DOD delete

Tech discussions on the L77 6.0L V8.
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amx1pxp
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DOD delete

Post by amx1pxp »

Getting ready to do the DOD delete on my car soon. Here's my dilemma; prefer to do it where I spend most of my time, at home in my garage. No lift here, plan to use some drive up stands so I can get under it as necessary.

At my other place out in the country, I have more room and a garage with a lift. Problem is, whenever I'm there I have a ton of other things I need to get done and don't have the time to devote to the car. If I get into it here at home, without the lift, will I regret it? According to the manual, oil pan needs to come off to remove the front cover of the engine. Really? I'm hoping to do most of the work from above, (yank the heads, swap out cam, lifters, etc.) get it running again, and take it out to my other place with the lift, then pull the oil pan and plug that pressure relief valve, maybe change the oil pump.

Thanks as always,
Paul
GammaFlat
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Re: DOD delete

Post by GammaFlat »

amx1pxp wrote: Sat Oct 16, 2021 9:01 pm If I get into it here at home, without the lift, will I regret it?
The engine will not need to come out but you may need to wrestle with A/C lines if you are not disconnecting them thereby discharging your a/c system. Whether or not regret is in order... If you feel compelled to remove the oil pan from underneath... read on.
amx1pxp wrote: Sat Oct 16, 2021 9:01 pm According to the manual, oil pan needs to come off to remove the front cover of the engine. Really? I'm hoping to do most of the work from above, (yank the heads, swap out cam, lifters, etc.) get it running again, and take it out to my other place with the lift, then pull the oil pan and plug that pressure relief valve, maybe change the oil pump.
There are two bolts that go through the oil pan into the timing cover. You obviously need the timing cover off. You don't need to remove the oil pan to get the timing cover off (that I recall in my last disassembly). To get it back on and aligned properly (the timing chain cover), you may want to lower the pan - the timing cover needs to be aligned so the front seal doesn't leak (one of my few beefs about LS engines). BTW - you can remove the pan with the engine in the car.
In terms of modifying your oiling system.. Changing the oil pump, screwing with the relief valve, etc. is up to you. The pan does not need to completely come down to change the pump - see this vid as an example: https://www.youtube.com/watch?v=nmKEnUhS8_o

What is most important in making your oiling system work properly-ish is to block off the "towers" under the valley cover that feed the "part time lifters". This can be done with rivets, threading and then blocking the holes with allen screws or a valley cover for the specific purpose of blocking the new "oil pressure leaks". Ask three people which way they prefer and you may get three different answers.
Back to oil pumps: closing the oil ports to the DOD system does change your oil system. Melling (oil pump manufacturer) has recommendations for L76/L77 engines in terms of replacing the oil pumps. I believe high volume is not recommended (others will disagree). I suspect the factory oil pump will be fine with less "load" than before the DOD delete. If you need/want to change the pressure of the relief valve, you can do so with the factory pump - see this video: https://www.youtube.com/watch?v=mo4FSUmHj0I&t=3s.
Current: 2013 9C3, deeper trans pan, 12VoltSolutions Remote, Class III hitch, Android Auto capable radio
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Mooseman
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Re: DOD delete

Post by Mooseman »

If you replace the oil pump, it MUST be a high volume type if you leave the pressure relief in the pan. When I did a DOD delete on a 5.3, I mistakenly replaced the pump with a regular volume and wound up with lower pressure than before the delete. Replaced it with a high volume pump for DOD and pressure was back to normal. I also just did a pump replacement on my L76 Avalanche with a high volume and pressure pump and it brought it back up to 40ish PSI. If your engine doesn't need the extra volume, it will bypass in internally and keep the pressure up regardless but if if does have some wear and pressure is lower, it will bring it back.

And the pump can be replaced without having to remove or lower the pan. Have done it 3 times this way:

https://www.youtube.com/watch?v=DoCQEdX ... D-RaySmith

However, I used a pump pickup girdle like this instead of the method D-Ray shows (can't since the bracket is welded).

https://www.amazon.ca/gp/product/B07YQ1 ... UTF8&psc=1
2011 Caprice PPV, former RCMP test vehicle, never put into service
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amx1pxp
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Re: DOD delete

Post by amx1pxp »

Thanks Mooseman...
GammaFlat
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Re: DOD delete

Post by GammaFlat »

I would definitely use the girdle that Mooseman recommends. I consider one bolt holding the pickup tube a factory mistake - they want to "tilt" and pinch the seal. Also, make sure sure sure you are using the correct o-ring - talk to the guys at Melling. They provide them by color code. Sucking air is very bad for oil pressure. If you have the wrong seal or your pickup tube gets canted a little, you can suck air here and experience low oil pressure. I haven't done it but I know folks that have.

I have always thought more volume was good. I'm starting to question that thinking. Mostly because of reading I've done and my pesky machine shop guy. Reminds me of the "you can't put too much water in the nuclear reactor" skit. If you run a high volume pump, you might outrun your oil pan - in which case you will suck air out of your oil pan. Since getting to this state will probably require high RPM's, you could spin a bearing(s).

We have very large oil pans so this problem is potentially mitigated but I don't think I'll be going outside the recommendations of the manufacturer of the oil pump and my "scolding" machine shop manager. (I'm a big fan of Mooseman's recommendations and he may have this correct.) Do some searching around. I spend time on LS1Tech.com (dedicated to LS engines). I looked today and many say unless you have larger than factory clearances, the standard Melling is recommended. Others say, "oh, go high volume for sure". Don't take my advice and be cautious about what you see on the internet. I'd say talk to the manufacturer of the oil pumps. They probably have some good ideas.

You may say I'm talking out of three sides of my mouth but if I had it my way, I'd be modifying my factory oil pump (I have low miles - 60K-ish) with some spacers behind the spring in the oil pump as seen in the video I linked above. My machine shop guy wants me to get the standard Melling ($131 vs $174 for high volume) - therefor I will. He's the same guy that sold me a 4 inch crank and rods.. so he's kinda invested in my results. When I get this done, I'll report back my oil pressure numbers.

I'd also consider upgrading the dumbbell.
Current: 2013 9C3, deeper trans pan, 12VoltSolutions Remote, Class III hitch, Android Auto capable radio
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Mooseman
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Re: DOD delete

Post by Mooseman »

My take on the pressure bleed off. It bleeds internally to itself so if it bleeds off oil, it refeeds the pump instead of pulling oil from the pickup. And the one in the pan bleeds off into the pan. Neither of these would affect the supply of oil in the pan. If the engine has high mileage and/or hours, I would go with a high volume pump. And the stock DOD oil pump is high volume to begin with.

It is a good idea to talk to Melling as they would know what works and what doesn't.

Another thought. The bypass in the pan has been known to go bad and bleed off too much. This video shows it and how to fix it. (queued to relevant part)

https://youtu.be/mo4FSUmHj0I?t=317
2011 Caprice PPV, former RCMP test vehicle, never put into service
Build Thread: http://www.newcaprice.com/forum/viewtopic.php?t=2419
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