FordSix Performance Forum

MechRick

The first turbo 4 I built, I tried 24 lb injectors at 10 psi. The duty cycle maxxed out before 4000 RPM. On an engine with 39 ci cylinders. Moved up to 46 lb-hr low impedance injectors scavenged from cfi Ford cars. That creates power supply noise issues, but it worked. Ended up with 63 lb-hr high im...

MechRick

You'll need 30 lb-hr injectors even at 6 psi.

It might be possible to run a bigger injector and a MAF system with a bigger MAF sensor.

Running a carb head will drop compression to a more boost friendly level.

MechRick

Last time I dropped a block at the machine shop with KB pistons he quipped "oh, you want to install 'made in Mexico' pistons?" I've used both brands, the Sealed Power pistons were better weight-matched than the KB-performance ones I used on a previous build. The Silvolites are a cheap rebu...

MechRick

If you installed the pickup *without* moving the distributor, and then had to move the distributor to get the timing back, the pickup wires are likely backward. The pickup pulse would be negative and the cap/rotor phasing way out, causing crossfire.

MechRick

HOW SURE ARE YOU ALL THAT IF I GO WITH THE SNIPER UNIT I CAN MAKE A BLOW-OFF VALVE WORK? The problem is the valve will vent whenever there is sizeable pressure in the inlet duct and sizeable vacuum in the intake. Turbos only get there on throttle lift, blowers more often. Imagine a high speed coast...

MechRick

Have you checked the fuel pressure regulator? Unplug the vacuum line and see if it is weeping fuel.

MechRick

If the base timing has been adjusted higher than the stock 10 degrees, it can create this symptom. I ran mine 12-14 degrees and lived with it. If you don't have one already, one of the cheap code pullers that are capable of displaying data are useful. When the engine is warm, accessories off, look f...

MechRick

And if you were going to machine the pedestals, might as well set it up for screw-in studs. Bummer. Scratch the high-dollar rockers then.

Still, I wouldn't toss a pedestal (rail) head if the cam lift was mild. The .060" length difference with the aftermarket valves isn't extreme.

MechRick

No screwing around making shims with flats on the edge like you have to do for all the engines that have a channel machines in the pedestal for rocker alignment. ...Like the Clevelands and BB Fords. I guess the '85-plus heads should be called rail rocker like the small block Ford stuff. Someone loc...

MechRick

I would junkyard hop, find an '85 plus head, port it, get the Scorpions and swap it in at some point. The vast majority of 300 sixes out there never see more than 5500 RPM. Spring tension can be kept light (and should be with a flat tappet cam). Running pedestal heads avoids dealing with studs that ...

MechRick

I have three. First was back in '95, Lady overheats a Contour to the point that the cylinder walls change shape. There were no oversize pistons or factory short blocks yet. Ford sent me all the parts to assemble a short block. When I get done, there is one oil gallery plug left over. "Must be a...

MechRick

If your truck is speed density *and* you have a high idle, suspect a vacuum leak somewhere.

Could be causing your evap code too.

Remove the IAC, cover the holes with duct tape, see if it still idles high.

MechRick

http://www.msextra.com/forums/viewtopic.php?f=4&t=41683&start=0 Scroll down a bit to see Megasquirt timing tables. Those numbers must be added to base timing, giving ~50 degrees of ignition lead in some parts of the table. Low kph = high vacuum. I've seen some references that suggest setting...

MechRick

Thanks that makes sense. How could that be accomplished? High volume pump or high pressure pump? Or reworking a standard pump? When Ford turbocharged the 2.3L they added a high volume pump for the reasons Paul mentioned, and also because some of the oil is supplied to the turbo. 2.3's carry super h...

MechRick

https://fordsix.com/viewtopic.php?p=615617#p615617 https://fordsix.com/viewtopic.php?p=607029#p607029 https://fordsix.com/viewtopic.php?p=605254#p605254 I finally peeked at the PCM in my '88, when I was chasing a strange random rough running condition that ended up being a blown fuel pressure regula...

MechRick

From the ad they appear to be pedestal mount. An original '84 head should have studs, you would have to pull the valve cover to be sure. Or maybe check the casting number on the head.

