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Resident Asshole
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Discussion Starter · #1 ·
So as many of you are aware, Crow sold his car a few weeks back. A guy named Matt ended up purchasing his heavily modified GTS and then unfortunately blew the engine up a few hours later. From talking to Matt on the phone, what he described to me sounded like he had spun a bearing and was experiencing rod knock. Matt and I squared away the details and he had the car towed to me from PA so I could fix it. Seems that a few people are interested in seeing what happened to this motor as it is the first race built block with CP pistons to have a failure.

I have to admit that I was pretty anxious to pull this motor apart. Since I've built my fair share of race blocks I wanted to see if the CP pistons lived up to the hype or if they would meet the same fate as a few Ripp pistons I've seen.



In the disassembly of the engine I noted a few things. The first was that whoever built it, I'm assuming Donny did, did a pretty good job. The only thing I could say something about was the fact that a good number of the headbolts were WAY over torqued. I'm talking about torqued down so good that even my expensive impact wouldn't get them out. I ended up using a 3' breaker bar to break about 5 of the bolts loose. Could it be that this was from detonation applying a lot of stress on the bolts? Perhaps, but I'm in no real position to venture a guess.

So I get the front head off and I'm greeted with this:



Looking good so far. The front bank had no chips or obvious damage to the crowns of the pistons.

I pull the rear head and I saw a mirror image of the front.



Now I want you guys to note something... In this picture with the head gasket removed, you can clearly see that the block has been decked. The machining marks are still clearly visible even in this low resolution photo. For comparision, here is a picture of a motor I pulled apart that was built by Ripp. Notice the forged pistons that are missing parts of their crowns. This motor had less than 3k miles after Ripp's rebuild and it's obvious the deck surface has not been machined. Was this motor built w/ the motor still in the car? 10:1 says yes! :lol:



So the tops of the pistons look ok. Now it's time to pull the pan off and see what we can find down below!



Ooops... that doesn't look too good. Notice all the copper shavings?



Even got gunk on the bottom of the oil pan pickup plate!



The main bearings have some wear but nothing that appears to be abnormal.



This ladies and gentlemen is what cuased this motor to fail. Spun rod bearing on cylinder 1. One of the bearings completely disentegrated and became all the shavings found in the pan. The other 1/2 of the bearing got fused to the crank. DOH! All other 5 rod bearings were ok. Some showed some slight wear but they were still in operating condition.

Tomorrow everything goes to the machine shop for inspection. There is unfortunately the possibility that the crank will need to be replaced along with the rod that spun the bearing. I will NEVER cut the crank and install oversized bearings in a performance motor. That is bad bad bad bad bad!

What have I learned from this? CP pistons OWN! They took the abuse and came out looking almost new. I really can't say the same for Ripp's line of pistons, but then again, maybe those pistons will work good if they are installed by a shop that will take the time and money to build the motor right.

I'll keep you guys updated as to the progress of this car. Barring a major delay at the machine shop, in the next few weeks this car will be going vrooom vrrooooom vrooooooooom again! :)
 

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Kampfbereit
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Why don't you drain the block before taking the heads off :fawk:

To be fair, I'm sure that if you put in CP pistons without proper piston to wall clearance required by the piston like Rippmods does with their Weisco installations, I'm sure they would fall to the same fate. I'm a big fan of CP, but I don't think this is a fair comparision to say why CPs are better than Weiscos.

All of that bearing wear is abnormal from what I can tell, everytime I pull bearings out of a stock engine they practically look brand new.
 

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Resident Asshole
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Discussion Starter · #3 ·
Because it was 3AM and my head wasn't thinking straight. I told Dave to do it while it was in the car but I guess he forgot.

About the CP / Weiscos... hence my statement about them being installed properly... ;)

The entire assembly is going to the machine shop. Gonna have them check the main bore for alignment. In regards to the bearings... a little wear seems to be the norm from what I've seen but then again I only pull apart motors that have been beaten on.
 

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Kampfbereit
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PharmEcis said:
The entire assembly is going to the machine shop. Gonna have them check the main bore for alignment. In regards to the bearings... a little wear seems to be the norm from what I've seen but then again I only pull apart motors that have been beaten on.
All of the motors that I pull apart that I know for a fact that were beaten on like Rulez stock engine for instance, the bearings still looked brand new.
 

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Discussion Starter · #5 ·
Interesting.
 

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Kampfbereit
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Greg, when you pull the oil pump off let us know if those o-rings for the feed/return are still in tact or if they are there at all. I've really been thinking on how this could happen, I'm thinking that this was either due to a serious loss in oil pressure or improper bearing clearances. I wonder if the same oil pump was reused the first time crow spun a bearing with this engine or a new one was used, or if the oil pump Donny used was mic'd within spec.
 

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Holy shit thats a pair of f'ed up pistons! Does this seem to be a common occurance from RIPP's engines? That is installing the pistons without any prep work.
 

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So was this a result of detonation?
 

