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Farticcus of Plenticcus
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http://300mclub.org/forums/viewtopic.php?f=18&t=29542

I just want to let everyone know that 4.0L cams are bolt in swaps!!! Same valve lift, slight change in duration.

I bought my new to me 02 Special with a nasty knock. I found the rocker assembly on drivers head was broken. A roller from assembly had been punched thru the head into water jacket. I replaced the head with a used head and I installed 4.0L cams and sprockets. I have about 100 miles on the repair so far with no issues. I will be changing the oil to synthetic on Friday and will then be ok with doing a 100% throttle pull on it. So far it feels awesome!


4593616aa,4693618aa are cams, 4792580ac,4702025ab are sprockets. Less than 250 retail for all. 1 3.5 cam retails for 300
4.0L
CAMSHAFT
DESCRIPTION SPECIFICATIONS
Metric Standard
Bore Diameter 43.038-43.059 mm 1.6944-1.6953 in.
Diametrical Clearance 0.078-0.12 mm 0.003-0.0047 in.
Diametrical Clearance (MAX) 0.15 mm 0.0059 in.
Bearing Journal Diameter 42.939-42.960 mm 1.6905-1.6913 in.
End Play 0.05-0.51 mm 0.002-0.020 in.


VALVE TIMING-INTAKE VALVE
DESCRIPTION SPECIFICATIONS (CRANKSHAFT DEGREES)
Opens 4° BTDC (A) — 1° ATDC (B)
Closes (ABDC) 60° (A) — 65° (B)
Duration 244°
Centerline 118° (A) — 123° (B)


VALVE TIMING-EXHAUST VALVE
DESCRIPTION SPECIFICATIONS (CRANKSHAFT DEGREES)
Opens (BBDC) 61°
Closes (ATDC) 21°
Duration 262°
Centerline 110°


3.5L
Camshaft
Bore Diameter 43.038–43.059 mm
(1.6944–1.6952 in.)
Bearing Journal Diameter 42.939–42.960 mm
(1.6905–1.6913 in.)
Diametrical Clearance 0.078–0.12 mm
(0.003–0.0047 in.)
—(Max.) 0.15 mm
(0.0059 in.)
End Play 0.11–0.35 mm
(0.004–0.014 in.)
Valve Timing—Intake Valve
Opens (ATDC) 3°
Closes (ABDC) 61°
Duration 238°
Centerline 122°
Valve Timing—Exhaust Valve
Opens (BBDC) 56°
Closes (ATDC) 16°
Duration 252°
Centerline 112°
Valve Overlap 13°
Thoughts??
 

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It's sounds like a nice mod. Might as well change the rocker arm assemblies while you're at it.
 

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I hit **** with sticks!
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Very interesting. The numbers look good, might give a 3.2/5 a tiny bit of extra ass.

I have been wanting to change out my cams to 3.5's at least for some time. Just havent gotten around to it, since it involves pulling the engine...or the heads at least....i'd rather pull the engine...less parts cost...

Might be something to consider doing over the summer; and it may very well solve my under load spark knock issues...that have been present since the 02 wiring swap. My main concern is the sprockets, but that issue seems to be solved according to the OP.
 

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The heads have to come out to get the cams out with the engine in the car? That's news to me? When I had my car apart in the fall it looked like I could just take the cams out of the head as it sat. Do they only come out from the back or something?
 

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I hit **** with sticks!
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The heads have to come out to get the cams out with the engine in the car? That's news to me? When I had my car apart in the fall it looked like I could just take the cams out of the head as it sat. Do they only come out from the back or something?
Yeah, they come out of the back. Not enough room with the engine in the car.

Much cheaper/easier to just pull the engine IMO, saves you a ton of $ on gaskets and stuff, plus, much less time.....I'd just pull the plenum, engine harness, valve covers and rocker assemblies....pop the cv shafts, mounts, accessories, and yank the engine/trans assembly far enough forward to get enough clearance for the cams....swap them, then stuff it all back in quick.
 

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Because the tone wheel for pre-'02 is different. To do pre-'02, you'd have to either figure out a way to adapt the pre'02 driver-side sprocket (with tone whee) to the 4.0 cam, or swap harness, flex plate, and PCM to '02+. For '02+, you need the 4.0 sprockets (correct tone wheel), which the OP got.
 

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I hit **** with sticks!
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Priced these at the DD this morning.

4593616AA = $66.69
4792580AC = $38.57


4702025AB , and 4693618AA are not good part numbers. Tried them on moparparts as well and they didnt come up.

Edit: I grabbed a Nitro vin and called the DD. The correct part numbers for the others are:

4593618AA = $59.65
4792025AB = $29.33
 

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Yeah, they come out of the back. Not enough room with the engine in the car.

