Engine Designation Question

I have two Ford Explorers (1999 & 2000). The two engines LOOK different, but that may be just because certain non-engine items were rearranged or redesigned between the

1999 model year and the 2000 model year.

Under the hood of the 1999 model the engine is designated as: 4.0L SOHC.

Under the hood of the 2000 model the engine is designated as: 4.0L EI/4.0L SOHC/5.0L 4.0 EFI.

(When I say "designated" I mean printed on a label on top of the radiator, and/or cast into a large piece of plastic on the top of the engine.)

My question is: Are these two engines the same, or is there a significant difference between them?

Owner's manual not useful to me for this question.

Thanks.

Reply to
CWLee
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You'll need to find a different tag for the 2000... you have just described every engine available in that year/model (post the 8th digit of the VIN and someone will chime in... )

Having said that, the 4.0 liter in the Explorer came in two basic flavours. The earlier design was a push rod (cam in block) engine and the other was the SOHC (single overhead cam) engine. What can further confuse is that both engines had their intake manifolds redesigned over time...

Both engines share the same bore spacing and bank separation (60 degrees) but there are major differences between the tw

Reply to
Jim Warman

Here are the first 8 digits of the VIN codes for each:

1999 VIN Code = 1FMDU34E

2000 VIN Code = 1FMZU62X

Since the 8th digit is different, I assume the engines are different. In layman's terms, how would you describe each of those engines as being different than the other, in addition to what you wrote below?

(Since the 4th, 6th, and 7th digits are also different, what does that tell us?)

Would that be those with the 8th digit being E?

The term SOHC appears adjacent to both engines, even though the VIN codes are different - does that tell us anything significant?

What might those "major differences" be?

Thanks, Jim, for your always helpful replies.

Chuck, who brought his railroad speeder to your town several years back, but wasn't able to connect with you.

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Reply to
CWLee

OK.. your 99 is indeed the 4.0 SOHC motor while the 2000 is the 4.0 pushrod engine... (4.0 OHV or overhead valve).

As far as describing each one in laymans terms.... I can only try but there is going to be an assumption of some knowledge of engine design...

The single overhead cam engine has a camshaft located in each cylinder head.. In the case of your 1999 4.0, one chain is driven by the crankshft and, in turn, drives a jackshaft located in the engine block casting in the same location as the cam in the OHV engine. From the front of this jackshaft, another chain drives the cam that is located in the left (drivers side) cylinder head. The jackshaft extends to the rear of the engine, where another chain is used to drive the camshaft in the right side cylinder head. In 4X4 vehicles, there is a balnce shaft driven by yet another chain off the crankshaft. We'll discuss valve actuation in a bit.

In the overhead valve engine, one camshaft is located in the cylinder block directly above the crankshaft. One chain is used to drive the camshaft. Valve actuation is achieved by a combined lash adjuster/cam follower which actuates a pushrod - this transfers the motion to the top of the cylinder head where a rocker arm is used to reverse the motion opening the valve.

In the OHC engine, the cam follower and lash adjuster are separate.... while more moving parts are used to turn the cams, less moving parts are used to transfer the motion from the cam to the valve. Some of Fords more recent engines us DAMB followers (direct acting metal buckets).

Currently, all Ford production engines use (in North America) either SOHC or DOHC camshaft arrangements. The soon to be released 6.7 liter Scorpion diesel engine will be a pushrod engine (difficult to build a OHC diesel with the amount of stuff competing for real estate in the cylinder head). The 6.4 used in the F Super Duty trucks and the 6.0 used in the E series are both Navistar produced engines.

Hope this helps some...

Still disappointed we couldn't hook up...

Reply to
Jim Warman

Thanks, Jim.

After I read your reply I did some more research, and ended up at the "Ford VIN Decoder" site, shown below:

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I entered both the VIN codes, and the Ford site output for engines is the same for both the 1999 and the 2000, as follows:

Engine: 4.0 L Cylinders: 6 Fuel: Gasoline

No mention of one being SOHC and the other being OHV. Seems strange to me, but then again Ford never asked me to contribute to this topic. :-)

Again, best regards, Chuck.

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Reply to
CWLee

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