Oil pump drive shaft failure.

[wesbeech]

Ok well the 7mgte in my cressida started making a knock so i pulled the motor. To find out the oil pump ds was going from its proper spot in the block and walking back untill it hit the timing cover by the block. Which also caused the ds to make contact with a rod wearing a chamfer on the ds and a grove in the rod. i have found out what happend. The front part of the ds where the seal rides and the retention plate sits. well the plate actaul wore away the front 1/4" of the seal diameter which allowed the ds to walk back and forth in the block causing the knock and alot of metal shaving in my oilpan and whole motor. The ds bearings are perfect size and in spec as is the ds bearing od's and there ways no up/down side/side slop or play only in and out. Has this happend to ne one before? Ne ideas what caused it?.

Trashed ds on the left good stocker on the right. As you can see they are the same height and every thing is the same except that top od that is worn away.

 

[wesbeech]

I am in the process of fully building my motor so i ned to find out what caused this and make sure it dose not happen again.

 

[grimreaper]

worn a little? thats got to be the understatement of the night!

interesting way to kill the 7m, good luck with the rebuild. Much more refreshing to hear a tear down in progress then "oh my god, wtf is that knocking, help me!"

 

[wesbeech]

No one else hase ever seen this?

 

[Tanya]

holy hell, that's nuts...

I'm interested to see if anyone's ever seen that before either...

 

[JoeyJ]

that's strange, a guy in here in Sweden had a similar problem just a couple of weeks ago, and now you, and I had never heard of it before either.

This is the result...

I don't think he had as much wear as you so he just replaced the shaft

 

[need new tires]

well since we are posting pics of this failure. back in feb. a motor i had built had this happen to it.

note the thread lock on the bolt that was still tight(proper)

i wish i would have documented the aux shaft but it looked close to the pic that wes posted up. it had myabe a 1/2 inch of play in/out.
-shane

 

[wesbeech]

Shane clames thin or watered down oil Ne one else?

 

[rtrdpenguin]

This happened to my 7M while going ~90 mph on the highway Needless to say I needed a rebuild and mine was broken in the same way yours is.

 

[TooGoode]

why has this problem just recently come up? i havent heard of this happening to our motors that often. What causes this?

 

[gofastgeorge]

I have an identical one in my shop.
I thought it was due to high RPM that my shaft turns,
and high oil pressure.
(overdriving oil pump, and 8500 rpm read line, and 80 psi)
And the fact that the front of that retainer has no direct supply of oil.

I reworked a retainer plate so that
it has an angled oil grove from the back side, down to the ID,
then back up the front side of the plate.
The angle is in the direction of rotation,
so that oil is now pulled down the grove,
through the ID, and back up the front.

I also copper plated, then silver plated the thrust surface
(making it like a rod insert)

That was a year ago, and I am still running high oil pressure,
still revving the dog snot out of the engine,
without any more problems.

I cut the oil grove in with a dremmel.
And moly coat could be used in place of the plating.

 

[IJ.]

Was running 100Psi a few years back without a failure so not sure if that was a factor George, was also spinning that engine to 8300 daily.

I like the groove idea.

 

[wesbeech]

I have an identical one in my shop.
I thought it was due to high RPM that my shaft turns,
and high oil pressure.
(overdriving oil pump, and 8500 rpm read line, and 80 psi)
And the fact that the front of that retainer has no direct supply of oil.

I reworked a retainer plate so that
it has an angled oil grove from the back side, down to the ID,
then back up the front side of the plate.
The angle is in the direction of rotation,
so that oil is now pulled down the grove,
through the ID, and back up the front.

I also copper plated, then silver plated the thrust surface
(making it like a rod insert)

That was a year ago, and I am still running high oil pressure,
still revving the dog snot out of the engine,
without any more problems.

I cut the oil grove in with a dremmel.
And moly coat could be used in place of the plating.

Do you have any pics of it?

 

[gofastgeorge]

Nope, sorry.
Pictures were not even on my mind when I found the pulley starting to rub on the inner front cover.
Just pulled it all down, seen what was happening.
Figured out how to keep it from doing it again,
and put it all back together.
Thankfully, I had a spare shaft, and retainer plate.

Next build will get a needle thrust bearing there.

 

[rtrdpenguin]

If it's any help mine was completely stock and I was babying that engine since I had just dropped it in. JDM 7M with an untouched bottom end, all I did was replace the HG. I bet it's just age and wear, 20+ years is a long time for an oil pump driveshaft to turn!

 

[wesbeech]

If it's any help mine was completely stock and I was babying that engine since I had just dropped it in. JDM 7M with an untouched bottom end, all I did was replace the HG. I bet it's just age and wear, 20+ years is a long time for an oil pump driveshaft to turn!

It was a jdm motor i checked all specs and tollarances before it went in the cressida everything was perfect. It lasted 240 miles

 

[gofastgeorge]

Was running 100Psi a few years back without a failure so not sure if that was a factor George, was also spinning that engine to 8300 daily.

I like the groove idea.

Well, it accured to me that the dumb-ass who assembed it (me)
missed some dirt, or debres in the block above that point,
and it just happen to wash down onto that scantilly lubed thrust surface
upon started it up,
seeing the failure happened within a couple of days of the engine going back in.
No proof, but it is a possibility.

Like they say, 99% of the 7M problems, are because of the owner.....

 

[IJ.]

Yep any failure's I've had have been 100% my fault

 

[Zumtizzle]

http://www.supramania.com/forums/showthread.php?t=78456&highlight=collar

http://www.supramania.com/forums/showpost.php?p=1110454&postcount=28

it's a very good idea to check out thrust clearence.

 

[wesbeech]

Well im gonna look into cryo treatment for the front colar or something iv got a date with the race shop tomorrow to talk about it