Junk Motor

[jeffko]

Have any of you guys ever heard of a fuel injection leaning out off idle and trashing a motor to where 6 of 8 cylinders were 30% of the 2 decent cylinders on a compression test? By the way, the engine has less than 10 miles on it.

[HI Cobra]

If it has aluminum pistons I could see that happening. We lost a cylinder in
an airplane engine when one of the injectors clogged and it ran lean enough
to melt the piston. More than $12k to fix - ouch.

[Bill Wells]

Jeffko....who built the motor ? Bill

[jeffko]

I would rather not say who the builder or injection guys are until this thing is hashed out. Motor was built by an engine builder and dynoed before delivery. He is blaming the feul injection guy and the fuel injection guy is blaming the engine builder. Both have been paid and everything is supposedly warrantied, but guess who is stuck in the middle. Also, let's not forget that there is only 10 easy going break-in miles.

[Tony Ripepi]

Hello Jeffko,

If the fuel injection is controlled by an engine management computer the fuel map itself may be the culprit. When the Engine Mamnagement Sytem is installed there is a matrix of Fuel/RPM installed that controls how much fuel is fed into the injectors at what RPM. Typically there is a start up matrix for a new engine that is a little rich to prevent the kind of issues you described. If the EMS was installed with a lean RPM map it would always be lean, melt the pistons and destroy the engine no matter how easy you were on it. When it was run on the dyno this may be where the damage started.

Some EMS systems control iginition only, some fuel only and some fuel/ignition combination.

It may be the place to start asking questions of the people involved and determining the root cause of the damage.

TR

[aldersonjames20]

If the VE table was initially set to lean, wouldn't that be the same for all cylinders? I read it to say that 6 cylinders are burnt and the others are perfect...is that the case?

Edit : What are each of the possible culprits blaming the other for doing exactly?

James

[fastrods]

Hey Jeffko,
I have an Accel DFI setup that I installed on a Pond aluminum block.
I have had nothing but troubles with it.
Their dual sync distributor broke twice on me and now the injectors went.
I was told 2 were stuck open, 2 were not firing and the other 4 were not flowing right.
If your injection is Accel, I would question them.
Injectors do break, so it is hard to blame the engine builder or injection guy.
I had everything break on my build, 2 msd coils, dove expansion tank, starter, aeromotive pump, 2 bad Pond blocks.
If I did not build my own engines I would have never believed this!
Bill

[decooney]

fastrods,
2 bad Pond blocks?

I'd like to discuss with you offline if at all possible.

[jeffko]

What do you guys think about the timing somehow jumped to allow it to be way advanced and cause detonation? I guess I am having trouble with thinking the injection could be the cause for that much damage so quick.

[RICK LAKE]

Jeffko Befor I jump into this, do you have any pictures of the piston tops? If this motor was running real lean you would have felt it. Motor would be knocking. You should have an innovate air/fuel monitor. This runs separate from the FI system in your car. Call it a backup checker. Pull the plugs and O2 sensor and see if they are all wet or Black fouled. The motor sound like a washdown job with 2 bad injectors damaging the O2 sensor and the FI system trying to adjust by leaning out everything. If you want to send me a private mail I will try and help you find out what happened. Pictures would really help. It's hard to find a REAL fuel injection person to setup a system. It took me 3 months and a 200mile trip for my FAST system. It was worth every dollar. Is not Wheel to Wheel in your neck of the woods? Rick Lake

[jeffko]

Rick, you have mail.

[RICK LAKE]

Jeffko Jeff give me a number to call you at tomorrow night around 8:00pm Rick L I can't type this much to explain

[ByronRACE]

It's very difficult to break a ford V8 by running it lean.

That is, unless it begins to detonate.

So, did it run lean ONLY...and cause thermal damage like melted pistons (near impossible to achieve, the engine won't hardly run at that lean air/fuel ratio), or did it rattle and you didn't hear it and/or didn't back out of it and holed/broke pistons. If you have broken rings, lands, and associated damage...it detonated.

