Join Date: Oct 2003
Location: Nth NSW
Re: performance rebuild
here is some thing for you to read I found it on some web site. Its about JIM MOCK"S 4L motors.
In no way am I advertising. Just found this article and thought it was good.
Doubt whether you can - affordably - get a lot of power out of an atmo Ford 4.0-litre six? Read on and be amazed!
Initial Scepticism by Michael Knowling, Pix by Julian Edgar
Snake oils and magic potions. We've seen our fair share of them here at AutoSpeed - everything from Turbo Zets to oh-so mysterious airflow meters. So you can imagine what was in the back of our minds when some bloke rang to tell us he can squeeze 175-plus rear wheel kilowatts out of Ford's almost untunable 4.0-litre six. Apparently all it needed was a cam, headwork and a few traditional hot-up techniques.... and "no engine management mods required", he claimed.
Oh yeah, we thought - bloody prove it!
Well, a couple of weeks down the track we caught up with our caller - Mr Jim Mock. We jumped in behind the wheel of his EF Falcon 4.0-litre development mule and, bugger me, this thing blew our socks off. That's right, we can tell you from our ever experienced seat-of-the-pants this thing really does haul. While we didn't have a chance to dyno the car, having driven it we can say that its claimed 175 rear wheel kW now seems very believable - oh, have faith!
So who is this Jim Mock bloke?
Jim's had considerable experience in motorsport R&D (including setting up the Holden Torana GTR XU-1!), and - more recently - has also owned a Ford dealership in Mildura, Victoria. Over the 16-year stint selling Fords, he couldn't help notice the number of 3.9/4.0-litre six cylinders that were going out the door. Puzzled why no one was getting into modifying them, he bit the bullet in 1998 and branched out into his Jim Mock Motorsport business.
Equipped with his in-house Dyno Dynamics chassis dynamometer, Jim has just released a series of enhancement packages for the 3.9/4.0-litre Ford six. These packages are known around the Mock workshop as DEVs - DEVelopment 1, 2, 3 and so on.
DEV 1 - the mildest upgrade - provides you 112kW at the rear wheels, while DEV 6 - the most extreme package - pumps out up to a claimed 185kW at the wheels.
Let's look at how Jim achieves it...
Headers and Exhaust
Each DEV package - except for the final-phase DEV 6 - receives exactly the same headers and exhaust system. Jim says they tested a myriad of different header designs and - oddly enough - the most successful was one that theoretically shouldn't work. Best results came from a 6>3>1 arrangement using quite small diameter primaries - these, Jim says, proved essential for scavenging the Ford's combustion chambers.
The rest of the exhaust system appears pretty straight forward, but we're told the Mock team took pains to ensure there are no resonances or illegal noise problems. Two-and-a-half inch mandrel pipe (available in either stainless or aluminium coated mild steel) is used from the collector back, with a high-flow cat and two straight-through mufflers along the path to the tailpipe.
It's nothing extreme in design, but it isn't too loud and - as intended - we didn't detect any resonances. Note that Jim can supply various other mufflers and resonators as requested, but we thought that the exhaust on the car we drove was fine, both in note and noise - although it is likely that it's louder than a factory Ford hottie.
The large factory airbox is retained but it takes a washable aftermarket air filter element.
Headers, exhaust and air filter are the items you receive in the entry-level DEV 1 upgrade. Oh, and you also get a set of US-sourced spark plugs as part of every DEV. These basic DEV 1 mods should see a healthy EA - AU Falcon six producing around 112kW at the rear wheels - a tad more than a stock non-VCT XR6.
Already you're out in front of Tickford!
Pick a Cam
Following the intake and exhaust, Jim swings his attention to the camshaft.
For the DEV 2 and DEV 3 upgrade, Jim sets about installing a subtly upgraded cam and adjustable timing gear. Note that the only difference between DEV 2 and 3 is the cam spec. Not surprisingly, though, Jim doesn't want to give away too many of the cam details, other to say they're a non-conventional design. Hmmm....
So how much power can you attain with headers, exhaust, filter, spark plugs and a mild camshaft upgrade? Try 125kW in DEV 2 form and 135kW in the DEV 3. We're told idle quality remains virtually stock with both.
