Timing belt skipped.
#19
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Car Info: 1998 Impreza L
Is it possible that it's a head gasket or wrong timing that's why the compression's that way?
#20
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headgasket unlikely. youd overheat or see massive amounts of coolant ontop of block if it were leaking from HG. wrong timing, yes could cause misfire. a skipped belt with 2 or more teeth skipped at crank, can and will bend intake valves. replacing valves is a complete overhaul of the engine (minus shortblock) youd have to pull engine and do some head work as well as buy new valves. before that though, you need to determine why it skipped in the first place. do a leakdown test and youll for sure know what is leaking is anything. i have a leakdown tester if you need to borrow one. but youll need an air compressor. PM if needed. GL bud
#21
If a valve is bent, you're going to want to do a full cylinder head overhaul. At the very minimum, to function properly, a new valve would need to be lapped and correctly shimmed. I don't know of your mechanical skills and resources (tools/time), but if that is the issue pull the engine, remove the heads. Find a good machine shop in your area and have them service the heads. This will typically involve surfacing and a valve job. They will setup and reshim the valves after machining. Personally, I have never machined a cylinder head for flat 4, being as small as they are I imagine that surfacing MAY not be necessary since warping will have less effect over a shorter distance, but I don't know that for sure.
Any engine guys/machinists chime in. I'm still fairly new to these engines myself.
Any engine guys/machinists chime in. I'm still fairly new to these engines myself.
#22
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No compression = pull motor.
Pull off your heads, plenty of YouTube videos out there, and look at how the valves are sitting. Probably will be able to see the bent valve not seating right.
Take the heads to the machinist, have him replace the bad valve (s), if everything is seating right and gets the ok from him slap it back together with new head gaskets and done.
Have fun
I actually just went through this.
Pull off your heads, plenty of YouTube videos out there, and look at how the valves are sitting. Probably will be able to see the bent valve not seating right.
Take the heads to the machinist, have him replace the bad valve (s), if everything is seating right and gets the ok from him slap it back together with new head gaskets and done.
Have fun
I actually just went through this.
#23
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Car Info: 1998 Impreza L
headgasket unlikely. youd overheat or see massive amounts of coolant ontop of block if it were leaking from HG. wrong timing, yes could cause misfire. a skipped belt with 2 or more teeth skipped at crank, can and will bend intake valves. replacing valves is a complete overhaul of the engine (minus shortblock) youd have to pull engine and do some head work as well as buy new valves. before that though, you need to determine why it skipped in the first place. do a leakdown test and youll for sure know what is leaking is anything. i have a leakdown tester if you need to borrow one. but youll need an air compressor. PM if needed. GL bud
#24
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If a valve is bent, you're going to want to do a full cylinder head overhaul. At the very minimum, to function properly, a new valve would need to be lapped and correctly shimmed. I don't know of your mechanical skills and resources (tools/time), but if that is the issue pull the engine, remove the heads. Find a good machine shop in your area and have them service the heads. This will typically involve surfacing and a valve job. They will setup and reshim the valves after machining. Personally, I have never machined a cylinder head for flat 4, being as small as they are I imagine that surfacing MAY not be necessary since warping will have less effect over a shorter distance, but I don't know that for sure.
Any engine guys/machinists chime in. I'm still fairly new to these engines myself.
Any engine guys/machinists chime in. I'm still fairly new to these engines myself.
#25
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Car Info: 1998 Impreza L
No compression = pull motor.
Pull off your heads, plenty of YouTube videos out there, and look at how the valves are sitting. Probably will be able to see the bent valve not seating right.
Take the heads to the machinist, have him replace the bad valve (s), if everything is seating right and gets the ok from him slap it back together with new head gaskets and done.
Have fun
I actually just went through this.
Pull off your heads, plenty of YouTube videos out there, and look at how the valves are sitting. Probably will be able to see the bent valve not seating right.
