusing.

To fix the issue you machine out the old seat and put in a valve seat made for a diesel head. They are super hard and a little expensive but the issue will never return.

However your taurus could have a 3.8 in it and which this whole story made no difference to you. But i promise you, if you ever work on a taurus that just seems to runa little funny, check the compression. Ill bet you will find a cylinder that dont got none or next to none. And when you diagnos that and look like a bad ass, you will think to yourself "holy shot, that weird guy from the internet was right!"

 

[damn-I-Suck]

it is the 3.0 BTW, it's pretty damn obvious since it says it right on the valve cover

But TBH, the only thing wrong with the car right now is a slightly rough idle that goes away as soon as you let go of the brake pedal. I've tested MAF, IAT, IAC, throttle pos sensor, even my fuel trim numbers are close to zero, which is amazing considering how old it is. Everything checks out as far as what would affect idle. (BTW this car does not have a MAP sensor). Edit: I also checked for vacuum leaks with propane and I got nothin. I suppose there was no need to check for vacuum leaks, since the fuel trim was damn near perfect, but there wasn't much left to test at that point.

What about a bad torque converter? It seems to make sense because the rough idle is NOT RPM related, since letting off the brake and letting it coast (not changing the rpms from an idle) makes everything smooth again.

And SOMETIMES, but very rarely, when it's idling, it stumbles as if it's going to die, then immediately springs back to life. The sensation is like when your driving a manual and you drop the clutch at a stop and stall the engine.

All things considered, this car has been THE most reliable car I've ever driven. You wouldn't believe how well this engine runs, ESP for one with 223,000 miles on it.

Just in case you were wondering, the engine I got was the ONLY one they made that year that still uses pushrods. And it also has an electronic distributer. So yeah, the engine is kinda old school technology.

I don't know shit about automatic trany's yet, but I do know that torque converters sort of take the place of a clutch in a manual. I can imagine that if it's not allowed to slip very well then it could cause vibration (which is mostly what I mean by rough idle).

Oh and I forgot to mention that if I put it into park or neutral, the rough idle goes away. It's ONLY when it's in drive and ONLY when the brakes are applied at a stop.

I WILL say however, that my GF's family had a 98 taurus with a 3.8 engine, and a 2000 windstar with the 3.8 engine, and BOTH of them crapped out before 200,000 miles. This 3.0 I got is still running FAR FAR better than those engines were at 150,000 miles.

Here's my guess as to why. When ford made the switch to OBD2 in 1996 (as everyone did), they hadn't worked out all the bugs and kinks of the new system. Also, right around that time ford starting outsourcing their manufacturing to places like mexico. So it's quite possible that a few years after the OBD2 switch, a lot of fords were crap.

my 94 uses old school technology that was well established and was tried and true at that point.

I could be wrong, but that's my theory.

 

[damn-I-Suck]

I think the compression is supposed to be somewhere between 150 and 200 PSI?

And when you disable the ignition and crank the engine, do make 3 complete engine turns for compression testing or more? less?

I need to write that shit down. I forget alot

 

[Hot Rod Dave]

I would be suspect of the brake booster. The symptoms you describe would lead me to believe that. Of course the booster works off vacuum. And would make sense if you feel a stumble when you got your foot of the brake and then trying to take off. Take off the vacuum hose to the booster. Then remove the vacuum switch. Make sure its not plugged.

The issue you describe can be a difficult one to figure out since its a problem that doesnt happen consistantly. Could be lots of things really but the booster would be the first thing I would check.

Yes 3 revolutions is what you want to test compression. Compression isnt controlled by anything electronic. Its a combination of cylinder head chamber size (measured in CC's) and in the dome of the piston. Compression is lost one of 2 ways. Either down past the piston rings (in which case you would have blue smoke out the tail pipe) or up past the valves (this would warrant a valve job type thing). IIRC the 3.0 should have 180lbs of compression or so. A difference of only about 10lbs between all the cylinders is what you would want to find. Anything more than that indicates a problem.

The old ford IAC motors are an arrow in the knee for old fords. Im suprised it checked out ok. Typically those things will make your engine rev really high at idle. You can typically take those off, clean out the inside with some carb cleaner and put it back on.

There is indeed a MAP sensor for those. But they call it a DPFE sensor. Looks like a MAP sensor cause it also runs off vacuum but works a little different.

 

[damn-I-Suck]

the thing is, I looked it up on alldata. Doesn't show a MAP sensor.

The MAF sensor on the other hand, on the description it says something like barometric pressure, which I would guess indicated that it measures pressure somehow. I'm thinking they worked some kind of pressure sensor/MAF assembly possibly? Or am I just interpreting it wrong?

Also, I can identify everything attached to the upper intake manifold, and I don't see a MAP anywhere.

Next time I get access to alldata I will type in DPFE and see what I get, have to wait till monday though.

The brake booster thing makes total sense, and I'm surprised I didn't think of it. Cause yeah that's how boosters work, they pull from intake vacuum. Plus, it only goes rough when I push the brakes at an idle. Thanks for the tip mate :)

Oh and BTW, I recently cleaned out the main EGR port by taking off the manifold, cause that shit was clogged as hell! Didn't seem make any difference, But I suppose I wouldn't cause EGR only opens under cruising and coasting.

 

[Hot Rod Dave]

To test out the booster i suggest disconnecting the big vacuum hose from the booster and plug it off with a bolt. Try to replicate the instance that you notice the stumble, and see if anything changes. Dont think i would suggest actually driving it without the bosster hooked up, instead chalk up the wheels, put it in drive and with YOUR FOOT FIRMLY ON THE BRAKES, give it some gas and see how the engine behaves.