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HOT ROD Rescue: Missing 25-cent Oil Plug Ruins Engine

HOT ROD logo HOT ROD 2018-05-15 Hot Rod Network Staff

The Combo


After Tevete "T" Usumalii gained title to a 1988 Ford Bronco 4x4 that had been sitting derelict in an old buddy's driveway since 2008, he soon realized its tired 302 motor needed some major help. As T puts it, "I wanted a weekend fun truck, off-road-capable that I could take to the mountains, desert, or beach. It had to have good performance under load. When I put my foot to the floor, does it do what I want?"

What "T" wanted was a 349ci stroker (4.040-inch bore by 3.40-inch stroke), with a high-performance RV cam and free-flowing Air Flow Research (AFR) aluminum cylinder heads. "Two different guys had their hands in this project and they turned out to be real shady," T says. When the engine was finally finished and installed, it was transported to Westech Performance in Mira Loma, California, to tune-in its aftermarket MegaSquirt EFI system.

The Initial Diagnosis

Running on Westech's SuperFlow chassis dyno, right from the start (err—no start?) the Bronco had a crank/no-fire condition. Turns out, the engine wasn't getting any spark because the motor's new aftermarket coil had burned up. The bad coil was temporarily replaced with an OE coil, and the truck then started right up—but now the motor wouldn't shut off. It turned out the ignition circuit was incorrectly wired. There was a feed-back to the ignition switch key, so the system never de-energized. The electronic control unit (ECU), relays, and coil received constant power all the time (at least until the battery died). This overheated the coil, causing the failure.

The Get-it-Running Fix

Nearby ace Ford tuner Mark Sanchez (Advanced Engineering West) was called in for a consultation. "I went to check the engine at Westech," Sanchez says. "The lifters were making noise, so before looking at the wiring, I checked the oil. There was no dipstick tube in the motor. The dipstick tube hole had been sloppily filled with silicone. We drained the pan to find if there was any oil in the engine. There were 5 quarts in the pan. It was already dirty, so we threw it out and put in another 5 quarts of clean oil.

"I got the engine to shut down on its own without disconnecting the main battery ground by hooking up a late-1980s factory Mustang ECU using my Ford service 60-pin breakout box—think of an old-school switchboard deal—and bypassing all the crappy wiring. Once we knew the no-start had nothing to do with the motor, I partially reworked the butchered harness so it would start with the MegaSquirt. Westech then attempted to tune the ECU, but the engine had a constant miss. Every lifter on the driver side was noisy. Westech aborted the tune; they were worried about the noisy lifters."

Westech Performance is a tuner shop and doesn't usually get involved in long-term internal engine repair, so Sanchez and HOT ROD decided to ride to the "rescue." The Bronco was transported to nearby AEW for hard-core diagnostics.

The Main Problem

AFR heads have a fully adjustable, stud-mounted valvetrain. When Sanchez received the car, he hooked up an external oil pressure gauge to the standard pressure-gauge port above the oil filter and removed the spark plugs, disconnected the ECU (which turns off the electric fuel pump), and cranked the engine over to fully pump up the lifters. "During cranking, the oil pressure gauge read 65 pounds," Sanchez explains. "I tried to adjust the heads' Scorpion roller rockers, starting at the No. 1 cylinder and working my way through the firing order. When I got over to the driver side, I noticed the rockers on cylinder Nos. 5 and 6 (the first two driver-side cylinders on a Ford) weren't getting any oil out from the pushrods. At that point, I thought there must be something wrong in the lifter area.

"The Bronco had a two-piece Edelbrock EFI intake. To check the lifters, you must remove the upper plenum half, pull out the distributor, and then remove the lower half. After I removed the distributor, I saw it had a cast-iron distributor gear, typical for a 1988 that would have originally come with a non-roller cam. Looking more carefully down the distributor hole in the block with a flashlight, I observed the motor had a hydraulic-roller cam, which requires a different distributor gear. Suddenly, I saw there was no plug for the passenger-side oil galley (which is the only one you can see through the hole—I got lucky). Unfortunately, the motor had already run for about 15 minutes."

The Main Diagnosis

D'oh! The engine now required a complete stem-to-stern damage inspection. Although the top half could be checked in the vehicle, the easiest way to check the condition of the cam and bottom-end bearings was, according to Sanchez, "To just go ahead and pull the motor. Only a lazy man works twice."

With the motor on an engine stand, Sanchez noticed the oil pan's rear lip seal had slipped into the oil pan when it was being assembled: "It was leaking big time. Some idiot had put silicone sealant through the top, bottom, and edges of everything."

Sanchez removed the pan, then the No. 3 main cap. "That's the thrust bearing on a Ford, so it usually receives the most abuse. The thrust end turned out to be OK, but the bearing's crank-journal surface had serious scratches and wear for an engine that had almost no running time on it." Further teardown revealed additional cam, rod, and main-bearing damage; scuffed piston skirts; and deep vertical cylinder-wall scratches.

Nevertheless, the pistons and crank journals appeared salvageable, while the cam was fortunately undamaged.

The Fix: Short- Block

YearCasting No. Main Webs
1986-1995E7TE-CA or -PAHeavier

0.740 (0.040 2) = 0.720

The Results (So Far)

Lessons Learned

"25 cents cost him a whole engine!" — Mark Sanchez, AEW

Just because there's good oil pressure at the standard pressure checking point doesn't necessarily mean all areas of the engine are getting oil. Pre-prime a new motor before installing the intake. That way you can see that oil is going where it should go, not where it shouldn't. Over-looking one small thing could cost you an entire motor, so don't rush through an engine build—check everything! If farming out the build, choose a reputable, legitimate shop with a quality reputation. You may pay a little more up front, but end up saving a bundle in the long run.

002-1988-Ford-Bronco-Tevete-Usumalii-static© Hot Rod Network Staff 002-1988-Ford-Bronco-Tevete-Usumalii-static

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