Pick My Winter Project: Cam the M3, or Engine the Cougar

Kinja'd!!! by "MikaelVroom" (mikaelvroom)
Published 11/30/2017 at 14:35

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You guys.

I need help.

Well yes, psychological help obviously, but also help making a decision.

Kinja'd!!!

The race slash project cars have been parked for the winter. Now is the perfect time to dig in deep and get some work done on one of them. But what to do?? I’ve narrowed it down to two options, but I can’t figure out which one to jump on. Due to time and budget constraints, I can’t do both. Help me, internet, you’re my only hope.

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I’ll introduce you to the two potential projects. First comes the M3. I bought this car in December 2014 and spent the first half of 2015 swapping in a 5.0 V8 from a Ford Explorer. I wrote about it here on Oppo.

Since then, the car has been raced, beat on, broken, and fixed over and over again. It’s taken everything I’ve dished out with only (mostly) minor failures, and I’ve had a blast with it. In 2017 alone, I hit up eight autocross events, two autocross schools, a rallycross, and a drag strip.

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The car is well-sorted and a blast to drive. The only downside? Power. I’m still running a nearly bone-stock Explorer engine, including the stock towing cam and horrible exhaust manifolds. The thing was rated at 215hp and something like 285ft-lb. By 4500rpm the engine is just about done and power drops off precipitously. I have my rev limiter set to 6200rpm, but that’s only so I don’t have to shift into third before the end of any long straights. There’s no power to be made up there.

Here’s the thing. It’s not that bad. Having all of the torque on tap from 2000rpm is glorious for tearing out of corners and around cones. On a rallycross circuit, I can spin the tires at any place and at any RPM by putting the pedal down. Torque is tasty. Torque is glorious. Torque is life.

But when horsepower matters, the car falls short. At the drag strip I was cutting 1.8 60' times but only managed a 14.0 et. If I want to step it up this next year and do any open track events, it’s going to get really old getting passed on every long straight by stock Miatas. And if I care to dabble in drifting? It sure would be nice to spin the rear tires.

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So what’s it gonna take to radically transform the character of the engine? To convert it from a low RPM snoozer to a high RPM bruiser? A cam. That’s it. Well, and probably headers.

See, that’s the great thing about the Explorer engine. It comes from the factory with the GT-40 heads, Ford’s best factory offering and the heads they used on the 351 Lightning pickup. Also, the Explorer intake is functionally the same intake used on the Mustang Cobra, and it makes more low- and mid-range torque than any of the aftermarket 5.0 manifolds while only giving up a few horsepower above 6000rpm. The engine has the supporting parts already, it just needs a bumpstick to open those valves a little further and hold them open a little longer and it’s more than willing to pump out the ponies.

And headers. The Explorer is saddled with some of the worst exhaust manifolds I’ve ever seen. Seriously, just look at this garbage.

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See that part on the passenger side manifold where the exhaust from three cylinders is being routed through an opening the size of a steak fry? Yeah that’s not good.

The manifolds are shaped that way because Ford squeezed the 5.0 in between the frame rails of what, today, would be considered a fairly small SUV. I retained those exhaust manifolds because they fit perfectly between the frame rails of my M3. But they’re not good. And obviously there’s not an off-the-shelf solution for putting an antiquated Ford engine into a beat up German sedan, so I’ll have to make my own.

All of the calculators tell me headers and a cam will be good for a bump of about 100 horsepower. And the cam I have picked out maintains the same 275ft-lb at 2000rpm that the stock cam provides, so I’m really not losing any low end. Win-win? Mostly.

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The car is decently reliable, the engine especially. Not that much stuff is going wrong with it. I had to throw a water pump on it because the old one was weeping, but that was $22 and an hour or so because the front end of the car was already off.

But if I break into the engine, I could be opening up a can of worms, and I’m not sure I’m ready to do anything more just yet. If I end up having to pull the heads off, I’m not sure the car will be ready to race by next season. That’d be sad.

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Here’s option #2.

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I’ve spent the past year working on getting the car road worthy. It’s basically there, minus a few minor considerations like doors and windows and reliability.

Kinja'd!!!

The car is running and driving (up and down my driveway) on the stock 2 barrel 351W. But two barrels is not enough barrels.

So I pulled another 351W from a truck in the junkyard.

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The late model truck 351 is ideal due to a few things:

1. Factory roller cam

2. The strongest factory 351 rods (football rods)

3. Serpentine belt drive with high(er) output alternator

Buying just the lifters to convert my current 351 to a roller cam would be nearly $500, and I got the entire engine for under $300 and like an hour and a half with an 18V impact and a cordless sawzall.

I’ve also been scrounging around on Craiglist and eBay, and I’ve accumulated a stroker crank, aluminum heads, a cam, 10.6:1 pistons, an oil pan, and a few other goodies yet to be revealed.

So I could spend the winter building this engine. I’d have the time to go through and blueprint everything. Perfectly balance each rod and piston. Polish and perfect the oil pump. Clean the block, chamfer the oil return passages, then send it off for machining.

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All told the thing should be making more than 500 horsepower when I’m done with it. Sound badass? You bet your Little Pony it sounds badass.

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Again, there are a few downsides.

First and foremost is cost. Slamming an engine together really doesn’t take that much time (depending on how anal you get with prep, cleanup, balancing, and assembly), but it does take some money. The biggest question mark and dollar sign still remaining is what transmission to run.

I mean, obviously it’s gonna be a manual. I know who I’m talking to here and I’m not looking to get burned at the stake. The issue is that Ford never made a factory overdrive transmission that will bolt to a small block and hold more than 300 ft-lb. So my typical solution of sourcing my junk for pennies from scrapyards really won’t work.

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Occasionally a TKO or other aftermarket transmission will pop up on Craigslist, but they’re pricey, usually well above $1500, which is more than I want to throw away on this POS. I could adapt a T56 originally intended for a 4.6L Cobra or an LS, but that’s another layer of headaches on top of a car that’s basically one giant headache.

But I need to have a transmission picked so that I can get a flywheel, and I need to have the flywheel purchased so I can send it to the machine shop to get the full rotating assembly properly balanced.

So in theory I could have the engine all torn down and ready to go get machined, but I’d be unable to make any progress on it until I either scrounged up $2000+ or committed grand larceny to get my hands on a decently strong transmission.

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What do I do?

Hop up the M3 for mad 2018 domination and potentially ruin a car that (usually) runs and (mostly) drives?

Or start putting together an engine for a car that already has a working engine, and perhaps not finish that engine for another year while I find other things to spend money on that aren’t a transmission?

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So you tell me, intenet. Vote below.

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