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Kampfbereit
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Jetblackness said:
Holy shit thats a pair of f'ed up pistons! Does this seem to be a common occurance from RIPP's engines? That is installing the pistons without any prep work.
A forged piston under heat expands more than a cast piston thus requiring more piston to wall clearance. If you do not properly bore out the block to match the forged piston requirements for the ones your putting in, your probability of what happened to those pistons is very likely.
 

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Id say bearing clearence... I thought they put a new oil pump in? I know when Ron Anderson has his motor redone by Ripp, they did an in-car install, and forgot to put a new pump in.
 

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Kampfbereit
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ICEMAN99TURBO said:
Id say bearing clearence... I thought they put a new oil pump in? I know when Ron Anderson has his motor redone by Ripp, they did an in-car install, and forgot to put a new pump in.
The types of pumps used on these engines are supposed to last an extremely long time. At a minimum when redoing your engine you should at least mic the pump to insure the clearances are within spec, but oil pumps are very expensive to replace.

Just like my sig says, "A proper engine build requires taking the motor out of the car".
 

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PharmEcis said:
Because it was 3AM and my head wasn't thinking straight. I told Dave to do it while it was in the car but I guess he forgot.

About the CP / Weiscos... hence my statement about them being installed properly... ;)

weisco piston swap, 14hr job, 16psi, 320+whp, all clearences in speck, 60k miles and never an issue. if anyone else wants to run reliable 300+whp for $1000 upgrade that has lasted well over 60kmiles just do the job right like i did and your motor will last. that bearing clearance was obviously not checked right or worse reinstalled on the wrong cylinder. dont believe the hype of the necessity of a race motor for a crappy 6g72, its overkill unless you are going for 400-500. obviously if u fuck up a piston like that you'll need to rebore that block to remove the damage (if its even possible)
 

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Tearstone said:
A forged piston under heat expands more than a cast piston thus requiring more piston to wall clearance. If you do not properly bore out the block to match the forged piston requirements for the ones your putting in, your probability of what happened to those pistons is very likely.
I understand that. Just to add, boring is also used to remove any deformations to the cylinder walls. Though my question was in regards to if this is a common practice from RIPP mods? I would think that someone like RIPP would do atleast minimum prep work before dropping in the pistons.
 

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Kampfbereit
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Jetblackness said:
I understand that. Just to add, boring is also used to remove any deformations to the cylinder walls. Though my question was in regards to if this is a common practice from RIPP mods? I would think that someone like RIPP would do atleast minimum prep work before dropping in the pistons.
I would like to safely assume they do an extrude hone on the cylinders prior to putting the pistons back in.
 

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Kampfbereit
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TheFranchise said:
weisco piston swap, 14hr job, 16psi, 320+whp, all clearences in speck, 60k miles and never an issue. if anyone else wants to run reliable 300+whp for $1000 upgrade that has lasted well over 60kmiles just do the job right like i did and your motor will last. that bearing clearance was obviously not checked right or worse reinstalled on the wrong cylinder. dont believe the hype of the necessity of a race motor for a crappy 6g72, its overkill unless you are going for 400-500. obviously if u fuck up a piston like that you'll need to rebore that block to remove the damage (if its even possible)
According to the pictures that Greg posted above, it's still a gamble either way. Like Toyota has done in the past with their sport platforms, you should over engineer your setup to want to take 400~500 for a long lasting reliable engine. All new bearings were used in Crow's engine.
 

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Tearstone said:
According to the pictures that Greg posted above, it's still a gamble either way. Like Toyota has done in the past with their sport platforms, you should over engineer your setup to want to take 400~500 for a long lasting reliable engine. All new bearings were used in Crow's engine.
if you want 400-500hp then you should build accordingly for it no doubt. if you are only looking to add another 100-150 then there is no reason to go overboard on a build unless you like to spend money. build a motor TO SPEC, check THE SPECs, and reassemble to SPECs will allow a motor to last.

the fact that new bearings were installed in that motor tell you a TON about the amateur mechanic that reassembled that (or the lack of oil the previous owner ran)
 

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Kampfbereit
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TheFranchise said:
if you want 400-500hp then you should build accordingly for it no doubt. if you are only looking to add another 100-150 then there is no reason to go overboard on a build unless you like to spend money. build a motor TO SPEC, check THE SPECs, and reassemble to SPECs will allow a motor to last.

the fact that new bearings were installed in that motor tell you a TON about the amateur mechanic that reassembled that (or the lack of oil the previous owner ran)
I know we'll never agree on this, but I sincerely think it's very half ass to just swap pistons out in the motor. How did you measure piston to wall clearance? Plus did you guys balance all the pistons out with the counter weights since the weight of the pistons differs from the cast pistons? I think basically with the piston swaps you guys are doing, your relying on how well built the motor actually is to cover up a lot for the errors of doing such a job.

I'm glad I now have a guy with 15 years of experience building mostly VR-4 and 2JZ motors doing engine builds for me now.

But with further investigation I'm hoping the answer will be very clear soon as to exactly what happened to that motor because it concerns me greatly.
 
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