Subaru timing belt slipped

T

Turbo_Manx_Maniac

Active member
Joined
May 5, 2021
Messages
106
Reaction score
125
Went to Borrego last weekend, car was running fine. On Sat I let my brother drive the car, we ended up at Rams Hill for a beer. When we went to leave, the car wouldn't start. It would turn over about a revolution and a half and sort of lock up, like it had hydraulically locked. It just kept doing this with no signs of firing up. I tried to bump start it and it started popping like from what seemed like 1 cylinder. I suspected the timing was way off. 

Skip to tonight, I removed the belt covers and discovered the crank timing mark was about 3 teeth counter clockwise from the mark with all 4 cams perfectly aligned. The cams did not slip, just the crank.

I pulled the belt and inspected the crank gear and it looks new, no bent or worn teeth. I clean the outer covers yearly and blow out whatever I can reach. Tensioner seems good as well as the belt and idlers. Only thing I can think of is that some oil or grease got on the belt and made it slippery?

So now I am wondering what I should do. Clean it all and put on a new timing belt?

Gates blue belt, Subaru belt?

Hate to call Outfront for this, they gotta be busy on more important stuff.

Sucks we lost all the Subaru info.

The motor is a quad cam 2.5, gt28 turbo at 10 psi with meth injection. It's a JDM from OutFront I got about 10 years ago. It's gonna need some attention in the off season, it's burning a quart of oil every 2 to 3 trips and has about 10-15% leak down. 

 
I had a timing belt slip once on a little neon, didn't realize that is what had happened and it basically tore up the head, smashed valve train. I hope you stopped running the motor before something catastrophic happened.

 
Never leave a Subaru in gear on any hill.  We have had them skip a tooth (or belt slip) while parked in the past.  Buy a new belt and install.

 
It was parked on an incline, I suspect my brother let it roll back and let out the clutch to stop it, without the engine running.

Gonna try the gates blue belt.

 
show a close up pic of the timing belt area with covers off so we can see some detail and maybe some things that are not right

 
Here's what I have on my phone, I'll take a better shot of the idlers etc tonight. These pics show the timing marks as they were when I removed the covers. Looks like one of the cams is off 1 tooth as well.

@John@OutfrontI was looking at your website, I want to replace this shortblock after the season as it's worn out. I want to make about 350 hp at the crank, should I just get an STI shortblock, rebuild this one, another JDM, or get one of your grocery getter short blocks? What's the advantage of the long rod option? Do all forged Subaru piston engines make that loud knocking sound when cold, or just the S&S motors 🤣?

20220103_201059.jpg20220103_201226.jpg20220103_201151.jpg20220103_201126.jpg

 
Last edited by a moderator:
We had several issues with belts skipping teeth when we all had Subarus. Never could really find a real reason. 
We ultimately changed the tensioner and stock belt, worked every time. 
We would change every season and never had issues again. 
As  others said, don’t leave in gear, I always removed the covers every few trips blew them out. 

 
Turbo_Manx_Maniac said:
It just kept doing this with no signs of firing up. I tried to bump start it and it started popping like from what seemed like 1 cylinder. I suspected the timing was way off. 
Click to expand...
Can you cause more damage bump starting a subi?  I know you shouldn't tow in gear and try not to stop on hill in gear.

 
I am definitely missing the gold plate. Now I have to figure out where to get one of those.

 
Last edited by a moderator:
Turbo_Manx_Maniac said:
Here's what I have on my phone, I'll take a better shot of the idlers etc tonight. These pics show the timing marks as they were when I removed the covers. Looks like one of the cams is off 1 tooth as well.

@John@OutfrontI was looking at your website, I want to replace this shortblock after the season as it's worn out. I want to make about 350 hp at the crank, should I just get an STI shortblock, rebuild this one, another JDM, or get one of your grocery getter short blocks? What's the advantage of the long rod option? Do all forged Subaru piston engines make that loud knocking sound when cold, or just the S&S motors 🤣?

View attachment 22391View attachment 22394View attachment 22393View attachment 22392
Click to expand...
do you not have the derailer that bolts right above the crank gear or did you remove it already--that part is a must

all forged pistons can make noise but the trick is in the boring tolerance.  we typically dont have that issue

350 is not a tall order, what fuel and how much boost do you run?  i ask this to determine options on the rebuild

 
John@Outfront said:
do you not have the derailer that bolts right above the crank gear or did you remove it already--that part is a must

all forged pistons can make noise but the trick is in the boring tolerance.  we typically dont have that issue

350 is not a tall order, what fuel and how much boost do you run?  i ask this to determine options on the rebuild
Click to expand...
I run pump 91 octane, methanol injection. I run 10-11 psi now, but want to run 15 psi. I am willing to run higher octane gas if I need to, and ditch the meth injection. I don't have a good spot for an intercooler or there would be one. The way my radiator is situated, there is little air flow in the back of the car. 

IMG_1246.JPG

IMG_1244.JPG

 
as you can tell the derailer at the crank is important, on the newer four cam motors like sti and Wrx's they even have options for timing belt guides at three of the cams too

note: this option only happens on manual tranny cars as the Atuo's can "decell" an engine like a manual can

IMG_9847.JPG

 
John@Outfront said:
Outfront of course  $15
Click to expand...
I need one!

I returned to camp no issues and then would not start for the next run. Sounded like it was trying to start found rear 2 cylinders plugs super wet and the 2 front dry. I haven’t pulled the covers but hoping that it is just the belt slipped. I know from previous belt changes that I never removed or installed this piece. Previous owner must not have reinstalled at some point. After I hopefully reveal that the belt slipped I’ll order a new belt and guide thingy. 
 

unless my symptoms sound like something else??

 
John@Outfront said:
as you can tell the derailer at the crank is important, on the newer four cam motors like sti and Wrx's they even have options for timing belt guides at three of the cams too

note: this option only happens on manual tranny cars as the Atuo's can "decell" an engine like a manual can
Click to expand...
How does this work?  Doesn't the belt follow the yellow line?

cover.png

 
You must log in or register to reply here.
Back
Top