MechRick

I edited my original post (typo). Torque comes in at 2000 RPM. But I agree with your conclusions. I would add that my experience with the Comp 268 in my truck would prevent me from using a cammed 300 in a 4x4. Below 1200 RPM it exhibited nasty behavior that made idling over obstacles a chore. It mig...

MechRick

The second combination would be to use a turbocharger which could provide over 500 ft lbs of torque at low rpm. This is the direction I would go. Typical hot rodder tricks with induction, exhaust, cam and porting will move the peak torque and HP to higher RPM. The 4.9L makes 265 ft lbs at 2000. The...

MechRick

The one barrels seem to get fantastic fuel economy. I remember a sign in the Lincoln-Mercury dealer I worked at in the 80's had a sign displaying the Capri stating "The cat's full of surprises" showing an EPA highway MPG rating of 40 mpg. 2.3L manual trans 1 bbl. That was back when the spe...

MechRick

So you are going to completely remove the dividers? The only problem I forsee is you *might* create mixture distribution problems. If you can make the plenum and intake floor appear like a known configuration (like an Offy 'C' or Clifford), you should be able to avoid that. If you remove the divider...

MechRick

Modern front wheel drive cars seldom run fans as long the A/C is off. I've had customers that have driven for weeks with inop fans (in the winter) and never knew there was a problem. I rigged a Mazda pickup to use the torque converter lockup signal to shut the fan off when lockup speed was reached (...

MechRick

What he said...

I converted from the two-piece shaft to the aluminum CV unit. Longer driveshafts generally have a lower critical speed, aluminum helps raise that a bit. Police shafts are certified for higher RPM.

The Crown Vic shaft was the correct length for my combination of parts.

MechRick

How does that gear reduction box work when reaming guides? I've had a big honking 1/2" drill on my wish list for that...

MechRick

Simple answer: Primary pipe should be 80-90% of the exhaust valve size. The in depth answer takes account of camshaft duration, intake tuning, intended usage and intake/exhaust port diameter. Tuned headers provide a torque bump around a certain RPM. You can raise or lower the RPM point by changing p...

MechRick

The 1996 trucks need the air injection and EGR to be working to keep the check engine lamp off. Although you could make a header work with some creative welding, the EFI manifolds work fine. You will notice two converters on your truck. The forward converter acts as the Y pipe, and has a big enough ...

MechRick

What;s the year-make-model of the vehicle?

MechRick

Both were 80% highway, 20% city. The 19 mpg was in Ohio when the speed limit was still 55 mph. The Bronco would drop off to 13-14 mpg with heavy city use. The 390 Holley was a 4bbl... https://www.holley.com/products/fuel_systems/carburetors/classic_holley/parts/0-8007 I highly recommend them. The Br...

MechRick

I did that on my '81 years ago. Ran a 2bbl and then a VV on an Edelbrock 4-2bbl adapter, lined up over the fatter side of the intake runners as a temporary solution while I saved money for a 4bbl. I got 19 mpg with the VV. An open spacer should be a better solution. It's similar to the carb adapter ...

MechRick

If the open 2V part of the 2x4 adapter sent air/fuel mixture down the Pri runner & some down the Sec runner would it be at different rates? Yes. Probably dependent on RPM and intake runner resonance. I would be concerned with mixture distribution. I think less plenum actually helps in this rega...

MechRick

I wonder if those pistons are 351m-400? The pin size would work with late rods. Not sure on the comp height though.

MechRick

I've been told that all rings spin on pistons that are in motion, and are not supposed to stop with the gaps lined up. Ford had a problem with this when switching to SEFI in 1986. SEFI allows low-tension oil rings to be used (along with a PCV valve that flows enough to scavenge the extra blowby, mor...

MechRick

The one engine I built with Total Seal rings, upon teardown had all the ring gaps lined up. If you intend to spend the extra money, I recommend going with a moly-faced slant or step gap ring instead...

