A tale of two Foresters (sigh)

[Gnuman]

OK, I have been fixing on a lot of Subies but this week I saw two things I have never seen before:

 

1st is a 99 Forester, 2.5l SOHC. I got the call to repair this after the owner discovered the hard way that "it runs better with oil in it". I was called in to check out the replacement engine and make it the best it could be, before I swapped it in. OK, done. two days later I get a call that a loud clattering had been heard and could I check it out? I go to the car and there is a hole in the side of the timing belt cover, and a couple of bits of broken plastic laying on the top of the rock guard that covers the bottom of the engine. Inspection shows that one of them is a part of the t-belt cover, and the other looks to be part of a cam sprocket. When going over the engine, I had noticed that one cam sprocket was plastic, and the other one metal. I found this strange, but I had seen other things on Subarus that made me suspect that large amounts of sake were used during the design process. I thought nothing of it. I also had remarked that the P/S pump had a bent pulley. Now I suspect that the plastic cam sprocket was either a replacement for a broken metal one, or had tiny stress fractures that were invisable to my eye. I will be taking the front of the original engine apart for comparison. Have any of you seen this one metal and one plastic arangement on any SOHC 2.5?

 

the other is a 98 with the DOHC 2.5. Now, I have done dozens of these with never a problem. This one is running real rough, and even trying to run backwards (it will backfire through the throttle body first, then start running backwards) The only thing I can think of is that I read the cam sprockets wrong, setting the timing a tooth off, or it jumped somehow. Anyone have any other ideas on what it might be?

[Cougar]

The valve timing does sound like it is way off.

[OB99W]

[...]

 

the other is a 98 with the DOHC 2.5. Now, I have done dozens of these with never a problem. This one is running real rough, and even trying to run backwards (it will backfire through the throttle body first, then start running backwards) The only thing I can think of is that I read the cam sprockets wrong, setting the timing a tooth off, or it jumped somehow. Anyone have any other ideas on what it might be?

It may not be related to what you've got, but "Incorrect Parts Substitution" on page 12 of http://endwrench.com/images/pdfs/Emissions.pdf is interesting anyway.

[Gnuman]

That is interesting, but the engine ran well before the work, and I did not replace any of the sprockets. I did replace the seals and timing belt, but not any of the sprockets. That bad part replacement may have been an issue with the 99 unit though, as I have never seen cam sprockets that are of differing materials.

[idosubaru]

i've seen these "plastic" cam gears on DOHC Legacy GT Sedans as well. i was very surprised as well. and they do chip/break easily, i cracked one and replaced it. still have it at home, if i remember to take a picture i'll post it. i remember just thinking that "was normal" since i haven't worked on nearly as many EJ's as i have older gen stuff.

[Gnuman]

Yeah, I have seen all plastic (DOHC engines) and all metal (SOHC engines) before, but not one of each. that is what is bothering me about that engine. i'll be taking a look at the front end of at least one of them today or tomorrow.

[Gnuman]

OK, took a look at both of them yesterday. the DOHC had jumped time on the crank sprocket and I had not noticed it when putting the belt on. three teeth, IIRC. that one is fixed.

 

the SOHC had the passenger side cam sprocket break where it seats on the camshaft. the pin that holds the sprocket in place came out and ate the keyway. It'll be needing a new sprocket and camshaft. The engine came with a warranty, and we will be trying to get them to pay for the repairs. The 99 Forester did come with one metal and one plastic cam sprocket. This still feels to me to be an engineering decision based more on sake than science. . .