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why do i keep going through motors like candy?

Utter99

Utter99

New member
Ok so the car is a 99 gt gp and i have a question as to why i keep going through motors so fast.

I swapped out my motor and transmission from a gt setup to a l67 with the hd tranny. I did a 3.4 setup with headers at the same time of this swap with a tuned ecu

Now i know these motors are externally balanced via the harmonic balancer and the flex plate . Well when i was doing the swap i noticed the hd trannsmissions touqe converter was in rough shape so i was going to use my gt tourqe converter but this required i use my gt flex plate also i marked were the weiight was on the motor when i swapped the flexplates as too not unbalance the motor but i didnt pay attention to see if there waa any weight difference

I havent goten an engine to last longer then 1000 miles in this car since this swap so obviously something is wrong here and i want to find out whats wrong because im going to try this one more time before i give up on this. I apreciateany help you can give me and feel free to ask me anything im looking at all options right now. I dont beat on these engines and that whats been stumping me as too why this is happening i mean its not like im putting out a crazy amount of power

So i was wondering am i unbalancing my motors by doing this and causing stress on the bearings causing my engines to gernade?
 


They are the rod bearing that have been going out . It's happened to me with two engines now. The first one was a rebuild and that one lasted for like 900 some miles then it started a rod knock. Now the second one was from a 2002 Gtp with 90k on it . The car was totaled out from rear end damage and that one only lasted 650 miles
 
I'm hoping its just a string of bad luck and not something I have been doing because ill really kick myself in the but if it could have been prevented . Twice ...
 
3.4+headers= your situation.

I hope you prime the hell out of the oil system before you ever start it up......
 


The ecu is not a problem he is very notable on these forums and I'm sure all you would trust your cars with him.

And how would headers and a 3.4 have anything to do with how it's being torn up?

I pumped up oil pressure before I even tried to start it for the first starts on each engine .
 
Plus I was only seeing 1-2 degrees of knock at the end of 2nd so the tune and car was set up correctly with that
 
Yeah but that would chip a piston before it would destroy a bearing. Or am I missing something here?
 
Considering they come with 8* of knock usually from stock I assumed I was pretty safe even considering the more modded you are the more deadly knock is even in smaller amounts
 


Oil or something in the oil, or lack of prep to getting the motor to spin can cause the bearing to fail. Detonation can cause bearing failure. Could be a number of things on your part, or just simply the part you got.

I replaced my engine with one with 105k. Primed the hell out of it. Primed the hell out of it again. Charged the battery, primed again, then fired. No problems.
 
I guess it was so basically I'm looking at either its not being primed enough before I start it and I should swap out to a larger pulley ill throw the stock back on and drive it ? I could care less if its modded or not just thought it would be safe to do headers plugs intake thermostat and pulley drop by going off of the safely modding thread .

So I take it the engine and the balancing issue would have nothing to do with with rod bearing failure and if it was a balancing issue it would be the crank bearings to fail ?
 


And Dan I knew some cars knocked more then others . Not just because it could have been bad bad engine like Ihurtz says . It's had factors as such as altitude and temperature
 
balancing could destroy everything in the engine. To eliminate your end, I would run stock pulley, throw all the supporting mods you want. Drive it. Change oil and filter after 500miles imo as you dont know whats been in that engine. Dont beat it. Drive many more miles. Drop pulley. If goes boom, YOU DID IT!
 
On this next motor you could try and help the oil flow a little better.

The 97-03 timing cover has a very poor casting that limits oil flow, the 04+ is a better design, you can also do the 04+ oil pressure spring to bump it up a few lbs. Its just a thought.
 
Ill go find a stock replacement torque converter for it so I can use the flex plate that's on the l67 since nobody here know if they are the same weight or not and if that could be just the simple little fix . I would like to keep the pulley but if its just my luck it's my luck. Ill start off and drive it a couple thousand on the stock pulley and switch my fuel over to e85 so ill have no knock on the 3.4 . I was already making progress on the e85 so it's not going to hurt me there
 
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