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1G Engine “failure” diagnosis

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SasaniFab

Proven Member
2,433
782
Dec 1, 2013
Mexico, Connecticut
So I got a message on Facebook from a guy who purchased a built motor for me awhile back. The engine had the best of the best. New oem head, new oem 6 bolt crank , all new oem timing components including the oil pump with straight cut gears. He took the car out for a spin and oil started leaking out of the oil pump gear seal. He pulled the motor and noticed the oil pump gear was hard to turn. I assembled the shortblock , oringed the block and installed the head. I didn’t install the timing belt or cams. This is what he found when pulling the front cover. Everything else is in perfect order? The motor has less and 600 miles on it.

He believes he overtightened the timing belt and side loaded the gears.... The scuff marks look pronounced on once side , almost like it was spinning Off center

To clarify , the motor has 3k
 

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Thats some bad scoring. I haven't seen that particular problem before. Did the oil filter catch the debis???
 
Rear shaft installed or were the shafts eliminated (using stubby shaft)?
 
Looks to meet like it was eating in the direction the timing belt would pull if overtensioned. I feel like it would have to be extremely overtensioned to cause that damage in that time frame.

Does look like a stub shaft to me.
 
The engine had a oem stubby shaft ... He believes that he overtightened the timing belt significantly. Can’t believe how much scoring. The motor is heathy otherwise.... thankfully
 
@SasaniFab thanks for confirming. What about the oil pump? OEM or aftermarket?

Overtightening makes sense, at least. I mentioned something about similar wear patterns in a thread over two years ago, trying to help explain why overtightening would cause this wear pattern: Helical gears and OEM stubby shaft.
 
@SasaniFab thanks for confirming. What about the oil pump? OEM or aftermarket?

Overtightening makes sense, at least. I mentioned something about similar wear patterns in a thread over two years ago, trying to help explain why overtightening would cause this wear pattern: Helical gears and OEM stubby shaft.
Oem oil pump from extreme psi with new straight cut gears.... first time I’ve ever had an issue with an oil pump like this. Makes me want to grab a frontline cover. The fact that steel gears are sitting in a aluminum housing suspended in oil terrifies me
 
I appreciate the extra info! Hopefully he's back up in running in no time!
 
For the record , this motor was built to run in a Subaru Legacy. The owner made his own adaptor plate and custom wiring harness
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Motor sounded spot on in the video. With our pickups where they are, any RWD application should probably think about that and try to move it rearward, if thats what a Moroso pan does. Did he ever mention oil pressure to you because the video sounded like a healthy motor BEFORE he went for a spirited drive perhaps????? :idontknow:
I say you did your job fine and starvation was the culprit as has already been pointed out. If you are even in the pallpark, the tension on the belt shouldn't have hurt it IMO. Especially with straight cut gears. Just my thoughts.
 
Any more info on the build? I met a guy who's doing a 4G63 in a STi.. he's getting a bell housing adapter from Europe so he'll be using Sti drive train... sorry to derail the thread :)
 
Any more info on the build? I met a guy who's doing a 4G63 in a STi.. he's getting a bell housing adapter from Europe so he'll be using Sti drive train... sorry to derail the thread :)
Car is an 06 legacy, bmw 6 speed transmission. The adaptor plate was a modified evo adaptor plate made by pmc motorsport out of Poland. Custom flywheel adaptor. The car has two ECUs , one to run the car electronics and ecm link to run the engine. The engine I built .... 2l 6 bolt with wiseco hds, turbo tuff rods. I oringed the block with stainless steel wire and I used a oem mls
 
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