I am new to the late model trucks and was wondering what,(if any) other engine the 4.2 is based from? Is it a punched out 4.0, or is it a 5.4 with two less cylinders? I just want someone to shed some light on this.

 

It is a bored&stroked 3.8 liter from the mustang. Many of the parts are interchangeable.There's even a site called rpm mustangs, that has many hi-po parts for the mustang and the f-150,btw, welcome to FTE.

 

It is simply a stroked 3.8 engine. Most parts for the 3.8 RWD engine will work perfectly.

 

Just some extra info: the 4.2 is an older overhead valve (OHV) design while the 5.4 (and the 4.6) is a newer overhead cam (OHC) design. I am no expert on engines, but I believe (someone correct me if I'm wrong) that the OHV designs are generally more torquey at low RPMs than the OHC designs (this is a nice feature of OHV engines), while OHC engines tend to have more power at the higher-RPMs due to being better able to breath when working hard. There's a lot of guys that like the old fashioned "punch" from an OHV engine - also OHV engines sound "cooler", with that cool blub blub blub sound percolating away, while OHC engines tend to sound more modern and civilized (until folks change to exhaust systems meant to make their engine sound louder). Again, someone let me know if I am misrepresenting their differences.

 

Thanks guys. BTW The sound of a 13b Mazda rotary is the best imho. But back on topic, What reliability issues (if any) are with the 4.2? I just bought a 02 F150 plain truck yesterday.

 

Scott, The cam grind probably has more to do with the torque curve and the sound than whether it is OHV/OHC. A key advantage of an OHC engine is that the valve train is far lighter (i.e., the lifter, pushrod, and rocker are heavier than the follower on an OHC). This reduces valve float allowing the engine to rev higher.

We've already seen Ford producing dual overhead cam engines with variable valve timing. This is primarily to replace the EGR but they can tune the torquiness of the engine that way also.

 

dohc with variable valve timing.

honda started that in '93. I love ford, and i respect honda. Don't let the civics with 44 piece body kits and coffe can mufflers ruin the reputation!

and from what i understand, the ford 4.0 (from rangers and explorers) are based off the 2.8 platform. The 4.0's that i've driven are bad *** dude, i like them more than the 4.2....

 

Correct!


The 97 and 98 models have the dreaded leaking gasket issue... www.leakingfords.com <---I wonder how many times we've posted that!
Otherwise, some trucks develope rattling catalytic converters and vacuum leaks. If you just keep the maintenance up on it you should be just fine. It's a great engine though!

 

Thanks for the information. I've been reading too many truck reviews where they praise the exhaust note of the Chevy pickup since they all have those old pushrod (OHV) engines under the hood still. And I've noticed that the exhaust sound from big Suburbans and Hemi's (OHV) are really nice and blurb-y. However given a choice I'd still choose a more efficient OHC (single or double) if it's a good engine. It's the future, right?

 

vacuum leak, just took mine in for that.

 

Scott the exhaust note and blurby sound (much like my stepdad's snoring) comes from #1. the displacement of the engine, bigger = lower and 2. that blurby sound comes from the combination of the specific cam grinds and ignition timing.

as alot of 4.2 owners realize when they put flows on their truck is it sounds kinda like a boat. that is because 4.2 liters will never sound like 5.3 liters, and the 4.2's ignition is timed evenly, every (i'm not sure but i'm gonna guess here for the example) 60 degrees the crankshaft rotates, a cylinder fires. on a chevy v8, a cylinder might fire once at 45 degrees, then the next at 30, then the next at 45, the next at 30 and so on. (again those numbers are just wild guesses)

 

Interesting info - thanks.

 

99 f150 4.2 auto, 120,000 miles

Does the 4.2 have roller or flat tappet lifters? If they're flat tappet I may switch to a "fleet" motor oil before it's too late.

 

110,000 on my '99 with no unscheduled maintanence (I also havent done a lot of scheduled maintanence too, but thats just me being lazy).

I cant think that the difference of OHV and OHC cause a major difference in power / sound all other things being equal. The cam is there to open valves in a specific pattern. What difference is it to combustion if the cam is over the head or in the block? There are advantages, like listed above with the less weight, etc. But I think ultimately the cam pattern is what determines the sound / power , etc. I have never worked on an ohc motor nor do I plan on, I have heard they can be much more a PIA than a good ol pushrod engine.

 

Its a full roller motor. The lifters are hydraulic rollers.

As for the engine design, Most ford pushrod V6s are based off of the Essex 3.8 V6 motor which certainly does not originate with Mustangs. Ford first introduced the Essex as an option in the 1982 Grenada. Although I have never seen any definative proof, its a common belief that the Essex was loosely based on the Buik GN 3.8.
Production variants of the Essex motor can be found in the Taurus, Mustang, Windstar, F150, E150, Cougar, Grenada, a ****load of European and Austrailian Fords and even in the Nascar truck series. There are quite a few other cars that use an Essex motor as well but thats just what comes to mind.
One more little fun fact, the only other pushrod V6 produced by Ford was tha Cologne V6 wich was offered in smaller displacements than the Essex and used a 60* design as opposed to the Essex 90* design.

Sorry for the boring history lesson.