Detonation is usually caused by excessive spark advance. Yes, a lean mixture can influence it...but it's a lesser influence. A properly timed engine can tolerate a very lean mixture; even at wide-open throttle...unless this is some exotic high-compression thing.

Byron

[Rwillia4]

Could it be the gas? O2 sensors don't like leaded fuel.
Are the pistons trashed or the cylinder walls?
Is it a new tank with (maybe) some crap in it that clogged the fuel injectors.

[Jerry Clayton]

Jeff

Call me at the shop around noon

Jerry
630-365-6737

[jeffko]

Well we have found it, I would even say remarkably easy to break a Ford engine under a lean condition. Let me just say I am convinced of it, but the engine has not been disassembled yet. However, I think they will find severe heat destruction due to the fuel delivery system being inadequate, very inadequate.

This engine dynoed at 670 with 42lb injectors. We still do not know what the fuel delivery was at that time, but the fuel delivery system that was sold as a kit with the car was a 110 gallon/hr pump that was delivering 40 psi. Keep in mind that this engine has a 9lb supercharger?

I never did know much about fuel injection and still don't, but I can say that based on what I have been told by people that do know fuel injection, formulas and the engine build sheet this is more like what the engine should have had for fuel delivery. The injectors should have been 65lb with a pump delivering fuel at 275 gallon/hr at 53 psi based on an 80% duty cycle and 9lbs of boost. The exact calculation is 67.4 lb/hr at 708 cc/min instead of the 42 lb/hr at 441 cc/min. Another term I learned of is BSFC which stands for brake specific fuel consumption. This is how much fuel an engine uses in terms of pounds/hr per horsepower. It should have been .60 rather than the actual .41.

I have built several engines, including the 470 rwhp 393 in my cobra, and spent a lot of time over the last year with the finer points of carburetion so I have some knowledge of car engines. Originally I had though detonation to be the more likely suspect. Even though it is unlikely that the timing slipped or the distributor advance malfunctioned I thought it more unlikely that a lean condition could kill this engine is less than 10 miles.

Guys, this is what makes this website so valuable. It's a classic case of buyer beware!!! Do your homework and stick your nose where they don't think it belongs. Because in the ends it will be you sitting in a $50k car that won't move for whatever reason and may still have at least a fight and maybe even more money to spend on your hands.

Now what is left to see is if the people responsible make good.

[ByronRACE]

Originally Posted by jeffko

Well we have found it, I would even say remarkably easy to break a Ford engine under a lean condition. Let me just say I am convinced of it, but the engine has not been disassembled yet. However, I think they will find severe heat destruction due to the fuel delivery system being inadequate, very inadequate.

This engine dynoed at 670 with 42lb injectors. We still do not know what the fuel delivery was at that time, but the fuel delivery system that was sold as a kit with the car was a 110 gallon/hr pump that was delivering 40 psi. Keep in mind that this engine has a 9lb supercharger?

Hold the phone! Supercharged, then OF COURSE you can kill it VERY easily with a lean condition; I concur. However, I'll still bet that the failure mode was detonation...which is even easier to achieve with a supercharged engine; especially if the timing was too high. What was the total advance?

Injector size. If it dyno'd 670 on an engine dyno with 42lb/hr injectors without running lean, that's the first Ford I've ever seen do that. You should not have been able to get past 630fwhp at 12:1 AFR and I wouldn't be running a 670fwhp supercharged engine any leaner than 11.5:1 AFR personally; so it should not have made it past 600fwhp with those injectors unless you did something and raised the fuel pressure well beyond the 40ish psi typical operating pressure.

That said, 42's are too small, 48's are barely large enough; and I'd go directly to the Mototron 55/60's...why not; there's little reason not to...they can be tuned down just fine. I street 160lb/hr injectors in my cobra...if I can do it with 160's, you can do it with 60's easy.

Spark. Tell me what heads are on it, and what the static compression ratio is, and I can tell you what the spark should have been up top for CA 91 fuel with 9lbs of boost. Also, what kind of supercharger? Centrifugal or screw? I keep experimental records of every engine I've tuned since the late 80's...I have notebbooks full of small block ford data.

