Did the SOHC come with a cam synchronizer?

[snoranger]

Like the title asks, Did the SOHC engine ever come with a cam sync?

The reason I ask is that im swapping a SOHC from an '01 sport into my '95, using the EEC-IV electronics. The '01 engine doesn't have a cam sync, only the cam position sensor in the valve cover. I tried to use the V/C mounted sensor, but I still have no spark or injector pulse. I pulled the oilpump drive out of the SOHC and compared it to the cam sync from the 95. No dice, the SOHC is a little longer (approx 12mm). So if I can find the right cam sync, I think I may be able to fire this thing up.

Any help will greatly appreciated, I HAVE TO get this done before the baby is born next month!! (orders from the boss!!)

[steev]

I can't help one bit with your question, but the fact that you are going to be someone's father is still a scary thought!

[snoranger]

I offered her to your girlfriend, she said she's not raising a baby on her own.

Lets keep this on topic, the clock is ticking. (Feb. 16)

[2000StreetRod]

According to my Haynes Repair Manual the camshaft position (CMP) sensor on the OHV is a Hall effect sensor mounted on the camshaft synchronizer assembly driven by the camshaft located in the block. The CMP sensor on the SOHC is a magnetic pickup (variable reluctance) sensor mounted on the left valve cover. It senses a tooth on the left camshaft similiar to the way the crankshaft (CKP) sensor works. The PCM voltage source for the OHV CMP sensor is 10 volts or more while the PCM voltage source for the SOHC CMP sensor is about 1.5 volts. I doubt seriously that the pulse shape of the two different sensors are comparable.

Someone who has done such an engine swap should back me up here but I suspect that you will have to use the SOHC PCM to be compatible with the SOHC engine.

I believe that the SOHC oil pump is driven by a shaft that engages the jackshaft whereas the OHV is driven by a shaft that engages the synchronizer assembly. I don't understand your comment about driving the SOHC CMP sensor since it normally does not rotate.

[snoranger]

Originally Posted by 2000StreetRod

According to my Haynes Repair Manual the camshaft position (CMP) sensor on the OHV is a Hall effect sensor mounted on the camshaft synchronizer assembly driven by the camshaft located in the block. The CMP sensor on the SOHC is a magnetic pickup (variable reluctance) sensor mounted on the left valve cover. It senses a tooth on the left camshaft similiar to the way the crankshaft (CKP) sensor works. The PCM voltage source for the OHV CMP sensor is 10 volts or more while the PCM voltage source for the SOHC CMP sensor is about 1.5 volts. I doubt seriously that the pulse shape of the two different sensors are comparable.

Correct, Thats why im asking if the SOHC ever had a cam synchronizer. I cant use the valve cover mount CMP.

Originally Posted by 2000StreetRod

Someone who has done such an engine swap should back me up here but I suspect that you will have to use the SOHC PCM to be compatible with the SOHC engine.

There's one person on here (Brett) that has done this swap using the EEC-IV computer.
http://www.explorerforum.com/forums/...rett+sohc+swap
I PM'ed him to find out what he did, waiting for a response.

Originally Posted by 2000StreetRod

I believe that the SOHC oil pump is driven by a shaft that engages the jackshaft whereas the OHV is driven by a shaft that engages the synchronizer assembly. I don't understand your comment about driving the SOHC CMP sensor since it normally does not rotate.

You may be right about the oil pump, I dont know. I havent opened the engine up.
Im not trying to rotate the SOHC CMP. What Im looking for is a cam sync that fits the SOHC block. It has a hole in the block and what looks exactly like an oil pump drive from an early 4.0l OHV (pre-cam sync 90-92), installed in said hole. Only problem is that the 2 OHV and 1 oil pump drive (OHV also) are too short.
You can see in the pic below the 95 cam sync and the 01 "oil pump drive" for lack of a better term. maybe that will help you understand what im getting at.

[2000StreetRod]

You might try finding information on the 2.9L V6 that was also manufactured at the Cologne plant. I recall the block has a slightly different height and I think the later year models were fuel injected so may have a distributorless ignition system.

[snoranger]

Originally Posted by 2000StreetRod

You might try finding information on the 2.9L V6 that was also manufactured at the Cologne plant. I recall the block has a slightly different height and I think the later year models were fuel injected so may have a distributorless ignition system.

I've never seen a DIS 2.9l (they may exist). Good call though, the 2.9l did have a taller deck height.

