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11-04-2019, 11:26 AM | #1 |
Scooby Newbie
Member#: 84253
Join Date: Mar 2005
Location: Old North State
Vehicle:05 REX PSM |
Engine Rebuild (Jumped Timing) - Advice Needed from DIY'ers
Greetings -
I typed out a long post, but it seemed to vaporize so forgive me if this is a double - Purchased a new '05 WRX and it was one of the best cars I've ever owned. It became so much a part of the family that I had it rebuilt when it spun a bearing at 185k (about 25k and 2.5 yrs ago) - not logical, but we are emotional about cars around here. Sadly, it appears it jumped timing. Shop that did the rebuild is out of business so I towed to a local for a diagnosis. They tried to re-time as a hail mary, but no compression on one cylinder. No apparent intermix, car will start, no CELs. Dang shame. So here we are. When I rebuilt, we upgraded internals (racing rings, forged pistons, Killer B, etc). I do not need the car, but I want the car. However, I am not paying $5k - $10k for another total rebuild. So I was thinking maybe, just MAYBE I can tackle this myself. I am an experienced shadetree, but have never done anything like this. What I have going for me:
But there are limitations. I had the following questions/request some input on the following from those that have more rebuild experience than me:
Thanks in advance for any input/advice - if successful, this cars future would be as a toy, not a DD. Just trying to see if I can keep her goin'
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11-04-2019, 01:18 PM | #2 |
Scooby Specialist
Member#: 111755
Join Date: Apr 2006
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im in to hear what the experts have to say about this.
i think u can jump 3 teeth without banging into things, so it is savable. i'l prob get the timing covers off, get some really good light on it, and see if all 4 cogs are in the same orientation looking timed correctly for this one. |
11-04-2019, 02:31 PM | #3 |
Scooby Specialist
Member#: 220971
Join Date: Aug 2009
Chapter/Region:
South East
Location: NC
Vehicle:2004 Impreza |
Step 1, slap a belt on it, and perform a leak down test. Will tell you how many damaged holes. Miracles do happen, you may escape undamaged.
Step 2a, Dead hole(s), pull the engine, pull heads. (if only light impact marks on piston crowns, replace and re-lap only damaged valves and seals, check all valve clearances. Ship it.) Step 2b, Heavy impact marks on pistons, highly likely piston is fractured or visibly cracked. Find a used or JDM long block, or sell it all as is. |
11-04-2019, 04:31 PM | #4 |
Scooby Newbie
Member#: 318247
Join Date: Apr 2012
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One time, one of my idle pulleys exploded from lack of lubrication and my timing on the passenger intake cam pulley jumped 11 teeth without damaging the engine so miracles do happen. If there is damage its probably bent valves, in that case you could replace the head with a used one to save time or replace them yourself. I personally would buy a used head. I happen to have 3 heads for sale right now if your interested for an ej205, 2 passenger and 1 driver side all with good compression.
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11-04-2019, 06:10 PM | #5 | |
Scooby Newbie
Member#: 84253
Join Date: Mar 2005
Location: Old North State
Vehicle:05 REX PSM |
Quote:
Assuming no piston damage, does it make sense to replace all the valves when in there or will it be pretty obvious which ones are bent by checking clearances? Does anything else need to be done to head before re-installing? I take it if pistons are fractured/cracked that means damage to bore, correct? Thanks again! |
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11-04-2019, 08:30 PM | #6 |
Scooby Specialist
Member#: 220971
Join Date: Aug 2009
Chapter/Region:
South East
Location: NC
Vehicle:2004 Impreza |
Replace only the valves needed, and it will keep costs in check, otherwise you'll fall down the rabbit hole of "while I'm here".
Most machine shops do this test with Red ATF to see the dye trace. If the valves hit hard enough, besides bore score, the issue is the person working on the engine, you start getting into piston size, ring gap, on top of engine condition. Unless you're dealing with a known Surbau engine builder with lots of engines back on the road after repairs; you would be much further ahead, to just buy a used US or JDM long block and swap it in. |
11-05-2019, 02:48 PM | #7 | |
Scooby Newbie
Member#: 84253
Join Date: Mar 2005
Location: Old North State
Vehicle:05 REX PSM |
Quote:
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11-07-2019, 10:07 AM | #8 |
Scooby Specialist
Member#: 29292
Join Date: Nov 2002
Chapter/Region:
SCIC
Location: Orange County CA
Vehicle:2004 WRX wagon silver |
i second the jdm ej205.. plus you will get avcs that a big plus
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