Rebuild 6.0L help
02-03-2009, 04:09 PM
#91
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Post #82 and #84.
With the heads milled and the LQ9/LS2 pistons did you ever calculate the actual compression? If you only took a few thousandths off you should still be around 10-10.1:1 or so. At any rate, that cam was made with the assumption you were going to end up with close to 10:1 compression but should be ok for anything between 9.7 and 10.3ish, maybe a little higher if the tuner is really good and you don't mind using premium grade gasoline. It's designed to make some pretty good cylinder pressure so that could be why it's detonating if you filled up with bad/low-grade gas and haven't tuned it yet. Once the tune is dialed in, that 370ci should out-torque your Vette until 3-4k rpms.
With the heads milled and the LQ9/LS2 pistons did you ever calculate the actual compression? If you only took a few thousandths off you should still be around 10-10.1:1 or so. At any rate, that cam was made with the assumption you were going to end up with close to 10:1 compression but should be ok for anything between 9.7 and 10.3ish, maybe a little higher if the tuner is really good and you don't mind using premium grade gasoline. It's designed to make some pretty good cylinder pressure so that could be why it's detonating if you filled up with bad/low-grade gas and haven't tuned it yet. Once the tune is dialed in, that 370ci should out-torque your Vette until 3-4k rpms.
02-03-2009, 04:47 PM
#92
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Yep, fixed er right up! gotta love LONG extensions and swivel sockets!!!
We didn't mill the heads, they were good and with them stock, we calculated (via math) 10.1. It basically should be an LQ9 now.
It still had a 1/2 tank of 87, so I just filled it with 93. Switched to some better plugs gapped at .060. Still same result. Poor idle and detonation. It sounds similar to piston slap, but only at RPMs above idle. It idles quiet. Hoping my tuner can get to it soon. Our guess is that it is looking for the EGR. I assume that is why the timing is so high. 30-40* timing at 1/8th throttle and 2k rpm sounds nuts.
We're gonna check a few more things tonight.
Yea, stock longblock on the vette is killing low/mid torque. I'd easily be 9s with something other than stock cam. I'm just trying to push the record further and also hit 9s with stock longblock. It is 595rwhp/495 rwtq.
Post #82 and #84.
With the heads milled and the LQ9/LS2 pistons did you ever calculate the actual compression? If you only took a few thousandths off you should still be around 10-10.1:1 or so. At any rate, that cam was made with the assumption you were going to end up with close to 10:1 compression but should be ok for anything between 9.7 and 10.3ish, maybe a little higher if the tuner is really good and you don't mind using premium grade gasoline. It's designed to make some pretty good cylinder pressure so that could be why it's detonating if you filled up with bad/low-grade gas and haven't tuned it yet. Once the tune is dialed in, that 370ci should out-torque your Vette until 3-4k rpms.
With the heads milled and the LQ9/LS2 pistons did you ever calculate the actual compression? If you only took a few thousandths off you should still be around 10-10.1:1 or so. At any rate, that cam was made with the assumption you were going to end up with close to 10:1 compression but should be ok for anything between 9.7 and 10.3ish, maybe a little higher if the tuner is really good and you don't mind using premium grade gasoline. It's designed to make some pretty good cylinder pressure so that could be why it's detonating if you filled up with bad/low-grade gas and haven't tuned it yet. Once the tune is dialed in, that 370ci should out-torque your Vette until 3-4k rpms.
It still had a 1/2 tank of 87, so I just filled it with 93. Switched to some better plugs gapped at .060. Still same result. Poor idle and detonation. It sounds similar to piston slap, but only at RPMs above idle. It idles quiet. Hoping my tuner can get to it soon. Our guess is that it is looking for the EGR. I assume that is why the timing is so high. 30-40* timing at 1/8th throttle and 2k rpm sounds nuts.
We're gonna check a few more things tonight.
Yea, stock longblock on the vette is killing low/mid torque. I'd easily be 9s with something other than stock cam. I'm just trying to push the record further and also hit 9s with stock longblock. It is 595rwhp/495 rwtq.
Last edited by clemsondave; 02-03-2009 at 04:58 PM.
02-03-2009, 06:20 PM
#93
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Everything mechanically appears fine. Getting the dreaded P0300 random misfire. Was on 6 & 7. Now on 4, 5 and 6. We're still leaning towards tuning.