I got an answer to how to make the V/C mounted CMP sensor work. We'll see if it works. Thanks for your help.

Kevin

[2000StreetRod]

I suppose it's possible to build an electronic circuit to make the SOHC CMP output mimic the OHV CMP signal. Maybe use a triggerable programmable multivibrator or something similar. Please post the proposed solution.

[snoranger]

Problem solved. IT STARTS!!!!!!!!!!!

It was an easy fix, once I got a little help (Thanks Brett). It needed a ground signal not power. I had to cut the power power wire and grounded the CMP. Fired right up!

[2000StreetRod]

Well done! Glad to hear your problem is solved.

There are other issues to consider.

The SOHC has a higher compression ratio than the OHV and has a knock sensor to retard the timing when detonation is detected to prevent engine damage. The OHV PCM will not support that capability so you will want to make sure that your A/F ratio is correct at WOT to prevent detonation. Do you have a wideband A/F ratio meter or plan to install one?

I hope that you are planning for a custom tune. Are you using the SOHC intake system or the OHV intake system? The MAF sensor part numbers are different for the two engines. The PCM uses the MAF sensor output voltage to determine the load of the engine. If the two MAF sensors have significantly different transfer functions then the PCM will determine the load incorrectly and the fuel mixture and ignition timing will not be optimum.

The camshaft timing on the OHV is different than that of the OHV. According to past dyno pulls my stock SOHC increases in max RWHP from 4500 rpm and peaks at about 5300 rpm. The max RWHP at 5800 rpm is about equal to that at 4500 rpm so 4500 to 5800 is the max power band. I believe the stock OHV power plummets above 5000 rpm. Your PCM rev limiter should be increased to more than 6000 rpm. Mine is set at the stock 6250 rpm. If your transmission is an automatic then your transmission shift points should be adjusted (especially for WOT).

[Brett]

Originally Posted by snoranger

Problem solved. IT STARTS!!!!!!!!!!!

It was an easy fix, once I got a little help (Thanks Brett). It needed a ground signal not power. I had to cut the power power wire and grounded the CMP. Fired right up!

Glad I could help Kevin.

Brett

[snoranger]

Ok, I'm digging up an old thread of mine.


I never did find a can sync that fit the SOHC and I've had a problem with my swap. I've been getting a check engine light and code for the CPS... The truck runs great about 50% of the time. The rest of the time I have a slight lack of power, poor idle, and occasional stalling when cold. I assume thats due to the fact that the computer is firing the injectors at the wrong time since it doesnt know when its #1 or #5 at TDC.

The truck stalled at a toll booth on the Parkway on friday, and its pissed me off for the last time. (It started right back up, but thats not the point.)

So, If I cant find a cam sync, I guess I'll have to make one. I have a mini lathe in my basement "R/C car" workshop, a few "spare" OHV cam syncs, and a SOHC oil pump drive plug ( I cant go to the shop to work on my diesel swap, I have to watch my 2 year old this weekend). This is what I came up with:


(Left to right) Stock '95 cam sync, modified OHV cam sync housing, stripped down SOHC oil pump drive, SOHC oil pump drive shaft, OHC cam sync shaft.



Upper half of the cam sync and lower half of the oil pump drive, machined and ready to be assembled.


2 halves pressed together and ready to be cleaned and welded.

I'll stop by the chassis shop one of these days and weld it. Then its just a matter of putting the shaft back in and pressing the gear back on.

[2000StreetRod]

Originally Posted by snoranger

Problem solved. IT STARTS!!!!!!!!!!!

It was an easy fix, once I got a little help (Thanks Brett). It needed a ground signal not power. I had to cut the power power wire and grounded the CMP. Fired right up!

It's been over two years since you performed the above modification. If there was a problem the PCM should have detected and reported it long before now. I suggest that you check the electrical connections - especially the ground.

[snoranger]

Originally Posted by 2000StreetRod

It's been over two years since you performed the above modification. If there was a problem the PCM should have detected and reported it long before now. I suggest that you check the electrical connections - especially the ground.

Yes, there has been a problem the whole time. The check engine light has been on the entire time (almost 40K miles) with a (IIRC) p0340 code. Nothing I have done has solved the problem. I just left it like that and figured "who cares, I'm doing a diesel swap anyway". I'm only doing this because:

1) The check engine light has been annoying me.
2) I may put this drivetrain into my plow truck.
3) It may help someone else out. There are a few people who have done this swap, and all of them have the same code..
4) I couldnt do this until now, my lathe had a broken gear until about a week ago.
5) I'm stuck at home and bored this weekend.
6) The little one fell asleep early, and I had the time.


