Broke #5 connecting rod w/tt @6.6lbs.
07-05-2004, 07:22 PM
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Originally posted by gq_626
APS, richer A/F mixtures do cool the combustion chamber, but at a point, usually in the sub 10:1 range, you can still detonate the motor.
APS, richer A/F mixtures do cool the combustion chamber, but at a point, usually in the sub 10:1 range, you can still detonate the motor.
If you want to prove this to yourself....... just get on the dyno or the road and adjust the air/fuel ratio to 9 or 10 to 1.......the engine may rich miss.........though it will not detonate because of a rich air/fuel ratio only.
Peter
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07-05-2004, 07:27 PM
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Man..that 7Eleven guy is a cool cat....glad he helped you pull out the motor.
Joe and his guy came up with the idea to take the front off to pull the motor. It worked out very nicely.
Gary
07-05-2004, 08:32 PM
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Originally posted by gq_626
Then how do you explain blown motors due to stuck open injectors?
Then how do you explain blown motors due to stuck open injectors?
Peter
07-05-2004, 08:34 PM
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Joe,
I am really sorry to hear about this happening, but there is actually a good thing about it. I am sure since you went with the Greddy kit you intended on going into the motor to get more power out of it later. Unfortunately a new block was probably not part of it. It is definitely time to invest in rods, pistons and some better fuel. Let's face it, that clutch will be doing a lot more good behind something putting over 500 rwhp on pump gas. I would like to see the pics of the engine after you tear it down. In particularly, the piston, rod halves and rod bolts to see what the actual failure was.
I am really sorry to hear about this happening, but there is actually a good thing about it. I am sure since you went with the Greddy kit you intended on going into the motor to get more power out of it later. Unfortunately a new block was probably not part of it. It is definitely time to invest in rods, pistons and some better fuel. Let's face it, that clutch will be doing a lot more good behind something putting over 500 rwhp on pump gas. I would like to see the pics of the engine after you tear it down. In particularly, the piston, rod halves and rod bolts to see what the actual failure was.
07-06-2004, 12:09 AM
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Anyone have a copy of the book called "Turbocharging", by Hugh McGuinnes? I loaned mine out about twenty years ago, and never got it back.
It had some data from Ricardo, the British combustion scientist from the 30's. He stated that adding fuel will reduce knock, but richer than about 9.5:1 will make it knock again.
It had some data from Ricardo, the British combustion scientist from the 30's. He stated that adding fuel will reduce knock, but richer than about 9.5:1 will make it knock again.
07-06-2004, 12:09 AM
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I agree with APS..... Really rich condition wont cause detonation, but it could wash out the rings if u kept going at it. So its still not a good thing to run that rich.
07-06-2004, 01:37 AM
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Originally posted by John at J&S
It had some data from Ricardo, the British combustion scientist from the 30's. He stated that adding fuel will reduce knock, but richer than about 9.5:1 will make it knock again.
It had some data from Ricardo, the British combustion scientist from the 30's. He stated that adding fuel will reduce knock, but richer than about 9.5:1 will make it knock again.
Well just goes to show how old technology and theories can be absolutely WRONG..........a richer than 9.5 :1 air/fuel ratio may cause an engine miss........... though will NOT cause detonation.............time to move into the 21st Century.
Peter
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Last edited by APS; 07-06-2004 at 02:03 AM.
07-06-2004, 01:44 AM
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Originally posted by LSs1Power
I agree with APS..... Really rich condition wont cause detonation, but it could wash out the rings if u kept going at it.
I agree with APS..... Really rich condition wont cause detonation, but it could wash out the rings if u kept going at it.
Peter
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Last edited by APS; 07-06-2004 at 01:59 AM.
07-06-2004, 08:32 AM
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hello there,
i have just been reading this post (sorry about the motor joe) but i will interject to give my opinion on motor failures due to overly rich conditions.
when fuel is sprayed into a motor it is typically atomized with the air, and burned (which you all know). if an injector is stuck open, it will dump tons of fuel in, but only a small portion of the fuel will be burned, and the rest will be in the chamber during the compression stroke. since liquid (fuel) is not compressible, you would see some extreme cylinder pressures. it is almost like putting a rock on top of your piston. this could cause a blown head gasket, at a minimum....and apparently our head gaskets are stronger than the rods.