Much cheaper/easier to just pull the engine IMO, saves you a ton of $ on gaskets and stuff, plus, much less time.....I'd just pull the plenum, engine harness, valve covers and rocker assemblies....pop the cv shafts, mounts, accessories, and yank the engine/trans assembly far enough forward to get enough clearance for the cams....swap them, then stuff it all back in quick.
Damn, of well it's out of the question for me then!
 

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Because the tone wheel for pre-'02 is different. To do pre-'02, you'd have to either figure out a way to adapt the pre'02 driver-side sprocket (with tone whee) to the 4.0 cam, or swap harness, flex plate, and PCM to '02+. For '02+, you need the 4.0 sprockets (correct tone wheel), which the OP got.
I honestly haven't even looked at the way the engine is built with enough detail to follow what you're saying. I'm going to have to look through the FSM to see what part your talking about when you say tone wheel. I'm sure I've seen it but had no idea what it was called.
 

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How different is the cam sensor? I'm pretty sure I know the answer, but is it possible to use the right cam sensor for these wired to a 98-01 ECM?

I'm sure the answer is no, but why would they change the sensor itself so much?
 

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the tone ring on the cam gear for the sensor is the difference, not necessarily the sensor itself.
that's why it(drivers side cam gear which operates the cam sensor) and the flex plate must be changed when crossing years.
so the 4L cam gear must have the same design on it for triggering the cam sensor as 02+, because it has worked for 1 person as a straight bolt in.
 

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the tone ring on the cam gear for the sensor is the difference, not necessarily the sensor itself...
If I may elaborate to help clarify: The PCM is programmed to look for a certain pattern of on-off signals from the sensor - corresponding to the holes in the tone wheel. For '02, they changed the pattern telling the PCM where to look for the actual timing point. IOW - there is a series of holes before the timing mark to tell the PCM "OK - the next hole is the timing point". So the firmware in the PCM is different to recognize the correct pattern.

If you know anything about UARTS (in electronic communication), think of the first holes as the start bit. Anyway - there is a certain pattern for the start bit - if the receiver doesn't see the right pattern just before the data (in this analogy, the "data" is the actual timing), it won't read the data. In '02, they changed the pattern (spacing, and or number) of holes for the "start bit". S-o-o-o - the tone ring is punched with a differnt pattern of holes, and the PCM is programmed differently from the earlier year PCM's to recognize the correct pattern of holes for the year engine.
 

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If I may elaborate to help clarify: The PCM is programmed to look for a certain pattern of on-off signals from the sensor - corresponding to the holes in the tone wheel. For '02, they changed the pattern telling the PCM where to look for the actual timing point. IOW - there is a series of holes before the timing mark to tell the PCM "OK - the next hole is the timing point". So the firmware in the PCM is different to recognize the correct pattern.

If you know anything about UARTS (in electronic communication), think of the first holes as the start bit. Anyway - there is a certain pattern for the start bit - if the receiver doesn't see the right pattern just before the data (in this analogy, the "data" is the actual timing), it won't read the data. In '02, they changed the pattern (spacing, and or number) of holes for the "start bit". S-o-o-o - the tone ring is punched with a differnt pattern of holes, and the PCM is programmed differently from the earlier year PCM's to recognize the correct pattern of holes for the year engine.
That's what I was looking for.

The reason I asked about the sensor was to see if it was possible to put an 02+ sensor with an 02+ tone ring on an 01 or earlier engine. As Bill points out the reason this problem exists is because the PCM firmware is different.

The next question from me is could a tone ring that works with the 98-01 programming be machined to fit the newer cams?
 

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That's what I was looking for.

The reason I asked about the sensor was to see if it was possible to put an 02+ sensor with an 02+ tone ring on an 01 or earlier engine. As Bill points out the reason this problem exists is because the PCM firmware is different.

The next question from me is could a tone ring that works with the 98-01 programming be machined to fit the newer cams?
I'm sure that is a possibility but, I was thinking it may be possible to press off the tone ring and press one on that is programmed for your car.

FWIW, the two types of systems are easily identifiable. If you are at the junkyard say, and can't figure out what the year of the car is. The '01 and earlier systems use a two plug PCM and have the TCM as a separate module, (SBEC Single Board Engine Controller).

The '02 and later (NGC Next Generation Controller), has a four plug PCM and, has the transmission controller (TCM), incorporated in the same unit.
 

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I'm sure that is a possibility but, I was thinking it may be possible to press off the tone ring and press one on that is programmed for your car...
That would be good. I wonder if there is some kind of keying to positively clock the tone ring to the sprocket. If so, then great (assuming the keying details of the two designs is identical - probably so, but not necessarily), but if not, the accuracy of that manual positioning would determine the accuracy of the ignition timing relative to the crank at higher rpm's. Cam timing would not be affected by any errors in that positioning.
 
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