What does a stock Evo rod look like before it breaks?
Nov 3, 2011, 04:25 PM
#1
What does a stock Evo rod look like before it breaks?
This-
We are thinking it hydraulic'd somehow (despite the headgasket being fine) and caused this failure. Owner parked the car and left it, ended up bringing it to us for a motor build last week and pulled it apart to find this and an extremely scuffed cylinder.
We always thought that Evo rods would break before the bend, so either this customer got really lucky and avoided a window in his block, or we are wrong. It bent around the factory "gusset" that is cast into the small part of the rod. I guess Mitsu's failure analysis is pretty good after all. That or all the 7 bolt 2G rods that hang out of blocks taught them something
Aaron
We are thinking it hydraulic'd somehow (despite the headgasket being fine) and caused this failure. Owner parked the car and left it, ended up bringing it to us for a motor build last week and pulled it apart to find this and an extremely scuffed cylinder.
We always thought that Evo rods would break before the bend, so either this customer got really lucky and avoided a window in his block, or we are wrong. It bent around the factory "gusset" that is cast into the small part of the rod. I guess Mitsu's failure analysis is pretty good after all. That or all the 7 bolt 2G rods that hang out of blocks taught them something
Aaron
Nov 3, 2011, 05:27 PM
#5
I have only ever seen them snap. It normally has been caused by one of 2 things, methanol (I assume preignition or hydraulic) almost always leads to death or 45psi on an already aggressive E85 tune. Boost controller failed on that one and the motor did last for awhile to its credit but let go. The driver didnt realise that the boost gauge being rapped out wasnt normal (driving a customer's car).
Nov 3, 2011, 05:46 PM
#7
All the failures we have seen are the result of over 400 ft lbs or methanol malfunction (generally related to more than 400 ft lbs) and always result in a window'd block. We have never seen a stock 7 bolt rod of any form bend, this is the first. I have seen 6 bolt rods bend before they break but not 7 bolt stuff. The only other normal cause of failure is a broke rod bolt but those have been seemingly rare as of late. When Evos were young it seemed like there were more, but not as many anymore.
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Nov 3, 2011, 07:33 PM
#8
i guess that proves that meth is dangerous when not properly setup along with over 400 ft lbs on stock rods. 380 tq is fine, but then once you get a ride in a 450 tq car, you realize how fun it is. If the rod is made from pure billet, it should bend only and not snap, but then again one can't complain for a snapped rod when it was designed for less than 300 wtq stock. I'm surprised it can handle 400 as is.
Aaron, I'm surprised I don't see much talk about the carrillo pro h beam with 3/8" carr bolts. Those are rated real high and also are much lighter than manley i beams. More costly, but I'm sure being lighter helps. I guess the gsc h beams you run are the Gsc version for lighter weight and strong enough for 500 tq.
Aaron, I'm surprised I don't see much talk about the carrillo pro h beam with 3/8" carr bolts. Those are rated real high and also are much lighter than manley i beams. More costly, but I'm sure being lighter helps. I guess the gsc h beams you run are the Gsc version for lighter weight and strong enough for 500 tq.
Nov 3, 2011, 09:15 PM
#9
At what point have you seen the 6bolt rods bend? Hydrolocked or from power. I know a lot of guys who have used large nitrous shots on stock 1G rods and they always blow other things and not the rods.
Nov 4, 2011, 06:32 AM
#13
I posted rod like that last year. I think many possibly all bent before snapping. Its just the average driver wont catch the warning signs that something bad is about to happen. The engine will not be running 100% on all four. It will feel like a slight misfire. In my case there was also a faint noise as rod hit lower edge of case.
Last edited by 94AWDcoupe; Nov 4, 2011 at 06:35 AM.