If you're building your fuel system now, you should use a -6 feed/return minimum; and there's little reason not to go to a -8 feed...it's about the same cost. What are you using for a fuel pump? Hopefully not one of the A1000's or similar; seen many many of those not live, and when they die the failure mode takes the engine with it. The seals start to give and pump output decreases as the pump warms up...which leans out the engine and kills it every time. I'd use either a pair of walbro pumps in parallel, or go directly to a pump design like a weldon or similar that doesn't use the fuel as a pump coolant; the best solution. Those flow-through pumps heat the fuel up. Using a pump controller helps, but the best solution is to not use the fuel as a motor coolant.

Anyway, rambling...

Byron

[Burgs]

um,... you never said it was a forced induction set up! That changes everything!

[Jerry Clayton]

Jeff

If I understand this ----you have not taken the engine apart--you have only taken a compression check, so the plugs are out---what did they look like?
Were the plugs checked after the dyno? Compression? Does the car have boost and fuel pressure guages? Did the dyno setup have boost and fuel pressure monitering?
What fuel was the engine dynoed with?
What fuel is in the car?
With a new install there is a strong possiblity that crap from the fuel cans, tank, fuel lines entering the injectors
What are you using for a controller?

The HP numbers you are quoting are possible without a supercharger--was the blower added after the dyno run?

How much timing advance was being run?

Ten easy break-in miles---sometimes the leanest conditions with advanced timing occur with easy driving

If the engine was in such a tune to cause that much damage, it would of run very poorly on those 10 miles

Jerry Clayton

[jeffko]

ON A BETTER NOTE MY CAR IS RUNNING VERY WELL WITH THE CARB I BUILT. I AM ANXIOUS FOR OUR SPRING BYRON EVENT. WITH A SET OF MT STREETS I AM HOPING FOR WAY DEEP 11s AND MAYBE EVEN THOSE 10s YOU SOMETIMES MENTION BUT MAY NEED A BETTER DRIVER. MAYBE CHRIS WILL STILL BE WITHOUT A CAR.

Originally Posted by Jerry Clayton

Jeff

If I understand this ----you have not taken the engine apart (THE ENGINE WAS TRAILERED IN THE CAR BACK TO THE ENGINE BUILDER)--you have only taken a compression check (I WAS NOT THERE BUT SUPPOSEDLY THEY DID), so the plugs are out---what did they look like? (I HAD #1 OUT TO CHECK DAMPER POSTION AND THEY WERE TOTALY BLACK FROM FUEL)
Were the plugs checked after the dyno? (DON'T KNOW) Compression? (I BELIEVE 9.5:1 AND HEADS ARE AFR 225) Does the car have boost and fuel pressure guages? (YES) Did the dyno setup have boost and fuel pressure monitering? (WAS NOT THERE)
What fuel was the engine dynoed with? (I WOULD GUESS 93)
What fuel is in the car? (93 PUMP GAS)
With a new install there is a strong possiblity that crap from the fuel cans, tank, fuel lines entering the injectors (I UNDERSTAND BUT DOUBT THIS WAS THE CONDITION HERE)
What are you using for a controller? (SEVERAL PEOPLE HAVE ASKED BUT I SHOULD NOT SAY YET)

The HP numbers you are quoting are possible without a supercharger--was the blower added after the dyno run? (DYNO WAS PERFORMED WITH 9LBS OF BOOST)

How much timing advance was being run? (12 INITITAL AND 38 TOTAL ON PAPER. I ONLY CHECKED THE INITIAL AND IT WAS 12)

Ten easy break-in miles---sometimes the leanest conditions with advanced timing occur with easy driving

If the engine was in such a tune to cause that much damage, it would of run very poorly on those 10 miles (IT WAS ONLY A LITTLE ROUGH THEN WENT TO HARDLY RUNNING AT ALL)

SUPPOSEDLY THEY WILL BE TEARING DOWN THE MOTOR THIS WEEK AND WE ARE ASKING FOR PICTURES.


Jerry Clayton