Running a DOHC head with stock computer?

mhrallyteam · Post by **mhrallyteam** » Sun Oct 29, 2006 10:11 am

How can i make the cam position sensor work with a dohc head sprocket. I know somebody here as done it, please let me know. Thx guys & gal

douglas vincent · Post by **douglas vincent** » Sun Oct 29, 2006 5:33 pm

Which set of heads are you using?

The early DOHC JDM heads use the same sprocket and cam sensor as our motors. I am using one right now.

mhrallyteam · Post by **mhrallyteam** » Sun Oct 29, 2006 8:25 pm

I'm supposed to use ej20G heads, but i might use a WRX set.

AWD_addict · Post by **AWD_addict** » Sun Oct 29, 2006 10:15 pm

douglas vincent wrote:Which set of heads are you using?

The early DOHC JDM heads use the same sprocket and cam sensor as our motors. I am using one right now.

Did you reuse the same sensor, wiring, and ECU from before? It runs well?

douglas vincent · Post by **douglas vincent** » Sun Oct 29, 2006 11:07 pm

yeah, i am using the same cam gear and the stock cam sensor off the 90 legacy and 90 legacy ECU.

The engine ran great for 500 miles, then for reasons unrelated to the heads, I lost #4 piston.

On my rebuild this weekend though, it "looks like" I was getting exhaust UP the intake valves? Don't know if this was really happening or not, it just looks like it......

douglas vincent · Post by **douglas vincent** » Sun Oct 29, 2006 11:13 pm

I just went back and compared the SOHC 90 cam gear, and the DOHC gear. I "think" they are different on the back side?????. I will be pulling the timing belt off and comparing before I start this thing up!

I may just have to swap the cam gears?

douglas vincent · Post by **douglas vincent** » Mon Oct 30, 2006 12:50 am

The cam gear of the DOHC is 4 teeth off compared to the SOHC cam gear.

douglas vincent · Post by **douglas vincent** » Mon Oct 30, 2006 1:22 am

But I found out why....

The LOCATION of the cam sensor is 4 teeth backwards on the DOHC, compared to the SOHC head. Rats, I was hoping I found something that was wrong....

douglas vincent · Post by **douglas vincent** » Mon Oct 30, 2006 1:45 am

In other words, the Heads that come with "our" cam, works fine.

AWD_addict · Post by **AWD_addict** » Mon Oct 30, 2006 2:13 am

Exhaust up the intake valves, like too much overlap?

Why use the SOHC cam gear in the DOHC head?

douglas vincent · Post by **douglas vincent** » Mon Oct 30, 2006 3:54 am

No, DON'T use the SOHC cam gear. Sorry if thats what came across

mhrallyteam · Post by **mhrallyteam** » Mon Oct 30, 2006 10:51 am

Ok, so other than the ej20G intake manifold what else did you have to swap, thx

waldo320 · Post by **waldo320** » Tue Oct 31, 2006 4:53 pm

So can you run a 94 cas while running dohc heads from a 99rs??? Also you need 2.5 head bolts I am doing the swap right now and the 2.2 head bolts are longer than the 2.5 one if I have time I ll post a pic, also make sure you get a dohc timing belt. Other than that Ill be putting in the 2.5 heads some time this week and will let you how it goes.

AWD_addict · Post by **AWD_addict** » Wed Nov 01, 2006 12:11 am

douglas vincent wrote:No, DON'T use the SOHC cam gear. Sorry if thats what came across

That's what I thought.

head2wind · Post by **head2wind** » Thu Nov 02, 2006 6:00 pm

So is there another gear solution (other than the original ej20g units) that will work? if the SOHC gears from a 90-94 EJ22t won't, I also believe that the gears from a newer WRX (USDM) will not work either (becuase of the same issue with the cam position sensor not being in the correct location relative to the marks/bumps on the gear). Anyone know? It would be awesome to be able to use current cam gear set from a WRX and just move the sensor or something like that since WRX cam gears are all over the place and if you want to get fancy adjustables are available also..... mmmm more thought to ponder.

dzx · Post by **dzx** » Fri Nov 03, 2006 2:58 am

The ones from a wrx won't work without welding new marks on or rigging something up to work. There are less marks on the wrx pulley then on the legacy one.

head2wind · Post by **head2wind** » Fri Nov 03, 2006 3:52 am

hmmmm so my next question is... are the marks that are there in the right spot? I don't mind too much if I have to add addtional marks by glue or by weld if I can make a similar solution to a set of 20g gears.

EDIT: and my basic problem with this is I don't have all three types on my bench or near my engine stand to compare. I don't want to buy a bunch of gears that won't work.

mhrallyteam · Post by **mhrallyteam** » Sun Nov 05, 2006 10:37 pm

Let's say i used ej20G heads, i'll use the ej20g intake manifold, but will my injector rail fit?

head2wind · Post by **head2wind** » Mon Nov 06, 2006 5:19 pm

no it will not fit. the ej20g intake is different, as are the rails

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Running a DOHC head with stock computer?

Running a DOHC head with stock computer?