A major attraction of the DEV 2 and 3 packages is that the cylinder head doesn't have to be removed - this helps to keep cost to a minimum. You can also continue using normal unleaded, if need be.
Head and Compression
For DEV 4 packages and beyond, Ford's SOHC head needs to be removed and - while it's out - reconditioned and modified.
DEV 4 sees mild port work, plus the fitment of a yet-again different camshaft and revised valve springs. The head is then re-installed using a thin metal gasket, which delivers a compression ratio of up to 9.6:1 (standard Falcon compression ranges between 8.3 and 9.1:1 depending on model). Note that increasing the compression ratio means you'll now have to fill the tank with premium unleaded at all times.
With a DEV 4 kit fitted, you'll enjoy 155kW at the wheels with a barely affected idle quality. Pretty good stuff, you'd have to say...
Taking It Further
Interestingly, the next two DEV 5 packages on offer - DEV 5 and 5A - involve simply more headwork, a further increased compression ratio and a wilder camshaft.
In both DEV 5 and 5A, extensive headwork is carried out with particular emphasis on port and combustion chamber shape. We're told a lot of time is taken with the die grinder and - yes - you are inevitably billed for it. Compression ratio is again bumped up to between 9.6 and 9.8:1, making the use of premium unleaded even more critical.
Both DEV 5s employ what Jim calls "a stout cam profile that delivers a huge area under lift" and, accordingly, the valve springs are again revised. The only difference between both DEV 5s is the 5A uses a higher performance dual profile cam design.
Your normal DEV 5 is designed to give around 170kW at the tyres (as with all these figures, as measured on a Dyno Dynamics dyno), while DEV 5A - the package we experienced - muscles out 175kW. In terms of idle refinement, the normal DEV 5 reputedly gives a noticeable throb - nothing too severe - but DEV 5A pushes the idle smoothness boundaries of an everyday streetcar.
Finally, the all-out Jim Mock DEV 6 is reserved for "the radical enthusiast." Fitted on a made-to-order basis, this package generally incudes a further-wild cam, 10.0 or higher compression, different headers and a 3-inch mandrel exhaust system.
Jim's seen a DEV 6 beast crank out up to 185kW at the wheels. Don't ask about idle quality - this is more of a remove-the-rev-limiter-and-go-circuit-racing engine.
Here we get to the bit that initially had us doubting the effectiveness of the whole Jim Mock kit - its fuel and ignition management.
Jim categorically states that all modifications behind each DEV package have been centred on what would work with the standard, un-modified Ford ECU. It was a case of not doing anything to upset the computer. As we can imagine, Jim says it was a huge challenge to pick a selection of camshafts that wouldn't send the standard MAP-sensed program into a tailspin.
However, some sort of fuelling increase was inevitably needed to cope with the heavy breathing of DEV 4 and beyond. Jim's not keen on giving away specifics, but he's achieved this with a remanufactured fuel pressure regulator, which forces more fuel through each injector whenever it's required. We're informed the leanest air-fuel mixture you'll see under full load is 12.9:1, while light load cruise is 14.7:1.
Seems safe enough to us.
The biggest downside of the current engine management approach is the lack of ignition control - there's no facility for zone-specific advance or retard. On the other hand, all Falcon 4.0s - except for the EF and AU series - run a conventional dizzy that you can turn for a crude across-the-rev-range timing change. While this is better than nothing, Jim recognises it's a less-than-ideal solution and will fit a programmable Link or MoTeC system if you insist.
The Moment of Truth...
Out on the road, we soon forgot any ideas on how a fuel and ignition set-up like this 'should' run. Scepticism quickly faded.
The DEV 5A promo vehicle gave strong throttle response together with absolutely no hesitations and zero sign of detonation. It also punched out very strong torque from 1000 rpm upwards (note that the EF-onward variable intake manifold must be partially thanked for that good bottom-end tractability). In the mid-to-top-end, the DEV 5A goes on to grunt like an easy-breathing V8 - all the way to its factory 5800-rpm limiter. It's very impressive stuff, especially considering how lame as a performance six the standard engine is.
