3500 CPS Adapter

[CNCguy]

This started out as a project to help a friend but I am thinking of making these to sell. A 3400 dampener is used in place of the stock 3500 dampener.

A few reasons that these were made this way.
1) No need to disassemble the engine.
2) No need for rebalancing the crank.
3) Adjustable timing (engraved -5 degrees to +10 degrees but adjusts +5/-15)





In the pics, the dampener still needs to have the 7 slots machined. My goal is to cut the slots and throw this on a 3100 for testing this weekend.

Any thoughts??

[SappySE107]

Awesome This is exactly what I was thinking about (adjustable timing) when going with an external setup. Heck, you could use this for the iron head motors that want to convert to DIS i bet.

[onefastV6]

Marc, looks great I was curious what you were working on for the 3500 swap. I will be anxiously awaiting the results.

[IsaacHayes]

Would that fit in a small bodied car such as an L body with a 3100 and 4T60-e? Not sure how much room is in that area.. What does it bolt to on the block?

EDIT: Just got to thinking, and does the CPS on a 3500 output someting different than a typical 3100/etc does? I mean they changed the cam shaft ring over the years, but the sensors all out put the same signal... I wonder if a electronic guru could build a converter. I know some people that might be able to do it, depending on what is needed, but not sure if they would be interested.

[SappySE107]

I just gotta ask though, how does the belt routing affect its position?

[tejohnson]

Definitely looks cool, but you would want to find a fairly static position, and would likey have to scrap the adjustable timing feature. Of course I am only saying this due to a perception that it may have issues upon attempting the CKP variation learn procedure. Facing the front, the lower right side would be a pretty nice place to mount (due to belt routing, etc). There is a beefy bolt that is used to hold a bracket in place to support the 24x sensor wire. (not sure about the 3500 tho)

[SappySE107]

CKP? Is that where it learns the crank position sensor to cam position sensor or the 24x sensor?

[Darin]

Is the balancer the same size as the reluctor on the crank? Wont it throw the timing out if they are different size? Say like the distance between each slot on the crank vs the distance between the slots on the balancer? I hope that makes some sort of sence, I know what I'm thinking but cant describe it.

The only problem I see with the belt is that the adaptor will have to go on after the belt.

[SappySE107]

It would be best to try this on a car already setup for what this is trying to do. Im not sure if the speed at which it gets the pulse matters but it very well could. That would mean the diameter will matter.

[Darin]

The speed it gets its pulse may have an effect on the later engines with the cam sensor.

[tejohnson]

CKP? Is that where it learns the crank position sensor to cam position sensor or the 24x sensor?

Yup. I kept having a arguement with myself thinking about this after I posted. But it always came back to the cam position sensor being off from the 7x sensor. Unless, it does not matter and the variation learn procedure is for the 24x only. I suppose one way to test is just fire it up, do the learn, and see how it runs. Then we may learn a lil bit more about assumptions of the PCM operation (while hopefully not detonating and poppin a piston)

[CNCguy]

I chose the lower left corner for a couple of reasons. There are two unused M12 holes (appear to be tooling holes for manufacturing) and the belt routing. It fits every engine that I have tried it on, 3100, 3400 & 3500.

As you can see in these pics, the belt easily clears due to the belts routing over the tensioner. On the right side, the belt goes out on an angle to the AC compressor.

The dampener is less than .5" smaller in diameter than the reluctor wheel on the crank, so my plan is to just make everything proportional in size and there shouldn't be any problems. The CPS has to be removed to change the belt.

I thought the adjustable timing would be a good feature for OBD-I applications. For other applications it could be set to zero and left there.

I do not know how much room there is in the different body styles but as you can see in the picures, the mounting block does stick out about 7/16" beyond the dampener.





Hopefully, I can get the dampener on the machining center this weekend and see how it works in real life.

[tejohnson]

The issue is with the tensioner for a setup in an N-Body since it is positioned a bit different (pointing the other way).... In this configuration, the pulley for the tensioner would be about where the passenger side engine mount is mounted to the timing cover.

[CNCguy]

The issue is with the tensioner for a setup in an N-Body since it is positioned a bit different (pointing the other way).... In this configuration, the pulley for the tensioner would be about where the passenger side engine mount is mounted to the timing cover.

I see what you mean about the engine mount. All of the engines that I have tried it on did not have an engine mount on the front cover. I have only owned one 60V6 car and it was a W-body. I also checked it out on my sons Jeep Cherokee and it would fit if the air pump was removed.

Does anyone have pics of the fronts of different engines showing the mounts and belt routing? I have a couple of other ideas but need to see what needs to be cleared.

This was developed for a RWD application and will fit a W-body for sure.

[IsaacHayes]

The L body has the tensionr like in the picture, but also has a side mount that the W bodies do not.