Spun Bearing Why Cylidner #1, Twice now.

[92TealSupra]

Cylinder #1 why? This would be the second JDM 7M-GTE I got that has had the spun bearing go on cylinder #1.

Even before tearing into the block I looked at the head and you can see a impression of the piston that hit the head. The reason why this happens? I can only guess since the bearing gets small in thickness it leaves the connecting rod to travel a longer distance, and hence hit the combustion chamber on the head.

I tried thinking of the oiling system, and seeing if maybe there would be a lack of fluid to this area in the block. Is it just that I got two motors that had this happen? Or is this a normal occurrence, sadly why is this happening to the ( low mileage ) JDM 7M-GTE's.

I would like to add that I talked to a import company and they said that most of the engine you see online, and EbAy, that claim 30-50K on the motors are all bullshit. he said most of the motors that are imported have upwards of 80K-150 on them. Also he get's the speedo out of every car and sends a picture with the motor, and any other additional info he can from Japan to the U.S.

I would just like to know if cylinder #1 has more of a problem then any other cylinder?

 

[grimreaper]

not to call your import guy a liar, but a picture doesnt do you much. I can take a pic of a low mile odo. and save it to use for all motors pertaining to that dash layout/gauge cluster etc..

why the imported crap over a rebuild?

 

[Sik89supra]

was the motor rebuilt at all? A spun bearing isnt gonna make the piston hit the head,Was the crank mic'ed to make sure its got the right sized bearings?

 

[92TealSupra]

was the motor rebuilt at all? A spun bearing isnt gonna make the piston hit the head,Was the crank mic'ed to make sure its got the right sized bearings?

head and deck of the block were both milled, if done incorrectly then this result may happen when the bearing gets smaller.

Hope IJ. Or JDub can chime in.

 

[TurboStreetCar]

Did you use a metal head gasket of proper thickness? If your deck height was that low your compression was most likely very high as result.

 

[gurley0916]

I had a motor that had a spun bearing in number 1 as well, the piston never hit the head there should be enough clearance regardless.

 

[Tanya]

^Werd, I would think so as well. I recently was "fired" from a 5MGE engine build so the owner could have his machinest rebuild it instead. This machinest told him "it must have knocked at some point" because both #5 and #6 looked like they had hit the head.

teh. wut.

I heard this engine, drove in the car run before I ripped it out. Besides the fuel issue, it was butter. NO tapping or knocking. It seems more and more machinists these days are either liars or morons.

 

[IJ.]

"might" hit the head if there's huge piston to bore clearence and the head and block have been surfaced and a thin MHG fitted.

 

[gaboonviper85]

"might" hit the head if there's huge piston to bore clearence and the head and block have been surfaced and a thin MHG fitted.

Motor I'm speaking of was an na factory original....when you rotated the #1 piston too bottom dead center you could push on the piston and it would fall an extra 1/4"! It left a very very unmistakeable ring on the head! I was going to purchase this motor but I told the seller that I wanted to inspect it first and he understood...needless too say he picked the motor back up and sold it for scrap!