02-03-2009, 06:21 PM
#94
Post #82 and #84.
With the heads milled and the LQ9/LS2 pistons did you ever calculate the actual compression? If you only took a few thousandths off you should still be around 10-10.1:1 or so. At any rate, that cam was made with the assumption you were going to end up with close to 10:1 compression but should be ok for anything between 9.7 and 10.3ish, maybe a little higher if the tuner is really good and you don't mind using premium grade gasoline. It's designed to make some pretty good cylinder pressure so that could be why it's detonating if you filled up with bad/low-grade gas and haven't tuned it yet. Once the tune is dialed in, that 370ci should out-torque your Vette until 3-4k rpms.
With the heads milled and the LQ9/LS2 pistons did you ever calculate the actual compression? If you only took a few thousandths off you should still be around 10-10.1:1 or so. At any rate, that cam was made with the assumption you were going to end up with close to 10:1 compression but should be ok for anything between 9.7 and 10.3ish, maybe a little higher if the tuner is really good and you don't mind using premium grade gasoline. It's designed to make some pretty good cylinder pressure so that could be why it's detonating if you filled up with bad/low-grade gas and haven't tuned it yet. Once the tune is dialed in, that 370ci should out-torque your Vette until 3-4k rpms.
02-05-2009, 02:52 PM
#95
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Wow!!! I checked mpg for the first tank. Higher than this truck has ever seen! 15.7! And that is with mixed driving/rpm breaking it in. I saw 15 one time driving the speed limit on the highway (rare for me 
) for a full tank.
Hopefully, I have fixed the last leak. It is still misfiring quite a bit (only tell on a data logger) and detonation is terrible. Getting it tuned Sat morning. Hopefully, that will fix those issues. Wonder what the mileage will be after that!
) for a full tank.Hopefully, I have fixed the last leak. It is still misfiring quite a bit (only tell on a data logger) and detonation is terrible. Getting it tuned Sat morning. Hopefully, that will fix those issues. Wonder what the mileage will be after that!
02-05-2009, 02:57 PM
#96
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If you're detonating, park it 'till Saturday morning. Chances are the mix is lean which could be the reason for the "good" gas mileage and detonation. If your motor build was any more on the wild side you'd probably run the risk of running out of injector ceiling, but considering this 370ci probably wont have much of a life above 5000rpms, I don't foresee a problem.
02-05-2009, 03:01 PM
#97
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Yea, my tuner said to run 93 octane and keep the rpms really low (which I pretty much knew anyway). I haven't taken it past 1/4 throttle and 3k rpms. I'm just trying to put on some miles to get everything seated properly. We're going to do a comp test and leak down tonight just to make sure all is as it should be.
02-05-2009, 03:13 PM
#98
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Hold off on my suggestion for breaking the motor in with a small trailer until after the tune. With my hauling trucks I prefer to break new motors in with medium loads (less than 50% of max trailer weight) behind on a trailer so the new engine breaks in with the loads that it will see for the remainder of it's life. Usually for 3/4 tons I hook up a single axle snowmobile trailer with a pallet of sod or something to that degree.
02-07-2009, 10:26 AM
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Update:
Did the tuning this morning. Man this thing has some power. Of course, it doesn't pin you to the back of the seat, but it is strong. We did WOT tuning and it was at 95 before I knew it. Fixed the rough idle issue and a bunch of other tweaks.
Still have some noise in the valve train. Thinking it is rocker arms or a lifter. We're going to pull the covers off tomorrow morning and check it all out.
Did the tuning this morning. Man this thing has some power. Of course, it doesn't pin you to the back of the seat, but it is strong. We did WOT tuning and it was at 95 before I knew it. Fixed the rough idle issue and a bunch of other tweaks.
Still have some noise in the valve train. Thinking it is rocker arms or a lifter. We're going to pull the covers off tomorrow morning and check it all out.
02-07-2009, 09:34 PM
#100
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Originally Posted by clemsondave
Still have some noise in the valve train. Thinking it is rocker arms or a lifter. We're going to pull the covers off tomorrow morning and check it all out.
Last edited by SynergyV8; 02-07-2009 at 09:41 PM.