The original problem, that I forgot to update this thread with, is that the early and late model crank position sensors use the same connector but + and - wires are reversed. I spent soo much time trying to figure out the CMP problem, I forgot that I had changed the CKP wiring.

[2000StreetRod]

There are two possible ways to solve the incompatibility problem - mechanical and electrical. The mechanical solution is the one you are taking - to drive the OHV synchronizer with the SOHC jackshaft spiral gear. The electrical solution is to make the SOHC camshaft position sensor simulate the OHV synchronizer output.

The OHV synchronizer uses a hall effect sensor with an embedded solid state device. That's why a power source is required (DB/OG wire, PCM pin #24). The other wire (RD) is connected to the PCM Power Relay on a 1995 model. The sensor generates a positive rectangular waveform. That's why it is tested with a multi-meter set to DC voltage.

The ON voltage is probably close to battery voltage. The OFF voltage is near 0 but separate from ground.

The SOHC camshaft position sensor is a variable reluctor similar to the crankshaft position sensor. It requires no power source and generates a positive and negative pulse. That's why it can be tested with a multi-meter set to AC voltage.

The peak voltage in each direction (positive and negative) is probably less than 0.2 volts.

It should be possible to build a fairly simple circuit that converts the AC pulse to a DC pulse of the correct amplitude. A transistor switch circuit may be adequate.

[snoranger]

Originally Posted by 2000StreetRod

There are two possible ways to solve the incompatibility problem - mechanical and electrical. The mechanical solution is the one you are taking - to drive the OHV synchronizer with the SOHC jackshaft spiral gear. The electrical solution is to make the SOHC camshaft position sensor simulate the OHV synchronizer output.

The OHV synchronizer uses a hall effect sensor with an embedded solid state device. That's why a power source is required (DB/OG wire, PCM pin #85). The other wire (GY/RD) is connected to the common sensor return. The sensor generates a positive rectangular waveform. That's why it is tested with a multi-meter set to DC voltage.
Attachment 69506
The ON voltage is probably close to battery voltage. The OFF voltage is near 0 but separate from ground. The common sensor return signal is not grounded.

The SOHC camshaft position sensor is a variable reluctor similar to the crankshaft position sensor. It requires no power source and generates a positive and negative pulse. That's why it can be tested with a multi-meter set to AC voltage.
Attachment 69507
The peak voltage in each direction (positive and negative) is probably less than 0.2 volts.

It should be possible to build a fairly simple circuit that converts the AC pulse to a DC pulse of the correct amplitude. A transistor switch circuit may be adequate.

When do you have time to build one for me?

[2000StreetRod]

Originally Posted by snoranger

When do you have time to build one for me?

I've already been thinking about the design. I'll start building a prototype
as soon as I receive the package you were going to send me. That will let me learn more about the reluctor signal. Since I don't have access to an OHV vehicle I'll send the prototype to you for testing. Did your SOHC sensor connector mate with the OHV sensor mating connector on the engine wiring harness? The wiring diagrams show the same connector number (C183) but that doesn't mean they are the same part number.

Like you posted, others could benefit if we can solve the problem.

[snoranger]

I have about 10 DIS style plug wires, 3 CKP sensors and pigtails, and a few other things all boxed up for you. I'll throw a cam sync, sensor, and pigtail in the box for you to mess around with (I have a few spares.). I looked all over trying to find a spare ICM, but I must have thrown them out.

You need anything else?

[2000StreetRod]

For your problem I could use a functional SOHC camshaft position sensor. Then I could wire the circuit board into it. To test would just require replacing a stock SOHC sensor with connector with the modified one containing the circuit board.

Edit: I just checked Rock Auto and realized there are no wires on the CMP sensor.

So the above idea wouldn't work. The next best thing would be a sensor and the mating connector with pig tails. If I could find a connector with male pins just like the one on the CMP sensor then I could build a short cable assembly containing the circuit board that plugs in between the stock CMP sensor and it's mating connector. That way no wiring changes would be required to add and remove the prototype.

[snoranger]

That looks like an EV1 style fuel injector connector, I'll see if I have any extension harnesses around.

I know I have a SOHC CMP sensor and pigtail around, I'll send them too.