Thrust Bearing Woes

[6667fan]

Block plate was in place. I like Dr. Danos suggestion about test assembling without clutch. The PB had a slight witness mark on the inner diameter of about 15 per cent of the total inside diameter. I did not take a pic as it did not look bad.
JB

[Faron]

which side of the thrust is worn was it forced forward or pushed back , had a customer install too long of flywheel bolts and they pulled the crank BACK , it wasn't by much , but .010 is not much

[6667fan]

No flywheel bolt interference. Wear on backside and frontside of thrust. Nothing on front of engine that is unusual, just a fan belt. The push always exists from the rear of course being a stick car.
Unless the valve guides prove to be very worn I will blame the stuff in the oil on the deterioration of the thrust itself. Mains not worn, one half of rod bearings worn more than other but not to the point of wearing past first layer.
The PB does not look bad. The ring on the flat surface was probably from an installation tool.
JB

[SSdynosaur]

I'll apologize in advance for not taking time to familiarize myself with details of your engine build but I felt the need to relate a similar experience. I race NHRA with an FE and broke an inner valve spring on heads fitted with solid bronze guides and, subsequently, chased the spring issue for 2 more passes without resolution, meanwhile creating a huge amount of bronze filing contamination inside the engine from the sharp edges of the broken inner spring "grinding" away at the valve guide. In 2 passes it completely consumed the steel skirt of the valve stem seal and cut the exposed portion of the guide so severely that it would no longer hold a valve seal. I could never have predicted the quantity of bronze filings that a single valve guide could produce and how throughly they were distributed inside the engine. Good luck, I hope your problem is simpler to resolve.

[dcm0123]

What oil pressure are you running at idle and about 2500 RPM when hot?

Were the two bearings shown in the lower picture from the same journal? Very different wear patterns which is why I ask.

The lines on the bearing maybe from the debris you saw in the oil.

Were the oil passages of the block and crank cleaned after machining?

[6667fan]

Hot idle psi is 20 @ 900 rpm. Would go to 35 @2500rpm. Engine was built clean. Contaminated oil came along later.
The deal with the uneven rod bearing wear  is there may have been some detonation.  The upper bearing in the pic is the one that is showing the first layer,(Black), having gone away.

JB

[Cobrajet2]

What input shaft are you using in your Toploader? I ask because in my most recent build,  my 4sp. fought me like no other trans ever had before regarding getting everything seated in the bell, disc and pilot. Try to put it in, pull it out, back in, pull it out. Pull the disc out, test the splines in the disc on the bench...no problem falls right on. Scat crank like yours, aftermarket big spline input but with the small block pilot tip. Only way you could get a wide ratio in a big spline, at the time.

After back and forth emails to Scat and some other checks, I am 99.44% sure that this combination is okay.  I have used the same crank and input in other cars and never had an issue.  Your gremlins have got me wondering all over again.  Curious to hear what you find.

Mike

[CDXXVII]

Mike,
I think it's the same now-small block only. The length difference of the input shaft pilot is significant (over .200" IIRC).
6667fan wouldn't even come close to being able to bolt up the bell housing if he accidentally installed an input shaft with the small block (long) pilot.

[6667fan]

The trans that fought me is a David Kee custom built unit. It is with him right now so I can’t measure anything but I did compare it to a Ford big I/O that I ran previously in the car and they were very close. Certainly not .200 different.
JB