built 7bolt with Eagle crank *crankwalked

[bigf4]

Hello,

Trying to get some insight on what caused my 7bolt with an eagle crank to walk, the engine has a few hours of idle time and maybe a mile on it (no boost).

The car would not stay running when the clutch was pushed in so that raised a red flag, i drop the oil pain to find that the thrust bearing was shot with a good amount of crank play.

The thrust bearing surface did not look too bad but the side of the bearing dug into the crank counterweight causing a 1mm cut.

What would cause this? Thrust bearing not properly aligned?

Specs on the short block (if i can remember, it's been awhile):
7bolt
.20 Over
88mm
Eagle crank
groden aluminum rods
weisco HD 1400 pistons
clevite standard main bearings
ARP main studs
New OEM oil squatters
Was blue printed and balanced

Running a ppt clutch.

What you all think?

 

[curt-s]

Pics of all parts involved? I don't know how you walk with that little of wheel time unless important shit was out of spec to begin with.

The last set of Clevite mains I had were out of spec so bad you couldn't fit the thrust bearing over the crank journal, it got caught up on the crank thrust surface. The entire run apparently was bad for the 6bolt 4g63 so they were all pulled last year. How that affects the 7 bolt? I don't know

 

[BogusSVO]

What was the measured crank end play when the engine was assembled?

What was the measured end play at tear down?

 

[bigf4]

Ill take some pics when i pull the motor. the crank end play when rebuilt was .03 not sure what its at now. Im sure its much more than that

 

[BogusSVO]

Ill take some pics when i pull the motor. the crank end play when rebuilt was .03 not sure what its at now. Im sure its much more than that

Crank end play was at .030???? when built.... That is 3 times the amount of max end play you should have had.

FSM lists .0098, I just call it .010

Are you sure it was not .003?

 

[bigf4]

end play after rebuild was .003. forgot the zero.

 

[JacksonAuto]

What kind of thrust bearing does your particular engine take? Some use thrust washers and others use a flanged bearing (like a 6 bolt). The latter type need to be aligned.

What kind of oil was in the engine?

If everything is/was mechanically sound and properly assembled, the problem has to be with the clutch.

 

[bigf4]

It's the flange style bearing, oil was a non-synthetic 10-30. For the initial startup of the motor, I had no plugs in her and disconnected the crank sensor and primed the engine.

Hypothetical speaking let's say it was the clutch that caused the thrust to go.

The pressure plates would have to be in backwards to cause that much resistance? If the clutch was over adjusted the car would move at idle. Correct?

 

[Twinturbo120]

No, the car will not move at idle. What you're referring to is clutch drag. The test involves putting the car in 1st gear and going to redline. If it moves, it has clutch drag.

 

[JacksonAuto]

That is the incorrect way to prime an engine. There is a strong possiblity that you had a "dry start" on your initial fire up which could have damaged the bearing.

Was the oil just some cheap 10-30 or was it a specific break-in oil? Being multi viscosity I doubt that is was a break-in formula.

What kind of assembly lube was used during assembly?

The flanged bearings need to be aligned perfectly. Even if you had .003" at assembly, the flanges could be misaligned and cause your issue.

Bearings don't just go bad for no reason. That's why I said that if you're sure there was nothing wrong mechanically with the engine that it must be the clutch. That's the only thing that would cause the thrust to fail.

 

[bigf4]

I'm sure she had oil pressure before start up, the full steps I took to achieve oil pressure:
• oil pump was pack with grease
• primed it with a hand drill before I did the timing
• Once the engine was in I disconnected the MPI/No spark plugs and primed again
• Check the turbo oil drain and oil cooler to confirm
• Plus I had a hand held oil pressure gauge attached to the oil housing to make sure my oil gauge was accurate


The engine was assembled with clevite 77 assembly lube

The oil was discount auto parts brand; I had one half quart of 5w-30 and 3 quarts of 10w-30 mix for the initial startup.

That oil was only in there for 10min before it was changed for full 10w -30 (same brand), with that oil we drop an idle tune on it until the AEM took a shit.

Twinturbo120, thank for the correction buddy. Early morning non brain prime (no coffee) on the idle clutch drag adjustment.

I'd like to thank all of you guys for your time and input. I've had this car since high school (10 years now) and it's been my longest goal / dream to get 1000hp out of it, Shits been a pain / garage ornament for the past 3 years trying to achieve that goal.

Thanks for the help guys, Ill post some pics of the bearings later today.

 

[JacksonAuto]

Cranking the engine over with no spark is the wrong way to prime a new engine. You are placing a load on all the components without proper lubrication. It will also displace most, if not all of the assembly lube you applied during assembly. The correct methods are to either use a priming tank with a pressurized bladder or to spin the pump drive with a drill. Once you see oil pressure, the system is primed. Stop the drill, put the timing belt on and fire up the engine. Continous running of the drill will wash away the assembly lube. The first few seconds are CRITICAL and it is imperative that the lube be present on all bearing surfaces. I would be good money that this was a contributing factor to your premature failure.