Off the line the LSD'd car could very easily light up both rears, and we're told getting the dry-road wheelspin happening right into second gear is not too hard.
But so what?
Getting good power from any engine isn't the huge task that some people believe - but getting it with tractability and responsiveness certainly is. And it was in this regard that we were amazed. Drifting along in 5th gear at the 60 km/h urban speed limit was dead easy - and then the car was happy to pull smoothly away without a downchange.
But it's much more exciting to drop back to second gear and be planted back into your seat...
Like all good naturally aspirated big engines, the Falcon never really came on cam with a rush; instead there was a constant and linear development of power that kept the tacho needle flying through its arc. In fact, in the first few moments of his drive, Editor Edgar damn-near hit the (standard) rev limiter in first gear, the engine revved so sweetly.
But the DEV 5A package is not perfect...
Our biggest criticism of the DEV 5A promo vehicle is its idle quality. It's more than just a bit lumpy - you can watch the gearknob rocking from side to side by about an inch! Certainly we'd suggest that if you're used to the dead smooth idle of any engine-managed car of the last 15 years, it'll be too wild for a genuine drive-it-every-day car. But then again, if you miss those days when hot NA performance meant a raunchy exhaust note and a shaking bonnet, you'll love it! Horses for courses...
When we relayed our concerns about idle quality to Jim, he explained that their DEV 5A promo car is just that - a promo car. If you're willing to sacrifice a measly 5 rear wheel kW in your everyday vehicle (bringing the total down to 170 RW kW), you can chose the normal DEV 5 package, which is apparently much more civilised in its idle behaviour. However, we should point out that even with the lumpy idle, the engine still coped fine with turning the air on and off, the sudden input of power steering demands, and so on. It won't unexpectedly stall on you, and we're told that it will also work OK with an auto trans.
Jim suggests fuel economy is not dramatically affected by any of the DEV packages. Driving the DEV 5A Falcon EF promo vehicle, he regularly returns 12.0 litres per 100km in Melbourne traffic and around 9.0 litres per 100km on then highway - not too far off standard consumption.
On the basis of the DEV 5A package that we experienced, the Mock DEV packages are a genuinely worthwhile upgrade for anyone with an EA - AU Ford Falcon six.
Unlike some power upgrades where you simply can't feel any difference - whatever the dyno says - the Mock Falcon went h-a-r-d.
In fact Julian Edgar and I arrived respectively at the Mock Falcon test drive in a twin turbo Supra and a Skyline GTS4... and we weren't at all disappointed by the pace of the modified Falcon. It was strong enough in fact to wipe our initial scepticism completely away.
What's more, Jim's prices aren't too bad, either...
Assuming you've got a healthy engine to build on, a DEV 1 upgrade costs $900, DEV 2 is $1800, DEV 3 is $2000, DEV 4 is $3600 and the two DEV 5s are $4200. The monster DEV 6 package is a price on application proposition. These are drive in, drive out fitted prices. Also - if you think the engine you've got is a bit tired - you can treat it to a full rebuild for $2000 - $2500. Note - for up-to-date prices we'd strongly advise giving Jim a call.
Backing the product is a 3-month warranty on parts and labour and, in terms of overall reliability, a well-maintained Falcon can hack the power of a DEV 5A upgrade without problem. The transmission - whether auto or manual - holds up well, as does the diff (if treated with some measure of sympathy). The Mock development vehicle has so far covered 20,000 hard kilometres and continues to run perfectly. It's had one clutch replacement, however, and the XR6-equivalent clutch that went in continues to perform very well.
If we were ordering a Jim Mock kit ourselves, we'd probably specify a normal DEV 5 or a DEV 4 - something that isn't quite so lumpy at idle. Certainly, with a rated 155-170kW at the wheels, a DEV 4 or 5 vehicle would still have the goods to line up next to your average exhaust and filter-equipped Tickford XR Falcon and come out w-e-l-l in front. And all for between $3600 and $4200!
Ahhh - at last - our faith in the aftermarket has been restored...
Jim Mock Motorsport
+61 3 9399 4401