Jump to content
Ultimate Subaru Message Board

Timing belt Snapped. Now it's wierd ...


Recommended Posts

I got a weird one …

 

I haven't ever taken any long(ish) trips in this Soobie. I did a 2.5 hour trip last Tuesday – expressway speeds, no problems on the way there. Sat 2 hours when I got there, and then I started back. 15 minutes into the return trip on the expressway, and POW! Total death. 100% down. 3500 rpm to zero in 0.0 seconds, hehe. Pushed the car off the E-way, and found a way to get him trailored the 150 miles back. As I suspected when we got him apart was the drivers side timing belt had sheared.

 

This isn't an interrupt engine, so I figured I'd be up & running. None of the pulleys, equalizers, whatever, were frozen. The belt was in otherwise relatively good shape. They weren't worn, no cord-rip, no signs of rubbing, etc.

 

Anyway, so maybe I got a bad belt. Hey – it happens. It's $17 bucks, no biggie (although getting him home cost me a coupla hundy). I dunno. Putting 2 new belts back on, now the thing runs like CRAP. Like it's missing on 2 cylinders. I checked compression, and I have 140 compression on both passengers’ side cylinders, and I'm at about 120 on one and only 100 on the other (drivers' side). Here's what I can throw into the mix:

  • The belts are only about a year and a half old. I'd say 10,000 miles ago tops. Replaced them January '07.
  • I changed the timing SLIGHTLY during this time, and occasionally, I'd hear some ping when I wanted to accelerate hard.
  • One thing I've noticed lately (about a month before this happened) was that the oil pressure was WAY UP for the first 5 minutes of running – always goes down to normal after a few minutes. Oil change didn't help.
  • The distributor cap kinda looks like there's some carbon build-up on it. And I haven't miked it, but it sorta feels like it's not sitting flat.

If I didn't know any better, I'd say it was cross-firing, but I haven't pulled any wires, etc. Any ideas? I'm gonna do cap & rotor, but this compression is messin' with me. Has something horrible happened? Am I about to feel really stupid? hehe...

Link to comment
Share on other sites

the only thing you did was change the belts - you didn't touch anything else?

one of two things:

 

1. you are off one tooth

2. you are 180 degrees out if you don't know how to install these belts. they're weird - lining the marks up is the opposite of how most cars (even newer soobs) do it.

 

i think you'll be good to go when you get a chance to track it down.

Link to comment
Share on other sites

Line up the the marks on the pulley to excactly straight up and down. Don't go by the notches on the plastic covers, they distort form heat and will be off slighlty.

 

It does sound like you are a tooth off on the drivers side belt. That throws off you're ignition timing as well.

Link to comment
Share on other sites

Check the oil pump the next time you are in there. I supect it was a seized oil pump that snapped my belt. It fired up and ran fine when I replaced the belts. I didn't find the pump was bad until I tried to reseal the it a month or more later. Could this have happened to you?

 

If the belt covers are not a good reference, how do you judge the timing mark is just right? I wouldn't trust my eyeball for this task. Is there a plumb bob trick that can be used?

 

I am wondering because my car hasn't run quite right since I did the belts and then the oil pump. Not badly, just a little more gas than usual, running a bit warmer than normal.

Link to comment
Share on other sites

i did my belts a few months back, (how i found this site)

got mine a tooth off, ran horrible, had to turn the distributor as far as it would go to get it to run at all.

 

just left my busted front timing covers off for easy access the next time. (even i can change them in about 30 min. with the covers off) and i keep extra belts and my old pulleys in the back.

 

after my 2nd or 3rd time redoing them to get em right, it started getting easy.

 

also, no real grime or buildup on the uncovered belt yet after several months.

 

good luck, Bill

Link to comment
Share on other sites

If the belt covers are not a good reference, how do you judge the timing mark is just right? I wouldn't trust my eyeball for this task.
it's not as hard as it sounds once you think about how it works. the timing belt can't be off by 1mm. being a toothed belt it'll be off by one tooth, that's enough to make it obvious once you pay attention to what you're doing.

 

you look at the mark, line it up straight up and down. once the belt is on you can then double check...is either tooth to the right or left of the mark closer to straight up (or down)? if so, you're off.

 

it's not as hard as it sounds. also - the valve cover mating surface is a close reference.

Link to comment
Share on other sites

Others have beaten me to the punch, but I was going to ask whether you had the covers on or not. It is ridiculously easy to have one belt off by a tooth if you are *somewhat* familiar with this job..... It is one of those situations where growing confidence can outrun actual ability, and cause patience to go out the window.. a careless mistake made by someone who has done it before, but not REALLY enough times to "just throw it together and be confident it was done right."