Take the heads to the machinist, have him replace the bad valve (s), if everything is seating right and gets the ok from him slap it back together with new head gaskets and done.
Have fun
I actually just went through this.
#26
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before tearing down the motor, you can do a leakdown test (wont be as accurate as when engine is warm) or you can pull off heads and either run water in the ports and check for leaks or run air through the ports as well. this will tell you of any valves not seating properly. then you can take the heads to a machine shop to have them replace the bad valves and deck the heads. they supply generic replacement parts, or you can order from subarugenuineparts.com and take parts in to them to have them install. Do both, an overhaul like this should only be done once every 120-150k if and when head gaskets start to wear. Do it right and do it once.
Parts youll need:
gasket set
timing belt (if near or over 100k. also bad tensioner)
valves
fluids and filter
misc hoses if brittle (air/oil) or bulging (coolant)
spark plugs
machining would probably be around 300 for decking and install of valves for both heads
youl need a SOHC cam gear holder. depending where in CA you are, you can borrow mine.
be sure to follow the factory service manual to the letter. study it well before touching bolts
Goodluck bud!
Parts youll need:
gasket set
timing belt (if near or over 100k. also bad tensioner)
valves
fluids and filter
misc hoses if brittle (air/oil) or bulging (coolant)
spark plugs
machining would probably be around 300 for decking and install of valves for both heads
youl need a SOHC cam gear holder. depending where in CA you are, you can borrow mine.
be sure to follow the factory service manual to the letter. study it well before touching bolts
Goodluck bud!
#29
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Join Date: Aug 2009
Location: California
Posts: 56
Car Info: 1998 Impreza L
before tearing down the motor, you can do a leakdown test (wont be as accurate as when engine is warm) or you can pull off heads and either run water in the ports and check for leaks or run air through the ports as well. this will tell you of any valves not seating properly. then you can take the heads to a machine shop to have them replace the bad valves and deck the heads. they supply generic replacement parts, or you can order from subarugenuineparts.com and take parts in to them to have them install. Do both, an overhaul like this should only be done once every 120-150k if and when head gaskets start to wear. Do it right and do it once.
Parts youll need:
gasket set
timing belt (if near or over 100k. also bad tensioner)
valves
fluids and filter
misc hoses if brittle (air/oil) or bulging (coolant)
spark plugs
machining would probably be around 300 for decking and install of valves for both heads
youl need a SOHC cam gear holder. depending where in CA you are, you can borrow mine.
be sure to follow the factory service manual to the letter. study it well before touching bolts
Goodluck bud!
Parts youll need:
gasket set
timing belt (if near or over 100k. also bad tensioner)
valves
fluids and filter
misc hoses if brittle (air/oil) or bulging (coolant)
spark plugs
machining would probably be around 300 for decking and install of valves for both heads
youl need a SOHC cam gear holder. depending where in CA you are, you can borrow mine.
be sure to follow the factory service manual to the letter. study it well before touching bolts
Goodluck bud!
I took the heads off while the engine is still in the car. I'm at the process of looking for a machine shop right now. It's my first time dealing with this head gasket replacement, bent valve stuff so hopefully all goes well.
Just a question. I bought a new timing belt and a new timing belt tensioner when I tried figuring out why my car was misfiring hoping that were going to fixing it.
Now I know it's a bent valve for sure but I'm afraid to use the timing belt and the timing belt tensioner that I recently bought because it kept skipping and skipping when I was trying to fix the misfire.
Is it possible that the belt was skipping all the time because the exhaust valve was bent? Once I fix the exhaust valve do you think if I use the same timing belt and tensioner that it would no longer skip?
I feel like just buying a new timing belt and a tensioner to be sure. Will that be a waste of money?
#30
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There's a great product by Company 23 or something like that. They sell tools to remove the pulley, camshaft and things like that. I would never do another timing belt job without those tools. Got them at rallysportdirect. I'm sure they can be bought somewhere else though.