MechRick

I assume the hypereutectic pistons would be better than the old cast pistons for a mild turbo application as long as detonation is eliminated and the fit is not too loose? A bit better. The stock cast early pistons are shockingly fragile. A good cheap turbo long block would be a good running late h...

MechRick

In the early days of EFI development dyno operators would sometimes call my office to tell me "something is wrong with your EFI system - the engine is not running right." I had to talk them down off the ledge and explain that under all that electronics there was still a conventional engin...

MechRick

I had the original version (Carter AVS) on a 340 Duster. The bowl is very similar to the AFB, and I have had heat issues with those with a header. Tried the thick Ford 4bbl isolator, didn't help. A sheet metal heat shield between carb and intake might have done the trick, never got around to trying ...

MechRick

So I'm thinking that two 2-1/4 pipes, considering that I've only got 2.5 L per turbo at lower rpm and smaller turbos feeding them will work for the level of performance I want From experience, bigger down pipes will help the turbos spool quicker. Ford Turbo Coupes (Garrett T3 turbo and IHI RB52 in ...

MechRick

Does it happen after the engine is warm? I'm wondering if the valves are sticking in the guides when warm.

You might try a running compression test after the engine is good and warm.

MechRick

Nice work!

If you are running EFI you may run into problems with fuel slosh. Some sort of a baffle surrounding the pickup and fed by the return line would solve that.

I'm betting there is an o/e tank that could be made to work, perhaps the rear tank from F series or Bronco II?

MechRick

Air gets trapped in the master and slave from the angle of the drive line and master cyl mounting. Raise the back end of the truck until the valve cover is level, and rebleed. Remove the master from the firewall and depress the master plunger with a Phillips screwdriver, keeping the line fitting hig...

MechRick

How does that engine push your 3/4 ton around? Those are some great numbers.

MechRick

Yes, Nebr Rex. along with arse_sidewards and Backwoodswalker375, your sharp eyes noticed yellow top injectors rated at 19 lb/hr installed where gray tops are supposed to be (14 lbs/hr). https://fordsix.com/img/i.php?/upload/2019/04/20/20190420094516-596b75c4-sq.jpg Truck had a stuck open thermostat ...

MechRick

Follow the vacuum line off the EGR valve, it is supposed to be hooked to the solenoid I'm talking about...

MechRick

You will see 3 solenoids at the left rear of the valve cover above #5 and #6 spark plugs. Two of them are identical, those are TAB and TAD for the air injection. The remaining one will have a round plastic cap covering the vent tube with a foam filter inside to keep dirt out of the solenoid. The rou...

MechRick

332 egr valve opening not detected. The egr solenoid is on the rear left of the valve cover. Probably a vacuum issue. Best way to check, pop the round black plastic cover off, start the truck and block the tube on the solenoid with a finger. The egr valve should open and the truck will stumble if th...

MechRick

Ding! Ding! Ding! We have two winners so far... The coveted fordsix silver star goes to arse_sidewards and Backwoodswalker375 who both spotted the problem. Bonus points to arse_sidewards for noticing the missing purge valve. Since it's speed density, that will make it idle fast. I'll post an after p...

MechRick

To give others a chance, PM me or let it marinate for a while.

MechRick

Carbs used with blow-through setups will need to be incrementally richer. I recommend getting a good book on the subject (if you haven't already). I like Street Supercharging (S A design books, Pat Ganahl). It has a whole chapter on carb tuning for use with blowers. https://www.amazon.com/Complete-G...

MechRick

I was diagnosing an emissions failure on a 4.9L F150 today. It was blowing 1300 ppm HC and 13% CO. Thought I would share an image of the engine compartment. The owner has had a few different mechanics (using that term loosely) working on it. See if you can spot what was wrong with it. https://fordsi...

MechRick

Unplugging the FP relay will rule out a stuck injector or shorted injector control circuit.

You may have to pull and dry the plugs.

Determining whether it's spark or fuel will narrow the list of possible faults.

MechRick

With the compression you have, the engine should run given proper fuel and spark timing.
It sounds to me like you are getting too much fuel.

Would it be possible to unplug the fuel pump relay, dry the engine out and see if it runs with an external fuel source?

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