 

Ask me how I know this :o:rolleyes:

 

If you ARE concerned with a lack of a "smoking gun" then I would consider replacing the oil pump... it sounds fishy, and I know you like to take proper care of your car.. if it hasn't been done yet, it may well be worth it for peace of mind alone.

Link to comment
Share on other sites

  • 2 weeks later...

Daeron! LTNS, Bro!

 

Well, SOMTHING musta happenned. I know it's a non-interference motor, but SOMETHING musta happenned @ that RPM (3500 or so). I had only 80 psi compression in 1 cylender (others were around 140), and i could NOT getthis thing to start ... and I've been fiddling with it for THREE WEEKS!

 

FINALLY, I said "Screw it!" And we pulled both heads. Sent it to the machine shop & ordered up the gaskets. Is it worth it to go to the dealer for springs? Or does someone have a good source for some great ones?

Link to comment
Share on other sites

You didn't have the belt on right. With the belt incorrect, the valves don't actuate in sequence with the piston reciprocation and you will get intake valves that don't open at TDC, and don't close and BDC (and exhaust valves that do similar). This doesn't allow the cylinder to reach full pressure so you can't get an accurate compression reading.

 

I would say you pulled the heads for no reason.

 

GD

Link to comment
Share on other sites

Is it worth it to go to the dealer for springs? Or does someone have a good source for some great ones?

The machine shop will (should) check spring pressures once the valves are ground and then shim or replace the springs as needed.

Link to comment
Share on other sites

Wouldn't a timing light give conclusive proof as to whether or not the timing belt was way off?

 

Nope. As long as the drivers side belt is correct (which it often is), spark will be in the correct place. It's just the passenger side belt that makes it run rough.

 

Easiest way to check is to take the covers off over the cams and see if the dots are aligned together (wrong), or 180* from each other (correct).

 

-Dave

Link to comment
Share on other sites

You didn't have the belt on right. With the belt incorrect, the valves don't actuate in sequence with the piston reciprocation and you will get intake valves that don't open at TDC, and don't close and BDC (and exhaust valves that do similar). This doesn't allow the cylinder to reach full pressure so you can't get an accurate compression reading.

 

I would say you pulled the heads for no reason.

 

GD

 

i have to strongly agree .

 

to eyeball them they look dead on but i had to repeatedly redo mine till i got it right.

i'll probably have to the next time too.

 

if you leave your front covers off (mine were busted anyhow) you can redo them in less than 30 min.

 

good luck, Bill

Link to comment
Share on other sites

  • 3 weeks later...

Well ... you were all right. I think I took them off for no reason.

 

HOWEVER ... I'm kinda prone to overkill/preventative maintenance, and I still remember the days of my E-350 costing me about $300 a month in various repairs, and the tires cost $175 instead of $28, hehe. Plus, at 8mpg .. I'm not gonna complain too badly. Live & learn.

 

I'm proud to announce I have 165psi in ALL FOUR cylenders. New springs, heads are like they were new. Let's see, about $70 for the gaskets, $200 for the heads, $80 for the springs, and a few cases of beer for my buddy.

Granted, the car was out of commission for 6 weeks, and I was scrathing my head down to the scalp for awhile ... but we finally got it. haha!

 

Whatayagonnado?

Link to comment
Share on other sites

Thanks ... one thing the machine shop pointed out to me when I picked them up was that on one side, there was a visible crack in the head between the 2 cylenders - he said it was really common, and nothing to worry about & didn't need to be filled or anything - he had already done a bunch of pressure-testing on it, so he was confident about it. To me, it looked kinda scary, but I trust Daryl (the shop guy). Dont know if anyone else has seen that - he said it was common.

Link to comment
Share on other sites

Thanks ... one thing the machine shop pointed out to me when I picked them up was that on one side, there was a visible crack in the head between the 2 cylenders - he said it was really common, and nothing to worry about & didn't need to be filled or anything - he had already done a bunch of pressure-testing on it, so he was confident about it. To me, it looked kinda scary, but I trust Daryl (the shop guy). Dont know if anyone else has seen that - he said it was common.

 

Yeah I haven't seen that on my Subaru heads but on my VW heads I see that all the time! Nothing to worry about. Some people peen the crack with a punch, dunno if that helps.

 

What to look out for on the Subaru heads is a crack up the exhaust port (like mind did when I bought it) if it has been overheated. Coolant will leak out when you turn the car off and give you a smokescreen when you start it up. :grin:

Link to comment
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
 Share

×
×
  • Create New...