P.S.--i have a copy of Turbochargers by Hugh Macinnes, so i will read up on the Air fuel ratio Vs. detonation. i borrowed it about 5 years ago from someone and never gave it back. i'm not sure if anyone actually ever buys this book. Corky Bell's Maximum Boost is also an excellent book. i loaned it out and never got it back.
Chad
i have just been reading this post (sorry about the motor joe) but i will interject to give my opinion on motor failures due to overly rich conditions.
when fuel is sprayed into a motor it is typically atomized with the air, and burned (which you all know). if an injector is stuck open, it will dump tons of fuel in, but only a small portion of the fuel will be burned, and the rest will be in the chamber during the compression stroke. since liquid (fuel) is not compressible, you would see some extreme cylinder pressures. it is almost like putting a rock on top of your piston. this could cause a blown head gasket, at a minimum....and apparently our head gaskets are stronger than the rods.
P.S.--i have a copy of Turbochargers by Hugh Macinnes, so i will read up on the Air fuel ratio Vs. detonation. i borrowed it about 5 years ago from someone and never gave it back. i'm not sure if anyone actually ever buys this book. Corky Bell's Maximum Boost is also an excellent book. i loaned it out and never got it back.
Chad
07-06-2004, 10:01 AM
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Hmmmmmmmmmm im starting to think perhaps when this motor is apart the inside of the cylinder chambers will show signs of scarring due to cylinder wash. Of course we cant ignore that the rod may have simply given way due to the boost pressuer however it does seem unlikely.
07-06-2004, 10:58 AM
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2) The second thing thing that came to mind is that maybe...just maybe...you had a defective or exceptionally structually weak version of the VQ motor. Nissan makes thousands of motors every day, and it would not be uncommon for there to be some poorly put together versions. Even though mass produced, we know that no two engines are identical, and no two ECU's are really identical in every way. These cars and ECU's seem to have a life of their own sometimes. I am just trying to think of any alternative, yet plausible reasons for this catestrophic failure. It is so bizzare, given only 6.6psi of boost....I still can't believe the rod just snapped, even if some detonation was present. Catestrophic engine failure usually happens under much more extreme conditions that this....
That said... I tend to agree with GQ. From the minute I started reading this thread, I thought this sounds a bit weirder than the other FI failure stories.
I'm not an expert, but if it was a detonation problem, it seems certain you would see some sort of evidence with the piston first, or maybe the rings.
The split rod in this case, to me, sounds more like a manufacturing defect. Possibly one that would have occurred even without FI being added to the car. If that's the case, the question then becomes, how many Zs got bad rods before it was caught and when did it start being an issue?
JOE... Whatever you find out, please continue to share with the forum. One way or the other, everyone is going to want to know.
Good Luck!
07-06-2004, 11:32 AM
#59
Yeah, Joe....your loss is obviosusly terrible, but some great learning can come out of this. Lets try to keep this thread alive for an extended period of time.
Oh, and for the owners of "Maximum Boost"....NEVER lend it out....or else you will NEVER get it back...LOL.
It's too good of a book to loan!
Oh, and for the owners of "Maximum Boost"....NEVER lend it out....or else you will NEVER get it back...LOL.
It's too good of a book to loan!
07-06-2004, 11:41 AM
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Dam...Dam....Dam.....
I feel your pain bro. Well, whenever my car gets done I will post some more pics of what was done to it. I was just told last week that my car should be done within the next 2 weeks. Suppsodely the sleeving is done already....but who knows. All I can say is I miss my car very much and if I had it to do all over again, I would have PROBABLY gone with a PE TT. I have not heard of 1 PE equiped engine taking a dump as of yet.....has anyone else?
I feel your pain bro. Well, whenever my car gets done I will post some more pics of what was done to it. I was just told last week that my car should be done within the next 2 weeks. Suppsodely the sleeving is done already....but who knows. All I can say is I miss my car very much and if I had it to do all over again, I would have PROBABLY gone with a PE TT. I have not heard of 1 PE equiped engine taking a dump as of yet.....has anyone else?
