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Welp it happened - 427ci lq9 ate it

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Old 04-25-2017, 03:45 AM
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Default Welp it happened - 427ci lq9 ate it

Cruising down the freeway minding my own business not even speeding and I notice I dropped a cylinder. Didn't hear anything, just all the sudden I was cruising around on 7cyl instead of 8.

i look down down and I have about have the oil pressure I normally do ~20psi and normally it's about 50psi at that cruise rpm.

I say say screw it's and keep driving it home. I turn down my street and as soon as I do the oils pressure builds back up. But the miss is still present.

i get home and check oil level, it's all good. Change the oil and about 5qts come out instead of the 6qts I put in. Fugure that's about right since it's a new engine it's probably gonna drink some during break in.

i change the oil and oil pressure is still 40-55psi pre-incident.

I use the scanner to drop the injector to see which one it is...and it's number 5 that has I change in rpm when you disable the injector.

question, do you all think that a.) dropped a lifter 2.) cracked a piston, or had some other valve train issue?
Old 04-25-2017, 07:12 AM
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Any metal debris on the oil pan drain plug?
Old 04-25-2017, 07:27 AM
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Man I hope it is nothing serious. I was/am pulling for you on this build. Do something out of the ordinary is never easy......
Old 04-25-2017, 09:00 AM
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Oil looked good and nothing crazy on the magnet - haven't had a chance to cut the filter apart yet.

Compression test and leakdown to be completed next week. I'll be in Indianapolis all week for a trade show so this couldn't have happened at a worse time.
Old 04-25-2017, 09:20 AM
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Originally Posted by Ken in AZ
Oil looked good and nothing crazy on the magnet - haven't had a chance to cut the filter apart yet.

Compression test and leakdown to be completed next week. I'll be in Indianapolis all week for a trade show so this couldn't have happened at a worse time.
sorry to hear about this failure.

Trade show - wonder if it's the same one the company I work for is going to- LADDERPORT-
Old 04-25-2017, 10:12 AM
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Mains dictate oil pressure right? So coming and going oil pressure/ dropped cylinder probably not main bearing related.

Lifter taking a dump might impact the oil pressure. I would pull the head, because like you said its only going to be visible without the head. Nothing you can change with the head on, except the cam. What heads? valve dropped?
Old 04-25-2017, 12:13 PM
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Originally Posted by trxmxzx
sorry to hear about this failure.

Trade show - wonder if it's the same one the company I work for is going to- LADDERPORT-
Yes sir, FDIC - my company is called Firewipes
Old 04-25-2017, 12:18 PM
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Originally Posted by Ken in AZ
Yes sir, FDIC - my company is called Firewipes
Thinking lifter on this one, pull valve cover and check to see if any rockers are loose hate that for you though. BTW...are Firewipes used on a Burning Ring of FIRE? AKA Bootie Hole!

RT
Old 04-25-2017, 12:24 PM
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Originally Posted by arthursc2
Mains dictate oil pressure right? So coming and going oil pressure/ dropped cylinder probably not main bearing related.

Lifter taking a dump might impact the oil pressure. I would pull the head, because like you said its only going to be visible without the head. Nothing you can change with the head on, except the cam. What heads? valve dropped?
Yup - they're just stock L92/LS3 heads. If I dropped a valve I would think I'd hear it. I do hear a slight rattle between 2000-2400rpm so that's why I'm thinking lifter but it could be a snapped rocker since I'm running Harland Sharp aluminum.

I'll run the standard mechanical tests and pull the valve cover to see what's going on before I decide anything drastic
Old 04-25-2017, 04:06 PM
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if you droped a valve, you would know it, you wouldnt have made it home. bad lifter, broken rocker or springs, those would could get home with and have a dead hole. first thing i would do is pull the valve covers then do a leak down



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