Cam timing

Posts specific to the 2.5 litre NA engine

Cam timing

Postby Daniel33 » Tue Aug 01, 2017 1:36 am

Hi all.

I just did the head gaskets on a newly aquired '06 Forester. It has the EJ2.5i NA engine in front of an auto. What bugged me though, was the cam timing when I pulled it down. I set the harmonic balancer to TDC but couldn't get the cams to line up properly. They were not sitting with the mark on top. Then, I pulled the plug on number 1 pot, to double check the position of the slug and sure enough, it was right on the money. Regardless, I put some paint on the wheels and stripped it down, leaving the cams in the heads, and got it back together and running fine.

So, my questions are these:

1. What advantage would advancing the cam timing by 6 teeth be? What would be the drawbacks, if any?

2. Would it be likely that it has cranky cams in it? (It has an aftermarket set of extractors). There is no warble from the noisy end. Just sounds normal.

3. It reaches up to 170 kph in third and nearly went into top when the road ran out, (or thereabouts) and redlines in 1 and 2 at about 6.7k rpm with the foot planted and the AT set to power. Is this normal?

4. Still had honing marks in the bores. There is a full service history, but a blank entry at I think around 40 000 k's ago. followed by shorter service periods. Would the head gaskets have blown so early after a rebuild?

5. Unsure yet of the mileage, but it is running a black exhaust. Possibly averaging 6 or 7 liters per hundred k's but it is not being driven by me, so accuracy is suspect.

It had a check engine light on when I got to it. It was throwing the P0032 code. I jigged around with it for quite a while, and ended up fixing it I think, but still suspect there is an issue with the sensor which might be the cause of the black exhaust. The main thing is the cam timing.

I am about to do another engine, but fully stock. Would there be any advantage in advancing the valve timing on it?
Daniel33
 
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Re: Cam timing

Postby Lane » Wed Aug 02, 2017 7:28 am

It's hard to comment without seeing it or some pics, often they aren't 100% exactly lined up as when you try to adjust it the other way it's out even more so for want of a better phrase its as least out as you can make it.

How much are we talking?
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Re: Cam timing

Postby Lane » Wed Aug 02, 2017 7:32 am

Advancing the timing mechanically may possibly add power while at full throttle and run poor everywhere else.

It will probably throw a code and make it run in limp home mode or run like balls, these are just guesses though as I've never tried on an ECU controlled engine with so many sensors.
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Re: Cam timing

Postby Daniel33 » Wed Aug 02, 2017 11:42 pm

Hi Lane.

The thing runs fine. It is using 10 liters per hundred regardless of load and altitude. Perhaps that is closed loop running, I am not sure. It has not displayed a code and she has done close to 1000 k's in it since it went back on the road. How much would it use in limp home mode? It does run a black exhaust, which is sooty on the finger.

If you can't get the notches to line up on the cams evenly, then either the belt is stretched, or something is out of kilter.

This was advanced 6 teeth. I have counted the teeth on the cam gear. There are 48. There are 24 teeth on the crank gear. The cam runs at 1/2 the engine speed. It takes 2 revolutions of the crank to effect 1 engine cycle. So, 48 times 4 = 192. 360 degrees divided by 192 = 1.875 degrees per tooth. Times 6 = 11.25 degrees advanced.

At least, I think that's how you would work it out!! I am not a mathematician nor a mechanic.

It wanted to stay in second gear and pull at around 5 grand under heavy load. But I don't know the road speed. I think it was 55 or 60 k's? It revs to 6.5 and is at 70.

I am just wanting to know if it has had some serious work done, like injectors, cams and possibly a re-map and perhaps even a high stall converter, in which case there is nothing I can do to fix the fuel use, or if they all perform like this at the gearing side, and I need to replace the AFR sensors and try to bring the mileage up.
Daniel33
 
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Re: Cam timing

Postby Daniel33 » Sat Aug 05, 2017 10:04 am

Perhaps I am asking too much? Or is it that there are not that many people who actually get into the meat of the engine to know what it is I am speaking about? If that is the case, it would be pointless for me to post anything about the injector hack I am planning.
Daniel33
 
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