COP Comparison

[DMadigan]

Looking for information on COPs I found a reference to Denso coils that seem to be popular at the end of the cam tower thread someone from AU mentioned (sorry, do not have your name at the moment). Anyway, the Denso coil is used on Lexus and Camry, part #90919-02234. There is another used on Celica and Corrola, part #90919-02239.
The problem is that I want to make new valve covers with studs to mount the COPs but no one publishes dimensional data on COPs so I bought one of each. The -34 measures 118mm from the seal to tip, the -39 measures 105mm. Attached are pictures of them on a plug, sticking out of the cam box. The -39 sits almost down to the cam box surface whilst the -34 sits about 10mm above.
Both have 15mm between the seal and bottom of the stud mount.
Both come with a simple wiring diagram showing battery, coil and IGBT drive but no pin numbering. I will measure the inductance when I get a chance.

[dap930]

Here is a picture of the coil pin out that I found on the internet. The tach signal is not used for aftermarket ECU use.



A lot of guys that use these coils just cut off the mounting tab and use RSR spark plug retainers to hold the coil in. "xbmwguy" on this forum uses the 02234 coils on his twin plug MS3 EFI conversion making over 700 HP with E85. I am using LS2 coils on my twin plug EFI conversion but they take up a lot of real estate, so I would like to convert over these COP's in the future.

[DMadigan]

I see the mounting tab as one reason for using these over an aftermarket COP such as Accel which has no mounting tab. Maybe xbmwguy did not want to make new covers.
I have seen pin #3 labeled as a tach output but I questioned that in this forum message:
Why are late cam towers so hard to find?
An ECU has the trigger input that it can use for a tach signal, no reason to bring in an external wire for it. More likely a misfire indicator required by the OBD2.

[lvporschepilot]

That would be sharp. I personally prefer the Bosch 4 wire COPs, as used in early 2000s VWs and Audi. While they do not have a bolt hole, I have not found it at all necessary. I use RSR clips for the lower COPs, but I don't think even those are necessary as the COPs fit pretty tight.

[DMadigan]

I modified the drawing that I made for the exhaust covers for the -34 Denso COPs.

After looking at it I should have rotated them 180 degrees so the wire plug would not need a cutout to clear the ribs.
Another thing to consider is the gasket thickness. To get the correct seal on the shoulder the COPs will have to be dropped down by the gasket thickness. McMaster has high temperature Buna-N sheets that can be laser cut. They are harder than the silicone gaskets so they will not squish out.

[DMadigan]

After rotating the COPs 180 degrees I found the boss underneath for the hold down studs would intrude into the rocker area. I found the best position is where the connector points away from the angle the COPs are tilted.
The dividing walls on the inside of the 930 covers are 5.5mm wide. The cambox walls are about 7.3mm on top to bottom walls and 7.9mm on front to back walls due to the angle of the cover on the cambox. The face of the cover walls could be machined with a pocket to take a gasket like the newer covers to keep the gaskets from sliding out.
Since the cover would bottom on the cambox the height of the COP would be independent of the gasket thickness.
Might be worth looking into.