Engine autopsy

[jpwalt1987]

I took my engine down for an inspection and refreshing after 3 years of hard use. I had a couple of oil leaks and figured what the hell nows a good time to do it.

I had decent oil pressure but it did seem to be a bit lower at cruise than usual. There was no noises to be heard.

This is what I found. The rod bearings looked like typical of a high HP motor. No copper showing but definitely worn.
The main were another story. I'll let the pictures tell the tale on them.
The crank looks like just a light polish will take care of it. All main journals were within .0002 of each other.
Check out the pictures of the cam bearings!! The front had the usual wear from the cam. The middle two were ate the f@&k up!! I have never seen a cam bearing get like this. It didnt hurt the billet roller cam though. This engine was professionally built by a well known builder. It has always had Valvoline VR1 10W30 in it with wix filters.
I also had 2 bushings in the wristpin gall up some and one appeared to be cracked a little.

Any ideas on why this happened? This is a pump gas and alky streetcar and I log every time I drive it with the powerlogger. The only tine knock ever shows up is when the tires are spinning. I keep a very close watch on the tune.

 

[jpwalt1987]

The cam bearing material looks like it was just peeled off.

 

[S10xGN]

Tore mine down 3 years ago after 10 hard years, yours looks exactly like mine did except for the cam bearings. Even had a couple wrist pins that were sticky! My crank needed a 0.010" cut, then just new rings and bearings. Even the valve springs were less than 5# off. I think this is normal for heavy use. I know mine had some pretty bad knock issues the last few months and during teardown, found the wastegate hose had melted through...

 

[jpwalt1987]

I hear you Russ, the only time was detonated was for a split second when I had my boost controller hose backwards. Doh!! Its all at the machine shop now and I am getting a game plan together. Need to check the crank for taper on the journals, hone it with a plate for new rings, check the rods for roundness and replace the bushings in the small end of the rods. Probably going to step up to an H-13 tool steel pin as well along with a few changes to the oiling system. This after 3 hard years of service and countless backroad Wot pulls to 6000rpm.

 

[cbird77]

Just curious about how much oil pressure you had at idle and at cruise rpm when the engine was up to temp.

 

[jpwalt1987]

it always had about 15 psi hot at idle and while cruising when the engine was fresh I had about 45 psi @2000 rpm. It had dropped recently and thats part of the reason I pulled the motor.

 

[ek02]

Those are TA cam bearings, at least the ones with the rear groove. The only time I have seen one tear like that was when a bearing slipped back from the bore and the oil hole got restricted. Cracked main webs was the reason, and the mains looked like that too from the clearance decreasing from the cracked main webs. I hope that is not your problem. It could be just not enough oil pressure.

 

[jpwalt1987]

I think that the builder machined a set of durabond bearings. The TA bearings I have seen have two smaller grooves instead of one wide groove. The cam bearings looked to be in the appropriate postion before I removed them.

 

[turbodave231]

Check your crank for TIR on #2 or #3 journal

 

[ek02]

I think that the builder machined a set of durabond bearings. The TA bearings I have seen have two smaller grooves instead of one wide groove. The cam bearings looked to be in the appropriate postion before I removed them.

You are right. I failed to notice the large oil holes. TA's have 2 small holes. I have seen them with one large groove on the back, but the ones I have bought lately have 2 grooves.

 

[SS/GN]

Interesting wear through out. Are the T/A cam bearing the bearing of choice?
Thanks and I hope it goes well for you.