Blog

May 03, 2023

Small

Related Video Progress on our 1986 Ford Mustang T-top coupe project remains on

Related Video

Progress on our 1986 Ford Mustang T-top coupe project remains on course, with all of the necessary parts acquisition happening and/or repairs being made at a pace that should have us firing the engine and taking the coupe on a maiden voyage by midsummer (we hope saying this doesn't jinx everything).

For those who are just getting up to speed with this build, HOT ROD senior editor KJ Jones recently reintroduced a heralded former 5.0 Mustang and Super Fords project car that has been out of commission for the last 10 years. Since the reveal, KJ and Saul "the Surgeon" Gutierrez have revamped the coupe's fuel system, and during that process, started disassembling the Paxton Novi 2500-supercharged, 350ci Ford engine.

Yes, the blown small-block really measures three-hunded-and-fifty cubes, which is an unconventional displacement for 8.2-deck Blue Oval powerplants. The combination was achieved with a 4.145-inch bore size, with a 3.250-inch stroker crankshaft and 5.400-inch rods, and decided on when the engine was hurt years ago. We opted for the horsepower and torque of a big-bore stroker 302, which also is considerably lighter than a 351 Windsor-based engine.

For this installment, we dismantled the stroker to inspect its internals, mainly on the top half. We were acting on the possibility that despite the coupe's storage in a dry Southern California garage (that does experience severe heat/cold temperature cycles as the seasons change), the Comp Cams valvesprings might be fatigued from rocker-arm pressure, and the Australian Muscle Parts timing belt may be dried out and cracking after 10 years of dormancy.

So, we removed the Novi, the Vortech Igloo intercooler and TFS-R intake manifold, leaving us with AFR Renegade 220cc small-block Ford cylinder heads

Read on through the following photos and captions, and watch the videos closely, as we take you inside Project T-Top Coupe's powerplant, detailing our findings and offering ProTips on how to correct the damage.

As a rule of thumb, rocker arms should be loosened (at least) or removed if/when an engine is parked for a lengthy period of time. Doing this relieves pressure on the valvesprings, which allows the valves to fully close, and keeps the spring rate where it should be while the engine is idle. Before loosening rocker arms, liberally spraying a rust-inhibitor into each cylinder (at the spark plug holes) is a best practice, as is making sure all of the valves are closed. In hindsight, KJ didn't do this, and by failing to do so, he learned a pretty big lesson.

Removing the AFR cylinder heads unveiled maladies that at first blush were a lot more concerning than weak valvesprings. We initially thought the substance on top of Number 4 and Number 8 cylinder walls was rust, and pitting on the pistons that typically warrants removing the engine and starting over. Closer inspection confirmed that what you see here is oxidized carbon, probably caused by a combination of residual fuel reacting to moisture that entered the combustion chamber over the years. And how did that happen?

Again, "fixing" our engine's problem thankfully was not a matter of yanking the engine and rebuilding it. A first plan of attack is to give the short-block a thorough soaking with a good rust inhibitor. Hot Shot's Secret's "Never Rust" spray lubricant is our go-to for this, as it cuts through the substance without damaging cylinders or pistons.

In our next report on Project T-top Coupe's resurrection, we continue detailing forensic discoveries, as Scott Hesselgrave at Air Flow Research and Greg Dawley at Vortech inspect the Renegade 220cc cylinder heads and Paxton Novi supercharger, and right their wrongs (yes, there were wrongs) accordingly.