questioning 3.8 strength

[JOHNZAZA]

I had a problem with my motor. The 3rd bearing is wiped.
I posted the question that if anyone had a idea what could
cause this?
Some people responded that the block must have the heads
bolted on when alinged honed.
If this is true then these motors are total junk, and weak.
I thought the blocks where fairly tough but not know if that
is true.
ONE PASS WONDER'S(3.8)


If anyone has any insite into this please respond.

 

[kenmosher]

EVERY block used in a performance application (Chevy, Ford, Mopar, etc.) should be align honed with a torque plate or the heads bolted on.

ALL blocks will distort a little with the addition of the heads (and most of the modern motors are DESIGNED to). It certainly isn't the fact that they are "junk" or "weak". Prestressing certain areas moves the clamping loads to where the block is designed to take them (into the webbing).

 

[Whitettype86]

How many miles were on your motor when the bearing wiped out? There is an oil provision that lubes the bearing it could be blocked or u could have had dirt or something on the bearings inwhich would also wiped it out. Who built the motor?

 

[JOHNZAZA]

IS THERE ANY OTHER REASON
WHY THIS COULD HAPPEN.
MY ENGINE BUILDER IS PRETTY GOOD. I HAVE ABOUT 10000 KM
ON THE MOTOR. WOULD RACE FUEL CAUSE A PROBLEM. IF IT WAS
STALE.

 

[kenmosher]

Whitettype had a valid question ... you need to have a "post mortem" done. Was it oil starvation?

If it was truly "burned" that would most like be due to improper clearance, the saddle was out of round, the bearing was starved for oil, or a combination of those problems.

However, if it was wiped down to the copper (especially on the upper bearing) and there is evidence on other bearings (particularly the rods), it could be detonation (possibly due to bad fuel) that beat the bearing up.

Lots of failure scenarios and it would be a good idea to talk to your engine builder about it. Have him mic the clearances and do a thorough inspection. Or if you don't think he did it right, find another machine shop and have them inspect it.

It's kind of one of those "you gotta see it" things.... all we can do without seeing the parts in question is present some possible things to look for.

 

[Whitettype86]

Did the engine builder use a torq plate when he lined honed the block? And did u take the motor back and have him inspect it and find out what happen? Race gas will not cause a bearing failure nor stalling the motor. If u ran out of oil that will cause bearing failure

 

[GNVAIR]

What were the main and rod clearances set to? If they were more than .0020 as most Chevy and Ford engines are set to, then the chances of wiping a bearing are very great.

 

[S2V6RACER]

Originally posted by JOHNZAZA
I had a problem with my motor. The 3rd bearing is wiped.
I posted the question that if anyone had a idea what could
cause this?
Some people responded that the block must have the heads
bolted on when alinged honed.
If this is true then these motors are total junk, and weak.
I thought the blocks where fairly tough but not know if that
is true.
ONE PASS WONDER'S(3.8)


If anyone has any insite into this please respond.

I understand your anger. The motor must be built right if it will live. You can see yours wasn't. I'd look for a better builder. Mine has over 26 full passes on it plus dyno time. I'd say it must be pretty stout for the times listed below.

Ted

 

[JOHNZAZA]

thanks for the reply's. I am definitely going to investigate.
the bearing is not burned just mauled.

THANKS AGAIN GUY's

 

[Justin Terry]

I am in the process of getting my motor built and having the middle steel caps installed. The block has already been lined bored but the heads werent torqued because I havnt got them back from the machine shop that is doing them. So i need to go back to the shop thats doing my motor and tell them to install a torque plate and re-line bore the block please answer my question somebody I really dont want this motor to screw up. thanks everyone

 

[JToups386]

Everything the guys listed above is true, and good sound advice. I am currently rebuilding my motor, due to having beat the bearings out of it, per detonation. The biggest enemy and instant death on these turbo motors is DETONATION! Once it's started, and happened for any small bit of time, you have begun to "beat the bearings", and soon enough you're stuck rebuilding a motor. I would certainly investigate the clearances, etc, but per your info provided, you may have to point the finger at yourself, if you allowed it to detonate. Sad but true...
And "YES", you should use a torque plate when having it line bored and honed. You want the machine work to be done in exactly the same stresses and forms that it will be operating in, once assembled. Not doing it is merely a lazy machinist, IMO.
These blocks are quite stout, when you consider many people are running them down the track to the tune of sub-10 second passes on stock blocks, cranks, rods, and more. Don't scorn your block, but rather, find out why it happened, and then maybe shoot your machinist, if he's to blame...